Fasteners for body panels

[Frank818]

I am about to order some fasteners for different thing ND wanted to know what you guys used to mount the body panels?

I need something removable, like most of us I guess.

[tmoretta]

I am using 5/16 riv-nuts with 10/32 x 3/4 bolts. Available, cheap, from Mcmaster Carr.

[Frank818]

Rivnuts seem what most of us are doing, I think?

I know Dan uses SS button head with washer 10-24s, but also with rivnuts.

I think I'll go that way too. Except I have to order from another place as McMaster, who seems to have everything, doesn't ship overseas. Probably Fastenal.com.

EDIT: Oh wait, it appears McMaster does deliver overseas! Little hidden function, but I think yes. I'll add all my fasteners to a list and give it a try soon.

[Frank818]

5/16 rivnuts? That's bigger than the 1/4-20 supplied by FFR.

I think I will go with 10-32 rivnuts and 10-32 x 0.5 SS button head screws, adding washers to them. Even cheaper.

EDIT: actually 0.5 long is too short, you are right tmoretta, need 0.75.

[longislandwrx]

plastic fasteners anyone?

http://www.ebay.com/itm/like/371060662792?lpid=82

[Frank818]

Long, I bought similar plastic ones for the cockpit, interior panels and other things around.

You think they can hold the body panels in place?

[tmoretta]

You are right Frank. I am using 10 32 rivnuts which require a 5/16" drill bit for the hole.

[Frank818]

I guess 5/16 and 10-32 are the same? I mean, if I get 10-32 bolts, does it mean I need matching 10-32 rivnuts? The 10-32 rivnuts require 19/64 drill instead of 20/64, but it might depend on the metal, 1/64th is not much!

But I am tempted by the plastic trim fasteners, those are super cheap. I just don't know how much they can hold and if it's gonna be tight enough to keep the panels on the frame without moving due to vibrations.

EDIT: According to what I read, it seems the cheap plastic retainers don't hold that much and don't have a lot of tension. If it's true, then I would question their use on the say the side panels or rear bumper, etc. Maybe I am not looking at the right plastic retainers but the cheap ones (20 pieces for 2-3 bucks) are probably not a good idea. I won't be a pioneer for that use, though.

[FFRSpec72]

I was going to use quarter turn fasteners for the body, I did these on my Challenge car but it basically has very few panels vs. the many panels that the 818 has. I was going to use these http://www.rjracecars.com/Quarter-Tu...-Prodlist.html or these http://store.skybolt.com/panel-faste...sets-c105.aspx in various spots as they fit.

[Frank818]

Looks good stuff Tony, but did I see the price correctly?

[Hindsight]

Is there an issue with the body mounting rivnuts and hardware FF supplies in the kit?

[FFRSpec72]

Is there an issue with the body mounting rivnuts and hardware FF supplies in the kit?

Not that I know of they just don't satisfy my need to have a totally removable body very quickly.

[FFRSpec72]

Looks good stuff Tony, but did I see the price correctly?

yep, expensive, about $5-10 for each fastener. one of my projects will be to try to combine hood and 2 front fenders into 1 piece and then have a tilt frontend, much like the cobra "turd" project or Daytona Coupe, this way I can et to things in the front, doors will have to be quarter turn so they come off with 2-4 fasteners, the rear, not sure how to handle that yet, will depend on how I mount the wing.

[Frank818]

Is there an issue with the body mounting rivnuts and hardware FF supplies in the kit?

Not that I know of they just don't satisfy my need to have a totally removable body very quickly.

Tony said it, it's one solution amongst many others, but many of us have that requirement called flexibility. The 3/16 rivets will do the job to hold in place, but if you need to remove the rear bumper, or side panels, or tunnel cover, dash, console, you'll have to drill them out. I know for sure all these previous parts will be removed many times within the next years, so I don't want to go with rivets.

yep, expensive, about $5-10 for each fastener. one of my projects will be to try to combine hood and 2 front fenders into 1 piece and then have a tilt frontend, much like the cobra "turd" project or Daytona Coupe, this way I can et to things in the front, doors will have to be quarter turn so they come off with 2-4 fasteners, the rear, not sure how to handle that yet, will depend on how I mount the wing.

So less fasteners per body parts? That's a nice option. Less of a hassle to install cuz less to install, quicker to remove the panels and would hold at least as good. Or are they less of a hassle to install? I admit I didn't check how these things get installed.

[Scargo]

Could NASA, SCCA or other racing Org have a say as to what is acceptable for holding bodywork on? Plastic fasteners were mentioned.

I may stick to the standard Dzus 1/4 turn fasteners, but I'm not in love with two pop-rivets and a big hole per fastener or having the fastener mounted on the outside. Imbed studs in the fiberglass as part of the finishing process and just have a hole? Not sure how many total fasteners are needed but those fancy, flush mount fasteners appeal to me. $7-10 fasteners would add up to several hundred dollars. Perhaps that is not bad, given the alternatives. I have a bare frame so I will weld on brackets.
I do not much like the idea of using the post and clip fasteners that FFR has provided. Heavy and not that aerodynamic. Pretty obtrusive in the landscape of the exterior. Fine for cool and retro bling but not what I personally want on my racer. Put them on my Prius?

[Hindsight]

I thought the panels were bolted to the frame with rivnuts. The rivnuts aren't removable but the bolts attaching the body to them obviously would be. I really haven't read this far ahead in the instructions so forgive me if I'm assuming incorrectly..... do the instructions really have you riveting the body directly to the frame in some parts? If so, that does seem odd!

[Frank818]

The bottom of the side panels and rear bumper are riveted with 3/16 rivets. I haven't read the front bumper or other panels, as soon as I saw these 3 it was a no-go for me and I started my quest for other fasteners.

Depending on the manual rev you got (take 1F for instance), check page 349 for side panels and 353 for rear bumper.
Looks like the front bumper uses rivnuts, a few pages forward.

[RM1SepEx]

Frank, all of FFR directions have panels attached with rivets. Anywhere that I might want to remove something I'm using rivnuts. I use 10-24s where I can as they are easier to install, smaller hole to drill and less force to install the rivnut. I've found that I have to assemble and disassemble multiple times to put the kit together, later assemblies require panel removal etc...

As an example would you rivet on the under engine aluminum panel if you have a rear diffuser? Do you want to drill rivets every time that you change the oil etc...

The GRM videos showed them attaching the bottom of the side panels with TEK screws... A sheet metal screw with it's own drill bit on the end. Will work to remove 2 or 3 times before the thin tubing metal won't hold and the screw comes out or doesn't hold. When it does, flat tires anyone? But a viable option and really easy to use/install.

My wife's Caddy uses so many of those push pop lock plastic pins for all kinds of body plastic panels, too much force they pop and she ended up running over a plastic panel on the highway last summer. I'm pretty sure all new cars use these all over the place in combination with regular fasteners.

Options abound, you can hold them on any way you choose.

[Frank818]

Well exactly. I also install and remove multiple times during the build (I am building the car 4-5 times overall lolll). Just for that I cannot use rivets.

And yes, the rear diffuser, under engine panel, under seat panel, front splitter and under battery panel (maybe not the front under radiator), I will use removable fasteners.

Yes, newer cars use more and more the plastic fasteners, mostly to reduce weight, cut costs and improve guess what, gas mileage. But I don't trust the plastic ones for our FB body panels.

[tmoretta]

What is the under engine panel? I see no mention of it in the manual, no picture of it, and I can't find it in my box of aluminum pieces. Does it come only with the optional rear diffuser?

[FFRSpec72]

What is the under engine panel? I see no mention of it in the manual, no picture of it, and I can't find it in my box of aluminum pieces.

If you have the rear diffuser then you should have the under the engine panel, some early ships of the diffuser did not get the panel, so call and you can get them to send it to you.

[Scargo]

I am in the process of fitting my body panels. With my R (built at the end of April, 2014, Sales Order# 094024) I have no issues with a warped radiator mount. It's withing an 1/8". I have other fit issues which I will address elsewhere.

Mainly, I wanted to comment about how compression fasteners are being used with fiberglass (FRP). Partially from reading and partly from experience I feel like pop-rivets and Riv-nuts are a less than ideal fastening solution. With the FRP being so brittle it stands to reason that if you squeeze it too hard, it will crack and if you don't distribute the load it will crack and loosen around the rivet. Washers to pull against help and using big-headed rivets help. I found the term "radial loading" which is the internal pressure applied to the hole. This seems to be a problem when using standard Riv-nuts and pop-rivets with FRP. Products like Versa-Nuts mitigate the problem and spread the load on the back surface as well. Also, choosing the proper grip range helps.

I have been looking for bonding style nuts, threaded bushings and studs. First, let me say that I am attempting to having as much be Metric on my car as I can. This creates a level of difficulty from the beginning for finding Metric fasteners state-side.
I am not finding exactly what I want (available here in the US) except for Rotaloc and I haven't heard back from them about how/where I can buy them. I see McMaster-Carr offers a limited selection of Metric nuts, but no Metric studs.
Click Bond makes similar fasteners, without perforations, and they're pricey.

I will probably use adhesive bonded, flush-mount, Aerocatch latches for the back corners of the hood and the two main rear panels. I'm looking at doing a tilt front-end where I have hinge pins I can pull to easily remove the complete front end as one unit.
UPDATE: Rotaloc (888-768-2562/303-948-5434) sells direct with the only stipulation being that it must be in stock. They had everything I was interested in!

[FFRSpec72]

I also have the goal to remove/tilt front, not sure if it will actually happen or not. I'm just starting on the side panels this weekend, not sure what I will be using yet to mount body, all I know is that all the panels must be removable at the track and w/o hassle

[FFRSpec72]

So I started to fit my panels this weekend and went with Nut Plates, this gives me a removable panel and a good draw on tightness, I used a nylon fender washer and a SS fender washer

WP_20150222_17_24_11_Pro.jpg

[Wayne Presley]

I just tapped the frame 10-32

[Scargo]

I think this is where I would err to the side of caution. Especially on my race car.
The tubing is .083" wall. A 10-32 is .190" nominal. I don't think that's enough meat.
You're not even getting 50% thread engagement, when recommended is 150%. If you do a sloppy tapping job and use a cheap screw then you are really looking for trouble, IMHO.
I plan on using 1/4 turns/weld-on tabs or M6 x .75 bolts with Rivnuts in the frame.

[Buzz Skyline]

What, if any, benefit is there to using rivnuts as opposed to tapping the frame? Would it make sense to ditch the rivnuts on things like attaching the front bumper to the radiator support frame or attaching the rear bumper to the transmission frame? Are 10-32 or 1/4-20 rivnuts stronger than 10-32 threads in the sort of steel the frame is made of?

[FFRSpec72]

What, if any, benefit is there to using rivnuts as opposed to tapping the frame? Would it make sense to ditch the rivnuts on things like attaching the front bumper to the radiator support frame or attaching the rear bumper to the transmission frame? Are 10-32 or 1/4-20 rivnuts stronger than 10-32 threads in the sort of steel the frame is made of?

It's more the thread bite that you get , so on the frame tapping you have .065" wall tubing

[Scargo]

Rivnuts give you the 1.5x grip range (relative to the diameter) that is typically recommended for thread engagement. Looking it up in a Machinery Handbook is ideal because it can vary (I think you can find this info on the internet, too). A tap drill hole that is too big will give you weaker threads. If you tap using a drill and don't use a jig to keep the tap steady you will get substandard threads. A rivnut is precise and it's likely that the steel is better than the tubing grade of metal.
A downside is that a Rivnut can potentially spin in the hole. Once they start to spin you may have difficulty removing the screw or bolt. Using a good quality Rivnut and getting it tight in the hole during installation is important.
The self-tapping screws that hold the body on when the kit arrives are hardened steel. Perhaps this seems like a contradiction, but there's nothing particularly wrong with them, if you don't keep disturbing them, cutting new threads and wallowing out the hole. They are more of a one-shot style of fastener but can be re-used.

Like Tony said, some of the tubing it is quite thin-walled. Then you really need to use a Rivnut.

[Frank818]

Tnx Scargo for the explanation, my intention was to use 10-32 rivnuts/bolts with washers. As many rivnuts as necessary to distribute the weight. Which I have no idea how far from each other they should be.

[Scargo]

I am rethinking my desire to go Metric. It is proving difficult to get a wide assortment of high-end or fancy fasteners in Metric.
I've decided to go with 1/4-28 as my primary size for body panels and lighter loaded brackets. That way I can get Grade 5 or better nylon locking shoulder nuts and 1/4-28 bonding studs and nut plates. Just a little beefier than the M6 x .75 I was trying to source.
How many you need per X area is an interesting question. Even a low-grade 10-32 has 824 pounds of clamping force and a lowly Grade 2, 1/4" bolt has at least 200 pounds of shear strength. Than means 10 of those could easily support the whole car in shear. Now, don't get me wrong; I am not an engineer. I've just been around them most of my life and I made a stab at studying engineering. There are lots of dynamic factors and safety factors to consider.
For the sail you could probably do four underneath and the same on the sides. I'll be at 8-10 per side.

[FFRSpec72]

As many rivnuts as necessary to distribute the weight.

I'm at 8 nut plates per side panel, 4 on the face and 4 on the underside, using 10-28 grade 5, I will use 3 on the rear 1x1 transaxle support and 2 on each side where the fenders meet the rear panel. I have not gotten to front yet

[C.Plavan]

I used Rivnuts with 1 1/4" aluminum countersunk washers on the side sails, then only three 3/16" large head rivets under the car each side. I attached the rear diffuser with 3/16" large head rivets. I drilled a 2" hole in the diffuser so I can drain the oil out of the dry sump tank without having to remove rear diffuser. I use a 2" cap to close up the hole (pops in/out) with a piece of racers tape for good measure.

For the front splitter I used a boatload of 3/16" large head rivets with 3/16" backing washers (important). Then I have 4 splitter attachment rods (APR). Also, your really should attach front splitter directly to radiator frame in some manner. I used L brackets that bolt (with rivnut) to radiator frame, then 2" hole saw through aluminum so I could attach to the splitter. I plan on doing 2 more "L" brackets just to be safe.

The rear bumper attaches with large head rivets underneath, then to the top of my wing mount with bolts.

I actually ran the car with only the side rivnut attachments and nothing under for the first test. It was fine with just that also.

[Flamshackle]

Yes, newer cars use more and more the plastic fasteners, mostly to reduce weight, cut costs and improve guess what, gas mileage. But I don't trust the plastic ones for our FB body panels.

Plastic fasteners (popits) are really a great option so long as there is very little lateral load on them.

Where possible I will endeavour to use them.

[cjcnj01]

RivNuts all the way.... but you have to get a decent RivNut tool ($100) to install them or they're a real pain.

[cjcnj01]

last point... I only used them for removable aluminum panels for access to key wiring, gas sending unit and pump, etc. not to hold the frame to the car..

[Bob_n_Cincy]

I have been using 1/4-20 FH screws, 1.25" conical washer, rubber washers and revnuts to hold on the body.
The side sails, rear bumper, and engine covers have been off after each race weekend.
So much easier to work on suspension without body on. Got it down to 15-20 minutes to install or remove the body.
Bob

[RM1SepEx]

I have been using 1/4-20 FH screws, 1.25" conical washer, rubber washers and revnuts to hold on the body.
The side sails, rear bumper, and engine covers have been off after each race weekend.
So much easier to work on suspension without body on. Got it down to 15-20 minutes to install or remove the body.
Bob

Remove doors to remove side panels ???

[Bob_n_Cincy]

Remove doors to remove side panels ???

Don't know. We don't have our doors on yet.
Bob

[R Thomas]

Got some of these when son changed his Celica front cover to a body kit to attach the splash guard. Don't get em from a dealer will cost you and arm and a leg.