fiberglass bumper materials

Alright I'm wanting to do my own custom fiberglass bumper.. I plan on molding the stock bumper and not making own from scratch or anything so what all do I need? I'm more concerned with what brand of fiberglass I should get.. I heard to stay away from Wal-mart brand... I want the stuff that wont crack and would do well on a body piece. Also, any tips you may have, feel free to let me know.

Thanks
-Jason

Well it's not so much the brand itself, but how long it has been sitting there. In most cases, the materials at Wal-Mart have been on the shelves for some time and may have lost some consistancy or have hardened.
Going to places where the resin and materials are more frequently bought helps ensure that your materials are not past their "use by" date.

Keep in mind though that there is debate on whether or not there is a use by date for most materials. I personally do not believe it too much myself. I'm sure that products do not stay in place for more than a couple of years (at least not in my city). I would prefer that we do not debate this, it was already done on another thread a few months ago.

As for tips, it's hard to say, I would just say that make your frame for the glass as strong as possible while making to to keep from distorting. Make sure you don't get any air bubbles and get rid of any that make it. lastly of course is to have fun.

Ganbatte ne!

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Never send your ducks to eagle school.
The difference between ordinary and extraordinary is that little extra.
The 3Ls of life: Learn from the Past, Live for the Present, Look to the Future.

Another quick question... Would it be a bad idea to use plaster of paris for a mold of the bumper? Seems like it'd be easier to me...

Thanks,
-Jason

It can be done, but not recommended. PoP gets VERY heavy for making a mold. It would be MUCH easier and much faster to use expanding foam (preferably AB foam if you have access to it) and carve the shape you want into that. Cover it with masking tape and foil. Then lay the glass over that. That will keep it lightweight for handling and much easier to carve those special shapes.

In summary, it could work, but try what you want. What I love about this industry is that the innovative people try new things and pass their knowledge along to others who refine the technique. A motto in the shop I work at: Adapt, Refine, and Modify.

Keep us up to date. Ganbatte ne!

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Never send your ducks to eagle school.
The difference between ordinary and extraordinary is that little extra.
The 3Ls of life: Learn from the Past, Live for the Present, Look to the Future.

Is the foam fine enough to pick up small shapes like bumper bolt holes and such? That's why PoP sounded niceee... lol

OHHH... I thought you would be taking a stock bumper and adding on to it. Here is what i would do then. I would use foam to form most of the bumper. If you get AB foam instead of expanding foam it should be good enough to roughly mold the bolt mounting locations and just a little bit of elbow grease will refine it to proper fit.

Another option is to use both materials. Just a little bit of PoP for the bolt holes (depending on design) and foam for everything else.

If the bolt holes are just for decoration (like bushwacker's flares) then it can just be done in foam. In the end it is all a matter of what you are comfortable with. What kind of design are you looking to do? I can help with planning if you like.

Ganbatte ne!

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Never send your ducks to eagle school.
The difference between ordinary and extraordinary is that little extra.
The 3Ls of life: Learn from the Past, Live for the Present, Look to the Future.

Honestly im just wanting to reproduce my stock steel bumper in fiberglass with the only difference being that the bumper bolts will be shaved (Cant see them from the outside of bumper) and Maybe fog light holes... Lol Pretty simple.. I can use all the help though

OOOHHHH!!!! >.<

Been there, done that... Well what I would do then is use the foam for the mold and cover the foam with a layer masking tape and a layer of heavy duty foil (spray glued in place) with masking tape at the seams. Then apply a HEAVY coat of mold release to the mold

I recommend molding the bumper from the outside So that way the outside fit is as close as possible to the factory fit with minimal work (ie after adding the bondo, primer and paint).

For primer, I recommend using epoxy primer as it will build up a much stronger surface for the paint to adhere to.

As for mounting tabs/locations, I would embed straps of metal into the layers of fiberglass as you build it up. Take a piece of metal like a piece of steel and position it to the mounting location as you build the mold. Before glassing to it in though, drill several small holes in the straps where it contacts the fiberglass.

Then when you finish the bumper to right before bondo, hold the bumper to the vehicle (best ot have a friend help you here) and mark exactly where you need to drill in the tabs for mounting to the vehicle. This will give you as close a fit as possible to factory and give the strongest hold.

After you have the holes drilled, give it another test fit to make sure everything is how it should be so after painting you don't have any surprises that could bite you in the rear. Once that is done, spray a couple of coats of zinc to it to prevent rusting (assuming you are using steel for the mounts, steel and zinc spray is cheap and easy to use. A good alternative to aluminum for this application; Also stronger).

This is just one way to get it done, I'm sure you can do it other ways with PoP involved too if you like. I just haven't really dealt with PoP for large molds. I just primarily used it for tweeter pods, etc.

If you do not have access to AB easily a good alternative would be low expansion Great Stuf (such as for windows/doors) It keeps a fair amount of detail for the mounting locations. Just let the layer of foam fully expand before adding the next layer. To reinforce the foam mold consider using lathe or thin rebar grids within the foam as it expands.

Well that's all I can really think of for now (4am here) If you have any other questions, please do not hesitate to ask.

ganbatte ne!

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Never send your ducks to eagle school.
The difference between ordinary and extraordinary is that little extra.
The 3Ls of life: Learn from the Past, Live for the Present, Look to the Future.

Wow thanks for all your help! One simple question though.. Where can I get AB foam? Would home depot have it? If so, where should I look? Is it really called AB Foam or does 'AB' stand for something else?

Thanks,
-Jason

Best to buy AB foam at car customization shops. I wouldn't expect HD or Lowes to carry it. But you never know. Ask for "epoxy foam" or "two-part foam" if they do not know what AB foam is. the AB stands for A-part and B-part for the foam. If they do have it, it would be most likely in the paint and chemical department.

Ganbatte ne!
Keiika

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Never send your ducks to eagle school.
The difference between ordinary and extraordinary is that little extra.
The 3Ls of life: Learn from the Past, Live for the Present, Look to the Future.