Project Fiberglass fenders

[spencevans]

Now that I have wider axles and wider tires on my Mitsubishi, I am in need of some flared fenders. I have a set of John Baker fiberglass fenders I am going to add some foam, sculpt, add some bondo, sand, sand, sand, wax, take a mold, and then make the 6" wider fiberglass fenders. Here are some pics



Adding the foam. The brand is "Dow for large gaps". Comes in a black can at Home Depot. You can only add a bit at a time so it cures correctly. Also it helps that it's hot, this stuff doesn't cure when it's cold. It takes several days to get to this point. Next I will start to sculpt with a 6" razor knife.:greg:

 

[MikeGyver]

This should turn out pretty cool. Make sure you coat all the foam with bondo. I tried making a fiberglass minibike gas tank from sculpted great stuff foam and skipped the bondo; the fiberglass curing heat ended up warped the foam very badly.

 

[Chevycrew]

I used to make the patterns for fiberglass tubs and showers. Foam never held up enough to make molds for us.

We used high density fiber board for the major structure, then bondo, then primer, then wet sand, buff and polish, then sealer, then mold release. This was all built on a 3/4" plywood grid with 12" squares, 12 inches deep (picture a bookcase 12" deep, then with shelves 12" apart, and dividers every 12") The HDF was fixed to that, then the pattern built on top.

Our molds would then be built on this. Molds would be 1/2 to 3/4 of an inch thick, with a gypsum filler in the glass. The same type of plywood backing structure would be added, and glassed into the mold.

We would still have minor amounts of shrinking and warping.

The part was first layer of gel coat, then chopped glass, then anything for structure. I would shoot for a 1/4" part thickness.


This was on a professional level, I just wanted to share my insight. Any questions, fire away.

 

[spencevans]

I carved a rough shape of the finished product. I plan to add multiple layers of bondo. I want to do my best to prevent warping, so the bondo will be atleast 1/4" thick.

 

[4x4_Welder]

A Stanley Surform tool is your friend for carving that foam. It makes debris that just goes everywhere, but gives a very nice final product quickly:
http://www.stanleytools.com/default...=21-115&SDesc=7-1/4"+Surform®+Shaver

 

[spencevans]

A Stanley Surform tool is your friend for carving that foam. It makes debris that just goes everywhere, but gives a very nice final product quickly:
http://www.stanleytools.com/default...=21-115&SDesc=7-1/4"+Surform®+Shaver

Yeah, got one of those. I just call it the cheese grater.


I am now working on bondo.

I am getting alot tips and pointers from a fiberglass buddy, hopefully he will also help me make the molds.

 

[*jrwiii*]

Please keep updated pictures on the process of making the fenders and molds. Who is doing the fiberglass for you? This is very interesting...

 

[TEAM FRED]

Please keep updated pictures on the process of making the fenders and molds. Who is doing the fiberglass for you? This is very interesting...

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