What is the best tool to use for cutting 2' foam board, In some areas I will have to cut the 4'X8' sheets down to other sizes. How do I get a nice clean cut.
Best option I found after trying a bunch of ways, is to get a large putty/spackle knife, and sharpen one side and the front edge. I found this trick searching the web for ways to cut foam and this came up on some home improvement site. I tried it and it works pretty well. There's no such thing as totally clean cuts, unless you use a hot wire cutter but then you better have ventilation. With the sharpened putty knife I just make repeated scores along a straight edge until I get through - I tried going most of the way and then trying to snap it, but the snapped edge ends up having all sorts of loose irregular chunks.
--Randy
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For straight cuts, I use a steak knife (I find the serrated edge works better than an exacto) and cut just part way through in a line - I usually go about 1/4 through. Then snap on the cut and it will split cleanly.
You can lean it on a piece of wood if it is a really long cut and might want to go 1/2 way through for long ones.
I generally mark the line with a marker and just cut on the line - I find that better than cutting with a straight edge ruler or similar.
For curves I use the same steak knife - just cut all the way through. You can use a sawing motion and pulling - both work.
The steak knife has been my best friend for cutting foam.
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Steak knife is my first tool. For rough straight cuts, just score and snap. For fancy cuts I have used the band saw, but not very often. The steak knife is the tool of choice because of the serrated edge. A bread knife would work, but it has no point, and someone else just suggested a grapefriut knife for hollowing out a lake. I have not tried that yet.
There are el-cheapo {59 cents each, 2 for a dollar OR less} with 4 or 5 inch long thin cutting blades with a sliding blade in it marked of every 1/4 inch to be snapped off when the tip dulled.
There are two models: one with a 1/4 inch wide blade and one with a one inch wide blade.
If you slide it all the way out it will cut through 1" or 2" foam rather quickly and easily. Either blade will work, but for the two inch buy the slightly more expensive 1 inch wide blade to make it easier to cut.
-G .
Just my thoughts, ideas, opinions and experiences. Others may vary.
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Steak knife or saws all. I don't care about a smoothe edge since I'd be working with it anyhow.
Springfield PA
Get one of the mini-hacksaws that has the blade more or less unsupported sticking out a handle. This gives you 4" or so of blade to work with; ample to cut most foam board. The edges are a little rough, but really no worse than the factory edges.
I also use a jigsaw on very slow speed to cut short (16" or less) curved cuts. For basic shaping, I use a Shur-form rasp and a vacuum cleaner to clean up the dust.
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A good steak knife with a serrated blade( long wide blade) will work or a good handsaw that you would use for fine cuts in wood.
I use a long straight board I keep as a guide
I also have hand held power jigsaw with a long blade the works well also
I also build and fly RC airplanes and have a custom hot wire foam cutter and a workbench ( 4 by 8 feet) I set up special for cutting foam with
In fact I used it this weekend to custom cut a 2% grade from 3/4 inch white foam.
I wanted the capability of running two trains side by side, so the Woodland scenics deal wasn't going to work, so I made my own setup.
Did it at far less cost also!
I'll take some pictures tomorrow to post.
TheK4Kid
Good stuff K4 BUT, you can use WS risers for double track by conpressing and stretching to match. It takes a few foam pins to hold it level while the caulk dries and then it is great.
Well I gave WS a try, but one set of risers was higher than the other .
I tried the compressing and stretching, but the but on would always be a little higher or lower than the other.
I found a way to do it, and it also was much less expensive than using WS riser sets.
With WS risers, I was left with having to fill the gaps in the stretched set
The way I did it, there are no gaps to fill in
I cut 8 pieces of 3/4 inch foam board , making them a 2% incline
Started at 1/8 inc thick at one end, first piece was 2 inches at far end, then 2 inches to 4 inches at far end.
Each piece was 8 feet long.
Total of 16 feet
Made 4-16 foot sets this way.
Then filled them with expanding spray foam that was on sale at Menards.
After I filled the first 8 feet of each riser set I let the foam dry over night, then trimmed it off and used the over expansion as extra fill in the last 8 feet ,then finished spraying with expanding foam.
I did try WS risers first, but was not satisfied with them, took them back to the LHS and traded them for something else I needed.Then after I figured this configuration out, plus Menards had a 11% back rebate on all materials, the cost of $40 vs $100 for WS risers, plus this came out great!The 3/4 inch white foam riser outside pieces I made flexed very easily to the radius I wanted.
The spray foam glues the whole thing down. I put a bead at the bottom inside of the risers, then let that setup.I used small brad nails to hold the white foam in place until the foam dried.
Next comes paint, then roadbed and track.
Works great!
Total costs was $40 in materials.
WS would have cost me $100 thru the LHS.
The K4Kid
I use a sabre saw with a knife blade, i.e. a sabre saw blade that doesn't have any teeth. Only place I've found the blades was Sears. Cuts the foam without creating any foam dust and with straight board for a guide you can make straight cuts. For shaping I use a sharp filleting knife and a hot wire cutter.
Mike
Simply score & snap is the best/cheapest method for cutting straight lines. Any razor knife can be sued but the key is changing the blade often so your always using a sharp blade and not something that won't cut your wife's meatloaf. A straight edge is a good idea just use ONE nice even smooth stroke depending on how long your blade if needed you can sore it a second time but i use a folding knife i bought in Lowes that has interchangeable blades and they sell various length blades for different uses. Once you've scored the piece simply grasp both pieces and snap them apart.
I use my band saw when a perfect edge is desired. Otherwise I score and snap the foam.
Craig
A super sharpe utility Stanley razor knife with industrial blades, thicker blades than most cheapo knifes and a steel T-square. You can't score and snap foam core board.
Frank
Edit: The good part about the T-square, is you can cut both sides, exactly the same, without a mess, from snapping.
i HAVE USED A 26" WOOD WORKING HANDSAW, AND CUT EIGTH INCHES OF PINK FOAM INTO A HILL SHAPE.
LION cuts foam on a table saw, same as ply wood. No problems. And the dust stays in the shop, not in the train room.
ROAR
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BroadwayLion LION cuts foam on a table saw, same as ply wood. No problems. And the dust stays in the shop, not in the train room. ROAR
That sharpened putty knife I use makes no dust. And, it is coming in handy to strip wallpaper in my new house. Works better than a fresh new putty knife because of the sharp edge - until your hand slips and you contact the sharp side.
I am laying 2" foam right now. I have now tried all the suggested tools except hot wire.
Serrated Bread knife with a sharp point: stabbing through to the supporting board beow and than using a cranking action to extend the cut. Repeat. Works but slow.
Steak knife (serrated) same as above but with less leverage for the cranking action.
Seaman's Knife (like a hunting knife): too dull.
Dry-wall hand saw. WOrks well but very jagged edge. Probably better for creating rock faces.
Sawz-All. Works great but lots of spit out messy particles.
BEST OF SHOW: Electric Saber Saw with fine tooth edge: cuts swiftly, easily, smooth edge (I care about this for flush fit to future fascia). Produces lots of fine particles.
Vacuuming necessary for all.
Unexpected Problem: My particular foam is scribed at 12 inch centers on both sides. Trying to cut and snap from the 4x8 breaks first at the scribes and then the piece I want emerges as several jigsaw pieces. Not the end of the world.
LAURENCE KEDES BEST OF SHOW: Electric Saber Saw with fine tooth edge: cuts swiftly, easily, smooth edge (I care about this for flush fit to future fascia). Produces lots of fine particles. Vacuuming necessary for all.
Ditto. Tried many, settled on jig saw as best solution. Affixed shop vac crevice nozzle to saw with hose clamps. Nozzle end very close to blade. Minimal clingy styrofoam leavings afterwards.
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Alan
Freelancing the LK&O Railroad
Anybody tried it?
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Instead of the electric knife, I use a serrated edge bread knife to cut foam. Quite a bit cheaper than an electric knife.
I use my Nack Knife:
I know. "That blade is too short," right? Well, it will make a nice clean cut 3/4 of an inch deep. Then I flip the foam sheet over and do the same thing on the other side. Then, snap! and I've got a clean, straight edge with no bits and pieces or foam dust. For curves, though, it's not as good because you can't get a good snap.
I've got a hot wire cutter, too, but I wouldn't waste the money on one if I hadn't already wasted the money on one. It's hard to get a good straight edge, and it can only cut about 6 inches from the edge of the board, so if you want to cut a 2x8 sheet down the middle, it won't help. If you want a "hot" tool, go with the knife, not the wire.
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A saber saw or even a circular saw with a combination blade works great. When using a strait razor blade or Exacto blade I have notist that green and blue foam seems to have a grain; cut it one way and its smooth; cut it the other way and it wants to tear. Is this just me?
Ray