View Full Version : Easy building with pink insulation foam!

Old Busted Hotness
10-04-07, 08:19 PM
Pick up a sheet at Home Depot (or Foam Depot, if you must). Owens-Corning Foamula R 150, comes in a 4x8 sheet, 2 inches thick, more than enough for several projects. Here's how you work with it:

Cut rough shapes with a click-knife or a hot-wire foam cutter (some hobby shops sell them in the train section). The hot-wire cutter gives a cleaner line and allows you to do some crazy shapes. Try cutting your name out of a block of foam!

If you have access to a belt/disc combo sander, so much the better. Make sure the shop-vac is hooked up to it. That helps with the rough shaping.

60-grit sandpaper does a fast job of shaping this stuff, but it makes an unholy mess. You'll have pink dust everywhere. Follow with 220 grit, dry.

Glue it up with foam-safe CA and foam-safe accelerator (not available everywhere; regular accelerator will work, but the heat generated can melt the pink foam. This isn't a disaster; you're going to cover it with epoxy anyway.

(not illustrated because I'm lazy)
Coat the foam with 20-minute epoxy mixed with Microballoons, and set it aside overnight. Wash your hands and go watch a good movie. Don't go back after 20 minutes and poke it to see if it's dry yet; it isn't. Microballoons will make the epoxy lighter and easier to sand, and it helps to hide the pinkness of the foam. This step is necessary to protect the foam from the solvents in the next step.

Afterwards, coat the cured epoxy with Bondo, Icing, or your favorite brand of filler. Sand as needed.

10-04-07, 10:15 PM
...... Someome say they wanted to build a dry lakes belly tanker??? Or maybe even a Deuce Coupe??? Thanks Busted! 1thumbup1

hot ford coupe
10-05-07, 12:11 AM
That's the solution I've been looking for. Thanks OBH. Great tip.

10-05-07, 12:55 AM
Yup Jeff! You could also make an engine block and heads from that stuff. Intake manifolds, valve covers, transmissions, etc. Maybe even carve out some tires. I'd love to get a sample of that stuff. 1thumbup1

10-05-07, 11:27 AM
I have been wondering about that stuff, but if it that messy, how different is it from floral foam?

Nice how to by the way.

Old Busted Hotness
10-05-07, 12:34 PM
Floral foam is more crumbly, falls to bits pretty easily. The pink stuff stays together really well.

One thing about sanding it, it has a "grain" like wood. And you can dissolve it with acetone, so if you used it to master a part, if any foam sticks in the mold it'd be easy to clean up. After sanding with 60-grit it has a nice cast-iron texture.

10-05-07, 05:03 PM
Busted is right, floral foam just doesn’t work that well, besides crumbling a lot easier it is very easy to dent and crush, besides that, it ends up being a lot more expensive than insulation. A 4 X 8 2in. sheet runs somewhere between $10.00 and $15.00, can’t remember how much I paid for one last year. They also come in thicknesses less than 2in. and are less expensive. There’s no way the full sheet would fit in my vehicle so I asked the worker to score and snap it into three pieces which he did…after I explained in detail what scoring and snapping was, it took awhile for that blank look to go away…sigh. I was buying some to build a small N scaled (1/160) railroad layout, still need some more track and accessories to do that sometime.

If you’re not in a hurry for gluing, Elmer’s works really good and sands just about as easy as the insulation, you can also coat the insulation with straight Elmers or a mixture of Elmer’s and white glue (which will take a couple more coats but will soak in a little more) and it will give a somewhat hard shell to the insulation if you want to protect some area from being easily damaged while you are working on it.

I’m going to try laying some fiberglass over the insulation and seeing how well that works after the installation is removed. If it works, it would be an easier way to make bodies with complex shapes like a 49 Merc or one of my favorite cars, a 40 Ford coupe.

hot ford coupe
10-05-07, 08:13 PM
Now you're talking my language, Slingshot. I want to use the foam as a buck so I can make some of those compound curves for those two cars plus a few more. The 40 Ford coupe both in deluxe and standard forms is also one of my favorite cars. No matter how stock the car is, it still looks like a hot rod especially the coupe. Same thing with a 49-51 Mercs. All you need to do is remove the emblems and put on a couple of fender skirts and you have a ready made lead sled. The place I really want to use the foam for is to be able to make the body parts for my 1/6 (yes, I said 1/6 1thumbup1 ) scale 49 Caddy or Buick. That's going to be a knockout.

10-05-07, 09:51 PM
Now that sounds like a great project! Not sure what happened in my post above, that was supposed to read 1/160 scale. Something really wild would be doing if one of my brothers favorite cars in 1/8 or 1/6, a 59 Caddy! We had a pink 59 Cadillac when I was a kid, what a great car.

Old Busted Hotness
10-05-07, 10:16 PM
I've thought about the 59 Cad, but damn there's a lot of chrome on that thing, and it just wouldn't look right done up in silver paint. Bare-Metal would look better, but still not as deep as aluminized plastic. I wonder if Chrome-Tech can plate this stuff?

Here's a body I did with Depron sheets. Same basic technique, different material.


It's not real good at releasing, if you want to make a mold with it. So you'd have to gelcoat the male buck and make fiberglass female molds, and make copies from that.

hot ford coupe
10-05-07, 10:46 PM
Wow, a 1/6 scale 59 Cad. I don't think I have enough plastic to make one of those. The 59 overall length was 225 inches and the 49 cad was about a foot shorter. That would make a 1/8 59 about 28 inches long. The tip of the rear fin would be 5.5 inches from the floor. Talk about an ambitious project. It would be cool though.

10-05-07, 11:40 PM
One thing I forgot to say, cutting and sanding insulation creates a lot of static cling and the insulation dust literally sticks to everything that doesn’t move fast enough! I wonder if a can of that static three stuff they have for the laundry would help?

The chrome on a 59 Caddy is definitely an issue! I have a can of the Krylon Chrome, I haven’t tried it yet but will be on my T build, hopefully it is good enough as that would simplify things a lot and would be tons cheaper than bare medal foil. A lot of the parts for it could be made out of fiberglass and/or using Busted’s method which would save a lot of plastic.

Getting WAY to many ideas for my own good here!

hot ford coupe
10-06-07, 06:28 AM
You're not getting too many ideas, sling, you're just becoming addicted to large scale modeling. I've seen this syndrome with these symptoms many times before. Take 2 styrene rods and call me in the morning.
Don has used some of the chrome sprays and I think he's had some success with it. He said when he dried it with a hair dryer, it got shinier. Hey Don, does the shiny last at all or does it fade back to dull?

Don Garrett
10-06-07, 05:47 PM
I'm sure it would fade...but I clear coat it and buff before it loses it's shine.....not perfect chome, but it's not expensive either. It doesn't work with all chome paints but we'll stumble across something eventually.

10-06-07, 08:25 PM
I am definitely getting addicted, and since it’s been very hard for me to build right out of the box since I was a kid, these large scales are really pushing my envelope, almost feeling like a rank amateur at times, just not used to thinking in these levels of detail and options for building. At least these 1/6 engines give a nice chance to build out of the box if you want. Picked up the Plymouth Hemi at Wal-Mart today to do just that.

hot ford coupe
10-07-07, 06:15 AM
I read a review of the Hemi Cuda in one of the model mags and they said it goes together really well. It's one of the better ones.

Old Busted Hotness
10-07-07, 12:53 PM
Just make your own engine. With a 4x8 sheet of foam you can build a whole fleet of 'em!


This is a first attempt. Those fins are nowhere near even.

10-07-07, 02:38 PM
Those Mickey T's look great! I knew that could be done. Thanks OBH. 1thumbup11thumbup1

10-07-07, 05:59 PM
I read a review of the Hemi Cuda in one of the model mags and they said it goes together really well. It's one of the better ones.

Thatís good news! At least I picked the right one for a change!

10-07-07, 06:01 PM
Just make your own engine. With a 4x8 sheet of foam you can build a whole fleet of 'em!


This is a first attempt. Those fins are nowhere near even.

Now that is really cool! What did you use to cut the grooves? The possibilities of what can be done with this stuff are almost endless.

Old Busted Hotness
10-07-07, 07:22 PM
Just a plain old X-Acto knife, with a fresh blade. Use a click-knife to cut the foam sheets.

08-26-12, 08:23 PM
sorry to start up old thred i just dint see point. well im wanting to try that pink foam but sence its solvible by acetone im wondering what could use as a pertectant on it sence i wanna layer it with glass. im wanting to make a trunk spoiler like off a 69 camaro and see what it looks like on a 65 mustang coupe model i have

08-26-12, 08:28 PM
i know the great stuff spray can expanding foam is solvible by acetone to but i know a hot rod builder used it in a trunk and then coated it with elmers and that worked. seems messy. would body filler work its solvible by lac thinner, could i do that then fiberglass?

08-26-12, 08:43 PM
Ive used high density insulation foam sheets (a bit pricey) to make fiberglass plugs..covers nice with glass and resin and you can scrape it out after it curses..carves well also but is a bit fragile when too thin but good for most all details..comes in 2" x about 36" sheets and should be available at most insulation shops..i used hot bondo to make thicker blocks....i got it here in chattanooga at a place called breeding insulation...

08-26-12, 10:09 PM
so bondo wont deteriorate the pink foam? thats what foam you were talking about? and neither does fiberglass resin

08-27-12, 05:31 PM
Its not the pink foam..Its a type of medium to high density type foam...Ill contact the folks that I got it from for the exact name and post it for you..I work for company that made concession go karts and bumper boats and such for the amusement industry for 20 years ..did lots of fiberglass work and found this stuff worked well..Ill be in touch...

08-28-12, 05:47 PM
You might try urethane foam for fiberglassing the old Popular Mechanix Magazine had a lot of
full sized auto & bike projects that used that stuff. And ol' Big Daddy Roth used plaster of paris to make a
lot of his body bucks.

08-29-12, 04:11 PM
I got the info I promised... The foam I used was called "poly iso urethane"....It is a limited production item now and the price has gone up by 5 times from what i was told..it was about 19 bucks a sheet 2" x 24"x 36" then.... wholly molly!!! ..the new stuff is called "thermasheath" and it is a 4 x 8 x 2" sheet with a real thin aluminum cover on one side for about 30 bucks..available at most insulation suppliers....could make a few thousand valve covers with that much...any urethane foam will work but some are not as fine as others grain wise....for all you east,west and gulf coast guys try your local surf board shop for scraps its a finer grain and carves and shapes well. I used to thin down my resin with acetone and reduced the amount of catalyst to coat the small stuff just to seal the foam and for the finer details i use a micro fine 2 part glazing putty its likea super fine bondo.
I hope this helps a bit or at least gives you a few options....oh, and its still messy....

Radio Control Trucker
08-29-12, 09:47 PM
Any idea is possibly a good idea. Thanks for the info.