Help electric foam cutter DIY

[wightbees]

Bored Bored Bored,so i thought i would make one of these.

Anyone made one and what is the easyest way please.
I have had a quick google and they look simple enough, but what would you do.
I have quiet a few bits and bobs about so i thought i would give this a go.
regards
WB

 

[Hivemaker.]

Just use a bandsaw normally......but is this in the link below the kind of thing you have in mind,or not?

http://club.cycom.co.uk/hotwire/Hot_wire_cutter_for_polystyrene_foam.html

 

[wightbees]

Yes thats the thing i'm after. Thanks HM

 

[drstitson]

car battery, jump leads and a piece of foundation wire.

 

[wightbees]

I think from what i have read, thats not a good idea.Although i was going to do that lol
But by using a car bat charger set @6volts i think is ok.

Thanks drstitson

 

[Hombre]

similar to Dr Stitson.
A length of stainless foundation wire. Secure it to a beam or something in the garage or workshop. Pass it through a board with a small hole or slot, for best registration and either put a tensioned bungee or suitable weight on the bottom of the wire to keep it nice and taught.

I use a 12v battery charger and put the clips on the wire above and below the board/working surface at a distance to give me the temperaure I require.

Steer your expanded polystyrene board against a runner of free hand through the wire.

 

[wightbees]

Thanks everyone for you help i have used the battery charger method.

WB

 

[fredbloggs]

Couple of qUestions to complete an interesting OP. ( I totally understand everything previously said of course, but there might be gaps in others knowledge ?? )

What is foundation wire?

Is the EPB you refer to the wall/loft insulation board?

What is the average feed rate when cutting?

Other than the more obvious hive insulation uses, are there any other applications you clever people use this for?

Finally, (and this is the bit where you all go "durr" ) what prevents the battery charger output fuse popping - surely you are shorting the leads




.... Or is it another " I'll get my coat" moment?
Thanks

FB

 

[oliver90owner]

What is foundation wire? in this case simpy an electrical resistance.

Is the EPB you refer to the wall/loft insulation board? It is likely that. Seems sensible and easily available.

What is the average feed rate when cutting? Depends on a wide range of variables.

Other than the more obvious hive insulation uses, are there any other applications you clever people use this for? As beekeepers or as clever in other circles, too? Not many uses in beekeeping other than insulation.

Finally, (and this is the bit where you all go "durr" ) what prevents the battery charger output fuse popping - surely you are shorting the leads It most certainly could but the same thing stops the fuse popping as in the case of charging a battery - the electrical resistance of the circuit component. Gets technical, as the power, and so the energy used (or work done), is proportional to the current (I) and the resistance (R) squared, and not related to the voltage (well no more than for purposes of Ohm's Law). Time dependent, of course, when converting 'power' to 'energy transferred'.

Hope that helps.

RAB

 

[Mike a]

What is foundation wire?

Very thin wire used to support the wax foundation sheets in frames.

What is the average feed rate when cutting?

Depends on the thickness of what your cutting but best to have a few practice runs first.

Finally, (and this is the bit where you all go "durr" ) what prevents the battery charger output fuse popping - surely you are shorting the leads

Its all to do with the resistance very much like a toaster, you want the wire to heat up not the fuse in the plug. I'll let the clever electrical types answer this one even though I trained as and mechanical electrical fitter many years ago amp-age, resistance, coulombs and such like did stick well enough to answer.

 

[Hombre]

I found that over a 14 inch length of stainless steel framing wire (used for wiring frames when using plain foundation - not quite the same as wireless LoL); I never pulled more than 4 Amps from a 12V car battery charger.

Feed rate - If you make the wire glow red hot, it will be too hot and should be moving rather fast. Too slow and you will possibly partially weld the cut that you are making.

Avoid inhaling the fumes, as they don't do you any good.

I suspend the wire vertically and put a weight on the end to keep it taut, passing it through a piece of wood with a small hole in it to keep the cutting wire where you want it when you start feeding your expanded polystyrene insulation board. Not suitable for polyeurethane. I believe.

I attach clips from charger to the suspended wire and adjust the distance between them to give me the wire temperature that I need.

Not so much a short circuit, but a low resistance path certainly. Probably in the region of 3 ohms to 6 ohms.

 

[Silvercleave]

If you want to cut foam the easy way is to use an electric carving knive.
Have seen this in use, very simple but effective

Ian

 

[Hombre]

Funny story about an electric carving knife.
Radar Tech working at Zuttendahl used to complain that his wife gave him corned beef or ham (can't quite remember) four days a week.

He bought his ever loving an electric carving knife for Christmas (c 1978). Instead of becoming more creative in the kitchen department, she discovered that she could cut the meat even thinner and the tin of corny beef not lasted the whole five days . . .

Looking on the bright side, at least the family name wasn't Bobbit.

 

[BobH1]

Gets technical, as the power, and so the energy used (or work done), is proportional to the current (I) and the resistance (R) squared, and not related to the voltage (well no more than for purposes of Ohm's Law). RAB

Correction: Watts = Volts x Current (Amps) = Resistance x Current squared.

Energy is related to voltage: Energy = Volts Squared divided by Resistance

If you're using a car battery, its far easier to gauge your voltage (in terms of number of cells in circuit) than it is to measure your current.