Yep, I made the mistake of using plain ole white styrofoam for a plug for my dash mold. This is why not to do it:
As you can see, I had it all over the place. It has a lot of static, and sticks to everything. I hope it's not too bad for your lungs, because I am still hacking it up almost 4 hours later. Next time I will use a different kind of foam.
Kris
[This message has been edited by shop_rat45 (edited 08-01-2004).]
That and the fact that polyester fiberglass resins (like the bondo fiberglass resin) will attack the foam , melting it into a new shape I learned this in my r/c airplane days. Epoxy resins won't attack the foam like the polyester resins do. I found that the green floral foam (called aqua brick i think) isn't affected by the polyester but its extremely messy to work with and the only come in brick size dimensions( 3" ,6" ,10" )
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11:34 PM
naskie18 Member
Posts: 6258 From: Commerce Twp, MI, USA Registered: Jun 2002
It may be a while before I finish it, but I plan upon puting a layer of resin and fleece on it soon. I'll be sure to let you know how it works. The Fiero in the garage is my current project car that the dash is going into. I don't really have a design on paper, just some ideas in my head. We'll see where it goes from there. This is my first major fiberglass project. I'm excited to see how it's going to turn out.
Kris
[This message has been edited by shop_rat45 (edited 08-01-2004).]
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11:49 PM
Aug 2nd, 2004
Spyhunter Member
Posts: 1254 From: San Francisco, CA Registered: Feb 2002
Latex will work, just seal the foam good. You can also use tape or plastic wrap like you use in the kitchen. It might wrinkle a littlebit but it wont melt....good enough for one-offs.
I also used the foamstuff that comes in a spraycan.
good luck.
[This message has been edited by Fie Ro (edited 08-02-2004).]
blue construction foam is what i usually use for mold cores - just make a hotwire foam cutter setup to cut out the main shape before using any sort of grinding/shaving/sanding action
as for the green floral bricks - those are really good for small object because you can form them with your hands without removing material.. they "crush" and hold the new shape
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07:36 AM
Fie Ro Member
Posts: 3735 From: Soest, The Netherlands Registered: Sep 2001
My mom is a florist and used the green foam a lot, she had big boxes full of that stuff! It might be easier to work with the green foam when you soak it in water first. Yes you can crush it nicely too. Then make the shape and let it dry when finished. I want to try that sometime...
I also used the finer density blue foam (see pic above) it is easier and better to make fine shapes from that then the rough white styrofoam.
pink should be the same only a different thickness and thus R value for insulating the key is to make a hot wire cutter for your main shaping.. basicly a peice of nickle/piano wire with a 9-12 volt wall transformer heating it - you can shape it for thicker wire - or just pull it tight on a little wooden bracket
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11:44 AM
Fie Ro Member
Posts: 3735 From: Soest, The Netherlands Registered: Sep 2001
The blue stuff is hard too find...I got some leftover pieces from someone who makes props and decors for TV productions.... Fiberglass specialized shops should offer resin-resistant foamboard for mold making but it is more expensive (but it might also save you a lot of time)
When you make bigger parts I advice to build a wooden support structure first, and glue the foam on it. It will maintain a better shape and you'll need less foam(board).
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12:24 PM
spddy Member
Posts: 815 From: Concord ,ca usa Registered: Mar 2003
Foam as used by homebuilders in the aviation hobby can be found at http://aircraftspruce.com or http://wicks.com this foam is used for "moldless forming" of airplane parts. S.Williams
------------------ 1988 Fiero Formula T-tops CJB 143 of 1252 "factory T-top cars"
Foam as used by homebuilders in the aviation hobby can be found at http://aircraftspruce.com or http://wicks.com this foam is used for "moldless forming" of airplane parts. S.Williams
man i should have thought of that - good sources - i have a few books on homebuilding airplanes
An easy source of power for the hotwire foam cutter is an auto battery charger. I use a battery charger , just hook the leads to each end of the wire and turn it on.
I've used the pink foam from the home depot... I can tell you with 100% certainty that it does melt when in contact with resin. However, the higher density allows intricate shapes, and now I always cover the foam with latex paint. It's just not worth the risk of having to build the mold again
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02:30 PM
PFF
System Bot
ryan.hess Member
Posts: 20784 From: Orlando, FL Registered: Dec 2002
An easy source of power for the hotwire foam cutter is an auto battery charger. I use a battery charger , just hook the leads to each end of the wire and turn it on.
I've used a small trickle charger (1.5A) as well, when I needed to be able to "sculpt" free-hand without having a bow get in the way of the work.
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02:31 PM
Wholf Member
Posts: 379 From: Cleburne, Texas Registered: Mar 2003
I had no problem with the white foam as you can see here in this thread https://www.fiero.nl/forum/Forum1/HTML/041114.html I used a fan pointed at me to blow the foam away from me I did cover everything with some cheap masking tape after I got the shape.. Here is a picture of the finished product. ------------------ Photo Gallery Harold 308 Rebody on 85GT Chassis Custom 2000 Firebird Interior 3800SC 3.4 Pulley w/WCF Headers & Reprogrammed PCM Complete Suspension & Brake Upgrade
[This message has been edited by Wholf (edited 08-03-2004).]
I learned this in my r/c airplane days. Epoxy resins won't attack the foam like the polyester resins do. I found that the green floral foam (called aqua brick i think) isn't affected by the polyester but its extremely messy to work with and the only come in brick size dimensions( 3" ,6" ,10" )
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