Cutting circles in foam

[peza2010]

Hi all.

Im looking for a cheap and easy way to cut nice, neat circles in typical "flightcase" foam.

 

I have tried a sharp knife, which still leaves jagged edges (did I mention im rubbish at most things craft like)

so any ideas would be great.

 

Would anything like a circle cutter drill bit work?

 

(holes upto 30cm in circumference)

 

 

Cheers, George

 

E2A: im also looking at sensible ways to label onto the foam.

each hole is going to house a different thing, so I would like to label each whole directly onto the foam.

I was originally thinking printing onto paper, laminating and gluing, but I have a bit of OCD when it comes to casing and what a nice looking way of doing it that doesnt have the labels falling off every few minutes.

[Gareth A]

Use something like Liquid Evostick - literally sticks anything you need. You will have to rip the actual foam before you remove the label.

 

What about a electric carving knife with a fine blade. ? Or even a jigsaw? I've seen people use both on polystyrene. No reason it wont work on dense flight case foam I guess?

[Ben Couch]

A hot knife is generally a good way to cut neatly through foam imo.

[the kid]

You may find modelling scaples perform better than normal stanleys.

[WiLL]

an electric drill will just snag the foam and you'll end up with a huge torn hole which I gather you don't want. Foam is a pita because it blunts knives really quickly. You can use a hot knife or hot wire if you have access to one, failing that a long sharp blade is your best bet. Depending on how rigid the foam is you can sand the final cut.

[Brian]

...a long sharp blade is your best bet....

If you use the craft knives with snap-off blades you can extend a fresh blade right out of the handle giving yourself a 3" cutting edge.

[d_korman]

...a long sharp blade is your best bet....

If you use the craft knives with snap-off blades you can extend a fresh blade right out of the handle giving yourself a 3" cutting edge.

 

I use a good quality filleting knife and keep it well sharpened with a steel. Not cheap - but can also be used in the kitchen!

[Lamplighter]

An electric carving knife works well with most foams. You can take off very fine slices and it leaves a clean face.

Brian

 

 

[Doug Siddons]

Heat is the key, heated a carving knife on the stove and it cut really well and neatly, missus wasn't pleased though!

[jonathan.1]

I have found a hot wire is the easiest way to cut practically any foam. if you don't have access to one you can use a 12v battery and fuse wire. but obviously this isn't the safest method so take care if you choose it

 

Jon

[Simon Lewis]

The hot wire method may release a certain amount of decomposition products from the foam. In a well ventillated space this may not be problematic. If not well ventillated, you could find yourself breathing in such nasties as gaseous hydrogen chloride, vinyl chloride or diisocyanates.

 

Although not giving a perfect finish on complex shapes, the electric carving knife is a pretty good tool, and I have used one extensively for case foaming.

 

 

[peza2010]

Thanks for the replys chaps.

 

I do have access to a hot knife, so will try that and the other suggestions on some off cuts.

 

I shall let you know how I get on.

[Ben Lawrance]

I would be looking down the route of maybe asking my local friendly flightcase company to CNC it for me. Bearing in mind, this is what they do everyday, so will more then likely take 5 mins for them, be a perfect finish, and only cost you a crate of beer.

[KevinE]

hotwire works great on flightcase foam but agree about the fumes. I do it outside.