Mr Hot Wire 4000

A slight detour from the regular program today as I make a new hot wire cutter...

After the untimely demise of my hot wire cutter yesterday, I decided that making a replacement was a fairly high priority. So while waiting for slow running test scripts to finish I scribbled up a quick plan on Inkscape for my new cutter:

Then once work was over I took a trip down to the Masterton Maker Crate where we proceeded to cut out my design from a sheet 3mm MDF on their 80W laser cutter (versus my 3W one). Cutting MDF sure is smokey work, perhaps it is just as well mine can't cut MDF as the sticky tar-like smoke goes everywhere.

Mrs A looked the other way as I took over the dining table and hurriedly assembled my new hot wire machine.

It is a fairly simple construction, the base is built up of layers of MDF glued together with regular old PVA. I troweled on a thin layer of spackling over the laminations to hide some of the rough edges; that is the white pastey stuff you can see.

This model has a built in automatic tensioner which is a rather neat improvement over the old model. Most things expand when they heat up, and nichrome wire is no different. This makes it hard to tension, as it gets looser as it heats up. So I integrated a small bungee cord hidden inside the handle, which tensions the wire around a small brass roller. I made the roller on the lathe; it has a notch in the middle to keep the wire nice and centred.

Some assorted bits of wire and an LED finish things off.

Here is the finished item after a quick lick of paint over the spackling. Notice how nice and perpendicular the wire is, and how easily it clamps into the WorkMate. It is also nice and compact for storage, with no loose cords. Huge improvements over the old model!

And does it work? Sure does, works very nicely indeed.

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Wednesday, May 11 2016, 11:26 AM jdLowe says...
That is a slick device. Nice job.
Thursday, May 12 2016, 1:05 AM Paul P (from CHC) says...
Impressive. You could market this on trade me.<br />
Friday, Feb 10 2017, 7:04 PM Friso (from London) says...
Do you have the file for the Laser cutter of the Hotwire 4000? I'd like to build one! I currently have a small one, but it only lets me cut about 100mm thick foam...