My previous heated bed was nichrome wire based, I counldn't get it above 60°C, so it wasn't usable for ABS, but worked great for PLA. It started out as an experiment, and through various hacks I kept it working. Finally, coming up to another necessary repair I decided to build a new bed. I bought some Ceramic wirewound resistors from Digikey, fireproof, I'm paranoid. I'm first trying to attach them to the same aluminum plate with JB-Weld. I needed a small putty knife to apply the jb-weld to small ceramic blocks, so a couple lines of openscad later:
cube([50,10,1], center = true);
translate([15,0,0])cube([30,15,1], center = true);
I have a putty knife the exact size. For now, I'm just waiting for the jb-weld to dry. If the jb-weld doesn't hold for the comparatively low temperatures needed for a heated bed... well I'll have to figure something else out...
Printing a Mendel Pen Holder, hopefully I can start making my own circuit boards with this pen holder and this post about using vinegar, Hydrogen Peroxide, and salt to etch. I found the etching post through Hackaday
So, where was I... I got through all the PLA tests I wanted to do, and actually used a whole pound of Black PLA. In the end I printed a full Prusa Mendel, and better quality than most of the parts on my printer... I've posted those Black PLA parts to eBay, since I still don't have all the electronics yet for a second printer. I decided in the course of my Prusa upgrades and switching to PLA that it's probably best to have two extruders for each printer. I don't mean a two headed printer, but and extra extruder sitting by in case something goes wrong. Then I can just swap in the second one and make repairs on the first. PLA Doesn't jam as much as I was led to believe, maybe older designs did, but Wade's extruder design works great. When PLA does jam, which it did on my old extruder, it... takes a while to fix... days. I did have more blobbing and lots, and lots of strings from PLA, it makes a thread like filament when the extruder moves. By the end of printing the Black Prusa I had the extrusion reversing far enough and quick enough that it mostly wasn't an issue (15mm at 100mm/s). I think I've gotten as good with printing as I can without more exact measuring devices. I'd like to try using a small digital scale to compare the grams output in Skeinforge to the actual weight of printed objects, and a caliper to get some measurements on plastic output vs. input.