I have been anodizing for nearly 2 years with fairly good results. The last several attempts have failed to produce an ano layer sufficient to dye. The voltage begins to drop after only 10 minutes. Thinking the problem was bad electrical connections, I purched a Sput Welder. No help. Has anyone encountered (and solved) this problem?
My "hardware" is:
Electrolyte: 5% H2SO4 (battery acid and distilled water at 1:3).
Electrical conections: 14 ga alum wire, previously bolted, now welded.
Power: Leader regulated DC power supply.
Tank: One with lead cathode, one with aluminum. 160 sq in surface area.
I have been following the LCD methed as follows:
1. Clean / degrease with Simple Green until parts pass water break test.
2. Etch in lye solution.
3. De-Ox/de-smut at 100 deg for 3 min. (Thermometer regulated)
4. Ano at 4.5 amps per square foot.
5. Neutralize acid with baking soda solution.
6. Dye at 120 degrees for 15 min with Caswell dyes.
7. Boil in Caswell sealant for 15 min.
Rinsing steps as well as all solutions use distilled water. The last venture involved 6 pieces of 6061 alum totaling 112.5 sq in surface area. Constant current was applied at 3.52 amps (4.5 amps/sq ft). Expected ano time was 102 min. The voltage peaked at 9.79 V and dropped steadily after 11 min without reaching the expected peak of 11.28 V for a .5 mil layer.
.
Does the electrolyte need to be changed periodically? I try to prevent contamination but I have been using the same stuff for 2 years. I hope I've provided enough details for someone to spot a possible problem.
Morgan
My "hardware" is:
Electrolyte: 5% H2SO4 (battery acid and distilled water at 1:3).
Electrical conections: 14 ga alum wire, previously bolted, now welded.
Power: Leader regulated DC power supply.
Tank: One with lead cathode, one with aluminum. 160 sq in surface area.
I have been following the LCD methed as follows:
1. Clean / degrease with Simple Green until parts pass water break test.
2. Etch in lye solution.
3. De-Ox/de-smut at 100 deg for 3 min. (Thermometer regulated)
4. Ano at 4.5 amps per square foot.
5. Neutralize acid with baking soda solution.
6. Dye at 120 degrees for 15 min with Caswell dyes.
7. Boil in Caswell sealant for 15 min.
Rinsing steps as well as all solutions use distilled water. The last venture involved 6 pieces of 6061 alum totaling 112.5 sq in surface area. Constant current was applied at 3.52 amps (4.5 amps/sq ft). Expected ano time was 102 min. The voltage peaked at 9.79 V and dropped steadily after 11 min without reaching the expected peak of 11.28 V for a .5 mil layer.
.
Does the electrolyte need to be changed periodically? I try to prevent contamination but I have been using the same stuff for 2 years. I hope I've provided enough details for someone to spot a possible problem.
Morgan
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