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Thread: Carl's Mk 4 Roadster Build

  1. #761

    The Land of Orange Peel

    As Jeff suggested below ... I went ahead and used spraying of the Slick Sand to get in some practice with the 3M ACCUSPRAY Paint Gun System.

    I have to admit that I futzed around Saturday and the early part of Sunday getting ready ... not so much physically but mentally ... it was like I had "painter's block". Well I finally took the leap yesterday afternoon and here are the results.

    As part of my futzing ...I spent a large part of Saturday evening watching videos on spraying Slick Sand and reading posts on its application on a fiberglass bodied car. Some of the additional insights I picked up:

    1. Don’t reduce more than 10% and don’t do it until the last coat although there sure is a lot of views about thinning this sprayable filler;
    2. Make sure the SS is thoroughly mixed ... the solids will settle in the bottom of the can;
    3. Reducer with acetone or reducer but the later is better;
    4. Filter the primer **before** adding hardener: don’t waste pot life time filtering;
    5. Have everything ready to spray (meaning panel preparations, equipment, etc.) **before** adding hardener;
    7. Remove the cup strainer; and,
    8. Do not let the primer kick in the gun ... virtually impossible to clean after it does (most said no more than 30 minutes in the gun).

    Painting Conditions

    Temperature: 71 to 77 deg F
    Humidity: 24%
    Coats Applied: 3 at least
    Thinning: Approximately 5% on final coat

    Gun Settings
    Fan Setting : 1 Turn
    Flow Settings: 3 is the baseline
    1st Coat - 4
    2nd Coat - 3.5
    3rd Coat - 3
    Stage One Pressure: 35 psig
    Stage Two Pressure: 20 psig
    Gun Cup Filter: 200 micron filter removed





    The panels were both cleaned off with compressed air and then wiped down with Eastwood’s Pre Paint Prep. For this “practice” I settled on bottom of the hood and the top of the trunk.

    I also “settled” on a whole lot of orange peel mostly on the trunk top. So I need input on what I am doing wrong.

    Trunk Lid After Final Application but Before Sanding



    Trunk Lid After Partial Sanding with 180 Grit.



    Here are some of the things I “think” I did wrong:

    1. I didn’t always keep the vertical fan perpendicular to the surface;
    2. I didn’t get close enough to the surface;
    3. One the first pass I increased the flow from 3 to 4 turns ... maybe I was trying to put too much paint down; and,
    4. I lost discipline layering more coats at the same time making kickoff of the covered layer harder.Some areas had little or no orange peel ... the rib line belowThis stuff also reveals flaws I missed with Rage Gold ... which is a good thing.

    Pinholes



    Bigger Holes (not the big round one below) After letting it cure for at least the minimum 2 hours i started blocking out some areas to seem how hard it was going to be to remove the orange peel.



    Less Orange Peel ...



    Any and all feedback ... even humorous feedback ... is of course completely welcomed. The learning curve is steep for me and I need all the help I can get!

    Impressions from using the 3M ACCUSPRAY Spray Gun System in another post ...
    Mk 4 Roadster
    October 25, 2012 - Kit Arrives
    April 8, 2013 - Build Starts
    August 23, 2015 - Rolling Chassis/Engine & Transmission Installed
    March 26, 2016 - Go Cart

  2. #762


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    Jeff Kleiner's Avatar
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    Looking at that trunk lid close up it shows a dry spray. I'd say you need to go up with your air pressure (I shoot SS through a 2.2 at 35-37), get closer to your panel, work on staying perpendicular and maintaining a speed that gets good coverage along with a nice wet edge. Let's see if Miller concurs...

    Jeff

  3. #763
    Jeff,

    Thanks for the feedback. I went out and inspected areas where I knew I had the gun a lot closer to the surface ... and by Jove ... I think you nailed it.

    I have spent time sanding to 150 grit today and have managed to get most of the orange cleaned up. It wasn’t has hard as I thought it might be but it sure is easier when there is less OP! I am amazed how smooth it gets ... ��

    Clearly ... I need a boatload of practice ... so my next challenge will be to flip the parts over and try again with the SS.
    Mk 4 Roadster
    October 25, 2012 - Kit Arrives
    April 8, 2013 - Build Starts
    August 23, 2015 - Rolling Chassis/Engine & Transmission Installed
    March 26, 2016 - Go Cart

  4. #764
    Last night I put up some poster paper and practiced with the following settings:

    Slick Sand: 8.4 oz.
    Acetone: 1.2 oz. (about 15%)
    Catalyst: 1/4 tube

    Gun Settings
    Fan Setting : 1/2 Turn
    Flow Settings: 3 Turns
    Stage One Pressure: 38psig
    Stage Two Pressure: 24 psig
    Gun Cup Filter: 200 micron filter removed

    Fan: ~ 5-6 inches from 6 inches from the surface. I also slowed way down which did create one run ...



    It was a whole different and positive outcome ...almost no OP on the practice so I jumped on the outside of my PS door to see if I could reproduce it on fiberglass.

    I will check out the link ... and I really appreciate your detailed feedback.

    Here are the photos ...





    I don't know if i got too close or slowed down too much but in any case it left this run ...



    With some 150 grit paper it cleaned up rather quickly ...



    Today I sanded it to 150 grit and it was much quicker than the hours I spent fixing the OP on the trunk lid and hood.

    Thanks again ... keep the feedback coming.

    Carl
    Mk 4 Roadster
    October 25, 2012 - Kit Arrives
    April 8, 2013 - Build Starts
    August 23, 2015 - Rolling Chassis/Engine & Transmission Installed
    March 26, 2016 - Go Cart

  5. #765

    Smooth is NOT Necessarily Flat ...

    Here is a short video of the results through last evening ...



    On the hood top I applied some guide coat to check for low spots ... and found some on the hood top. I did not use guide coat on the door but I found that there is enough difference between the sanded and un sanded SS to see the low spots. While the surface can seem to be perfectly smooth it is not necessarily flat ...

    Here is one example of a low spot on the hood ...



    Although a bit difficult to see these low spots continued down the side edges of the hood ...



    On the door ... where I did not use guide coat ... the darker areas are the low spots.



    On the inside of the trunk lid ... well I think I really did not get enough SS on the vertical sections of the ribs and the edges of the lid.



    Only one pinhole so far ...



    All has been sanded to 150 grit ... so here are my questions:

    1. Since I know that i have low spots ... do I respray SS the low areas now and then resand through 150 grit to eliminate the low spots before moving forward with the 180 grit?

    2. Do I have to have all the gelcoat, Rage or glazing putty covered with SS or can the 2K Urethane serve that purpose?

    Thanks in advance for your help ...

    Carl
    Mk 4 Roadster
    October 25, 2012 - Kit Arrives
    April 8, 2013 - Build Starts
    August 23, 2015 - Rolling Chassis/Engine & Transmission Installed
    March 26, 2016 - Go Cart

  6. #766

    Fiberglass Repair of the PS Door

    Before proceeding further with application of SS to the doors some repairs had to be completed ...

    Passenger Side Door: On my first attempt at mounting the door on the paint fixture, I dropped it on the floor. This caused a crack in the jamb about parallel with the top row of hinge studs.

    Last week I completed the structural repair of the crack by first opening up the hole and beveling out the fiberglass surrounding the hole with 80 grit grinding wheel. Using vinyl ester resin 3 layers of mat was applied to the hole. Today I finished the repair with Rage Gold.







    Mk 4 Roadster
    October 25, 2012 - Kit Arrives
    April 8, 2013 - Build Starts
    August 23, 2015 - Rolling Chassis/Engine & Transmission Installed
    March 26, 2016 - Go Cart

  7. #767

    HSRF on Top of Gelcoat ... A Disaster

    About two months ago ... or more ... after getting gaps at the back of the door completed I faired off the HSRF into the side of the door jamb. I don?t know if I made this repair before or after learning that HSRF will not adhere to gelcoat. In any case while cleaning up the HSRF it popped off the gelcoat (the compressed air lifted it off as well); I ended up removing a bunch of the gelcoat to get down to some solid substrate 😡.





    I also filled in some more pinholes/voids on other parts of the door as well ...





    So the work tomorrow will be to finish up the Rage sanding and then shoot 3 coats of SS on the inside of the doors and the outside of the DS door. After inputs from various forum posts, I decided that I will spot spray SS on the inside of the trunk lid, hood top, PS door exterior. Monday will be a sanding day!

    Thoughts/suggestions/warnings are always welcome.
    Mk 4 Roadster
    October 25, 2012 - Kit Arrives
    April 8, 2013 - Build Starts
    August 23, 2015 - Rolling Chassis/Engine & Transmission Installed
    March 26, 2016 - Go Cart

  8. #768

    Body Work Continues ... Some Lessons Learned So Far ...

    Some lessons learned from this round of spraying Slick Sand:

    1. Practice and check your spray pattern. Before applying it where it matters test somewhere it doesn't. I noticed the pattern looked wonky ... it turned out that when I put the new atomizing Head on I had the cap midway between the vertical and horizontal position;

    2. Spray the hard to get to spots first. As DanEC pointed out spray the ribs and other edges first and then the remainder of the surface to make sure you get good coverage;



    3. Make sure to have plenty of room to hold the gun properly over the surface. I had a few tiger stripes, some OP and a large ?blob? of paint on the hood and sone dusting on the trunk lid. This was caused by me being inconsistent in both distance, speed and angles of the gun to the surface. and distracted by the hose and my *** hitting the table behind me. Here is one result:



    4. SS shows off a whole lot of previous body work sins ... especially after just one or two coats ... pinholes, gouges and dings;





    5. Just as in the case of the Rage Gold knocking down my hood blob before it cured too much made it easier to sand later;

    6 As suggested by others using an artist?s brush I applied a little of the SS from the last spraying to all the pinholes and voids ...



    The shiny reflective spots are the ones where the pinholes were filled in ... next time I will be more careful so I can have less sanding;

    7. Respirator Storage. When not in use I sealed up the respirator in a plastic food storage bag ... to keep the sanding dust off and to extend the life of the filter media (supposedly if continued exposure to the fumes will shorten the life of the media);

    8. Cleaning Sandpaper. The life of the sandpaper can be extended by using compressed air to remove the dust and other stuff; and,

    9. When in proper tune ... interaction between the spray and sandpaper "speak" to you. I found when I got the spray gun the right distance and speed along the surface ... the sound of the spray hitting the surface changed. The sound of the sandpaper when it has done its job changed; if you then hit an unsanded spot changed. Off course this could be that my respirator has failed.

    Carl
    Mk 4 Roadster
    October 25, 2012 - Kit Arrives
    April 8, 2013 - Build Starts
    August 23, 2015 - Rolling Chassis/Engine & Transmission Installed
    March 26, 2016 - Go Cart

  9. #769

    The Doors ... The Darn Doors

    Over the last few days I have spent most of the time creating dust from the SS applied to the two doors. I have already swept a pile of the stuff into the trash can.

    After applying the last of three coats of Slick Sand to the doors ... it was time to get them sanded down to 180 grit. On the door exteriors, I used a guide coat when I sanded from 120 to 180 grit.

    With more practice, applying the SS has gotten better ... near zero orange peel and or dry "dust" on these surfaces.

    Here are a few photos of the progress on the doors ...

    Passenger Side Door

    On the painting fixture ..





    I have found it easier to sand the doors by removing them to a table top.

    After sanding to 180 grit. This door had a lot less Rage on it than the DS door; there was one area where the gelcoat was exposed after sanding but it is flat. My understanding is that, since it is flat, I can cover this area with 2K Urethane Primer before sealing and painting.



    Driver Side Door. The DS door was a different story ... as expected. When I originally fitted it to the frame and body it required a lot more HSRF/Rage Gold to get matched up to the body.


    On the painting fixture ...





    After sanding to 180 grit.



    This door has several spots that either went through to the Rage or Gelcoat.

    My admiration for the folks that do this for a living is going up exponentially each day...

    Carl
    Mk 4 Roadster
    October 25, 2012 - Kit Arrives
    April 8, 2013 - Build Starts
    August 23, 2015 - Rolling Chassis/Engine & Transmission Installed
    March 26, 2016 - Go Cart

  10. #770

    Trunk Lid ... Re Engaging with Rage Ultra

    First ... why Ultra? I am running low on my third can of Rage Gold and had a can of Ultra so I decided to use it on the final skim coats before Slick Sand.

    Second ... the interior of the trunk lid has been SS and sanded to 180 grit. It is flat but some gelcoat remains visible but I will cover that with the 2K Urethane Primer. I have something special planned for the interior of the lid so I don't need to go further with any SS.

    The exterior of the trunk lid was another issue ... I spent about 3-4 hours getting the exterior ready for another round of SS.







    Lessons Learned:

    1. I need to practice spraying horizontal surfaces more before getting to base coat and clear;
    2. Use a guide coat anywhere that an absolutely flat surface is required ... it is easy to use and reveals all the low spots;
    3. The Rage Ultra produces a finer dust than Rage Gold ... almost like a talcum powder ... so I blew off the surfaces of the hood and cleaned the sand paper often; and,
    4. There are very few flat surfaces, but lots of compound curves, on these cars ... so I use the largest blocks but sand with a light touch.

    Next ... another 3 coats on the areas re engaged with Rage!
    Mk 4 Roadster
    October 25, 2012 - Kit Arrives
    April 8, 2013 - Build Starts
    August 23, 2015 - Rolling Chassis/Engine & Transmission Installed
    March 26, 2016 - Go Cart

  11. #771


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    Jeff Kleiner's Avatar
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    Quote Originally Posted by carlewms View Post
    ... I am running low on my third can of Rage Gold...
    Three buckets of mud? Whooee! That's a lot of dust---but you probably realize that by now

    Carry on!

    Jeff

  12. #772
    Quote Originally Posted by Jeff Kleiner View Post
    Three buckets of mud? Whooee! That's a lot of dust---but you probably realize that by now

    Carry on!

    Jeff
    Darn ... I cannot count ... it should be two cans of Rage Gold ... I have just enough in the bottom of one can for some items on the body!

    I will say that between the Rage Gold, Ultra and Slick Sand it looks like a dust storm it the garage and my utility room. It gets into places I cannot mention ... but da Bat might
    Mk 4 Roadster
    October 25, 2012 - Kit Arrives
    April 8, 2013 - Build Starts
    August 23, 2015 - Rolling Chassis/Engine & Transmission Installed
    March 26, 2016 - Go Cart

  13. #773

    More Body Shaping ...

    After finishing the hood, doors and trunk lid ... time to focus on the body. With my newly developed sensitivity to finding irregularities in the body after SS, I checked the parting lines on the body ... and I found some areas that needed some more attention.

    This time I used Rage Ultra and the largest spreaders I had on hand to sort of skim coat the parting lines. The basic steps were:

    1. Clean the area with Eastwood?s Pre Paint Prep and lint free blue shop paper towels;
    2. Apply Rage Ultra (RU) with a large yellow spreader that I could shape around the curve of the fender and a large stainless steel spreader to get the smoothest results possible ... at least in some cases;
    3. Before the RU fully set:
    - Use the metal spreader to scrape off the excess around the edges and any high spots or ?droppings? on the gelcoat;
    - 80 grit on blocks used to further smooth out the ridges; and,
    4. After fully curing 80 grit was used to get to the final shape.



    After all this sanding or shaping ... one of the things I found myself constantly having to check or realize is that what may look smooth visually can be deceiving.



    To get the "truly" smooth transition you need to sand the RU to the point it blends evenly with the gelcoat as illustrated on the right side above.

    I spent almost all my time over the last 2 days working the lines on the body ... tops of the fenders and the line in front of the hood opening, and those from the trunk edge going down the quarter panels just in front of the tail lights.

    The front is ready for SS ...



    Parting line across the body forward of the hood opening.



    Lots of dust created ... DS Rear Fender



    PS Rear Fender



    Starting to look pretty "shapely" ...



    With the Rage Ultra ... less than 5 pin holes to fix on the body so far.

    I should be able to wrap up the RU shaping tomorrow and then get the body off ...

    Although the RU loads up quickly on the sand paper ... you can blow it off with compressed air.


    DS looking forward ...
    Mk 4 Roadster
    October 25, 2012 - Kit Arrives
    April 8, 2013 - Build Starts
    August 23, 2015 - Rolling Chassis/Engine & Transmission Installed
    March 26, 2016 - Go Cart

  14. #774
    Folks,

    Thanks for the encouraging words ... it keeps me in the garage even when it’s full of dust and pieces of used sandpaper.

    After a few more applications of Rage Ultra and the creation of more dust ... the fenders are ready for SlickSand. The ultimate test was “feeling up” the entire set of fenders and across the front of the car. I also used a profile gauge to compare the fenders at selected spots and they were comparable (remembering that the body is not perfectly symmetrical anyway).

    Here are some photos sighting down the fenders on each side of the car. Unless you all see something I have missed I plan on getting the body on the buck before heading off for the holidays.

    Passneger Side

    Looking to the rear of the car





    Looking to the front of the car



    Driver Side

    Looking to the rear of the car





    Sorry about the shadows

    Looking to the front of the car



    My plan is to get the DS roll bar tack welded in the next few days so that I can remove the body and flip it over on its back to:

    1. Apply some time of undercoating bed liner to the areas susceptible to rock damage;
    2. Reinforce the narrow areas around the rear door jambs (basically put some mat and cloth on the back side of the area;
    3. Glaze in all the lips of the wheel wells or fenders;
    4. Mount 1/4"-20 studs to support the cables to the lights; and,
    5. Fix a self induced cracks in the fiberglass.

    Carl
    Mk 4 Roadster
    October 25, 2012 - Kit Arrives
    April 8, 2013 - Build Starts
    August 23, 2015 - Rolling Chassis/Engine & Transmission Installed
    March 26, 2016 - Go Cart

  15. #775
    Senior Member AC Bill's Avatar
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    Your shaping looks great, Carl. Nice curves like a Playboy Bunny has..

    So how do get the roll bar off, if you tack the third leg to the hoop beforehand?
    As you lift it up as a unit, the third leg will contact the body before you can get the hoop legs fully out. Least that would have been the case with my MK 3.1..Perhaps with the MK4 it is possible..

  16. #776
    Bill,

    Regarding the roll bar the third leg actually fits on to another section of tubing that then fits on the stub on the frame. When mounted the end pf the third leg is just below the body. The other two legs have a similar setup but are a little farther into the body.

    According to the Breeze instructions there should be enough room to get the third leg off and then pull the front two legs off the mounts.

    Off course in practice it may be different ...

    I will let you know.

    Carl
    Mk 4 Roadster
    October 25, 2012 - Kit Arrives
    April 8, 2013 - Build Starts
    August 23, 2015 - Rolling Chassis/Engine & Transmission Installed
    March 26, 2016 - Go Cart

  17. #777
    After visiting family and friends for the Holidays and a visit by Mr. Flu .... I think I can get back to work.

    I have the beast on its back working on the edges for the fenders ... and my question relates to the lower forward end of the fender edge.

    Edge View



    Inside View



    Should I trim off the tab and fill in with Rage or leave it and fill in up to the tab with Rage?
    Mk 4 Roadster
    October 25, 2012 - Kit Arrives
    April 8, 2013 - Build Starts
    August 23, 2015 - Rolling Chassis/Engine & Transmission Installed
    March 26, 2016 - Go Cart

  18. #778
    Here are some better photos ...





    Mk 4 Roadster
    October 25, 2012 - Kit Arrives
    April 8, 2013 - Build Starts
    August 23, 2015 - Rolling Chassis/Engine & Transmission Installed
    March 26, 2016 - Go Cart

  19. #779
    Senior Member edwardb's Avatar
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    I trim that mostly off. Not the best view, but you can see that area in this pic from my Anniversary build:

    Build 1: Mk3 Roadster #5125. Sold 11/08/2014.
    Build 2: Mk4 Roadster #7750. Sold 04/10/2017. #7750 Build Thread
    Build 3: Mk4 Roadster 20th Anniversary #8674. 03 of 20. 2015 crate Coyote, 2015 IRS. Legal 04/18/2017. #8674 Build Thread
    Build 4: Gen 3 Type 65 Coupe #59. Delivered 12/2/2017. #59 Coupe Build Thread

  20. #780


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    Jeff Kleiner's Avatar
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    I trim them something like this eliminating the wide "triangle" and following the outer edge until it curves inward then widening the radius a bit.



    The idea to me is to make the edges appear to roll in more like the original aluminum skin.

    Jeff

  21. #781
    Paul and Jeff,

    Thanks for your responses ... I have trimmed the PS down and will get it smoothed out with Rage before tackling the PS. It sure makes it look better to have that "extension" out of the way.

    Carl
    Mk 4 Roadster
    October 25, 2012 - Kit Arrives
    April 8, 2013 - Build Starts
    August 23, 2015 - Rolling Chassis/Engine & Transmission Installed
    March 26, 2016 - Go Cart

  22. #782

    Trimming the Rear Fender Front Lower Edge ...

    It started like this ....



    Work in Progress ...



    Finished ... I think Let me know what else I need to do if I missed something here please



    Carl
    Mk 4 Roadster
    October 25, 2012 - Kit Arrives
    April 8, 2013 - Build Starts
    August 23, 2015 - Rolling Chassis/Engine & Transmission Installed
    March 26, 2016 - Go Cart

  23. #783

    A Break from Body and Paint Preparations

    Before taking the body off we first made sure that the parts were all in the right spots ...



    My friend Craig came over before the holidays and TIG welded a three spots on the Breeze Stainless Steel Roll Bars ...



    Two of the spots are seen here and the third is on the front of the roll bar. The markers around the tubes are the approximate locations where the tubes exit the body when it it installed.

    After getting the roll bar back fully welded by JB Custom Welding (they had fantastic service ... took them in the morning and they had them ready in the early afternoon); the distance between the two front legs needed some adjustment by about .5 inches.





    After a few more minor adjustments ... like polishing the tube extending from the frame to the rear leg ... the fit came out pretty good.

    Front or Hoop Legs to Frame:



    Rear Leg to Frame:



    My questions for the group ...

    1. Drilling the SS will be tough as I understand it; what tips/tricks can you recommend?

    2. What type of drill bits do you recommend for SS?

    3. Is there a better way than through bolts to attach the leg components? Some have actually tapped and threaded the inside tube wall in two locations and then used at screws to fix the location of the tubes vertically.

    Thanks in advance for your thoughts.
    Mk 4 Roadster
    October 25, 2012 - Kit Arrives
    April 8, 2013 - Build Starts
    August 23, 2015 - Rolling Chassis/Engine & Transmission Installed
    March 26, 2016 - Go Cart

  24. #784
    Well Used Member boat737's Avatar
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    Probably overkill (OCD), but for the third leg near where the body hole is, it is a bit tight for a through bolt. So I took two coupling nuts (3/8 - 16 if I remember right), put a small 1/4" or 3/8" square bar stock spacer between them, and welded them all together. Drilled two matching holes in both the upper and mid third leg, ground down the edges of the coupling nuts to fit in the third leg mid tube, then welded the coupling bolt assembly in the end of the mid leg (just inside the end of the mid tube). This way there is no bolt near or showing at that body hole. For the frame mounts, I just did a 5/16 " thru bolt.
    Attached Images Attached Images
    If Brute Force doesn't work, you're not using enough of it.
    Bought a partially completed MK4. The Basic Stuff: MK4 Complete Kit #8439. The Extra Stuff: Wilwood's, 17" Halibrands, Stainless brake and fuel lines, Breeze cooling and Battery mount.
    The Old Fart Stuff: Heater, Seat Heaters, Footbox Fresh Air, Stereo, Keyless ignition, Power Steering, Hyd Clutch.
    The Young and Dumb Stuff: 427w Dart, TKO600, 3 link Moser M9/Ford 9", 3.5:1, Eaton TruTrac Posi

  25. #785
    Boat,

    Thanks for the idea ... it sure looks clean and strong enough. I have about exactly the same amount of room to install some type of retaining device.

    I assume you used SS hardware for all the fittings???

    Carl
    Mk 4 Roadster
    October 25, 2012 - Kit Arrives
    April 8, 2013 - Build Starts
    August 23, 2015 - Rolling Chassis/Engine & Transmission Installed
    March 26, 2016 - Go Cart

  26. #786
    Well Used Member boat737's Avatar
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    Quote Originally Posted by carlewms View Post
    Boat,

    Thanks for the idea ... it sure looks clean and strong enough. I have about exactly the same amount of room to install some type of retaining device.

    I assume you used SS hardware for all the fittings???

    Carl
    I did use SS hardware. The funny thing is though, those mid legs on the Breeze roll bar may not be SS. A magnet sticks to them. Doesn't mean that they aren't stainless, but there does seem to be some ferrous material in them. I didn't notice that until after I had MIG welded my little assemble in the tube. It welded in fine though, so who knows. I'm not that experienced in welding different metals, but I didn't notice any problem.

    One more tip. Use anti seize with the stainless bolts in the stainless coupling nuts. It's amazing how those suckers want to gall and ruin a perfectly good project. I use that messy grey stuff that seems to get all over my hands, clothes, and work bench. Any lube or PTFE will help though.
    Last edited by boat737; 01-10-2018 at 09:38 AM.
    If Brute Force doesn't work, you're not using enough of it.
    Bought a partially completed MK4. The Basic Stuff: MK4 Complete Kit #8439. The Extra Stuff: Wilwood's, 17" Halibrands, Stainless brake and fuel lines, Breeze cooling and Battery mount.
    The Old Fart Stuff: Heater, Seat Heaters, Footbox Fresh Air, Stereo, Keyless ignition, Power Steering, Hyd Clutch.
    The Young and Dumb Stuff: 427w Dart, TKO600, 3 link Moser M9/Ford 9", 3.5:1, Eaton TruTrac Posi

  27. #787
    Senior Member CraigS's Avatar
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    Just in case that roll bar is ever needed for it's intended purpose, I'd use through bolts. The bolts would be loaded in shear and the short bolts would be taking that load right at their weakest spot-the threads. I would use a 3/8 G5 standard bolt that is sized so that it is solid all the way through the outer tube. Probably need a few extra washers under a nyloc nut. And it wouldn't hurt to cut off maybe half of the threads. You don't see them so appearance isn't an issue.
    FFR MkII, 408W, Tremec TKO 500, 2015 IRS, DA QA1s, Forte front bar, APE hardtop.

  28. #788
    Senior Member Straversi's Avatar
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    I like the floor jack/tubing bender. I read the post but didn't notice the photo. I was wondering how you corrected the bend. Great idea.
    -Steve
    MK IV #8901 - Complete kit, Coyote, TKO-600, IRS. Ordered 5/23/16, Delivered 7/14/16, First Start 8/13/17, First Go-Kart 10/22/17. Build Thread: http://thefactoryfiveforum.com/showt...V-Coyote-Build

  29. #789
    Craig and Boat ... thanks for the recommendations.

    It looks like I might have enough room for a through bolt if I came perpendicular or from the side of the rear leg. The marker is approximately where the tube emerges from the body.



    It will probably be easier to drill it off the car ...

    Thanks,

    Carl
    Mk 4 Roadster
    October 25, 2012 - Kit Arrives
    April 8, 2013 - Build Starts
    August 23, 2015 - Rolling Chassis/Engine & Transmission Installed
    March 26, 2016 - Go Cart

  30. #790
    Well Used Member boat737's Avatar
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    Quote Originally Posted by CraigS View Post
    Just in case that roll bar is ever needed for it's intended purpose, I'd use through bolts. The bolts would be loaded in shear and the short bolts would be taking that load right at their weakest spot-the threads. I would use a 3/8 G5 standard bolt that is sized so that it is solid all the way through the outer tube. Probably need a few extra washers under a nyloc nut. And it wouldn't hurt to cut off maybe half of the threads. You don't see them so appearance isn't an issue.
    Interesting point. I will swap out my two bolts for one's with a small shoulder, i.e., a partially threaded shank.

    More food for thought: With just a thru-bolt, there is no friction between the inner and outer tubes. So a compression of the roll bar tubes will only be prevented by the thru-bolt in shear, (unless the thru-bolt is tightened to the extent that the outer tube is deformed and collapsed onto the inner tube providing a friction fit. as opposed to a slip fit.) That would have the undesired effect of making the roll bar nearly impossible to disassemble and remove from the car.

    However, my two bolts (still in shear) will be fastening the inner tube to the outer tube without deforming either tube. The bolts are still providing the same amount of shear force, but the assembly has the additional friction of the two tubes being fastened together. I'm bettin' that mine is at least as strong as just a through bolt. Could be wrong though.
    If Brute Force doesn't work, you're not using enough of it.
    Bought a partially completed MK4. The Basic Stuff: MK4 Complete Kit #8439. The Extra Stuff: Wilwood's, 17" Halibrands, Stainless brake and fuel lines, Breeze cooling and Battery mount.
    The Old Fart Stuff: Heater, Seat Heaters, Footbox Fresh Air, Stereo, Keyless ignition, Power Steering, Hyd Clutch.
    The Young and Dumb Stuff: 427w Dart, TKO600, 3 link Moser M9/Ford 9", 3.5:1, Eaton TruTrac Posi

  31. #791
    Craig and Bolt,

    After further research .... here is the route I believe works best for me in terms of ease (I am not a proficient welder) and strength.

    There is enough room to install a 7/16" diameter bolt in the rear leg just below the body. I found the following McMaster Carr Grade 8 bolts that I believe will work.

    I need 3" to get a clear 1.5" of shank for the tubes that connect to the frame stubs.



    3 1/4" are needed for the roll bar to transition tube.



    Depending on tolerances I may have to put some extra washers and will probably have to cut off some of the threads to get the one for the outboard leg to fit.

    What do you all think?

    Carl
    Mk 4 Roadster
    October 25, 2012 - Kit Arrives
    April 8, 2013 - Build Starts
    August 23, 2015 - Rolling Chassis/Engine & Transmission Installed
    March 26, 2016 - Go Cart

  32. #792
    Well Used Member boat737's Avatar
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    Hi Carl. For the lower tubes into the frame studs, 7/16 may be overkill. If they are like mine, the tubes are bottomed out to the mounting stub base, so they're not going to collapse any further, even with no bolt. I would think 5/16 or 3/8 inch max at those three spots, especially Grade-8 (those are pretty strong bolts). As for the third leg below the body line, your choice. I'm still thinking 7/16 may be a bit much though. JMHO
    Last edited by boat737; 01-14-2018 at 02:31 PM.
    If Brute Force doesn't work, you're not using enough of it.
    Bought a partially completed MK4. The Basic Stuff: MK4 Complete Kit #8439. The Extra Stuff: Wilwood's, 17" Halibrands, Stainless brake and fuel lines, Breeze cooling and Battery mount.
    The Old Fart Stuff: Heater, Seat Heaters, Footbox Fresh Air, Stereo, Keyless ignition, Power Steering, Hyd Clutch.
    The Young and Dumb Stuff: 427w Dart, TKO600, 3 link Moser M9/Ford 9", 3.5:1, Eaton TruTrac Posi

  33. #793
    Boat,

    Thanks ... being an old ... well very old engineer (that has not done this type of analysis in ages), I decided to look into the materials and physics of it all. First I did not do any dynamic load analysis; I just looked at the shear strength of the different components. Here is what I found:

    1. 304 Stainless Steel has compressive strengths ranging from 29,733 to 44,962 psi (azom.com);
    2. The shear strength of the Grade 8 and Grade 5 bolts is summarized in the following table:



    3. Here is a graph of the same data:



    Thoughts or Semi Conclusions:

    1. Since the integrity of the roll bar system depends on the roll bar and the bolts, based on the compressive strength of the 304 SS the bolts would fail before the roll bar tubing (at least in compression);

    2. The dynamic loads during a roll over would be higher than the static loads of the car just sitting on the roll bar;

    3. The compressive analysis assumes that the forces would be perpendicular to the bolts but in a real rollover they would be on all three axes and would change as the car rolled; and,

    4. I am not sure that this a proper way to look at the static loads but assuming a car weight of around 2300 pounds ... a 3/8" or 7/16" diameter Grade 8 or 5 bolt should give about a 3:1 margin to potential collapse. A 5/16" diameter bolt is also close.

    Assuming you all agree I think that I would be safe with a 3/8" diameter bolt in all three legs.
    Last edited by carlewms; 01-14-2018 at 04:48 PM.
    Mk 4 Roadster
    October 25, 2012 - Kit Arrives
    April 8, 2013 - Build Starts
    August 23, 2015 - Rolling Chassis/Engine & Transmission Installed
    March 26, 2016 - Go Cart

  34. #794
    Well Used Member boat737's Avatar
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    Wow. That's pretty detailed. Just for grins, you don't happen to have figures for 304 and/or 316 stainless bolts that you could add to your graph and table do you? (It would be interesting to see the comparison between them all.) I'll keep quiet now...
    If Brute Force doesn't work, you're not using enough of it.
    Bought a partially completed MK4. The Basic Stuff: MK4 Complete Kit #8439. The Extra Stuff: Wilwood's, 17" Halibrands, Stainless brake and fuel lines, Breeze cooling and Battery mount.
    The Old Fart Stuff: Heater, Seat Heaters, Footbox Fresh Air, Stereo, Keyless ignition, Power Steering, Hyd Clutch.
    The Young and Dumb Stuff: 427w Dart, TKO600, 3 link Moser M9/Ford 9", 3.5:1, Eaton TruTrac Posi

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