Just got back from lowes... Picked up some polystyrene 3/4 inch foam...
Waiting for advice...
Once you make the shape out of foam I would put a thin layer of bondo on it to keep the resin from melting the foam. If you make edges on the glass you can use mold release wax on the part you make from foam and pull the fiberglass from the part and use it as a mold for more parts.
Anyone contacted wolfe lately, I haven't heard of him around...
Im making custom spoiler stands for a guy at the moment... Then from there a custom spoiler, decklid vent ferrari style, a nose mod... you name it... I've got numerous ppl comin to me for stuff...
Just tring to get as educated on these type of molds as possible...
Keep the info coming... Got any personal expierences...? post here...
Hmm.. I did something simlar, to make a subwoofer enclosure. But it was a 1-off part, so I 'glassed over the whole thing, then cut out the foam through the speaker hole. Kind of backwards from what you're doing! But I used the pink foam, it seemed to be much easier to cut / form than normal styrofoam, I kept getting the little foam balls all over the place from that stuff! Made it hard to get a nice clean edge too.. 3M super-90 spray adhesive seems to hold the foam together really well, and sets up in seconds. But yeah, just carve it up, coat it real good / smooth it, wax it, make some parting lines, then 'glass the heck out of it. Something that small you shouldn't have to worry about stiffening the mold with reinforcements, like you would when you do the wing. Good to see people making custom stuff! Keep it up...
------------------ Bob Williams Multi-colored '86 Mutt, a work in progress! (3800SC is installed and I was driving it... The Blizzard of '05 decided to drop 4,000 lbs of snow and steel on the roof, and bent it!!! Now it's parked... )
I thought I read somewhere that the resin would burn or melt normal polystyrene like the white stuff pictured. I have no experience with making anything with fiberglass, so maybe the experts can chime in.
you are correct... Thats the point of covering it with masking tape or something that stick to it (duck tape maybe) so that the resin won't eat through it... Correct me if Im wrong guys...
You're most correct. Polyester resin, the most common type used with fiberglassing, eats through polystyrene foam about as fast as gasoline does. So does polyester-based body fillers and putties, for that matter.
You're most correct. Polyester resin, the most common type used with fiberglassing, eats through polystyrene foam about as fast as gasoline does. So does polyester-based body fillers and putties, for that matter.
JazzMan
Covering the foam in duck tape would keep the resin from eating through the foam tho... right...?
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10:41 PM
Feb 1st, 2005
opm2000 Member
Posts: 1347 From: Versailles, Ky USA Heart of the Bluegrass Registered: Dec 2000
I guess that can be made to work, so good luck. But as close as you are to several FRP supply houses like Fiberglast, I don't know why you just didn't have a minimum purchase of two-part foam overnighted to you. It would be so much easier to work with, and your efforts would be spent refining the design instead of working around the melted or incompatable materials.
David Breeze
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06:06 AM
FieroBUZZ Member
Posts: 3320 From: Ontario, Canada Registered: Feb 2001
You can buy a spray can of the expanding urethane foam and fill a box to make a block. Carefull not to try to make it too thick all at once as the center will stay gooey.
I would recommend ordering a two part box disposable spray set than using cans -
www.mcmaster.com search for spray foam or i'd recommend PN 9325K47 its a one time use box od two part expanding spray foam weighing 1.75 pounds that will cover 12 sq ft 1" thick its $30 or you can get the bigger box sizes that can be closed and reused untill empty starting at 30lb (205sqft) $360
this is what I plan to use for my body alterations
(NOTE) they do sell cans too and per volume of foam it is a lot cheaper - just no fan spray action you would have to make many rows of single bead of foam
[This message has been edited by Kohburn (edited 02-01-2005).]
you are correct... Thats the point of covering it with masking tape or something that stick to it (duck tape maybe) so that the resin won't eat through it... Correct me if Im wrong guys...
~Tim
(bout time stevo chimes in ! )
I've known a couple people who used latex paint on the foam as the barrier layer
Years ago, I made front and rear fender flares for my Yenko stinger using foam as the base. I then covered the foam with wallboard mud, which, unlike plaster of Paris or spackle compound, can be reformed by wetting it. When the plug was the right shape, I sealed it with shellac. I used polyvinyl alcohol (PVA) as the barrier and release agent to take a female mold from the plug, and that worked fine. Good luck.
Years ago, I made front and rear fender flares for my Yenko stinger using foam as the base. I then covered the foam with wallboard mud, which, unlike plaster of Paris or spackle compound, can be reformed by wetting it. When the plug was the right shape, I sealed it with shellac. I used polyvinyl alcohol (PVA) as the barrier and release agent to take a female mold from the plug, and that worked fine. Good luck.
Would you happen to have any pictures of those flares ?
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06:20 PM
PFF
System Bot
Tom Piantanida Member
Posts: 527 From: Palo Alto, CA, USA Registered: Oct 2004
or email em to me at glassfabricant@gmail.com and I'll post em for ya... Thanx man...
BTW, I covered some of the rough shape of the 1 spoiler stand... Im gonna cover it totally with a few coats and hope for a warm day to start glassing... lol
If you use the pink or blue foam board insulation, you can use Epoxy resin which is better than poly resin and won't eat though the foam, but it is more expensive which is why people just use masking tape and poly resin, that's what I did with a custom sub box I built for a friend, worked pretty good. I used "pam" as a release, it worked, but didn't work as well as "real" mold release.
[This message has been edited by ds21 (edited 02-01-2005).]
What you have with your foam here, is a good start. On top of this, you might want to consider bondo, or spray insolation foam. With the type of foam you are using, it is not as dense. Therefore it will be harder to sand, and / or shape the edges to be exact to the original. Once you have filled the sides with spray foam for instance, you could easily use a hand saw or knife to cut the excess foam. Then simply sand down the edge until you get it right.
For your "mold" to not stick to the "plug", duct tape could actually work as a separation. I find the easier way is to coat the plug with a fairly thick coat of vasoline. Some people use spray on waxes, but I find that vasoline is alot thicker in general, and can be placed in alot of the places a spray can could easily miss.
Wallboard mud is great and so is lightweight spackling but the mud's best since you're not worried about weight. LAtex paint is always good unless it's the Quickdrying type. that usually has alcohols in it that will melt the foam. Tape works but you'll get your overlap lines in it. And last use the pink or blue foams for best results in a plug.
I'll use that blue / pink foam on my next effort...
So far The shape is kinda rough, and covered in latex (1 coat), Im not real pleased with it... So I'll probally start over with some of that other foam, and try covering that with latex paint...
Its actually latex (dover white, kinda like an almond color) we used it on the walls in our old house, dad was gonna throw it away today... So i snatched it... Seems to be working great..
We'll see how it goes... I gotta go get some of that other foam so I can shape it easier...
Ask your local glass supplier about bouyancy foam used in the boat industry. It is a green foam and can be bought in sheets or blocks. You can shape your part out of it and then cover it with a fibreglass laminate. After it has cured a sand down and a sprayed on coat of gelcoat with wax in styrene in it will give you a surface that is smooth and sealed. It is also a finished product when you dig the foam out. Alternatively you can cover the foam with one layer of glass and then use Qcell on it. Qcell is a filler that is very light and easy to sand. It is basically foam type bubbles mixed with resin. There is lots of other alternatives too such as wood to make plugs, bondo, etc etc.
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05:10 PM
NotAFieroAnyLonger Member
Posts: 4413 From: 75762/Texas/USA Registered: Dec 2003
I am like Aus, I use the green foam... You can get it pretty cheap at a florist or crafts store-in the fake flower section.. Sands easy and wont melt! I used the green foam for the widebody on the GT... Hot glued it in place-sand-and glass!
To the past two gentleman in the previous post (2 ppl on this forum i am very respectful of and would highly recommend their product / fabrications to anyone)
I know the exact foam you guys are talking about (didn't know it didn't ment though... nice )
I used to work in the horticulture area... (1st job i ever had was trimming plants, reproducing them etc.)
But yea, Im gonna get some of that stuff and try this Aus... Thanx alot (I'd give you 2 another plus if i could... But ya both already got 1 from me... )
Thanx again guys...
What about skitime, curly...? 2 other guys I respect alot on this forum... I wouldn't mind your input on this guys
~Tim Bonner
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09:40 PM
PFF
System Bot
Feb 3rd, 2005
NotAFieroAnyLonger Member
Posts: 4413 From: 75762/Texas/USA Registered: Dec 2003
how about making something that has to be solid on all sides? I wouldn't mind making like a ducktail type spoiler for my caprice but wouldn't know how to go about making it solid on the bottom. Figure i could possibly make a plug out of wood
something like on my MSpaint shop job here:
------------------ + an 88 Capirce 9C1 Police Package --Adam-- IM AOL: FieroGT5speed
I know the green foam your talking about too, That would be my first choice for the hard foam too, it sands so nice, I just can't find any cheap enough around where I live, the only palce I've found it is wallmart and fabric stores, do you think a flower shop would be cheaper or is there some place online to order from?
But I used the pink foam, it seemed to be much easier to cut / form than normal styrofoam, I kept getting the little foam balls all over the place from that stuff! Made it hard to get a nice clean edge too.. 3M super-90 spray adhesive seems to hold the foam together really well, and sets up in seconds. But yeah, just carve it up, coat it real good / smooth it, wax it, make some parting lines, then 'glass the heck out of it. Something that small you shouldn't have to worry about stiffening the mold with reinforcements, like you would when you do the wing. Good to see people making custom stuff! Keep it up... 
)
Sands easy and wont melt! I used the green foam for the widebody on the GT... Hot glued it in place-sand-and glass!
hehe... Are you gonna be able to see outta the rear window..?? 
