Printing Prusa

After several prints using ABS, I can now safely say that this low-powered heated bed is capable of printing ABS parts under some stringent circumstances.

First of all, to reach this performance, I did my best to insulate the bottom surface of the aluminium plate, which so far has involved taping a couple of strips of a few more cotton wool pads underneath, and (I kid you not) stuffing an old worn out cotton sock and a bandana underneath to fill out some of the remaining space. If I had one big piece of cotton wool to fill the whole gap, it would probably work better, but I don't.

So, by pre-heating the bed either by covering it with something insulating on top (slow) or resting a clothes iron on top (fast) and bringing the temperature above 110C, I could print some small ABS parts on the bed, and larger ones with the aid of raft material.

Testing ABS on Mendel Parts Heated Bed

It has been suggested that you can't print ABS on a RepRap Mendel built with the current kits supplied on mendelparts.com, since they include a power supply for the heated bed that only delivers 70W at the highest voltage, and that isn't enough to produce temperatures high enough to keep the parts stuck down.

Recently, I have been trying to challenge that claim with a few tests of my own. Firstly I taped some cotton wool under each of the heating resistors to provide a bit of insulation, hoping that would conserve some of the heat, and then pre-heated the printbed using an iron again, turning the thermostat up to the setting for cotton and leaving it for a few minutes, which brought the bed up to a temperature of around 110C.

Kapton tape hugs makeup removal pads over heating resistors under the printbed.

Quest To Use ABS

It's been a busy couple of weeks to say the least.
The design for my modular rotary hydroponic unit is now pretty much complete and ready for testing.

1 Ring with boards to support a PE sheet sump to hold mineral solution. Can be extended to more rings, and it has been suggested to use a stock drip-tray from garden stores underneath instead of hacking that sump together from scraps.

However, to start printing and testing parts for this, I really should be using ABS, not only for its superior strength to PLA, but because when being repeatedly dipped in a nutrient solution and stressed in a warm humid atmosphere, PLA could come under attack from microbes that would otherwise turn up to biodegrade it in a compost heap.