Fiberglass shape forming....

[Jbird]

Well I'm at it again, I guess the hood wasn't enough punishment.
I've been toying with the idea of making a fiberglass dash for Ugbugly. I've watched a couple of TV shows where a guy stretches some kind of fabric over a wooden frame then brushes resin into it. When the resin sets up he has his desired shape then lays glass mat and resin into it to get strength and a thick enough surface to use filler and sand paper on.

  Does anyone know what kind of fabric is used in the first step. It seems to be real stretchy and actually soaks up the resin. I think I may change Ugbugly's name to itchy *.
           Jbird

[EMSjunkie]

  Does anyone know what kind of fabric is used in the first step. It seems to be real stretchy and actually soaks up the resin. I think I may change Ugbugly's name to itchy #####.
           Jbird

The guy how does our body work uses
cotton tee-shirt material.

he is making me a box for a 12" sub-woofer.

Vance

[unklian]

I think I'd rather carve the shape I wanted out of foam,or plaster,
then lay up the glass on top of that,instead of hoping
the fabric would stretch the way I wanted.

[jaybee]

I had heard sweatshirt fleece, but T shirt material sounds at least as good if not better.  Once the resin-saturated fabric cures they cover it with additional layers of fiberglass mat to give strength.  I'm pretty sure there are people here who have done some work in this technique.

[Jbird]

I guess I'll have to make a trip to the fabric store. I tried using styrofoam, to get the basic shape for my hood. A friend works in a shop where they make those stucco covered styrofoam pillars, he got me two big blocks of foam and let me borrow his special hand saw and a couple of 12 grit sanding blocks. I spent a couple hours shaping the hood and another hour sweeping up tiny pieces of foam. I layed one light layer of mat and resin on my mold and went home. The next morning when I checked my hood, the glass had eaten into the foam. Droop city. I found out later polyester resin eats styrofoam, epoxy resin won't but it doesn't laminate very well. I ended up using some thinnish plastic sheets bent into shape then layed mat and resin over them. The plastic sheets peeled right off the cured glass. I laminated the newly formed pieces into the frame I made with my new invention, angle glass. Angle glass is mat and resin layed over or into a long piece of angle iron sprayed with mold release. Comes in real handy for making long straight edges.
          Jbird

[EMSjunkie]

Jbird, I talked to our body guy, he told me
his kid brother bought a video from E-bay
that shows step by step how to make the
forms. he said its really simple.

look in E-bay motors, under electronics.
they advertise them there.

good luck.

hope you wear a respirator when working with the resin  


Vance

[WZ JUNK]

I have used the white foam that you speak of with some success.  I cover it with plastic cling wrap that you use in the kitchen.  The heat from the hardening of the glass will distort the foam some but by the time it does, the glass has already taken its shape.  For small parts I buy the green floral foam at Hobby Lobby.  It is very easy to shape and the resin will not attack it.

If you go to the site about the changes to our Bonneville race car there is a picture of the green foam piece I used to shape the front of the scoop under the snout.

http://purplesagetradingpost.com/sumner/hooley/hooley-construction-2005-1.html

[Bruce Dorsi]

I found out later polyester resin eats styrofoam

Experience is a great teacher, isn't it?  

Styrofoam can be used with polyester resins if you seal the styrofoam with a couple coats of latex paint.  ...The resin vapors will attack any exposed styrofoam as well, so seal all surfaces, even those not being glassed.

WzJunk's suggestion of plastic cling-wrap is also effective.

[unklian]

You can also use white glue to seal foam or plaster.

[bcal]

What you are supposed to use is polyurethane foam.
It's usually green and very easily shaped though quite messy when doing so.
Lay the glass right over the top of it and then dig it out once cured.
I've heard of people dissolving it in petrol but haven't tried that one.
Go to my weblink and you see some examples of it's use.

[Leon]

I've heard of people dissolving it in petrol but haven't tried that one.

I used that technique years ago when I made an aux tank to go into a sidecar rig.  The gas worked great to disolve the foam, since it was a tank there was no way I could get into it to dig out the foam.  Had to seal the inside afterwards to make sure the gas didn't hurt the 'glass.

[Jbird]

Thanks for all the advice guys. I think I'm gonna get the video and try the T-shirt fabric method.

   I've come to the conclusion that some people(me in particular) shouldn't be allowed to play with loaded spray guns. here are some before and after pics of Ugbuglys' new nose. I sprayed on and sanded smooth what seemed like twenty coats of satin black lacquer in 90+ heat trying to get a decent enough finish to polish out. I think it's time to cash in on the favor one of my painter buddies owes me.