Hi everyone,
I am new to the forum, 1st post but have been reading and researching alot. I tried searching for some solid advice and feel like I am not finding it. Hopefully someone here is willing to answer my questions, here goes..
I recently purchased part of a FRP body kit "bumper extensions" for a Hummer H2. When they arrived there was two pieces of the corners that were broken off. Small, about an inch around that I need to fix.
I need to fill the pinholes and surface defects that are on the primered gelcoat.
If possible, I also want to reinforce the pieces on the back(backside is black primer over CSM).
And finally what I think will be the hardest part, I need to modify the ends of the pieces. The ends have like a 90-ish degree bend that matches and flows into the shape of the fender flares, and my existing flares are different then the body kits pieces. So i need to add onto this area.
Most of this work is relatively easy, I am just not sure of the correct materials and products to use to complete this. I possibly have a few more questions, but I figure these will get me started in the right direction.
Thank you in advance
John

John,
Any chance you could post a few pic.s of the damage first, and then possibly what you are trying to achieve with flowing those lines in?

I actually have been trying to figure that out. I dont have a computer. I took pictures with my iphone and still trying to figure out how to post them. Im not very computer savy. But Ill keep trying

[img][/img]

Okay, well that gets us started. On the chip you have I would simply tack that with a thick superglue, then build up some resin/and finally chopped mat on inside and outside to give it strength, sand to shape, fill-out with a 2k glazing putty and you are done. With the missing piece you could take some HVAC heavy duty aluminum tape and form it up from the inside and do the same lay up with some resin/ and finely chopped mat to bring it up to shape, sand and do the same thing in filling, feathering out.
I will need to see that contrast of the body part up against the vehicle to figure out that lay up extension. My initial thoughts are laying up some pink or yellow foam board to get the level you need, laying up your resin/mat on that, then simply dissolving the foam from the back. To get it to look right on the Hummer you probably could mount the piece in position and use a hot glue gun to hold the foam in place while you got the rough shape right on the vehicle. That is all a guesstimate at this point though.....

Okay, so nope, no modifying the TPO. So when I flip that pic. around it looks like you'll need a combo of a slice off of profile, then a build up material in front of that..... My way of doing that for myself would be laying up some foam from the local big box store (pink, blue foams work pretty good) and shape that profile out with files, rough grit sandpaper (80 to 100 is okay) and lay up my mat/ resin combo over that. You could even use that yellow insulating spray foam to build up the area. Only thing with that is it MUST be dissolved with some acetone when done as it can continue to off gas through the fiberglas causing paint problems. Materials can be as simple as some Evercoat glass mat and resin from your local Autozone, Pep Boys, etc. You could step up to West Systems epoxies but it's kind of overkill for something this simple. Try to find some videos on the subject.... look up "lost foam casting" or "lost foam fiberglas." If after researching a little more, you don't feel confident in doing the work just search out any Corvette or even boat shop at a marina and I'm sure they could do this for you. It should not be that costly. Fiberglas fab. like this is another one of those "acquired skills" like everything else in paint and bodywork. Some people work right into and some don't.
Hey, I just dropped on over to West Systems and found this.... It may help.....
http://www.westsystem.com/ss/the-lost-f ... abrication

Okay, this video is somewhat of "simplified" repair but it might help. And I did forget to mention that fiberglas resins will "eat" some foams so that's why this guy is using tape over the yellow foam in video. https://www.youtube.com/watch?v=CuHXM4KUrEY

Nice. Ok I totally understand what you are saying to do. I have already read alot about the lost foam method, it seems pretty straightforward. I work construction and used to be very into art, I just havent worked fiberglass yet. So I am really excited to get into this.
If u dont mind I want to pick ur brain a little more. The part of the bumper that these fiberglass pieces bolt to is made from textured tpo plastic. Because it has texture I was tossing around the idea of how to get the pieces to better match. And I think my only options are smooth out the plastics texture either by using some sort of flexible filler, or I think a high build primer may work, then paint. Or duplicate the plastic part in fiberglass. What do u think would be better?
The tpo part is about 1/8-3/16" thick. I took a close up of the texture, I can take a picture of the part but my snow plow is on the truck right now so its kinda hard to see. The piece doesnt have any difficult curves or lines its basically rectangular and houses the fog lights

Okay, yeah, I get the texture thing. Kind of a toss up, any of that should work as long as you are compatible and get good "stick" between stuff. You might want to go over to here... www.urethanesupply.com and read some of their tips on working plastics, fillers, etc.
If you can pick up your shaping skills as you go, absolutely no reason you couldn't duplicate the tpo parts in fiberglas as well. There's always lots of options with plastics and fiberglas. And on funny note here.... I could duplicate that texture I see in your picture on fiberglas just using Slick Sand poly primer and backing my gun off. It would be darn close... ha,ha....