Monday, July 11, 2016

Electro Etching - Heat Spreaders

I am trying my hand at electro etching, and the two common ways to heat and transfer the toner resist onto the workpiece (I'm using brass for a start) is either with a regular clothes iron or a modified laminator. Both of these methods appear to work very well for circuit boards, but I want to try my hand at something with fine detail, and I thought I'd try a different method I saw on youtube.

With the iron and laminator, I believe that there would be some level of shearing between the toner and the copper when heat is applied by an iron or laminator. Using two plates to hold together the transfer sheet/copper and then heating it up would remove the shear from the equation, possibly giving a higher quality result? Well that's what I think anyways.

Originally, I bought some 316 stainless steel round bars, similar to the video. THAT was a stupid idea. I only have hand tools, and the stainless steel basically chewed up anything I threw at it. After learning more about metals, I decided on aluminum for two reasons, a) It's got a good heat transfer co-efficient and b) workable with hand tools.

Copper has a much better heat transfer co-efficient, but I don't want to deal with oxidized copper (eww) and as I read, it's a harder metal.

The "heat spreaders" are basically aluminum bars I got cut from metalsupermarkets. 2inx2in an eighth of an inch thick. A small hand file was used to remove burrs and smooth the edges, then a series of wet/dry sandpaper, 400/600/1000 were used to smooth their contact faces. Sandwiched between these two prepared surfaces would be the brass plate as well as the toner-impregnated transfer paper. A c-clamp will be used to hold the pieces together while they are heated and the toner transferred from the paper onto the brass.

With this done, I am waiting for the last big piece of the puzzle - the laser printer to arrive. I've already got a bunch of copper sulphate for the mordant. As for the paper to receive the toner, I've got a bunch of  Pulsar's Toner Transfer Paper.

The container for holding the mordant is still being decided on... some articles I've read float the piece to be etched horizontally with styrofoam, and some have it held vertically. Each of them have their own pros and cons, and I'm deciding on what would be best for quality and usability indoors.

Should be fun :)

Decided to take a peek under the el-cheapo usb microscope to see what's the surface like between the original and polished surfaces:


No comments: