Amaco Balsa Foam Carvable

[regular guy]

What are guys like Jimmy Flintstone using to make body shapes from scratch?

Our scale models need to be about 1/8 scale.

Anybody used this carvable foam?

http://www.hobbylinc.com/american-art-clay-balsa-foam-5-lb-3x4-5x5-art-and-craft-miscellaneous-43016t

[Ace-Garageguy]

Here's a link to the manufacturer's website, with more info.   http://www.amaco.com/t/mixed-media/modeling-and-mold-making/balsa-foam

I've used Balsa-Foam and a similar product called RenShape for many years, as well as a variety of other urethane and styrene foams, clays and machinable wax....though I suspect MOST of the resin model prototypes, as they're primarily modifications of existing models, were carved using materials like traditional Bondo and original kit parts.

RenShape foam:   https://www.freemansupply.com/products/machinable-media/renshape-tooling-and-high-temperature-work-boards

Edited February 11, 2017 by Ace-Garageguy

[comp1839]

i have used ren-shape. great stuff to work with. while it's soft enough to sand an file by hand it's dense enough to machine. the stuff i use is 440.

here's a project i started a while back but never really finished. '41 willy's pro mod. 1-8 scale.

[Dave Van]

Balsa foam is made up the street from me.......but they will not sell it there.....yet to try it.

When I stopped by to ask there was a chunk of it out back the size of a 1/1 car!!

 

Edited February 11, 2017 by Dave Van

[Ace-Garageguy]

Balsa foam is made up the street from me.......but they will not sell it there.....yet to try it.

When I stopped by to ask there was a chunk of it out back the size of a 1/1 car!!

Tooling foam in various densities is routinely used today to CNC-mill full-scale prototype parts and even entire bodies, on huge 5-axis machines. The technique saves a lot of the time previously required by styling studios to build wooden armatures and under-structure...and has replaced a lot of highly skilled craftsmen.

CNC milling of tooling foam can produce what's referred to as "near net" shapes, that require only relatively minimal finishing using traditional manual methods.

                                              

Edited February 11, 2017 by Ace-Garageguy

[regular guy]

Dave

Is that hand made or CNC?

I think the Amaco foam is worth a shot.

Seems like there's a blizzard of ways to make a shape on the net.

We're making 'one-off's' or originals so molds are out first time around.

Do use mold on final though.

Edited February 11, 2017 by regular guy

[comp1839]

i do not own or use a cnc. i did use the bridgeport to remove large chunks, you could easily do that with a good band saw. much of the work was done with a die grinder and some good carbides. i literally made a left and right side profile of the body on self adhesive art paper printed on a regular HP printer. pieced it together, roughed it in, and started grinding away. MAKE SURE TO WEAR A RESPIRATOR OR MASK OF SOME SORT! you will make ALOT of DUST. heavy sand paper(80 grit for roughing) and sanding boards will also be needed.  you can also make small chunks of the body and glue it together. stuff glues really well.

[Ace-Garageguy]

There are a lot of ways to use foam. This is a full-scale model of one of my own designs, and it's made with foil-faced foam for the backbone and ribs, and planked with urethane foam sawed into flexible strips on a table saw. A similar method could work for a smaller scale model as well.

And as Dave said, definitely wear a GOOD FITTING RESPIRATOR. A cheapo dust mask won't cut it.

                                                    

[Ace-Garageguy]

Even small pieces of scrap foam can be used for custom work. Here, pieces of scrap structural aircraft foam are being shaped to form corners of a rolled rear pan. The foam is then filled with epoxy or bondo, and sanded to final shape, primed, and painted.

Edited February 12, 2017 by Ace-Garageguy

[Ace-Garageguy]

You're not limited to expensive "tooling" foam either.

Below, I'm using cheap polyurethane refrigeration insulation foam to rough-sculpt some custom bits for a Jag E-type. After the shapes are close, the surface is fiberglassed, and a thin application of bondo is used to develop the final contours. You make molds at that point, and can reproduce as many copies as you need. This technique also scales down to work on models perfectly.

 

Edited February 12, 2017 by Ace-Garageguy

[regular guy]

Ace

http://www.hobbylinc.com/woodland-foam-sheet-1:4-x1x2-4-model-railroad-foam-st1422

Finally ordered this.

Going to see if it's 'sandable' first.

[Ace-Garageguy]

Ace

http://www.hobbylinc.com/woodland-foam-sheet-1:4-x1x2-4-model-railroad-foam-st1422

Finally ordered this.

Going to see if it's 'sandable' first.

The product listing states that it's "styrofoam" and can be cut with a "hot wire". This indicates it's probably closed-cell "beer cooler" foam, not really very easily sandable (as opposed to "open cell" floral styrene foam, which sands kinda OK).

Similar "styrofoam" was used as structural elements in the Rutan-designed EZ series of homebuilt aircraft.

Bear in mind that "styrofoam" is not resistant to polyesters (bondo) or lacquers or acetone.

Only epoxy can be used reliably for surface finishing.

[LDO]

Ace

http://www.hobbylinc.com/woodland-foam-sheet-1:4-x1x2-4-model-railroad-foam-st1422

Finally ordered this.

Going to see if it's 'sandable' first.

If what you ordered doesn't work out for you, I can send a few pieces of Renshape scrap.

 

[regular guy]

Ace

"as opposed to "open cell" floral styrene foam, which sands kinda OK"

So is Amaco and/or Renshape better?

Edited February 14, 2017 by regular guy

[regular guy]

LDO

Appreciate it.

Where can we get sample pack?

 

[Ace-Garageguy]

Ace

"as opposed to "open cell" floral styrene foam, which sands kinda OK"

So is Amaco and/or Renshape better?

RenShape and Amaco foams are both made specifically for tooling and sand and shape well for that reason. They were designed for tooling use, so they work better than other foams.

 

[Ace-Garageguy]

Where can we get sample pack?

$25 SAMPLE PACK OF RENSHAPE :   https://www.freemansupply.com/products/machinable-media-sample-kit

[regular guy]

Ace

I have to get over the 'sketching' hump to do some drawings..

Got a 'leaded line' to draw curves.

Also need to quit whining and slug it out with Turbocad.

Need drawings/plans first.

Edited February 14, 2017 by regular guy

[regular guy]

Have the Woodland Scenics foam from Hobbylinc.

http://www.hobbylinc.com/american-art-clay-balsa-foam-5-lb-3x4-5x5-art-and-craft-miscellaneous-43016t

It does look like closed cel (Walmart foam cooler).

Okay. Going to get the Amoco or Renshape next.

First body will be simple slab side with radiused edges or corners.

Like the Mickey Thompson Challenger 1.

http://www.hobbylinc.com/revell-monogram-challenger-1-with-mickey-thompson-figure-plastic-model-car-kit-1:25-scale-854918

Edited February 20, 2017 by regular guy

[regular guy]

Update.

Going to saw off piece of Woodland Scenics foam and test sand it and use a rasp on it.

Should find out right away how sandable it is.

Will order Amaco Sandable Foam sample soon.

Going to get some Bondo Wood Filler too.

I've seen that work for sculping.