Originally Posted by Shortguy on BMW
You can get a hot knife blade for a soldering gun.
Thanks for the thoughts. That does seem like a good idea. What happens in practice is, the melted plastic from the previous cut needs to be removed from the blade before the next cut or it starts making the kerf of the cut uneven, which affects the part dimension. Removing the plastic while it's liquid makes a bit of a mess. (think cheese from a hot pizza slice) And there's plastic to remove from whatever you used to remove the plastic from the hot blade. A vicious circle.
Using a flame to heat the blade lets the plastic solidify between cuts, and the plastic can be removed easily. But in this case that doesn't matter. This was a surprise. Heating the blade with a flame also very cleanly burns off the plastic without residue if you can believe it. Well, surprisingly this type of PE plastic leaves no residue anyway.
Acourse all of this is really only an issue if you're trying to do a dimensionally repeatable cut.
Ok, I'm going in...