MK2/A/B etc... coating.

What is that black, or red, coating on the top, and bottom, of these? I would like to purchase whatever it is so I can paint an extra layer on top as I find most boards to use too thin of a coating (especially Sainsmart) but I have no idea what it is and where to purchase some (or Google for it).

Thanks.

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

I think it's standard solder resist, applied as part of the PCB manufacturing process. You could try several coats of spray on PCB lacquer.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

What exactly is that masking material as I have always wondered and when it started to get colors (eons ago now) I was fascinated. Do you think that laquer can handle 135c?

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

... for high-temp coating I've got sensors coated with clear or coloured polyimide - was stable until 180degC or short-time exposure until 250degC.

You can try with UV-curable paint used for painting boat hulls - this saltwater resistant paints are more heat resistant than conventional ones ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

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VDX
... for high-temp coating I've got sensors coated with clear or coloured polyimide - was stable until 180degC or short-time exposure until 250degC.

You can try with UV-curable paint used for painting boat hulls - this saltwater resistant paints are more heat resistant than conventional ones ...

This is precisely why I believe my board has a short as 120-130c melted the mask in a spot. Just a pinhole that I can't find but when I attach my aluminum heat spreader to it there is a dead short. I have a new one due here in about two days but I can't afford to have it short out as well and take my ramps, and a few other things, with it again (hence the reason I would like to put a thermally conductive, but not electrically conductive, coating over the board).

edit: I could always tape it with my Polyimide tape but that is something I never understood when people put Kapton tape over their beds because it is an insulator too so that wouldn't be any good to sandwich inbetween.

Edited 2 time(s). Last edit at 03/22/2016 08:00PM by Dark Alchemist.

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

Normal kapton tape is so thin that I don't think it will create much of a thermal barrier. It's probably not a bad way of adding some more electrical insulation if you're worried about shorts. Another option is to install the heatbed the other way up so that the tracks are away from the heat spreader, but then heating will be less efficient as the heat will have to travel through the pcb. Choices, choices!

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JamesK
Normal kapton tape is so thin that I don't think it will create much of a thermal barrier. It's probably not a bad way of adding some more electrical insulation if you're worried about shorts. Another option is to install the heatbed the other way up so that the tracks are away from the heat spreader, but then heating will be less efficient as the heat will have to travel through the pcb. Choices, choices!

Yeah, when I first made this printer back in 2014 I had it upside down like that then I realized the heat was more on the bottom so I flipped it around. I will say that by adding the heat sink (the heat spreader) it already is hard enough to get it to 130c as I had to fiddle with the voltage (24v to 28v) and change Marlin as well. I think I will give the Kapton a go and while it isn't very wide it wouldn't matter but man is it ever hard to not get bubbles or creases in it when you lay it out.

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

What are you printing on 130? If you need the bed that high it might be worth having an enclosure so that you can bring the ambient up to 50 to 60C. That will make life much easier for the bed as well as reduce cooling/warping of the print.

It occurred to me that instead of kapton you could get some of the heatsink transfer tape to go between the bed and spreader, but it might be a bit pricey for the size needed.

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JamesK
What are you printing on 130? If you need the bed that high it might be worth having an enclosure so that you can bring the ambient up to 50 to 60C. That will make life much easier for the bed as well as reduce cooling/warping of the print.

It occurred to me that instead of kapton you could get some of the heatsink transfer tape to go between the bed and spreader, but it might be a bit pricey for the size needed.

About as much as the board itself unless I am willing to wait 45 days. I'll try the Kapton tape and see if it is too much of an insulator or not.

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

After testing the tape was too much of an insulator to allow it to go beyond 91c. If I changed from 255 to 511 for max voltage in Marlin I could get to 108c (rounding both) but no more. Just too much insulation.

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

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Dark Alchemist
After testing the tape was too much of an insulator to allow it to go beyond 91c. If I changed from 255 to 511 for max voltage in Marlin I could get to 108c (rounding both) but no more. Just too much insulation.

Do you have thermal insulation underneath the PCB bed heater? 3-skin corrugated cardboard and cork are popular choices, typically with aluminium foil or tape on top if there is no danger of shorting anything out..

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

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dc42

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Dark Alchemist
After testing the tape was too much of an insulator to allow it to go beyond 91c. If I changed from 255 to 511 for max voltage in Marlin I could get to 108c (rounding both) but no more. Just too much insulation.

Do you have thermal insulation underneath the PCB bed heater? 3-skin corrugated cardboard and cork are popular choices, typically with aluminium foil or tape on top if there is no danger of shorting anything out..

Sure do but this board will short (hence the question about the coating) if anything metallic touches it. I already had issue with just the heat spreader but with the Kapton tape too it was too much. I think I may just do my own heater with some Nichrome wire since the Kapton is already on the spreader.

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.