Fiberglass fenders on plastic suggestions

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PostPosted: Thu Aug 10, 2017 5:21 pm
So the goal is to get some fenders mounted on my car (blended in )and I have a two questions .
1. What can I do to blend these fenders into the plastic rear bumper ?

2. I cut one side of my fenders about a half of an in too short (at an angle ) what is recommended to fill
I plan on bolting the fenders on, add a couple layers of fiber glass on top of fenders and car for bonding then bondo glass( 2layers) then some bondo filler to smooth it all out . Any suggestions WILL help me , even recommend some products to help me please.

(I currently hve , bondo filler, bondo glass, fiberglass cloth , and fiberglass resin that will only set in sunlight , and some gel coat .

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PostPosted: Thu Aug 10, 2017 10:43 pm
Uhhhh.....boy.....first....do you have any experience with doing body work? Just looking at your materials list, I'm guessing, no. Does the fender flare vendor include any instructions or refer you to an install video clip, etc? You are bonding 3 dissimilar materials here and it's in about the worst possible place for wear and tear. You should at least try to first identify your bumper plastic. You can go to the Learning Center at www.polyvance.com and that should tell you what that plastic is....next, CALL them and see what can bond that fiberglass to that plastic. You may not get an answer you like about that...as they may say that there is no permanent bonding agent usually for fiberglass to another plastic. Just guessing, they'll probably say an epoxy resin will be your best bet. As for mounting fenders flares like this what is normally done is the fender is taken down to bare metal (80 grit for me), the flare is trimmed a little on the "large" size and then I will use an epoxy resin with chopped mat to batter up the area, getting everything lined up with rivets. Once everything is hardened up I drill out the rivets, rough sand up (100 to 120 grit) the epoxy surface and add a second layer of epoxy/mat. Next, I do all of my final shaping of the flare for size, then start the regular filler work. Regular Bondo is not what I would be using for something like this. Evercoats Rage Ultra or Marson Platinum would be much easier to finesse and will have better flexibility if (more like when) these flares shrink/move. Working out your filler over the flares is a matter of blending out into the metal and continually guide coating to show what the "profile" looks like.
Again, I don't know how much experience you've got but flares like those would easily take me about 15 hours a piece until I got them to where I considered them "ready" for paint. And the bad news about this kind of work is still.....bonding dissimilar materials eventually results in failure....how long that takes....you just never know.....
Metal, wood, fiberglass, we work it all... www.furniturephysicians.com We can restore the irreplaceable!



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PostPosted: Fri Aug 11, 2017 2:58 pm
Is this a good example of what your explain to me ?? Using the epoxy on top fiberglass Matt for the bonding whole it's mocked up on the car?
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Based on your experience, what would use if you has to blend in the fiberglass on to the plastic bumper? A plastic filler or evercoat you mentioned ?
Thanks you for the tips, and product referalls . I have only made replicas of other fiberglass products.

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PostPosted: Fri Aug 11, 2017 5:48 pm
Yep, that's pretty much it.... just remember to remove the rivets before moving on to regular body fillers. If you don't those will be tension spots and will "ghost" through you successive coats of filler. Fill the rivet holes in with more epoxy and even feed a little mat over them as well. If you can get your fiberglass to attach to the bumper and the areas are grafting fairly shallow I'd use something like a super flexible glazing putty. I use USC's Pro-Flex which is about the most flexible of all the fillers you will find.
Please note I went back and edited this post..... It now says USC's Pro-Flex instead of Poly-Flex which is an Evercoat product. The USC product is what you want.....
Metal, wood, fiberglass, we work it all... www.furniturephysicians.com We can restore the irreplaceable!



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PostPosted: Sat Aug 12, 2017 8:11 am
You might even look into Lord Fusor adhesives. I recently bonded ABS to PP using a special Fusor glue that was meant for bonding dissimilar plastics. Not in service yet, but the bond seemed very strong.

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