sgraber
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| posted on 4/6/04 at 08:23 PM |
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Plug fabrication - fragile foam?
I plan on adhering strips of polystyrene foam (the stuff coffee cups are made of) between each of the ribs of my plug and cutting those to shape with
a hotwire. Then covering the entire structure with drywall filler, sanding, and hi-fill primer to finish at 600 grit. Similar to Alan's Meerkat
plug construction method except Alan started with a hardboard sub-structure.
I am thinking that the end product may be too fragile to pull a mold from since it will be filler directly over foam.
Do you think that I should encase the foam under a single layer of fiberglass cloth (6oz) before moving on to the drywall filler?
Here's where I'm at:
 
4 Ribs on car - Bodywork
Steve Graber
http://www.grabercars.com/
"Quickness through lightness"
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Mark Allanson
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| posted on 4/6/04 at 08:39 PM |
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Dunno, but its the biggest CD rack I have ever seen
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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JoelP
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| posted on 4/6/04 at 08:49 PM |
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how thick will the end layer of filler be? if its over 1cm i feel it would be ok. how about putting some batons in between the ribs, to add some more
firmness?
looking good anyway!
Beware! Bourettes is binfectious.
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Mark Allanson
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| posted on 4/6/04 at 09:20 PM |
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seriously, try some thermoplatic packaging wrap, staple it to the formers, wave a heat gun at it and in a few seconds it will be as tight as a drum -
very smooth too. you can get it from packaging wholesalers
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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sgraber
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| posted on 4/6/04 at 09:34 PM |
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quote:
Originally posted by Mark Allanson
seriously, try some thermoplatic packaging wrap, staple it to the formers, wave a heat gun at it and in a few seconds it will be as tight as a drum -
very smooth too. you can get it from packaging wholesalers
hmmm - interesting thought there Mark. I am thinking that the Drywall filler will not stick to the thermoformed plastic.... How to get proper
adherence then?
Graber
Steve Graber
http://www.grabercars.com/
"Quickness through lightness"
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stephen_gusterson
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| posted on 4/6/04 at 10:12 PM |
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I wonder if you can adapt model aircraft techniques.....
they cover the structure with tissue and then use dope (nowt druggy) over it that makes it go tight and firm.
Would be too delecate for your mould, but I wonder if some other tissue type substance could be made to do the same..... I wonder if grp tissue would
shrink in the right way if used with aircraft dope......
atb
steve
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sgraber
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| posted on 4/6/04 at 10:15 PM |
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To clarify, we are talking about deleting the styrofoam step and using a thermoformed skin (or some other skinning method) that is then covered and
shaped by filler (drywall mud) to final shape?
The thing about foam is that although it is soft and spongy, at least there is some rigidity when applied between all the ribs. It's the
spongyness that worries me.
Steve Graber
http://www.grabercars.com/
"Quickness through lightness"
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stephen_gusterson
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| posted on 4/6/04 at 10:21 PM |
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summat like this?
http://www.jperkinsdistribution.co.uk/list.php?subcat=58&cat=Solarfilm%20products&Navmain=Covering
prob too delicate, but there must be something heavier weight...
[Edited on 4/6/04 by stephen_gusterson]
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crbrlfrost
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| posted on 4/6/04 at 10:44 PM |
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A few cents worth of ideas. One way I've seen small molds done is using a water based latex exterior paint over the polystyrene and then using
body filler. A larger mold (full car body) filled the space in between the formers with rigid foam (though I'd guess styrene would probably be
acceptable given the following step) and covered it with CSM and then body filler. I know that made for a very hard shell that they pulled molds off
of. At least on this side of the pond we can get urethane foam insulation from home supply stores for very similiar price as styrene, and
doesn't break down to the polystyrene resin. Otherwise you;d be stuck with using epoxy and the ensuing price. One guy I spoke to said he'd
never use plaster again, and I can see where the difficulties lie, but hey, its dirt cheap and leaves a nice surface. Just a ton of work. Can't
wait to see it done though. Cheers!
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pbura
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| posted on 4/6/04 at 10:47 PM |
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I was pricing styrofoam once, and was surprised that it is not so cheap! If you haven't bought yet, you might want to consider pour foam. 40
cubic ft of 2 lb. density ought to be plenty, and easier to work with than styrofoam:
http://www.fiberglasssupply.com/Product_Catalog/Pour_Foam/pour_foam.html
Mark's shrink plastic would be a cool way of sealing off the bottom of your forms for pouring.
A layer of FB cloth over the foam would be cheap insurance, IMO.
The form's looking great! 
Pete
Pete
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Viper
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| posted on 5/6/04 at 12:21 AM |
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quote:
Originally posted by stephen_gusterson
I wonder if you can adapt model aircraft techniques.....
they cover the structure with tissue and then use dope (nowt druggy) over it that makes it go tight and firm.
Would be too delecate for your mould, but I wonder if some other tissue type substance could be made to do the same..... I wonder if grp tissue would
shrink in the right way if used with aircraft dope......
atb
steve
blimey, havent used tissue and dope since i was a kid, nearly allways solarfilm or fiberglass now days oh and the odd brown paper job too
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Viper
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| posted on 5/6/04 at 12:23 AM |
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blue foam makes for a good master, easy to shape too, made a few model aircraft from the stuff, worth a look at.
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sgraber
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| posted on 5/6/04 at 01:09 AM |
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I have not been able to source the blue foam (Dow/Corning) anywhere locally. Can anyone (state-side) give me a place to go for this stuff?
Pete, the pour foam would be cool, but it is $180. I have to calculate how much the styrofoam will cost. Maybe it will be more?
If I glue the styrofoam to the ribs with liquid nails, then hot-wire it to rough shape and finally cover it with drywall mud, I shouldn't have
to worry 'bout needing epoxy resin for my mould? The underlayment of styrofoam would be encapsulated by the drywall mud and the primer coats...
Am I missing something here?
Steve Graber
http://www.grabercars.com/
"Quickness through lightness"
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pbura
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| posted on 5/6/04 at 02:47 AM |
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The pink stuff should work just as well. Home Depot has a sale right now, 3/4" X 4' X 8' for $10.45. This is only 2 cubic feet
Really, I think your best bet is going directly to manufacturers, industrial and trade distributors, etc. Your sale will be peanuts to them, but
I'll bet somebody will be glad to help. There are polyurethane pour foams used for insulation, packaging, landscaping, etc., so hopefully you
can find something Locost. Be sure to specify ridgid foam, and you may want to ask about fumes from hot-wiring.
Found this list for your area:
Plastics - Foam
Biofoam Corp
3035 N Maple
Mesa, AZ 85215
(480) 854-7000
Custom Packaging Products Inc
5601 S 24th St
Phoenix, AZ 85040
(602) 232-2747
Excalibur Enterprises
8813 N 55th Dr
Glendale, AZ 85302
(623) 939-6107
Foam Block Construction Co
501 E Plaza Cir #4
Litchfield Park, AZ 85340
(623) 935-5428
Foamex
4011 W Clarendon Ave
Phoenix, AZ 85019
(602) 233-0528
Glacier-Cor
4300 N Miller Rd #243
Scottsdale, AZ 85251
(480) 947-2128
Highland Products Inc
43 N 48th Ave
Phoenix, AZ 85043
(602) 484-9331
Masters Technology Inc
6610 N 57th Ave
Glendale, AZ 85301
(623) 937-4495
Nesco Manufacturing Inc
1510 W Drake Dr
Tempe, AZ 85283
(480) 756-6675
Phoenix Building Products Inc
1004 E Vista Del Cerro Dr
Tempe, AZ 85281
(480) 317-0588
Preferred Packaging & Contnr
3330 W Cocopah St #1
Phoenix, AZ 85009
(602) 272-2040
Schaumaplast Precision Foam
101 S 30th St
Phoenix, AZ 85034
(602) 275-5524
Southwest Ice Block Inc
501 E Plaza Cir #4
Litchfield Park, AZ 85340
(623) 935-5428
Swd Urethane Co
222 S Date
Mesa, AZ 85210
(480) 969-8413
Tharco
640 S 51st Ave
Phoenix, AZ 85043
(602) 233-1331
United Coatings
2465 S Industrial Park Ave #1
Tempe, AZ 85282
(480) 966-8999
Western Insulfoam Corp
3401 W Cocopah St
Phoenix, AZ 85009
(602) 269-2272
Wincup Holding Inc
7980 W Buckeye Rd
Phoenix, AZ 85043
(623) 936-1791
Pete
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MustangSix
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| posted on 5/6/04 at 03:09 AM |
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Steve,
how about tacking some wire mesh screen over the framework first? A roll of the aluminum screen material would be pretty cheap and might provide the
added support you need for that thin foam.
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stephen_gusterson
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| posted on 5/6/04 at 10:34 PM |
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tissue and dope sounds like a druggy perve occupation dunnit?
Same here - not made model planes for ages
atb
steve
quote:
Originally posted by Viper
quote:
Originally posted by stephen_gusterson
I wonder if you can adapt model aircraft techniques.....
they cover the structure with tissue and then use dope (nowt druggy) over it that makes it go tight and firm.
Would be too delecate for your mould, but I wonder if some other tissue type substance could be made to do the same..... I wonder if grp tissue would
shrink in the right way if used with aircraft dope......
atb
steve
blimey, havent used tissue and dope since i was a kid, nearly allways solarfilm or fiberglass now days oh and the odd brown paper job too
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sgraber
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| posted on 6/6/04 at 03:23 AM |
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Wow Pete, that's a good list. Please don't tell me you googled it! I'd be embarassed. heheh I went to H Depot and didn't see
the pink stuff. What department is it in? Not construction materials. At least not in Phoenix, but maybe it's a regional thing.
Jack, do you mean put wire mesh underneath the ribs to hold the foam in place? Not sure what you mean actually. The foam I am thinking about is
like long solid blocks.
Steve Graber
http://www.grabercars.com/
"Quickness through lightness"
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Cita
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| posted on 6/6/04 at 06:32 AM |
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Why not try to use the stripwood concept as used in yacht construction.
Narrow strips of 1/8 plywood can be glued and stappled to the formers, fill the gaps with wood filler and sand smooth.
Final surface finishing can be done with plaster.
It's a time consuming procedure but it's cheap and gives a strong rigid surface.
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Peteff
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| posted on 6/6/04 at 09:14 AM |
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Get some polystyrene packing like they use in TV boxes and cut them down. PVA glue them with the flattest side up between the ribs to take up some of
the volume and add some rigidity without too much weight, then use the expanding stuff to fill in the rest. The stuff you are looking for is sold by
Dow as "extruded styrofoam billets". Type it in google, you should find a supplier.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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pbura
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| posted on 6/6/04 at 11:33 AM |
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quote:
Originally posted by sgraber
Wow Pete, that's a good list. Please don't tell me you googled it! I'd be embarassed. heheh I went to H Depot and didn't see
the pink stuff. What department is it in? Not construction materials. At least not in Phoenix, but maybe it's a regional thing.
Nah, it was from some online Yellow Pages (commercial phone directory for UK readers).
Come to think of it, the pink board has limited usefulness even in my area. I put some under a wood floor on a concrete slab porch once, but
can't think of anywhere else I'd use it. May be NFG in AZ because of termites, which are not much of a threat here.
One thought I've had for filling the gaps is to cross-brace between the profiles, staple chicken wire 1/2" below the surface, and fill
with plaster. I'd think that this would be very fragile, though (wouldn't dare moving it without many hands), and that you'd only
get one shot at making a mold.
Pete
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TheGecko
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| posted on 6/6/04 at 01:46 PM |
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Pete,
I can see what you're getting at - if I could find my copy of "Glass Fiber Auto Body Construction Simplified" (ISBN: 0966713303)
I'd scan one of the diagrams in it which shows exactly that process: ribs, braces, chicken wire, hessian, plaster, death from
frustration....sorry, finishing You would use a LOT of plaster and it would be HEAVY and FRAGILE.
Steve, surely you've seen the Televante project? It's linked off Alan B's pages. Although
he's abandoned the project now, there's some details of his use of pink foam and plaster finishing materials. The results look quite
good. Look in the Body/Buck sections.
Good luck
Dominic
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sgraber
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| posted on 6/6/04 at 03:15 PM |
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Hey Dominic, I had seen that project (Televante) before and thought it was well documented. Too bad he quit. It would have been nice I think.
PeteF, I need to find someplace locally that receives lots of product in styrofoam packing and then recycles or discards it.
PeteB, Using chicky wire and plaster does not sound like fun to me!
Thanks though guys. This is conversation VERY helpful to formulating my plan of action.
Graber
Graber
Steve Graber
http://www.grabercars.com/
"Quickness through lightness"
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pbura
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| posted on 6/6/04 at 06:04 PM |
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quote:
Originally posted by sgraber
PeteB, Using chicky wire and plaster does not sound like fun to me!
No, it sucks!  Just trying to think about how to get around the need for filler. I think I'd most rather work with pour foam myself, with
second choice being billets and third being sheets.
The price of foams of all kinds is shocking. It shouldn't cost any more than about 50 bucks for fill material for this job, but either pour
foam or sheet insulation (if you could get it) would be about $200  Outrageous!
Wish you good luck with the local companies. Never pay retail!
Pete
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Hugh Paterson
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| posted on 6/6/04 at 07:41 PM |
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Ah nutsack to all that grief foam, plaster,
MDF, latex,..... bahh humbug, have a decko for some C-flex save yerself lots of grief, or if u want the cheapskate version whats wrong with a single
skin of csm easy sand bodyfiller and a couple of tins of durabuild. If yer gonna do it do it right
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Wadders
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| posted on 6/6/04 at 08:20 PM |
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Slap a coat of PVA Bond on to it (watered down PVA wood adhesive) anything sticks to that.
hmmm - interesting thought there Mark. I am thinking that the Drywall filler will not stick to the thermoformed plastic.... How to get proper
adherence then?
Graber
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