tomikawaTTSomeone once told me it's possible to make a hot cutter by shaping heavy copper wire and screwing it into the bitholders of a high capacity soldering gun.
It's not uncommon for model airplane wings, especially long sailplane wings to be formed from foam using airfoil templates for accuracy. A slot for a spar can easily be cut using the above approach.
A u-shaped wire with horizontal bends to control the depth is fixed into a soldering gun. wood guides are laid temporarily across the surface and the motion should be smooth and rapid. The thickness of the slot may be wider than the shape of the wires and must be accounted for.
There are commercial units shaped similar to coping saws. I assume these are good for rough shaping and would avoid the mesh as others commented on.
I just tried using acetone on rag to shape the edges of foam and thought it can be a good way to shape foam: smoothing edges and making depressions. While wiping can work, it seemed just pushing the damp rag against the foam did a good job. An advantage is no mess.
greg - Philadelphia & Reading / Reading
The mind is like a parachute. It works better when it's open. www.stremy.net
tomikawaTTSomeone once told me it's possible to make a hot cutter by shaping heavy copper wire and screwing it into the bitholders of a high capacity soldering gun. No reason it shouldn't work. but the idea doesn't tempt me. Chuck (Modeling Central Japan in September, 1964)
I've tryed that, it did cut the foam, but the smell and fumes was not worth it
I, like Uncle Butch, prefer cutting to burning.
That said, if you are using anything that makes little pieces, work with the Shop-Vac nozzle in one hand and the cutter in the other. Cleanup is worlds easier when most of the oversize dust motes never get scattered around.
Someone once told me it's possible to make a hot cutter by shaping heavy copper wire and screwing it into the bitholders of a high capacity soldering gun. No reason it shouldn't work. but the idea doesn't tempt me.
Chuck (Modeling Central Japan in September, 1964)
I could never see to spend money on a tool ,to use a few time and then have it sit around.
I use old kitchen knives,rasps,and a wire brush. Got the job done, and the ''tool''went right back to where they where,sitting around. total cost 0$
and no fumes
Mutt can anyone give me some advice on what kind of hot wire to buy the ones I have read about all fall short on performance All help will be greatly appreciated
can anyone give me some advice on what kind of hot wire to buy
the ones I have read about all fall short on performance
All help will be greatly appreciated
Like Wayne, I experimented, and made a couple handles from 1/8 copper coated welding rod. You have to insulate at least one end, obviously. You bend the rod to the shape necessary to hold the wire fairly tight, and make for a handle. Look at commercial ones for ideas. For wire, I bought a small roll of Woodland Scenics hot wire (nichrome) at my LHS.
Using 4" blue insulation foam, it worked better than I might have expected it to, given my lack of practice. But I went mostly with glueshell, as I needed most of the space under what scenery I have for staging.
And I'll repeat from above, it's TOXIC. Kinda stinks, too. It's better than hacking away at foam with a hand saw, FAR less messy, and more controlled. Dan
While my layout is 3/4" plywood subroadbed with plaster-over-aluminum-screen scenery forms, I did build a hot wire cutter after reading an article on foam scenery in MR.
For power,I used a surplus transformer from an oil furnace (in a suitable electrical box), then fashioned a cutting tool using a wire coat hanger. A piece of wooden broom handle provide a handle. I tested it on a hunk of 2" extruded foam, and it cut quickly and neatly.
Had I gone with foam for the layout, I would have added some guides to keep the depth of the cut constant, as my intention was to cut roadbed, subroadbed and lineside ditch contours in a single pass. Without depth guides, it was difficult to maintain level cuts.I seem to recall that the article was by Bill Darnaby, with photos on his Maumee Route, one of my favourites.
Wayne
I bought a commerical cutter for cutting model sailplane wings that came with nichrome wire. I see 26 gauge nichrome wire is relatively inexpensive.
but I also use a wooded bow I built and use NyloStrand 0.024 dia fishing lead from a sports store. I also have crimps for the ends (sleeve size k). The fishing lead is nylon coated which burns off.
I use an old variac set relatively low (10 out of 150). But is sometimes gets nudge higher and breaks the wire.
Basically, there are two different kinds of hot wire cutters - hand-held wire cutters and stationary ones. It takes a while to learn how to work with them as you need a steady hand for both types. You need to practice quite a lot!
Hot wire cutters melt the foam, and the fumes are toxic. Work only in well-ventilated areas!
I bought a hot wire knife with a heated, but rather rigid blade instead of just a wire - a waste of money!
Hi, Mutt and,
I can't answer you about hot wire foam cutters, all my scenery is old-fashioned plaster over screen or cardboard strips. I know the Micromark one has been around for a while and generally they sell quality stuff.
There has been other discussions here about foam work, maybe that will help?
http://cs.trains.com/mrr/f/11/p/256481/2870006.aspx#2870006
http://cs.trains.com/mrr/f/11/t/250548.aspx?page=1
Regards, Ed