Does anyone have a good technique for cutting EVA foam block. I have a section that is 40mm wide by 20mm thick - about a 40cm lengths. I need to slice of 10 mm of the thickness and leave a flat surface.

I have already botched a piece as a stanley knife is too short (for 40mm) and the extender blade type cutter is too wobbly for a straight cut. Also is there any way to shave / sand the botched block to leave a flat surface.

Or is there somewhere that does professional cutting?

fret saw?

Try an electric kitchen knife...probably find one in the back of the second drawer in the kitchen.....but dont tell the wife.

You could try ask 'Clarks' rubber people.

Hotwire should work.. will only cost you a couple of $ for a length of nichrome wire from Jaycar or whoever your local electronics place is..

Run the wire over a table, support it on 11mm (slightly high because you'll lose a bit to the melt) blocks of wood, and hang a bottle of water (or something else convenient and heavy) off one end with the other end secured. Steal the car battery temporarily, hook it up, varying the length of wire between the two connections to get the right temperature, then simply slide the EVA block across the table.

I'd try it for you, but I think my spare bits of EVA have all been "borrowed".

Sanding it does work, but you get a rough sanded finish (good for traction)

I have no idea what sort of finish you'd get off the hotwire - probably depends on the steadiness of your hand, but I guess you could always glue it with the cut side down?

A flat rasp works well,thoug the job is neater if you pull it backwards across the foam to wear it down, may not be as neat as the hot wire and you' need to mark on the block all the way around to end up with the surface flat.

I have used the hot wire technique to make foam RC combat gliders. It works really well, but you have to make sure to keep the wire really tight otherwise you might get a slightly bent cut. Also (although this might not apply cos your EVA foam is quite thin) sometimes the middle of the wire is a littel cooler and wont cut as well.

basically - just make sure the wire is tight and you dont take to long to push teh foam through. sometimes it can get a bit melted if you take too long. good luck!

Thanks guys, the hot wire sounds like a 'cool' idea. I was also thinking that an electric planer, which I have, may work. I can shave the layers off gradualy providing it comes of clearly.

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Willaus0001 said...

I have used the hot wire technique to make foam RC combat gliders. It works really well, but you have to make sure to keep the wire really tight otherwise you might get a slightly bent cut. Also (although this might not apply cos your EVA foam is quite thin) sometimes the middle of the wire is a littel cooler and wont cut as well.

basically - just make sure the wire is tight and you dont take to long to push teh foam through. sometimes it can get a bit melted if you take too long. good luck!

I have a CNC hotwire machine that I built for cutting glider wings - it'd be a 2 minute job to slice the EVA, but that doesn't really help W4w!

If you're getting a bent cut with a hot wire, you're not cutting by radiance. The wire should never touch the foam - the radiant heat around the wire should melt the foam near it. Also explains why the middle of your wire is cooler - you're just going too fast!

That's why I built the machine - I can't consistently move my hands at 5mm/s in two dimensions, especially with a repeatable accuracy of 0.005mm, and I got tired of making new templates as the design changed.

The planer may work if it's really sharp, I'd recommend taping some paper or plastic to the sole though, metal is likely to 'stick' on the EVA. Be wary of kickback too - planers are meant to be used on stiff materials, not 'bouncy' ones like EVA.

Let us know how you get on - pictures would be good!

i have some 8mm divinicell sheets if you can get away with 8mm ill post some to you.
i have a ripping saw that works

Seriously, do a test piece with the electric knife, I think you will be surprised....

electric kitchen knife works a treat. I carved some foam for the seat of a chair I built and worked really well

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mikey100 said...

Seriously, do a test piece with the electric knife, I think you will be surprised....

I'll speak to my mum, maybe she has a knife tucked away. My only concern is maintaining an even cut along the whole length of the pad (40cm).

Keef, thanks for the offer, but I'm trying to cut an existing nose protector.

I'll tell you the story, it's one of these situations that's gone from bad to worse to ****e.

I was going to let my GF use my new JP FSW to learn transition to a short board. Being nervous about potential damage I bought a JP nose protector. This consists of two layers of different density EVA and a hard plastic liner on top, hence it's quite stiff.
When I tried to fit it I found it kept pulling up on one side of each rail because the stiffness didn't allow it to bend easily around the contour of the board. Then I noticed that the decals on the board to which the protector was stuck to had pulled up. I realised then that the whole front of the board is covered by one huge decal sticker, even the non slip is applied to this.
I decided to remove the whole thing leaving a nice mess on the graphics on the nose of the board. It would look better with a smashed nose! Keep in mind I'm the sort of anal person that sells his second hand gear in better condition than new.

The plan is now to trim a layer of the eva off so it's nice and flexible and then stick the protector down permanently to cover the mess, more for aesthetics and a little bit of protection. Hence I'm now contemplating how to approach the next stage of this saga.

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Waiting4wind said...

[Keef, thanks for the offer, but I'm trying to cut an existing nose protector.


. Being nervous about potential damage I bought a JP nose protector. This consists of two layers of different density EVA and a hard plastic liner on top, hence it's quite stiff.
When I tried to fit it I found it kept pulling up on one side of each rail because the stiffness didn't allow it to bend easily around the contour of the board.

des your not haveing a good run lately, with your mast exploding in a shoping center,( im pleased to hear your board escaped with out any damage) and now stuffing your board for a good friend( i hope it's a friend with benifits or i would be really pissed off)
i dont know any thing about eva foam or the nose protectors . but im thinking you need to heat the stuff, either dump it into some boiling water or use a heat gun to soften it up so you can re mould it to the shape of your board.
des your on my prayer list for 09,and ill send $10 to the sacred bleading heart of jesus located somewhere in NSW and may all your dreams come true
so if your luck changes in 09 thank keef

Some feedback! The power tools worked well on the EVA foam. I started off using a handheld electric planer to flatten out the hacked EVA block, this worked well.

I then remembered the oldman had a bench planer and saw. I used the planer to finish of the hacked piece and then tried the bigger block on the circular saw. The circular saw worked great. So I would say that a hand held circular saw would also be good. Just like cutting a piece of wood only easier to cut.

Just be careful with the fingers if your're trying to cut or plane a small piece.

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Waiting4wind said...


...

I decided to remove the whole thing leaving a nice mess on the graphics on the nose of the board. It would look better with a smashed nose! Keep in mind I'm the sort of anal person that sells his second hand gear in better condition than new.

...

Make sure you PM me next time you're selling second hand gear in better condition than new.