Cutting holes in foam

Feb 05, 2007 8 Replies

Hello



I have some 21oz 1" foam sheet (cheap stuff). This is cut into rectangles about A4 size. I'd like to cut some regular spaced 1" square holes in this (48 per A4 sheet), but don't know of a good approach. There are a few dozen sheets to do. Yes, scissors will work, but the result is poor. And a sharp knife also works, but it's time consuming and the result isn't what I want. Anyone got some clever tricks/ideas? Ta.


"Grumps" wrote >

Hi Grumps, how about a hot wire cutter, with the wire formed into a quare loop? A piece of square section tube the right size, heated over the cooker ring? You do know you can buy it ready made (with open-cell foam) from "hydroponics" shops, I assume?

Dave H, (The engineer formerly known as Homeless)

Ah yes, that may just work.

Nope. But thanks for the pointer.

I have used Electric carving knives, used them to make an oval cushion the other week., made a fairly neat job.. I have used them since we got them for a wedding present 24 years ago, exclusively for cutting foam, never for meat!

Des

=============================== Cut the foam into 1" wide strips and then cut some of the strips into 1" squares. Glue alternate rows of strips / squares. Messy but functional - it depends on how you want the finished job to look.

Cic.

Gasket punch ?

(they're like a chisel with a round cutting edge at the business end)

I don't recall using one so large myself, but they're probably available (we had a range of sizes for making new gaskets out of cork sheeting to fit over threaded studs)

depending on what the foam is made of, freezing the sheets may make them easier to cut as they will be stiffer. Some people advocate using them as a sponge and soaking them in water before freezing, though this has always seemed a little extreme to me.

Pete

In the rubber & plastics industry they would use a punch under a press. I have seen them made with sharpened edge hacksaw blades set into a plywood block. In the absense of a punch I guess standing on it would work in cheap foam.

If you make 2 hollow squares the size of the hole you want from wood, and attach these to the jaws of a quick-clamp, you can then quickly clamp the wood onto the foam where you want a hole, and cut the hole with a sharp pointed knife. The clamp controls the hole shape neatly, and simply removing any material within that area gives you a fairly neat hole.

You sure have got a lot of holes to cut though.

Slice & glue would leave tough glue lines in the soft foam, and be weakpoints for failure.

NT

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