I am actually doing a small amount of research on making a hotend from scratch with a compact format. It would be the thickness of a thick pen.
For this project, I may need to find some ceramic and nichrome wire.
The old PTFE way: http://www.a2aprinter.ca/index.php?route=pavblog/blog&id=15
Interesting, though it seems easier to use a Pico hot end.
I do wonder about the design constraints most apy to hot ends, if there are better ways.
To your plan, ceramics are available from McMaster-Carr if you want small amounts. Though it’s very very very hard to tap. If may be easier to use green ceramic and fire it in a furnace afterwards.
@David_Simmons I think it may be easiest to let the hotend bake itself. Nichrome can get up to 1400C. People have used nichrome wire to make forges for aluminum before.
Anyone know if 26 or 32 AWG nichrome is better?
I might just use kapton tape to insulate it. That or fireplace mortar or thermal compound or engine enamel.
Select the nicrome wire gauge based on the length of the wire and surface area you want to use, and the power requirements. With the power being the same, the thinner the gauge the lower the surface area.
I’m with @Stephanie_A – calculate the watts you need, look at the voltage you’re supplying to the heater, then from the resulting ohms, look at ohms/foot for different gauges and use that to decide. Although, personally, I’m a lot more fond of a metal hotend and a ceramic heater (mostly because I can fabricate metal nozzles.)
Currently, I have no idea what length of wire I will need, but the nichrome is cheap uncoated.
I have 22 AWG and 32AWG nichrome wire and jewelers drill bits on the way from ebay now.
https://plus.google.com/+Fre3formdCoNz/posts/U8y2sChnMYm fiberglass twisting nichrome wire.
You’re going to want to ream it. After drilling. Even a high quality bit isn’t going to provide the smooth surface finish you’ll want for as little friction as possible
The wire will need to be a specific resistance- so a certain corresponding length. Anyone know goid targets for 12v and 24v? I think our Printrbot ubis-3 is around 30-33 watts at 12v… Can’t remember the resistance.
@Brook_Drumm check out the foamcutter link above. And I think it will give you the info to calculate that.
@Brook_Drumm Hmmmm… Or your old notes…
I imagine you mentioned that hot end as a reference point.
@Brook_Drumm 4.8ohm for 30W at 12V it seems
5-6 inch for 32 awg is what my math says. It is approximately 10 ohm per foot.