Hello again, Mates,
As always, thanks for following, the likes, and of course, any questions or inputs you have.
So, I went ahead with the second round of tests. Here are my first-round results as I assessed them.
Round One Results
- Artwork - Passed, (I did adjust a few parameters)
- Increased the width of the sprue connectors (for hinges AND washers) as they were dissolving before the targeted brass was dissolved, causing them to fall off the frame before the process completed.
- Increased the diameter of the gun port hinge bolt holes, eliminating the need to drill them wider.
- Changed the washer holes from round to square, eliminating the need to force fit a "Square peg in a round hole".
- Metal Preparation - Passed, (I increased the brass's thickness from 0.2mm to 0.34mm.
- Development of Photoresistant Film - Unsure, further testing using different development times will continue.
- Etching Process - Failed,
- Using Ferric Chloride, issues are as follows,
- Dark brown color prevented me from seeing the etching process, unless I pulled the stock out of the solution.
- It STINKS!!
- It STAINS!
- Even at 40% concentration, it took almost 1.5 hours to etch and performed poorly.
- I did the etching in a small Tupperware container, where the sheet lay on the bottom of the container. I think this contributed to uneven etching.
Round Two Focus
Development/Exposure
- Test different exposure times, 1 minute each side, 2 minutes each side, and 4 minutes each side. Hope to see if different times result in different curing properties and better adhesion to the brass sheet during etching.
Etching
- Test other etchant solutions. All of the following etchants supposedly are faster etching than Ferric Chloride
- Ammonium Persulfate, Clear, allows you to see etching progress.
- Sodium Persulfate, Clear, allows you to see etching progress.
- Hydrochloric Acid (Muriatic Acid) + Sodium Peroxide
- Use a dedicated etching tank that allows test samples to be suspended, exposing all sides to the etchant, as opposed to lying at the bottom of my Wife's Tupperware, SHHHHHH!
- Observe/record etching times for all test samples..
Etching Unit
After additional research, I discovered a few additional things that might help improve results. Each of these has been incorporated into this unit. The unit itself required an additional $75
- Suspension & Aeration - It seems bubbles agitate the solution enough around each suspended sample to ensure all surfaces are exposed to the solution.
- Heat - Heat accelerates the process, especially when using Ammonium Persulfate and Sodium Persulfate.
So the unit is a rectangular vase, found at Walmart. I built a basic base with a secure foundation out of shelving and some scrap wood that keeps the unit from being knocked over easily.
Cut a top from Plexiglass and drill some holes to allow gases to escape and feed the aeration line and heater to be supported.
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The photo below clearly shows the exposed brass etched away on the Bolt Washer test sample. However, both of the other samples of the Gun Port Hinges still have not been etched away. It would take another 6 minutes for them to complete, and upon closer inspection, they could have gone longer.
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The mad science project in action.
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I was very pleased with the results of the Bolt Washers. Even the square hole, measuring about 0.4mm, came out clean. Being super picky, you can see the left have of the washers' edges are just a tad rough, something another 30 seconds might fix.
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The Gun Port Hinges could have gone another 2 minutes to result in cleaner edges. Something I can tweak for production runs. I'll see what 5 minutes with a micro file will do to clean these up.
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This test only tested Ammonium Persulfate. I will repeat the test, with the same parameters, only changing the etching solution. No rush on them, though, as I have a working solution for photo etching.
After conducting those tests, I'll make a final decision and record all of the protocols used to ensure I'm able to get repeatable results.
On another note, portside planking, above the wales, continues. I should have an update next week.
Thanks for checking in. Until next time...
Cheers.
