Jazzman’s #8745 "Flip Top" Build

[2bking]

For anyone interested in making a flip front, there is a complete set of drawings and material list available. All you have to do is ask. Kevin and I are teaming up to document the process from my build as well as his. He has demonstrated, so far, how easy the parts are to fab. I think the hardest phase is in the fiberglass work. Kevin is pioneering the idea of retaining the lip at the rear of the hood and utilizing the Type 65 hood latches. He has also found ways to speed the build.

Maybe I was wrong about the fiberglass work as being the hardest phase. It's gut check time just before the body gets cut apart!

[carlewms]

Nice work!

[wareaglescott]

Nice work Kevin! IF your neighbors haven't deemed you crazy yet about this car project try walking around the neighborhood midday in the bunny suit. That should seal the deal! haha

[2FAST4U]

Excellent and impressive!!

[Jazzman]

Thanks for all the support folks. 2BKing is the master engineer on this "Flip-Top" project. Without his drawings, there is no way I would have even attempted something this complex. However to be clear, it is not the fabrication that is complex, it is the engineering, but 2BKing has already done that . I am merely demonstrating that if you like it, you really can do it. I certainly do not possess any special fabrication background or deep knowledge of auto manufacture, composites, or other unique aspects of the Flip Top. Thus far there has only been two parts that I did not actually manufacture myself, and the only reason I didn't is that I have a friend who wanted to demonstrate his mill, and I wanted to see it work. You only have to want to do a Flip Top, 2BKing has already done the heavy lifting. I just hope that I can add a few new wrinkles and simplifications to the process. If you are interested in doing this mod, contact 2BKing or me privately to discuss it further.

[Jazzman]

Last night I fabricated the "Teeth" that will keep the sides of the body smoothly aligned when closed. It also designed to smoothly transition the body pieces together as the hood is closing. I purchased six 1.5" long bullet shaped license plate bolts. The ones I selected are from MoonEyes's. These will be the aligning "teeth". I began with 1.25" aluminum 90 degree angle stock. I cut the lower piece 10" long, the upper piece 13" long, one set for each side of the car. From the aft end of each angle channel, I marked holes 1/2" away from the 90 degree corner, and 1", 4.5", and 8" from the end. I drilled both sides with holes the correct size to receive the attachment bolts on the bottoms of the "bullet".

*****EDIT: IF YOU CHOOSE TO DO THIS, USE 1" ALUMINUM 90 DEGREE ANGLE STOCK, NOT 1.25". YOU WILL READ WHY LATER, BUT FOR NOW, TRUST ME: 1" STOCK!

*****EDIT #2: DON'T BUILD THIS PIECE UNTIL YOU GET TO POST #324. I REMAKE THESE PIECES LATER, MAKING THE LOWER RECEIVER PIECE LONGER.



Then I went out and purchased a 9/16"drill bit and enlarged the receiving hole to just fit around the "teeth". I ended up with a pair of these, ready to glue to the inside body on either side of the cut lines when it is cut.





I then started cutting out the area that will allow the exhaust pipes to pass through the body. Since FFR had already marked them on the body, I followed the instructions in the FFR manual and began by drilling the holes to form the curved tops. Right? WRONG!! The first one came out OK, just as FFR had marked it.



I drilled the holes for the other side as FFR had marked it. What did I forget? TO MEASURE TO MAKE SURE FFR DIDN'T GET SLOPPY! The holes I drilled were correct as drawn, but once they were drilled they just looked like they were too far forward. I began cutting with the sabre saw, but my mind said stop and double check. Now I think to measure, and sure enough, they are not correct. So now I have a hole too far forward, and a cut line that will have to be filled. Oh well, at least I now know how to do such a repair.

[Jazzman]

Today I began cutting the underside of the "old hood" to begin the irreversible march toward a full Flip Top. I began by carefully cutting out a section of the lip that would normally hold the "old hood" level. I started at the front of the car and worked my way back. It is important that I NOT cut off this support lip at the back of the "old hood" because this lip will be the beginning of the support structure for the trailing edge of the entire Flip Top. I used my Die Grinder with a cutting wheel to carefully cut back the lip until I could see how much to cut.



To control the fiberglass dust as much as possible, I laid my shop vac hose end right next to where I was using the cutting wheel and continued to move it along as I cut. This really did a very good job of sucking up the vast majority of the dust. There was still a little bit, so I would vacuum that up as I went.



Because my air compressor is severely under powered, I had to rotate between cutting, waiting for the compressor, grinding the seam smooth with a heavy duty sanding disk on the side grinder, and sanding the area smooth with 100 grit sand paper on the RO palm sander. WHile the shop vac could handle the small about of sanding dust created by the cutting wheel, it was no match for the large volume of dust created by the side grinder with the sanding disk. I gave up trying to control all the dust, opened the garage door, and let the 95 plus degree air envelop me.



After about an hour of work, this was the result. The lip is all gone except at the back, the entire area is sanded smooth, ready to have fiberglass and resin laid on.

[Jazzman]

My goal tonight was to cement the truss attachment disks to the inside of the body so that I could begin laying the fiberglass around the seam of the old hood. All of the attachment discs will get covered with at least one layer of fibreglass to make sure they stay attached, but one of the attachment points will be covered by the first or second layer of fiberglass going around the old hood seam. Since I want to attach the side wall body/hood alignment "teeth" using this same cement, I wanted to do all the cement work at the same time. Therefore I decided to begin the actual cutting process of the body and attaching the alignment teeth. This proved to be an exercise in trial and error. My first idea was to attach these alignment teeth to the inside of the body using the same type of attachment discs that I am using to attach the trusses. In Theory, This method would make the alignment teeth slightly adjustable.



After trying to position and mount the pieces using this method, I found that it had a couple of drawbacks. First, it held the positioning teeth mounting piece slightly proud of the body. I don't think this looks very good. I also don't think I would hold these weaker areas of the body securely, which is one of the main benefits of this design. It was also surprisingly difficult to get the mounting disks positioned and secured in position and still match up with mounting holes on the angle alumininum. Therefore after much trial and error I came upon a simpler method. Now you have to remember that the body is upside down and thus everything you are seeing is upside down. When I refer to the "top" piece, remember that you will see it at the bottom of the photos, and vice versa.

I had to start by cutting the body apart to separate the section that I would be working in. I cut only a couple of inches beyond where I would be attaching the positioning teeth.



I first attached the bottom piece of the positioning teeth to the lower half of the side. (Now that the "body" and the "hood" are cut apart, I will refer to the lower half of the side as the "body", and the upper portion of the side as the "hood". Therefore, what I just said means that the piece that is on the top in the photo was attached first, even though it is the bottom piece when the car is right side up. Got it?!!) The lower angle aluminum is the piece that has the large 9/16" holes that the teeth will slide into as the hood closes. After sanding the front edge to match the angle of the vertical cut which will end up over the exhaust pipes, I lined up the front of the angle aluminum with that vertical cut line. I then lined up the piece with the horizontal cut line. Using a small "C" clamp, I held the piece in place. I then drilled holes directly through the body and used 8x32 bolts to hold the piece in place.



I slid the upper piece of the alignment Teeth (The part with the actual teeth) into the holes in the lower alignment piece. To leave just a slight space between the upper and lower pieces, I inserted 1.5" box nails from the outside of the body through the marking holes that were still visible after the cut was made and between the upper and lower angle aluminum pieces. I used another "C" clamp to squeeze the upper and lower halves of the alignment teeth system together sandwiching the box nails between them. I again drilled through the body and attached the upper angle aluminum piece to the hood sidewall with bolts and nuts.



Now that the sides are aligned and the body is held in place against fore/aft movement, I added a retaining strap across the horizontal cut line to keep the body/hood from pulling apart vertically. ultimately I will glue each of the angle aluminum pieces in place to permanently position them. However, To make sure That everything works and fits after it gets back on the frame, I am leaving the alignment teeth simply bolted to the body/hood in case anything has to be some adjustment.

[Jazzman]

After spending most of the evening attaching the alignment Teeth, I was finally able to achieve the goal of cementing the truss attachment discs to the underside of the hood. I pulled out he 3M Composite and Metal bonding cement #08219, and the funny looking "caulking gun" that dispenses this stuff.



I tested it a bit to get a feel for it, then I began to apply it to the locations where the discs will go. On those locations that required it, I bent the base of the disc slightly to make it form to the curve of the hood. Then all there was to it was to put the disk in place and let the cement ooze through the holes. Pretty simple.



Getting the discs to adhere to the vertical surface of the front area was a bit tougher. I had to keep sliding them back into place until the cement set up sufficiently.



IN the next few days, I hope to begin applying the fiberglass around the old hood seam.

[2bking]

One trick to keeping the studs in place until the adhesive cures is to put a piece of duct tape across them. It's also easier to smooth the adhesive that comes up through the holes before the adhesive sets than have to sand it afterwards.

[WIS89]

Jazz (Kevin)-

All that goes through my head whenever I read one of your posts is: Huevos Grande!!

Holy smokes, it takes guts and skill to tackle this kind of project. I admire those that are willing and able to do it!

Quick question... Those discs that you are using; what are they called, and where did you pick them up?

Thanks in advance, and keep up the great and inspiring work!

Regards,

Steve

[Jazzman]

Thanks for the compliment, Steve. Yes, it does take a special kind of crazy to cut in half a perfectly good body! It is really exciting though. The challenges never stop. Today I have been consulting with 2BKing on how to best feather the fiberglass to glass in the seam where the old hood meets the body. This is situation where we have two differnet concepts. I so appreciate 2BKing's willingness to assist, consult, and challenge me. I am so glad that I returned to my original plan. I am going to be so happy with the finished product.

The attachment discs are from McMaster Carr. They are called "Perforated Base studs, 316 Stainless Steel, 8-32 thread, 1/2" long". They are part #97590A526. One day too late I learned a lesson on attaching those discs: smooth out the cement before it dries! You may (or may not) be surprised to learn that cement is very strong and very hard!

[GoDadGo]

Looks Great!

[Jazzman]

This may be a holiday shortened week, but the volume of work has not been reduced. Thus my time working on the car has been very limited. I have been consulting with 2BKing about surface preparation prior to fiberglassing. He suggested that my fiberglass bond strength would be more consistent and stronger if I did not have any of the red gelcoat remaining at that joint. He likened it to bonding two surfaces together with a coat of paint in between. We don't know how strong the bond will be to the paint, nor do we know how strong the paint itself might be. Therefore for maximum strength, we remove the paint before we bond the two surfaces together. That makes sense to me.

So with the help of my new best friend (an electric angle grinder with a flapped sanding disk) I made a lot of dust in short period of time. I got all the red gelcoat off the edge of the old hood, and I feathered down even more the intersection with the body. I have not yet decided if I will grind it all the way down to be a completely smooth transition. My intent had been to leave to small lip at the edge as one more stiffening edge that would be enhanced by several more layers of fiberglass. I will sleep on it, and look at it again tomorrow.





I did discover my new best friend has a temper. If I don't pay very close attention, he can quickly grind too deeply, cutting through the first layer of old hood glass.



After grinding to the depth I think I want, I used the RO palm sander to smooth and feather all the recently ground edging. I think I am going to have to complete the cut to separate the hood from the body before I can complete the grinding and feathering of the edge and being the fibreglassing process. I am not yet exactly sure where to stop attaching the old hood to the body. I know where it is on the top side of the body, but I don't know exactly where it is on the bottom side.

I began trying to sand off the green composite/metal cement used to attach the perforated discs. Wow, is that stuff ever hard!! It was like trying to sand granite! I am not sure what I am going to do about the little bumps. I may just leave them there and glass over them. I have been told that if I heat the cement with a plumbers torch, the cement turns into the consistency of chewing gum. I will have to use this technique to remove one of the discs that slipped. I hope I don't have to do very many more.

[Jazzman]

I continued cutting the body in half tonight. I cut slowly, and then bolted a support strap across that cut as I went.



I got almost done with the cut on the passenger side. With about 4 inches to go I realized that I must glass in the old hood from the back side before I complete the cut. If I did not glass in first, there would be a narrow triangular piece where the body connects at the rear of the old hood that would be loose.



I rechecked all the sanded areas, and finding them ready, began glassing in the seam from the back side. The first layer is narrow, just three inches wide. I think I am getting better with the vinylester resin. I mixed six ounces this time, which was plenty for the task. I used one drop less of hardener per ounce of resin, and the working time was quite useable. I did not take the step of pouring it into the plastic plate, because I was not convinced that it really was necessary. I had finished the entire job, had a little left over, and about 5 minutes later the leftovers turned to jello. Just about perfect.





Practice does make for improvement. I felt this glass session went very smoothly, and the glass itself also laid down very smoothly. A successful next step. I will let this cure for 8 hours, then lay a second layer with a wider glass panel.

[Jazzman]

Slow but productive day today. After sanding the first layer of glass to feather the edges and rough up the entire surface for better adhesion, I laid on the second layer. Before I began, I wiped down the entire area with acetone to remove any remaining sanding dust or other debris. This layer is four inches wide. It took 8 oz of resin for the job. I had a bit left over, but not enough to worry about. No photos because, guess what, it looks just like the first one! That's good I guess. Getting all the tiny air bubbles out is challenging. Just when you think you've got them all, a couple more show up. I pushed the entire body out into the sun. I finally found a good use for 106 degree heat! That layer cured up a lot faster than the previous one!

After one more complete sanding for smoothness and edge feathering and a thorough acetone wipe down, I laid on the third and last layer. This one is 5" wide. It sure looks and feels strong, and I haven't even done the permanent top layers yet. Tomorrow I hope to complete the body separation cuts and begin fabricating the support channel extension on the body.

[WIS89]

Kevin-

Thanks for the info on the discs! I will grab myself a couple for one of the projects I have going.

I admire your ability to stop mid-cut to remember that you had to do some fiberglass work. Once I get cutting, I take it through to the end; nice catch!!

Still looking good. I really enjoy following along. I followed King's build, and if you do as well, it will be great!!

Thanks for sharing your progress!

Regards,

Steve

[Jazzman]

The old hood and the body are now one piece. The glass is all hard, and is very smooth. I would like to say it is completely bubble free, but that would not be entirely truthful. Even after chasing bubbles in each layer, and believing I got every last one of them, there are still a few bubbles here and there. I hope that the overall strength will be enough to overshadow these minor imperfections.

I began the day by completing all the cutting to actually separate the body from the hood. I would cut about six inches, then attach a "Band-Aid": an aluminum strap that is bolted through the fiberglass skin to keep the two sides exactly where they were prior to the cut. I had taken a lot of measurements with the body on the frame, then made sure that when the body was upside down those measurements were the same. It was surprisingly simple to keep everything in line by this method. The "Teeth" really did their job nicely. Very solid alignment. Because I had everything dialed it like I wanted it, I hesitated to turn the body over to complete the dividing cuts. So I worked slowly and carefully, laying underneath the body and cutting from the underside of the upside down body (The "top" but it was facing the floor at the moment.) One side came out about as close to perfect as I think I could get. I was very pleased, confident that my process would work. I moved to the other side and . . .

I hate progressive tri-focals! Ok, I don't hate them, usually I am quite thankful for them. Yes, I am of that age that my once eagle sharp eyes are no more, and I depend upon the refractive assistance of glasses. So I am laying on the ground, covered in fiberglass dust (yes, of course I am wearing my breathing mask!!) and I am trying to get a clear view of the blade as it slowly slices through the skin. My vision gets out of focus, and I discover that I am off of my line by between 1/16" to 1/8". Arrrghh!! I get back on track, but I have a goofy curve in my cut line that I will have to sand out. I suspect that by the time I gap the hood and body, that miss will be very minor.

I move on to begin making the ribs that will stiffen the sides of the hood. I start by cutting 2" wide strips of 1" thick PVC foam board 48" long. This is H45 PVC FOAM that I purchased from Aircraft Spruce, part #01-12800. I cut this in half to have two 24" long pieces. I plan to put a 10 degree bevel on each end, so I draw that on the ribs. The PVC foam board is quite stiff. In order for it to curve around the inside of the hood, I am going to have to cut some relief cuts to allow the foam to bend without breaking. I start by make marks on the side of the rib 1" apart, and make a second mark on the side that is 1/2" offset from the first marks. The idea is that I will cut the side that will be bent inward on the table saw about 1/2" deep, and I will use a razor knife to cut the offset cuts on the other side to allow the rib to bend without breaking. Here is what I it looks like before I made the cuts:



And here is what it looks like after you cut the kerfs on each side, and discover that they are too far apart and the rib breaks!



So I started out again. Recut a second 2" wide strip, cut it in half, made my 10 degree angles on the ends. This time I make my kerf cuts 3/4" apart on one side, and offset my razor cuts on the opposite side, being careful to only go about half way through the 1" thick foam board. This time I also sanded the outside edges to put a nice rounded edge on them. I also sanded the bevel on each end to it was nice and smooth. (This had to be the easiest sanding I had done thus far on this project!!) Here is what I got:



Here is how it looks as it bends:



Now I have to figure out how to hold it in place as the glue dries. I need a few c-clamps that have a throat of 10"! Nope, even I don't have any of those. I am not even sure where to find them. I will have to go hunting.

[Jazzman]

Big moment tonight. In order to gain access to installing and glassing the ribs, I decided to finally separate the body from the hood. With my wife dutifully holding on to the hood, I removed all the "band-aids". Even after removing all the straps, the body remained joined to the hood. A little bit of the Vinylester resin had run down into the edge and glued the section together. After a couple of gentle taps of encouragement by my rubber mallet, the body and hood were officially separated.







Now that I have access, I can start laying in the ribs. I decided to place the primary side rib 1" behind the rear most point of side louver openings. (Yes, this time I rechecked all of FFR's measurements. They were pretty close, only about 1/8 inch off. I corrected that difference, and made appropriate markings.) I got to this point, and realized that I really don't have an effective way to hold the ribs in place while the cement dries. I also need to cut a couple more relief kerfs to relieve some stress along the long side wall. I think I will also bevel the ends of the ribs a bit more once they are glued in place. I will sort of feather them into the hood.

[Jazzman]

Two more steps forward, one back. I began by working more on the ribs for the side walls of the hood. After sleeping on it overnight, I figured a way to hold the ribs in place while the glue dried. I chose to use Gorilla Glue because it expands as it cures and seems to be impervious to almost everything once it is dried!



After the glue dried, I had a lot of glue that had expanded it way out around the rib. A few minutes with a utility knife, and the offending foam was cut away. I then used the RO Palm sander to shape the top end of the rib (the one nearest to the center of the hood) to feather it smoothly into the body.



I then moved on to smoothing out the rough spots on the perforated attachment discs. The King himself (2BKing to be exact) was kind enough to loan me a customized tool that he developed just for this purpose. When attached to a drill, and the business end placed over the threaded shaft of the perforated disc, it allows the cutters to shave off the excess cement that has squeezed out through the perforations.





The tool works great, and has one added benefit: it tests the strength of the bond that holds the perforated discs. In my case, several of the bonds were not strong enough.





I found far too many of these discs were failing. I am very glad I discovered it now rather than later. With 2BKing's assistance, I reviewed my preparations procedures. I sanded each area, I vacuumed it clean, I cleaned the area with Acetone, I mixed the cement using the mixing nozzles specified in the instructions. The only thing I did not do was clean the area with a wax removing compound. Since the area was sanded, I expected that any residual wax would have been removed. Appearantly not. The cement itself actually popped off the body. Therefore the weak link is the interface of cement and Vinylester Resin. The back of the failed discs had a vaguely waxy feel to them. It also seemed that the cement itself was not quite hardened in the center. It was suggested that I use House Of Color KC10 to remove any wax residue. I will see about ordering a quart of that and use it everywhere before I do any more bonding or glassing.

[Jazzman]

Yesterday I had a very productive email conversation with one of the many helpful people on this forum, Jeff Kleiner. I was asking questions about what sanding tools and supplies to buy. He was very gracious and offered very helpful suggestions. One of his best suggestions was to make contact with a local supplier so that I can get both supplies and useful information. I searched around my area, and found that there are really not that many choices even in an area as populous as Phoenix. I decided upon one that had been in business for 50 years. That seemed like they might know a thing or two. Today I went to talk to them, and learned a great deal. They were able to provide me the sanding blocks and Stickit sandpaper that I needed. They also were able to provide several of the circular grinding disks that I use with my Die Grinder. Scott was a wealth of information, and suggested that I get the cheaper box of discs because they will last a lot longer. I was very impressed, and he was right!

The one thing that blew my mind was the difficulty of getting wax remover. I discovered that in my area it is against the law to sell Wax removers for this purpose because they are not VOC compliant. (I am not entirely clear as to what a VOC is, but I did learn it is some sort of environmental risk. Hmmm) Anyway, he suggested that I first use a rough disk sander on the die grinder to buff away the top layer where I want to glue the perforated disks. Next he suggested that I use lacquer thinner to clean the area, using one rag to wipe on the thinner, then a clean rag to scrub off any excess. Finally he said that I should clean the area with a 50/50 mixture of alcolhol and water. I had to wait about 15 minutes to be sure all the water had evaporated even after wiping it dry with a clean rag. I did of these, then cemented new perforated discs on the five locations that had come off. For the ones that were on vertical surfaces, I used tape to hold the perf disc in place while the cement hardened. We shall see if they hold on better this time.

I spend the rest of my evening catching up on "Mr. Robot" while I waited for my air compressor to catch up. I could work for about 4 minutes with the Die Grinder, then I had to wait about 10-12 minutes for the compressor to catch up. I am grinding off the gunky welds that I did on the trusses that will hold the hood. I am trying to get all the hood hinge pieces polished and ready to go to the powder coater. I probably won't be done by Friday due to the long wait for the compressor, but hopefully by the first of next week I can get them off to be coated. I want to get all the parts back so that I can install the hood when it is ready for that step.

[Jazzman]

More truss grinding and glass laying tonight. I thought I would show you the specialized disks that they sold me. They are 3M purple grinding disks:



Appearantly the grinding compound on these disks is some sort of ceramic material. Regular grinding compounds round over and become dull. These ceramic materials don't round over. Rather, they break off in little shards leaving glass like edges always available (until there is nothing left to shatter.). They told me they were more expensive per disk, but would last two to three times as long. I still had a couple of the old style discs, so I tested their assertion. Sure enough, the Purple ones last far longer. Here is what I have been grinding on. Remember the trusses that hold the hood? Remember my less than entirely professional looking welds? Well this is the way to make it look nice.





I am still trying to find the right scotch-brite disks to smooth out the scratches and really polish the trusses. I am not sure how to choose them or what grit to use to polish steel. I hope to get that done this weekend.

Last night I re-cemented the perforated disks to the underside of the hood. I used all the new cleaning techniques that I had been given. For some reason the bonding cement looked more thoroughly mixed this time when it came out of the nozzle. It shouldn't have been any different, but It seemed better. The technique of using a piece of blue masking tape to cover the perforated disks and hold them in place while the cement dries worked very well. Look at how nicely these are bonded. Hopefully that will be the last time I have to bond those discs.



After just a bit of sanding and cleaning around the perforated discs, I laid on the first layer of glass over the discs. I threaded a nut on each of the studs to protect the threads from the resin.



Then I laid the first layer of glass over the nicely sanded and feathered ribs.



Learned a number of lessons.
1. Compound curves like this are much more difficult to do.
2. PVC foam sucks up resin, but doesn't really stick to the fiberglass.
3. because of the compound curves, I had to cover the rib in two overlapping pieces. I will offset the seam on the next layer of glass.
4. getting all the air bubbles out of this this compound curve is very difficult.

I think it came out OK. I will have to see after I lay the second layer of glass. I am not sure if I will need a third layer, but I will consider it after the second one is cured.

[skullandbones]

Hi Kevin,

Are you polishing the steel just to smooth it for paint prep or are you actually going for a high polished steel finish that's cleared. Sounds like a lot of work for the latter. I guess you have gotten to be such an expert with that polishing tool, you just have to put the new found talent to good use (ha - ha). Great project! I'm building an observatory and the 12 ft dome is killing me as it all has to be custom designed and fabricated (brackets and such). So I can really appreciated your journey. Even with a few guys doing it ahead of you, it looks like you are putting your on stamp on the work.

Good luck and continued success.

WEK.

[Jazzman]

Thanks, SkullandBones! I will be having it powder coated black. I just want it to look like I care! My welding is getting better, but still has a ways to go. This just cleans it up a bit. I will look forward to seeing your observatory. I'll bet that your location will be good for that purpose. If you are building it in the middle of summer in 108 degree heat, you are crazier than I am!!!

I am certainly standing on the shoulders of giants, but I am trying to add my own mark to the project. The standards of this crowd are pretty high, I am just trying to keep up! Hope to see you soon.

Kevin

[Jazzman]

I now have three layers of fiberglass on the hood sidewall ribs. (It doesn't look much different than two or one layer, so no photos of this.) It is already clearly apparent that the ribs are really going to stiffen the sidewalls of the hood. The sides are much more rigid than they were before the ribs were installed. They will get several more layers of glass.

I began this evening by making up my first batch of HSRF filler to fix some of my errors. I had previously placed a layer of fiberglass and resin on the inside of the DS opening for the exhaust pipes. I filled in the mistaken cut with an ample supply of HSFR filler. I will sand it back to shape tomorrow, then lay a layer of glass or two over it just to make sure it stays where it should.



I made up too big a batch of filler, so I decided to fill in the off line cut that I made when separating the body. Same basic process here, fill, shape, glass, sand.



I have been considereing how to extend the ledge at the front of the body that will hold the hood when it is closed. I left that section of the body intact, but of course it doesn't go all the way across the top of the body. I also wanted to construct a structural rib to support the weight of the hood when it is closed. After considering several methods to accomplish these goals, I decided to integrate the rib into the design of the ledge. I decided to create a foam rib that would go entirely across the underside of the body. I had to cut it and notch it to fit around the existing ledge. After it is glued into place with Gorilla Glue, I will sand and carve the remaining foam board to flow smoothly into the next phase of joint design. (I am drawing on 2BKing's design for that phase, but I will show it to you when it do it.)

This is how I formed the rib. I started with a 3" strip of 1" thick PVC Foam board. I notched the rib lengthwise 1" deep and 3/8" wide. I trimmed off this notch with a razor knife held at a 45 degree angle and held straight against my 18" metal ruler. I then found the section that had to be deepened to allow the new Foam rib to fit behind the existing fiberglass ledge. That series of cuts were slowly but easily done with a sharp razor knife and a straight edge. I



After a bit of fitting and carving, I glued the rib to the underside of the body.

[wareaglescott]

Very interesting watching this progress! Can't wait to see the tilt in action.

[Jeff Kleiner]

Oh man, you're gonna learn a lesson about HSRF today...that you really don't want to slather it on any heavier than absolutely necessary. It's like sanding granite! No harm, no foul, just extra work.

Cheers,
Jeff

[Jazzman]

Well Jeff, it wasn't bad at all. Just a few minutes carving with the die grinder, and it fell right in to shape. I will want to add a skim coat and resand, but it came out fine. Here was the results:







I had to add a couple of 5" extensions to the rib/ledge that I am making on the underside of the body. I can't say enough good things about this Gorilla Glue. It really holds on well. A bit messy with the foamy excess that squeeze out, but it sure does the job.

[Jazzman]

I had to open the shop for this next job: grinding off the top layer of glass in preparation for putting the final glass layers in, sealing the seam forever. It was a nice 79 degrees in my shop before I opened the garage door. It was 106 after I opened it! Oh well, nothing worth doing comes easily, and this must really be what they call "sweat equity"! You can see by these pictures, I created a LOT of sanding dust. It is now everywhere!!







2BKing said to grind it to created a valley that the glass will lay into. He said to grind it almost all the way through to the back side I just laid on. Here is what happens when I take his instructions too seriously and do not control the grinder for about 1 second:



The results seem good though. I was much more aggressive with the grinder than I have been in the past. I now understand that virtually anything can be fixed, it just a matter of how much time it will take.





I can see that the convex portions of the hood or body will be easy to sand with hand or electric sander. However, The concave portions will be a challenge. I only have square sanding blocks. I may have to look for a round sanding block. Hmmm.

After doing all that sanding, It took me over 45 minutes to hose out the garage. It still have sanding dust everywhere , but I have at least blown off the first layer and washed it out of the garage. That was a chore.

Interestingly, up to this point I have not really had any problems with feeling itchy after sanding. I gave up on the bunny suit. Just too hot to survive. My system is to do all my sanding, vacuum up what I can as I go, then go outside, hose myself off, and jump in the pool for about 30 minutes. It is a nice way to relax, plus it seems to wash off and float out the majority of the fiberglass from my skin. However, after today's session, I am really itchy!! Oh well.

[Jeff Kleiner]

You might already have a round sanding block right out by the pool---a foam pool noodle! If not get yourself down to Wal-Mart or the Dollar Store to pick one up. A 12 inch or so long section works great for the concaves around the headlights and such.

Jeff

[Jazzman]

Now why didn't I think of that!! perfect. Thanks Jeff.

[Jazzman]

Five layers of glass take a while to lay, but they take longer to cure, even in the heat. Somehow I was able to get five layers laid on in the past two days. The high heat we have does a nice job of curing the resin in about two hours, so I set the hood in the sun between each layer. Sadly, it doesn't really look like much in the photos.



When 2BKing provided me the shopping list for this project, he includes a gallon of Vinyl Ester Resin, a full box of disposable paint brushes, a full box of tongue depressors for stirring, a full box of latex gloves, and 50 (!) Mix and measure cups to make up batches of resin. I sort of thought this was excessive, but I dutifully bought all the specified materials. As of tonight, I have made 13 batches of resin, used 13 cups, paint brushes, and depressors, something over 30 gloves, and laid on a half a gallon of resin . . . and I am not done yet! As always, 2BKing was right. I am actually pretty surprised how good I am getting at laying the glass. Not that I want to make a career of it, mind you, but I am now pretty much able to get the resin to harden whenever I want it to.

Because of all the waiting for the Resin to cure, I spent some time shaping the rib at the front of the body.





I also took the body off the upside down rack, placed it on the floor, and shaped the top half of the rib. It will need a bit of HSRF to smooth a couple of the intersections, but it should be pretty straight forward to shape the ledge that will support the hood when it is closed. I am preparing and shaping the rib so I can lay on the fiberglass. I can't do this, however, until I re-assemble the body and hood into one unit. Otherwise, the body could end up with a different contour than the hood. tomorrow I will put the body back together using the "band-aids" to make sure everything lines up before I begin glassing the forward body rib.

If you are bored with this stage of the process, hang in there. This part is slow, but is critical to the way the hood and body will interact.

[carlewms]

Very nice work. Where did you pick up the foam and what type is it?

[Jazzman]

The foam board is Divinylcell H45 PVC Foam Board, 1" thick, from Aircraft Spruce, part #01-12800. It comes in several sizes, I bought the 32" x 48" sheet. it is quite solid, but light. It is easily shaped with 100 grit sandpaper. It soaks up a bunch of resin when you lay the first layer of glass over it. Hope this helps!

[Jazzman]

A bit of trimming and sanding on the edge of the hood where the old hood meets the body, and I can now see that the laminations are working nicely. I will need more layers of glass, probably at least three-four more so that the hood is uniformly thick along the seam.





I am trying to smoothly flow the rib at the front of the body (the one that will also support the hood at the top) into the sides of the body. The idea is to create a ledge all the way around the cut area that will support and align the body and hood, as well as give the entire package a nice finished look. In order to do that, I had to put the body back together. I started by reattaching the teeth to the inside of the hood.



It was then time to see if the ribs on the sides of the hood kept it all lined up with the body. With just a little bit of encouragement, it slipped back together very smoothly. I reattached most of the "bandaid" aluminum straps. It was all working fine . . . all except for one area. When I cut the body apart, my saw blade drifted a bit, leaving too much material on the body side and not enough on the hood side. I have already added some HSRF filler to the hood side of the mistake area, and shaped it back to its correct form. However, I had forgotten to sand back the body side so the two would not conflict. So off came all the bandaids, and I slipped the two halves apart just enough to allow me to sand back the edge of the body in that area. A few minutes with the die grinder and the edges look complimentary. Back goes the hood, back on go the bandaids, and this time the body and hood align very smoothly.



The next evening I got to looking at the previous days work and realized an important point. In order to keep everything aligned while the fiberglass is curing, I need to leave all the bandaids on. They are on the outside of the body, so no conflict there. However, they are held in place by bolts coming through from the inside. Because it was the easiest when I was reattaching the body, I had put all bolts through from the outside and the nuts on the inside. However, I realized that I will have to lay glass over the nuts. This would make it very difficult to get the bandaids off. I decided to reverse the bolts so they would come through from the inside, and have the nuts on the outside. When laying the glass I will have to be very careful to notch the glass around the bolt heads. Just in case I miss, and some of the resin glues in the bolts, I should be able to grind away the resin and pull the bolts out. At least that's the plan.

I have read on several threads that there is a significant air leak along the inside of the body that dumps hot engine air into the cockpit. Some have suggested filling this space with a pool noodle cut and stuffed between the body and the footbox walls. I may do that, but I have been considering another option. Since I am already installing a number of fiberglass ribs, I am thinking about installing another one along the inside of the body just aft of the separation cut. I was considering using the expanding insulation foam that you might use to seal cracks in your wall or foundation to create a custom formed rib between the body and the footbox sidewalls. I think the foam would work, but I am concerned that the fiberglass that I would lay over it would stiffen the sides of the body so significantly that the body would not be able to stretch to fit over the frame at installation. Because of this limitation, I am still thinking about this modification. Perhaps I am over-thinking it. I have been known to do that before!

I am pushing to get the body ready to temporarily reinstall on the frame this weekend. Both my sons are coming home for a visit, so I will have extra hands to install the body. After doing it several times, they are getting pretty good at it! Now that the body is all back together, I am going to have to make a trip to Home Depot. I need some supplies to form an effective and visually pleasing ledge around the sides of the body where it intersects the hood.

[skullandbones]

Nice glass work. I've done my share and there is nothing fun or easy with regard to this process. I really like the "teeth" on your hood closure. You've added one more way to hurt yourself on a Cobra along with the hot side pipe "Cobra bit" (ha!).

Good luck,

WEK.

[Jazzman]

I really like the "teeth" on your hood closure. You've added one more way to hurt yourself on a Cobra along with the hot side pipe "Cobra bit" (ha!).

HA!! I thought about that, was wondering if will hit my head on those things for the rest of my life! However, they look soo good and they function so smoothly that I just had to go with it. I guess in the context of a Cobra, they are not "teeth" . . . they are "FANGS"!

[Jazzman]

Inspiration can come from the most obscure places. Its HOT here in Arizona this time of year! (I know, not exactly news there.) My garage AC unit is working hard to keep it modestly cool in there. I have been concerned about all the dust I have been kicking up recently getting into the AC unit. I have cleaned it out twice in the past few weeks, but I am sure that it is not designed for the extreme dust environment that I have it in. I have been thinking about adding a secondary air filter in front of the AC unit. I went to home Depot today to get a 12"x25" air filter. While there I found some 3/16" thick by 1.25" wide self stick "Camper Seal" strip which I hope will help to seal the air going into the AC Unit and force it through the external air filter.



I laid a strip around the edge of the AC unit cover, and then taped on the additional AC filter.





I reinstalled the cover, and presto, a dual filtered air intake. It's not exactly pretty, but I think it will serve it's purpose. This is when inspiration struck . . .

[Jazzman]

I have been trying to figure out a way to create a ledge around the leading edge of the body that would allow the hood to slide by it and help to direct the hood into its correct placement. I wanted this ledge to be set back from the level of the inside of the body, and I wanted it to have a smooth rolled over edge so that It would not catch on the hood. When I saw the "camper seal" I found the perfect material to create a smooth inset ledge around the body. Then I wanted a smooth rolled edge. That's when I noticed the bag of round "backer rod". This insulation material was the perfect size and shape to form the rolled edge.



I first laid one strip of the "camper seal" along the edge of the hood. It was self stick and quite flexible. It is easy to lay around the curves. I laid the strip from the carved center rib to the aluminum "teeth". (or should I say "Fangs"?) Then I began adding the "backer rod" by using blue masking tape to tape the rod along the front side of the camper seal strip to form the shape that will create the rolled edge.





When it is all taped up, it came out like this:







I will lay multiple layers of fiberglass from the leading edge of the inside of the body, over the taped up "camper seal" and then over the taped up backer rod. After the multiple layers cure, I will cut and sand off the rolled edge to make it all look symmetrical. The tape, the camper seal, and the backer rod are all sacrificial. I just hope that the resin does not stick well to the top of the painters tape. We shall see.

[wareaglescott]

Nice inspiration. I hope you dual AC filter keeps your unit healthy and cool. AC and surround sound in a garage! Pretty impressive.