Just made a power supply for a 6' hotwire - foam cutting wand. The fab’ shop is making the wand part including figuring out what wire for cutting will be used, (trial and error). They are a little behind schedule as normal so at this point only the power supply is done. Goal is to cut blocks of 4x8x6" thick expanded polystyrene sheets made into 8' dia. convex discs for a project. Saw the design and it’s very ambitious.... glad I am only making the PSU. But the concept will in me making a variable voltage high amperage power supply be very useful for future projects also.
Dia., type of wire and it's length is given below in a linked chart (below in the links, but limited) but still very much a subject for trial and error. Dependant on wand length, the above and type of material to be cut. Hot wires are not a easy, cheap or scientific thing to do in any way to say that if you are using X foam at Y length of cut, use Z voltage, and you at least need AA amperage etc. You are re-inventing the filament of a lamp that's sufficient to cut thru foam, hot enough it cuts cleanly but not too hot or cool. Hot enough it don't burn thru the filament etc. Cool concept.
Very bad memories from when I was a scene shop carpenter in working with the above material. Dots of foam everywhere, and looking at such foam makes me hack due to the smell. Granted I was chain saw, spary paint, grinder chain saw wheel, belt sander etc shaping and never tried a hot wire before. Hotwire is the best solution - but still wear your masks and operate in a ventilated area.
Masks were optional when I was doing such things and masks got hot. Probably wore one at the scene shop but probably not at the store front theater where I also used the technique I learned in less ventilated areas. Young and stupid in spoiling the fun of wanting in some ways to take part now. I’ll probably look in on it though.
http://www.rcgroups.com/forums/showthread.php?t=628704
http://epp540.com/index.php?option=com_content&task=view&id=89&Itemid=43
http://www.instructables.com/id/Hot-wire-foam-cutter/
Above links were very informative on the concept - though read all like 300++ posts and related links as there is a lot of important information very thoroughly examined on the design, safety and various forms of such a cutter. Found it interesting that CB hasn’t had a conversation on this topic.
The above links are also balancing wall wart transformer and door bell ringer transformer "advice" in very unsafe conditions with more semi-pro and dangerous grades of the cutter in design told about. This as with other in-line transformer concepts and electronically controlled options that I wouldn't do but I could not avise on. Amazing, all posts were based on the "cheapest way you could do it." People taking pride in how cheap they did it, yet what were they producing and or was it for many safe? Really, using a CD disc storage container one found at a 5 and dime store to house your electrical components and it melted down... A few posts recommended more Cadillac like things, but everyone was still very economy in building such a thing. If a tool and building one better than one can get commercially... I at least had no budget, but wanted to keep it under like $500.00 overall in parts, and it was under that in a comfortable estimate. I’m salary so my labor won’t be counted even if very extensive - six hours alone in studying the concept.
Most powerful hotwire ever... But I have concerns also such as instead of breakered output, fusing the project to what is needed for amperage. 28v/20A variac controlled, breakered in every step with analog output dials for voltage and amperage on the output. Analog dials for low voltage was all that was available which was economical even if pricy. Will have loved to digitally dial in the settings for what material was to be cut.
EDIT: I have returned this post and only removed the portion asking for permission for it to be visible. As always, please proceed with caution on projects such as this if you do not have the relevant experience.
Dia., type of wire and it's length is given below in a linked chart (below in the links, but limited) but still very much a subject for trial and error. Dependant on wand length, the above and type of material to be cut. Hot wires are not a easy, cheap or scientific thing to do in any way to say that if you are using X foam at Y length of cut, use Z voltage, and you at least need AA amperage etc. You are re-inventing the filament of a lamp that's sufficient to cut thru foam, hot enough it cuts cleanly but not too hot or cool. Hot enough it don't burn thru the filament etc. Cool concept.
Very bad memories from when I was a scene shop carpenter in working with the above material. Dots of foam everywhere, and looking at such foam makes me hack due to the smell. Granted I was chain saw, spary paint, grinder chain saw wheel, belt sander etc shaping and never tried a hot wire before. Hotwire is the best solution - but still wear your masks and operate in a ventilated area.
Masks were optional when I was doing such things and masks got hot. Probably wore one at the scene shop but probably not at the store front theater where I also used the technique I learned in less ventilated areas. Young and stupid in spoiling the fun of wanting in some ways to take part now. I’ll probably look in on it though.
http://www.rcgroups.com/forums/showthread.php?t=628704
http://epp540.com/index.php?option=com_content&task=view&id=89&Itemid=43
http://www.instructables.com/id/Hot-wire-foam-cutter/
Above links were very informative on the concept - though read all like 300++ posts and related links as there is a lot of important information very thoroughly examined on the design, safety and various forms of such a cutter. Found it interesting that CB hasn’t had a conversation on this topic.
The above links are also balancing wall wart transformer and door bell ringer transformer "advice" in very unsafe conditions with more semi-pro and dangerous grades of the cutter in design told about. This as with other in-line transformer concepts and electronically controlled options that I wouldn't do but I could not avise on. Amazing, all posts were based on the "cheapest way you could do it." People taking pride in how cheap they did it, yet what were they producing and or was it for many safe? Really, using a CD disc storage container one found at a 5 and dime store to house your electrical components and it melted down... A few posts recommended more Cadillac like things, but everyone was still very economy in building such a thing. If a tool and building one better than one can get commercially... I at least had no budget, but wanted to keep it under like $500.00 overall in parts, and it was under that in a comfortable estimate. I’m salary so my labor won’t be counted even if very extensive - six hours alone in studying the concept.
Most powerful hotwire ever... But I have concerns also such as instead of breakered output, fusing the project to what is needed for amperage. 28v/20A variac controlled, breakered in every step with analog output dials for voltage and amperage on the output. Analog dials for low voltage was all that was available which was economical even if pricy. Will have loved to digitally dial in the settings for what material was to be cut.
EDIT: I have returned this post and only removed the portion asking for permission for it to be visible. As always, please proceed with caution on projects such as this if you do not have the relevant experience.
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