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I'm cutting foam cushions into foam storage trays for my vehicles and large models right now. I have a hot foam knife (it actually was a wire that would heat up) but the wire keeps breaking. Does anyone know where I can get a decent (and relatively cheap) foam cutter? I tried using a knife but it makes terrible cuts and leaves bits of foam everywhere. Thank you.

What sort of wire are you using? We made a wire cutter for cutting foam from nichrome wire and we had a bit of problems initially with it breaking until we dialled in the correct amount of power and we haven't had breakages since (though we buy heaps of it so it's not a big deal if it does break). We cut through blocks up to a few feet thick with it and don't have a huge problem, though at those lengths you start to have issues with wire drag (where the wire in the center of the block cuts slower than the wire at the edges, so instead of cutting a straight line it cuts arcs through the foam).

I think part of your problem is dragging the foam cutter through the foam. If you pull the foam through the cutter you may have better luck? They make foam cutters styled like a table saw that you can find at most craft stores, where you drag the foam across the fixed wire. Something to check into, anyway. Not really cost effective for one project.

I'd be interested in seeing a good knife for cutting foam too, but the foam I use is like the battle foam bags instead of the styrofoam. I've been collecting sheets of this packing foam at the hospital I work at and have tried cutting with a sharp knife too, with mixed results, so any good options you give dave I would also enjoy

 Theophony wrote:
I'd be interested in seeing a good knife for cutting foam too, but the foam I use is like the battle foam bags instead of the styrofoam. I've been collecting sheets of this packing foam at the hospital I work at and have tried cutting with a sharp knife too, with mixed results, so any good options you give dave I would also enjoy

I would love to get my hands on foam like that. Does anyone know where it's sold. If not, can you tell me what kind of foam it is? All I can find for sale is cushion foam. Thank you.

Im not sure what it's called, but this is what I've been getting

Just gave that stack to the assistant pastor at our church, he was moving last week and it's perfect for wrapping China/glasses. They are 10"x15" by 3/8 give or take on thickness. I've got 5 people looking and setting them aside for me in the supply room at the hospital. We specialize I. Heart issues here and one of the common one use devices comes ) to a box with each one having two sheets of the foam protecting them. Between Thursday and today I've picked up another 24 sheets of it.

 Davespil wrote:

 Theophony wrote:
I'd be interested in seeing a good knife for cutting foam too, but the foam I use is like the battle foam bags instead of the styrofoam. I've been collecting sheets of this packing foam at the hospital I work at and have tried cutting with a sharp knife too, with mixed results, so any good options you give dave I would also enjoy

I would love to get my hands on foam like that. Does anyone know where it's sold. If not, can you tell me what kind of foam it is? All I can find for sale is cushion foam. Thank you.

Haven't poked at it enough to know for sure...but most use a foam like this:

http://www.foambymail.com/CR/solid-charcoal-regular-foam.html




Automatically Appended Next Post:

 Theophony wrote:
I'd be interested in seeing a good knife for cutting foam too, but the foam I use is like the battle foam bags instead of the styrofoam. I've been collecting sheets of this packing foam at the hospital I work at and have tried cutting with a sharp knife too, with mixed results, so any good options you give dave I would also enjoy

Snap knives are about the best option for an actual knife. Foam (both the soft stuff you are talking about and the actual extruded or expanded foam) dulls blades very fast. Upholstery shops will also use a wavy jigsaw blade or a knife that looks a bit like an electric carving knife - both work quite well for the soft foam and reasonably well for rigid Styrofoam.


Automatically Appended Next Post:

 Davespil wrote:
I'm cutting foam cushions into foam storage trays for my vehicles and large models right now. I have a hot foam knife (it actually was a wire that would heat up) but the wire keeps breaking. Does anyone know where I can get a decent (and relatively cheap) foam cutter? I tried using a knife but it makes terrible cuts and leaves bits of foam everywhere. Thank you.

One thing to remember with hotwire cutters is that you don't want to wire to cut the foam...you want the heat from the wire to melt the foam. If you are pulling and breaking the wires...your temperature is too low or your speed is too high. A lot of the soft foams are designed to have a higher melting temperatures - so you will need to find the specific speed needed to slice through it without causing it to start to melt a mess. The kerf of the cut should be wider than your wire by a bit. Takes some practice and figure out the speed and temperature you will need, but once you figure it out - you can slice through most foams (and even some plastics) - keep ventilation in mind if doing it in a house though.

If you want to cut it with a knife - use a snap knife...but the real trick is to compress the foam before you cut it. Use a straight edge that you can clamp down to hold the foam almost completely flattened - slice through and then when you unclamp it - it will pop back up with a clean cut. Every few cuts - snap off the tip and extend out a new, fresh edge.

 Sean_OBrien wrote:

 Davespil wrote:

 Theophony wrote:
I'd be interested in seeing a good knife for cutting foam too, but the foam I use is like the battle foam bags instead of the styrofoam. I've been collecting sheets of this packing foam at the hospital I work at and have tried cutting with a sharp knife too, with mixed results, so any good options you give dave I would also enjoy

I would love to get my hands on foam like that. Does anyone know where it's sold. If not, can you tell me what kind of foam it is? All I can find for sale is cushion foam. Thank you.

Haven't poked at it enough to know for sure...but most use a foam like this:

http://www.foambymail.com/CR/solid-charcoal-regular-foam.html




Automatically Appended Next Post:

 Theophony wrote:
I'd be interested in seeing a good knife for cutting foam too, but the foam I use is like the battle foam bags instead of the styrofoam. I've been collecting sheets of this packing foam at the hospital I work at and have tried cutting with a sharp knife too, with mixed results, so any good options you give dave I would also enjoy

Snap knives are about the best option for an actual knife. Foam (both the soft stuff you are talking about and the actual extruded or expanded foam) dulls blades very fast. Upholstery shops will also use a wavy jigsaw blade or a knife that looks a bit like an electric carving knife - both work quite well for the soft foam and reasonably well for rigid Styrofoam.


Automatically Appended Next Post:

 Davespil wrote:
I'm cutting foam cushions into foam storage trays for my vehicles and large models right now. I have a hot foam knife (it actually was a wire that would heat up) but the wire keeps breaking. Does anyone know where I can get a decent (and relatively cheap) foam cutter? I tried using a knife but it makes terrible cuts and leaves bits of foam everywhere. Thank you.

One thing to remember with hotwire cutters is that you don't want to wire to cut the foam...you want the heat from the wire to melt the foam. If you are pulling and breaking the wires...your temperature is too low or your speed is too high. A lot of the soft foams are designed to have a higher melting temperatures - so you will need to find the specific speed needed to slice through it without causing it to start to melt a mess. The kerf of the cut should be wider than your wire by a bit. Takes some practice and figure out the speed and temperature you will need, but once you figure it out - you can slice through most foams (and even some plastics) - keep ventilation in mind if doing it in a house though.

If you want to cut it with a knife - use a snap knife...but the real trick is to compress the foam before you cut it. Use a straight edge that you can clamp down to hold the foam almost completely flattened - slice through and then when you unclamp it - it will pop back up with a clean cut. Every few cuts - snap off the tip and extend out a new, fresh edge.

Thanks for the info! That link is exactly what I was looking for.