First off, I'm making custom widened quarter panels for my car. Its not just a fender flare, its a little more complicated. About 1/2 of the panel will be custom, and the other 1/2 will be stock.
I can't remake the entire quarter panel out of fiberglass, that would be an insane amount of work, and I would never get it right.
I want to make the widened part of the quarter panel out of fiberglass, and mold that to the rest of the metal body. I want to use fiberglass because of the weight savings, its ease of working with, and the fact that it will never rust.
I've read every single thread on this board about bonding fiberglass to metal, some things were mentioned, but nobody really came to a solid conclusion.
I know that fiberglass and metal expand and contract at different rates, so you can't just slap one on the other an expect it to last.
But I do want it to last, so is there some type of buffer material that i can place between the fiberglass and the metal, like some kind of malleable adhesive to allow the glass to move around a bit?
Also, I hear there is some stuff that you can mix in with your paint so that the paint will not completely dry, to make the paint more flexible. Could I use this ontop of where the metal meets the glass (where the cracking is going to be) so that when the glass does move around, it wont crack the paint?
Is this ever going to work or am I just going to have to bite the bullet and rig up something ugly with metal? Please be open minded, I really want this to work.
Just use sheet metal \, the fiberglass will not work.
Weld it up grind it down and bondo it.
Troy:thumbup:
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It is really impossible to obtain a permanent bond to metal with fiberglass. One of the arguments made by builders of fiberglass cars using wood reinforcing is that very point. Wood will absorb the resin and will form a much more permanent bond. Metal will absorb no resin and the bond is on the surface only.
Thats why I asked if there is a buffer material that can be placed inbetween the glass and the metal, to allow for expansion.
So again, is there a material that can be placed between the metal and the glass?
What if i did not fasten them together with an adhesive, and did this:
1) drill holes in the glass where I want it to attach to the metal approx 1/4" in diameter.
2) drill holes in the same spots on the metal, appox 1/8" in diameter.
3) line the glass up to the metal, and feed a bolt through each hole.
The thread of the bolts would be 1/8" in diameter, so they would be snug in the metal hole, but there would be room for expansion in the fiberglass hole since they are 1/4" in diameter.
4) attach a nut to the other end of the bolt, but have some kind of gasket between the nut and the glass to allow things to move around a bit.
Maybe I could use the process above in conjunction with an adhesive.
If the above process will not work, please do not just say "it will not work, you are crazy", please tell my why it wont work and give suggestions on how to make it work.
You are getting blanket statements that it won't work because it won't work! Sorry. The only way I would try that is to build the fender flare, then encapsulate the entire fender in a couple of layers of 'glass mat & resin so the outer surface will be all one material. This would give you a fighting chance.
You seem determined so give it a try. You may come up with the magic bullet we all missed. All we are telling you is that we have tried all the things we can think of and IT DON'T WORK!!!!!! :drunk:
Then how does anybody make fender flares?
Just by banging them out of steel?
I was thinking I could get some pipe, bend it to the contour of my wheel well, and then cut a 1/4 of the curvature of the pipe out and weld that to the quarter panel.
But my flares are going to be a 3" radius, which means I would need a 6" pipe. I've never used a pipe bender before, can you bend 6" pipe?
Either do the steel body work or take a fiberglass mold off a mockup and make a fiberglass version. Either works great by itself, the problem comes in mixing the two. I don't have a mind's eye view of what you want to do. Can you cut some radial slits in the fender opening, form the resulting tabs to the bulge then weld in pie shaped wedges of sheet metal to fill the resulting gaps? That should be fairly easy to do and with a little Bondo, you will have a stable fender.
I'm not a very good welder so welding little patches together might not turn out very well.
Anyway, here is a little concept drawing to give you an idea of what i want to do. I bought different tail lights that are going to fit right on there, so yes I'm cutting the metal where the original tail light is.
Call me stupid, but I think I'm going to go for the fiberglass / metal frankenstien. Im going to do alot of research and experimenting though before i take the plunge.
When we are taking about expansion and contraction of the metal, can you give me some idea of how much it expands and contracts relative to the glass? Are we talking like a 1/4 inch here or thousandths of an inch?
FRP coefficient of thermal expansion is about half that of steel (0.0000044"/"/F vs. 0.0000084"/"/F). Thus assuming you install the 'glass @ 70F and the panel heats to 140F in service (hot summer sun) and the longest joint in your setup is 36", then differential expansion will be about 0.010". 1/100th inch is plenty to overstress the bond between polyester resin and steel giving you a nice, long crack, regardless of the mechanical aids you incorporate.
Your design is pretty involved and will require some skill to pull off even in fiberglass. I suggest you take a welding course @ your local junior college and develop the skill to MIG weld sheet metal. It is a really easy skill to learn. Then you can do the job right and you will have a skill that will last a life time and that is one of the great side benefits of do-it-yourself hot rodding.
I would do that job using exhaust tubing. Someone out there surely does bends in 3" tubing. A good source to investigate is exhaust system suppliers for big diesel trucks.
Just an idea here but, I'm looking at the Feb. 2003 issue of Classic Trucks magazine, and in it is an article about gluing in patchpanels with Eastwoods Structural Panel adhesive. I can't help but wonder if that stuff might work for what you want to do. The article does illustrate a metal to metal bond, doesn't say anything about fiberglass though. Maybe you could call Eastwood and find out.
We use a similar product in the aviation industry for graphite to titanium bonding. But there again, the joints I'm talking about are specifically designed with expansion rates in mind.
Personally, I prefer welding steel to steel. Ain't very good at it yet, but I'm learning.
Psionic, I reread the entire article and there's no mention of a website or anything. I'd say though, go ahead, experiment. But I'd be real hesitant about putting an expensive paint job over it. For a while anyway.
Dubz, you might be OK, just because the cowl is welded to the hood. All you can do is wait and see. Personally, I think I would have opted for a plastic filler for your hood. I may be wrong, but it seems like bondo is more adhesive and flexible than fiberglass. But Hey! It wouldn't be the first time someone has had to do a job over again.
Actually, funny you would mention, because I'm painting my car John Deere Green!
My younger brother painted his car john deere green, and it looks REALLY nice. Its also $40 Canadian for a big can from the JD dealership...
Busted Knuckles said:
Personally, I think I would have opted for a plastic filler for your hood.
I would stay away from cheese on your hood, unless its just a little bit. Theres alot of flexion in the hood, especially when you open and close it, so the cheese would be cracked off right away.
You might be right Psionic. In my experience, which isn't much, it seems like fiberglass pops off easier than plastic when I'm trying to remove it.
That Jon Deere paint is some good stuff though. I used the blitz black on my frame. I just can't bring myself to paint my F100 JD green. I've also heard that its pretty hard to remove if you change your mind later. And I don't know how compatible with other paints it is.
not sure if anyone came up with this idea already...
Make the fiberglass pieces detachable. Don't actually adhere them to the car. Build them as good as you can, nice and rigid so they last...kind of like how Willys made his fiberglass front end.
Drill the pieces and mount them to the body with gaskets. THen you don't have to worry about the expansion/contraction rates of the different materials.
You could glass over the mounting hardware after it's done.
not sure if anyone came up with this idea already...
Make the fiberglass pieces detachable. Don't actually adhere them to the car. Build them as good as you can, nice and rigid so they last...kind of like how Willys made his fiberglass front end.
Drill the pieces and mount them to the body with gaskets. THen you don't have to worry about the expansion/contraction rates of the different materials.
You could glass over the mounting hardware after it's done.
Thats what I just said any everyone told me I was crazy!!!
Maybe I didn't explain right.
However, I wouldn't glass over the seam, I would use UV plastic filler made by bondo. Its more flexible than glass or regular cheese so it would allow for the metal and glass to move around a bit underneath.
Busted Knuckles said:
That Jon Deere paint is some good stuff though. I used the blitz black on my frame. I just can't bring myself to paint my F100 JD green. I've also heard that its pretty hard to remove if you change your mind later. And I don't know how compatible with other paints it is.
There are all different kinds of john deere green. Get the agricultural automotive grade paint. The color looks REALLY sharp on my brothers acura integra. If you want to change the color later, just sand it down, primer, and paint the new color over. But yes, the quality of the paint is much greater than regular automotive paint. PLUS the paint is dirt cheap. I would recommend it to anybody.
Bolt on yes, bonding to steel no. If the panel were steel, you have a fighting chance in bonding it. With a fiberglass one, problems arise when bonding it to steel. Rest assured, you still are crazy!!
That Jon Deere paint is some good stuff though. I used the blitz black on my frame. I just can't bring myself to paint my F100 JD green. I've also heard that its pretty hard to remove if you change your mind later. And I don't know how compatible with other paints it is.
There are all different kinds of john deere green. Get the agricultural automotive grade paint. The color looks REALLY sharp on my brothers acura integra. If you want to change the color later, just sand it down, primer, and paint the new color over. But yes, the quality of the paint is much greater than regular automotive paint. PLUS the paint is dirt cheap. I would recommend it to anybody.
Oops, sorry. 2x post. Moderator, please delete.
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