Cutting and shaping foam

[Anonymous]

I am planning to use the pink insulation (foam) as a base for building up the topography of my layout as well as a bridge or 2.

Is there an easy way to cut and trim this stuff? I tried an electric knofe but it didn't work very well at all.

Anny Suggestions??

Thanks,

Len

[Anonymous]

I have had the best luck with a serrated letter opener of all things. It has a very thin blade (VERY flexible), with very small serrations and is about 5" long. I believe that serrations are the important part. I also have an old steak knife that I use but it leaves things more ragged.

Steve

[mls1621]

First and foremost, have a shop vac handy to clean up the mess at regular intervals. No matter how careful you are, the styrofoam gets everywhere.

The best tool for rough shaping is a keyhole saw.

For fine tuning the shapes and adding subtle contours, get a cheap surform tool at the hardware store. It resembles a small cheese grater and grinds the styrofoam giving a good base for the covering plaster or sculptamold.

I suggest that you put a coat of neutral colored paint on the styrofoam prior to applying the plaster. It covers the pink and requires less plaster to cover it.

Hope this is helpful.

[orsonroy]

Actually, the best tool for general cutting of foam is a snap-blade boxcutter. It goes through foam like, well, a sharp knife through foam. I use sharp knives for any dimensional cutting, initial shaping, and cutting roadbed and drainage contours. Replace the blades often; foam has a tendency to dull sharp blades rather quickly. Replacing blades is cheap and fast; replacing fingers when you try to force a dull blade and it slips, isn't.

Hacksaw blades work well too. Keyhole saws are too short and too rough a tooth to do much good with foam, since the teeth have a tendency to break off pieces of the foam, instead of cutting through it cleanly. I use a hacksaw blade (no handle; it gets in the way) to cut precise and strange dimensions, when taking off large quantities of material on contours (the end works it's way through foam just fine), and when trimming up the edges of foam at the layout edge.

A shop vac is an essential tool when working foam, just as a tarp and sink are essential when working with plaster. With either method of scenery construction, stuff gets everywhere.

A Stanley Surefoam tool is extremely useful for making detailed contours. This is generally the messiest part of using foam, but the results are well worth it.

I also have various other hand tools lying around for cutting and shaping foam. I've found that hot wire cutters aren't worth the investment, so (almost) everything I use is a hand tool. I have an old bread knife that I use for rough contour shaping, a wire brush for carving stratified rock cuts, and a dental pick for scribing lines when carving retaining walls. Screwdrivers work well when you need to dig a large-ish hole in foam.

If you REALLY want to live on the edge, I have a pretty unconventional technique that I picked up from a theater design friend: a 3" wire wheel chucked into a power drill. It'll snow pink in your layout room while using it, but it's THE tool for professional foam carving. You can do almost everything with it, and it eats foam like nothing else. With a little practice, you can do extremely fine detailing work with it, and do it in no time. Since it's so messy, I generally only turn to this technique as a last resort. It's perfect for cutting riverbeds and shallow drainage ditches.

[snowey]

I've had sucsess with the WOODLAND SCENICS foam knife. It's an alluminum knife, about 4" long, with a round handle & an interchangable,removable blade about 2" long.

[Anonymous]

Hi all,

Are the electric wire foam cutters any good?

[orsonroy]

QUOTE: Originally posted by 2nd telegrapher leverman

Hi all,

Are the electric wire foam cutters any good?

Well, sort of. They do their job of slicing through foam well enough, but the wires break often, they don't like to cut through glues, they emit noxious fumes, and they're not very good at cutting strange angles. Frankly, if I were starting, I'd spring for a hot knife over one of the hot wire cutters. Hand tools are simpler to work with, don't require electricity, and can be used for more detailed work, which is why I only use hand tools.

[cacole]

A cheap serrated edge bread knife works well for cutting any type of styrofoam, and you probably already have one laying around the kitchen somewhere that can be used. Styrofoam leaves no residue of any type on the knife, so a quick washing can be done after cutting foam with it and no one will ever know it has been used for anything other than laying unused in the cutlery drawer.

[orsonroy]

True, but it's easier to buy a bread knife exclusively for layout use, than it is to duck a flying frying pan thrown by your wife when she finds out!

[Anonymous]

One word - 'dremel'

[orsonroy]

Two words: "never again!" I tried using a Dremel tool to cut gulleys, etc, into foam. I had it set at the lowest speed setting and was using wire brushes and sanding drums. The Dremel tool died on me, and had to be tossed. When I cracked open the case to clean it out, hoping that I could clean out the foam and get her running again, I found foam EVERYWHERE, even deep inside the commutators of the motor. No matter how much I did to try to clean it out, the Dremel was a complete loss. I now only use my cheap Black & Decker power drill for stuff like that.

[Anonymous]

I have always used the white 2" foam, but with it I use a razor blade knife for cutting small cuts, a skill saw for very long straight cuts, and for shaping rocks, hills, etc I use a drill with a wire brush attachment.

[Anonymous]

a mask would be a good idea also, so you don't inhale the fine powder when cuttingthe foam . it seem to go everywhere.

[Anonymous]

A wire brush is a good hand tool for final shaping of the foam. Get one with brass bristles, about the shape of a toothbrush only 2-3 time larger. You can find them in the plumbing section at Menard's, etc. - they use them for cleaning pipe threads or something.

Hot wire cutters are good for cutting out the initial shapes (yes, I know they get hot, that's why they call them that.) For cutting ravines, rivers, etc, I've taken a piece of 14-16 AWG bare copper wire, formed it into the shape I wanted, and mounted it into the ends of a soldering gun in place of the normal soldering tip.

[Anonymous]

Has anyone used 'spring wire' in place of the 16AWG copper wire? I'm looking for something that will hold its shape a bit better than copper wire.

Brian

[dano99a]

Foam cutting blade, buy em' at Sears for $1.49 it fits into a utility knife. Cuts foam really well, sand foam afterwards.

Wire brush and a bunch of different files and a dremmel tool work well together to shape and refine your foam to the way you want it. Sometimes I'll even use a belt sander to rough in basic forms with foam then go back into it with the above tools.

[eng22]

I tried the three inch wire wheel method described above and was verry happy. Makes a huge mess, be ready with the shop vac. Also, I used the keyhole saw, an old knife, a file, a razor, and a wire brush. I believe any work with foam will require a multi-tool approach, and that desired results will dictate the tool/method needed.

[loucad]

I have used a dinner fork for rough contours. The shape of the fork and the leverage can help you get some sizable pieces out of the way in a hurry. Don't overlook rough grades of sand paper, in small pieces, for those areas too small for a sureform.

[ndbprr]

I saw some guys web site where he made custom shape hot wire cutters which intrigued me. We use a hot wire cutter all the time in cutting the foams that go in packaging. It is a very fine stationary Nichrome wire and is very thin. the thinner the wire the less the smoke and we don't even ventilate it is so minimal. the key is to keep the foam moving at close to the point it bogs down. The longer you keep it in contact with a given area the graeter the chance of heavy smoke. The web site I reffered to showed a multistrand copper wire that was put in an electric soldering iron in place of the tip. In the area of the cutter he cut out all the strands but one and it worked fine. You can even bend it to a preffered shape like ditch contours and then just throw it away. Could be worth trying.

[n2mopac]

I have great success cutting nearly any contour with a hacksaw blade without the hacksaw. It is fine toothed and very flexible to cut curves and gulleys. I then smooth the contours with a wood rasp--I have one that is flat and one curved--and finally I sand it with150 grit sandpaper. I would reiterate two things said above: 1) have a vac handy--I run mine constantly with the hose near my work when I'm working with foam, and 2) wear a mask--the dust from this stuff is hard on the lungs in the short term and cannot have a good effect in the long term.
Ron

[Anonymous]

I used a form tool that i use for car body work. Works well for shaping and other things. It is about 7 inches long and about 2 inches wide.