Today I finished making a hot-wire foam cutter for Shelly for her birthday. (Which was actually last December
![Rolling Eyes :roll:](./images/smilies/econ_rollingeyes.gif)
)
![172400](http://tnttt.com/gallery/image.php?mode=thumbnail&image_id=172400)
We made one a few years ago while building the teardrop walls, to cut the one inch thick foam down to 3/4 inch thick to fit with the plywood skeleton. That one had a 6 foot long wand, and Shelly's since mentioned a nice bench version would be good for her doll house making business. A few weeks ago I was attempting to organize my junk, and realized I had almost everything I needed to make one.
The MDF was scrap from a pair of work benches we made while dating (they're both still in the shop, btw), the volt meter was one I decided not to use in the teardrop, the front panel was a piece of fiberglass covered Baltic birch that was scrap from the teardrop, etc. etc.
The antique radio knob and the quarter inch telephone jack are from a small parts cabinet I bought from an estate sale this past Spring. I think the previous owner must have been an amateur radio operator. Incidentally, I bought the small parts cabinet to try and orgainize
my junk. It doesn't necessarily work so well if you buy the cabinet already full of even cooler junk. (Pro tip!)
I did buy the black track, but that's mostly for a miter saw station I'm hoping to get around to building this Winter. It wasn't surplus, but preplus, if you will.
I did buy the light dimmer used to control the temperature, because I decided it was worth it not to take apart the original hot-wire cutter, just in case we need it for something someday.
I did buy the aluminum extrusion used to make the arm. It's called 2020 because it is 20 mm by 20 mm. It's used for frames for CNC machines, 3D printers, and the like. While studying this and the hardware that goes with it on Amazon, I accidently ordered nuts for 3030 extrusion. It has the same pictures as the 2020 kit. If, like me, you are new to this material, don't do that! (Another pro tip!)
There are two sizes of nuts that go with this extrusion
![172402](http://tnttt.com/gallery/image.php?mode=thumbnail&image_id=172402)
The one on the left will not slip into the slot, but must be installed from the side. The other one will go in sideways, and then is supposed to turn 90 degrees to the right and lock. Note two sides are rounded, and two aren't. Works okay, but I found they often need to be poked with a jeweler's screw driver.
These are all M-5 threads. For the knob that adjusts the arm angle, I wanted a bolt with a long nut as a head (if you know what I mean). Couldn't find them, so I decided to solder a regular bolt onto a long nut and then cut off the original bolt head. Worked just fine, but I discovered I didn't have any M-5 bolts long enough. That's when I discovered a 10-32 bolt works just fine! When the M-5 knob arrived this morning (oh ya, I ordered those too) it fit just fine!
Got a few more boring details, but this is already getting long, so I'll post them below. Feel free to ignore unless interested. Actually, I suppose you can do that with most of the comments above too.
I'll close this by answering how much foam can a hot-wire cutter cut, if a hot-wire cutter can cut foam?: It does.
Tom