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Having Issues with Etching and Photo Resist on Stainless Steel

July 23, 2009

Wondering if anyone here can help.

I am scale model vehicle collector and builder (1/32, 1/24 & 1/25 scale), I have used Photo etched Stainless Steel detail parts for years that were commercially produced...

Recently, I have started to create my own Brass Photo etched Parts using ferric chloride ⇦this on eBay or Amazon [affil links] for the etch, and from previous uses on making my own electronic circuit boards a product called "Press-n-Peel Blue (PnPB)" as the resist (PnPB is a Mylar sheet with a "Flat Blue" substance on one side, Fed into a Laser Printer, the "Negative" resist image is printed on to the PnPB, then transferred to the material via heat from a Cloths Iron or a Heat Laminator.)

I have a 5 Gallon fish tank, with approx. 2.5 gallons of FeCl3, A 20 watt heater that brings the FeCl3 up to 115 degrees and I am using a acrylic block as a bubbler manifold (standard fish tank airstones all seem to fall apart when introduced to the FeCl3), Air is pumped from a standard fish tank air pump to create agitation in the tank. I have used this tank and method for years to make circuit boards. I typically use .003 or .005 Brass shim stock as the material... It takes me approx. 4-8 mins to etch a 1 inch x 1 inch pattern depending on the percentage of open exposed Brass.

So far, it has worked well on the Brass and have been happy with the etching results...

I have found a need to have Stainless Steel detail parts now, But so far, the results have been pretty much junk...

As with the Brass, When I Prep the Stainless, I use a 3M greeny and dish soap to remove any oils, I have also tried to use 90% Isopropyl Alcohol just before I place the PnPB on the Stainless and then run it thru the Heat Laminator. Here's the bulk of my problem. I can't get the PnPB to adhere to the Stainless completely, some adheres, some doesnt...

Does anyone have any suggestions what I can use or what I need to do to get PnPB to adhere to the Stainless, or do I need to go to a more traditional means of using Photoresist?...

Thank you in Advance...

Robert Mapplebeck
Hobbyist - St Paul, Minnesota

Years ago we had intricate gear parts to mask with lead tape with problems. Baking the part for a few minutes at 400F gave the part a faint yellow tint and the tape stuck very well. It is cheap to try.

James Watts
- Navarre, Florida
July 24, 2009

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First of two simultaneous responses -- July 28, 2009

I had tried pre heating the stainless via the laminator which according to the specs, it heats up to about 275 degrees. I didn't get any better results...
I will have to give 400 degrees a try...
Were you able to remove the "Yellowing" you experienced with heating it?

Robert Mapplebeck
- St Paul, Minnesota

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Second of two simultaneous responses --

Try a fast dip into etchant before taping.
Good luck

Khair Shishani
aircraft maintenance - Al Ain, UAE
July 28, 2009