Fiberglass over foam?

**gork** · 08-15-2003, 06:20 AM

OK Well my dash piece is coming along very well. I have it all sculpted out of foam at this point (I squirted spray-in foam into the fiberglass mold I made of the dash and carved it up when it cured).

Now I need to cover the foam with something rigid that I can smooth out and paint. Fiberglass cloth will not work because of all the small angles and bends. I have experimented already with putting resin onto the foam, which works but is not particularly rigid. I also have a can of Bondo Glass fiberglass reinforced filler. What should I do?

1) Resin over the foam, let it harden, finish with fiberglass filler

2) Just put fiberglass filler on over the foam. Will this result in a nice, rigid part?

3) Use a couple layers of fiberglass cloth, small, tight angles be damned! Is this the only way to get a part that is strong enough?

I guess it might also be possible to use fiberglass body filler outside the foam, then wehn the filler cures, scrape out the foam and reinforce the INSIDE with fiberglass.. but it seems that that would likely result in me damaging my outside surface and not having the foam to put it back with...

Ideas?

**Skraggy_uk** · 08-15-2003, 08:44 AM

I think Petrol/Gasolene fill eat away a lot of polystyrene typew foams. Don't know what it does to self expanding foam though.

Might be worth a try. make blob of foam. When it has hardened, add some fibreglass paste to the top. Once that has cured succesfully (maybe leave it overnight if there is time), poor just a little petrol into the foam.
1) see if it eats the foam.
2) see if it eats the fibreglass.
3) if it eats the foam, don't get any of the gunk on you and near a naked flame.

Napalm is basically plastic foam disolved into petrol until it is thick enough to form a paste. It burns well, and sticks to anything it touches while burning.

**thenominous** · 08-19-2003, 06:16 AM

Originally Posted by Skraggy_uk

I think Petrol/Gasolene fill eat away a lot of polystyrene typew foams.

Petrol & polystyrene = napalm

**Skraggy_uk** · 08-19-2003, 06:19 AM

Thats what I said

"Napalm is basically plastic foam disolved into petrol until it is thick enough to form a paste. It burns well, and sticks to anything it touches while burning."

**gork** · 08-19-2003, 10:07 AM

Hahaha well I didn't pour gasoline in there to dissolve my foam, but I did remove it. Here's how it worked out:

1) I covered teh outside of the foam piece with a layer of Bondo Glass (The fiberglass-reinforced body filler)

2) I flipped it upside down and meticulously scraped out the foam with needlenose pliers and an x-acto knife.

3) I globbed some more body filler onto the back of the existing stuff. It's now very strong, but heavy. There are a lot of holes and stuff I had to slice away and will have to refill again.

I will post pictures of my whole thing after it's done (a week or two) so you can see what I'm talking about...

**Skraggy_uk** · 08-19-2003, 10:10 AM

Nah, should have have tested the Napalm making capabilities of expanding foam

**gork** · 08-19-2003, 01:07 PM

I fully expect that it would work. What I do not know is if gasoline will also eat away at recently cured body filler

Here are some preliminary pics. I am already a lot farther along on it (eg it's looking a lot better than these show) but I don't have pics posted yet.

Foam Original:

Covered in Bondo Glass:

First Rough Filing:

Foam Removed:

**Skraggy_uk** · 08-19-2003, 02:08 PM

Definatley coming along nicely.

**thenominous** · 08-20-2003, 05:23 AM

Sorry, I just read petrol and ploy and my inner child ran away with me!

/me off to make smoke bombs

**Skraggy_uk** · 08-20-2003, 06:57 AM

LOL. Yeah. Same thing here. Used to love ligting the corner of the plastic sheet that builders use as dampproofing.

As it burned, it would drip molten plastic, and as the burning drops fell, they would whistle and scream.

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