Cutting blue insulating foam

[NMBob]

Hey youse guys!

 

I haven't been around much lately. Kinda lost my workspace in the warehouse at work when someone jacked up a vehicle with our forklift. Now we are all on the crap list. I wasn't even in town when it happened.

 

Anyway, I have to cut some ~8" high letters out of some of that 2" thick blue insulating foam. Got a scroll saw. Might as well use it. I was wondering about the blade type and speed. I don't want to look like a complete idiot this evening.

 

Thanks!

 

Bob

 

[LarryEA]

If you have enough foam,,, try one until you find one.

I would try a cheap wood burner that has an exacto blade... 

You kinda can burn/cut your way thru the foam....

[NMBob]

If you have enough foam,,, try one until you find one.

 

 

That was the 'not looking like an idiot' part with everyone standing around that I was trying to avoid.

 

The one kind of blade I don't have. I never even thought of ones like a knife. There should be plenty of foam to play with. I'll figure out something. Thanks!

[jerry1939]

I've never had a need to try what you want to do.  Would it work to put the blade in backwards and run the saw at top speed, in an attempt to get it to burn???

 

This would only be an experiment.  Wish I could be of more help Friend.

 

jerry

[NMBob]

Hi Jerry!

 

It's almost time to head for the shop. Glad I saw this. That's a good idea. I'll certainly give it a try. Maybe a very small blade backwards. That might be like a rough piece of string. I have some of the spiral blades, but I think they will be too rough and rip the foam. I'll post the results.

 

Thanks!

 

Bob

[amazingkevin]

My beginning day i cut Styrofoam .thinking that wood would be to hard to cut on a scroll saw .Slow and easy was the way to,go i remember.the letters i cut were 1"block letters

 

Hey youse guys!

 

I haven't been around much lately. Kinda lost my workspace in the warehouse at work when someone jacked up a vehicle with our forklift. Now we are all on the crap list. I wasn't even in town when it happened.

 

Anyway, I have to cut some ~8" high letters out of some of that 2" thick blue insulating foam. Got a scroll saw. Might as well use it. I was wondering about the blade type and speed. I don't want to look like a complete idiot this evening.

 

Thanks!

 

Bob

[Lucky2]

Trail and error Bob, that's the way to go. You won't look like an idiot, if you know how to do it in advance.

Len

[NMBob]

My beginning day i cut Styrofoam .thinking that wood would be to hard to cut on a scroll saw .Slow and easy was the way to,go i remember.the letters i cut were 1"block letters

 

ONE INCH! You showoffs kill me. You guys do some amazing stuff. I can almost cut a straight line.

 

The "customer" was right there helping, so I didn't have time to practice. ...It was just a friend from work. They were letters for his daughter's graduation party.

 

Well, now we know. A #1 forwards seemed to work well on 2" foam. If the foam had been thinner running the blade backwards might have worked. I was afraid the blade would get too hot on the 2" and would start melting the foam badly. For the short test cuts it left a really smooth/melted edge, but it was already getting a bit warm. Larger teeth didn't do well, so the smaller the better. I had some 2/0 spirals, but didn't try them. I could almost cut sideways without turning the foam as it was. I could cut a straight line without angling the foam. That threw me for a bit. Results below. Thanks for the input!

 

Bob

[NMBob]

If you have enough foam,,, try one until you find one.

I would try a cheap wood burner that has an exacto blade... 

You kinda can burn/cut your way thru the foam....

 

The guy with the foam tried with a non-heated knife. He said it took him about 15 passes to get 3/4 of the way through, then either the blade got a bit dull or physics kicked in and it all started to drag and rip. The good part was REALLY smooth, but the bad part was REALLY bad.

 

Bob

[JimErn]

Really nice cutting NMBob, in the future you might also try an electric knife (like you use to slice a turkey).  I use that to cut all densities of foam and Styrofoam - works well

[LarryEA]

B-R-I-T-T-A-N-I   

What does it spell?

Brittani

RAH RAH RAH

 

_{Bob, Great 'POST' and a good job cutting.}

_{I liked JimErn's solution also..}

[NMBob]

B-R-I-T-T-A-N-I   

What does it spell?

Brittani

RAH RAH RAH

 

_{Bob, Great 'POST' and a good job cutting.}

_{I liked JimErn's solution also..}

 

Ha! I think she WAS a cheerleader in high school. Now she's gragiating college. Too fast.

 

I wonder how tight of a curve could you do with an electric knife, or do the come with really narrow blades? I've only seen the turkey butchering kind about 1" front to back.

 

Bob

[CharleyL]

Electric kitchen knives cut foam real well, even mattress type memory foam, but if you need to cut curves and follow lines closely you will likely do better with a scroll saw and spiral blades run at a slow enough speed to not melt the foam. You want it to cut, not melt. Start at the slowest speed and gradually increase the speed on a piece of scrap to find the best speed and then cut your letters at that speed or slightly slower.

 

Charley

Edited April 27, 2016 by CharleyL

[Chiloquinruss]

Harbor Freight hot knife.  I build a lot of model railroads for folks and we use foam for scenery.  The tool of choice is a hot knife.  Stinks, smokes, but it works.   Russ

 

http://www.harborfreight.com/130-watt-heavy-duty-hot-knife-60313.html

 

If you are doing complicated stuff like letters for a sign, scroll saw a piece of wood and use as a tracing / edge template.

Edited May 1, 2016 by Chiloquinruss