When I went to plate the bolts for the front shock absorbers I was getting a very dark plate and after the chromate the parts were looking very brown and pretty bad all around. I think there is a good chance that I have contaminated my electrolyte solution by sandblasting and wire brushing the old bolts without removing the old zinc finish. I’ve read that I’m pushing the old zinc into the pores of the steel and this is contaminating my electrolyte. So I’m going to revisit my system and make some improvements. Then I will plate a dummy to see if I can clean up my solution and in the process run a series of test billets.
Improvements I will make
- Add two additional rinse buckets and a distilled water spray bottle so that each step has its own rinse
- Add new zinc anodes
- Add a 20% acid bath and rinse for removing zinc plate prior to blasting
- Buy a more powerful air compressor that can keep up with the my blasting setup
- Switch blasting media from aluminum oxide to glass beads to increase the shininess of the blasted part and hopefully eliminate the wire brushing step
- Add a flood light to blast cabinet so I can see the parts better when blasting
- Improve electrolyte agitation by using a fluid pump and a dispersion cone
- Add heaters for the plating and yellow chromate tanks
- Create a plating log to record:
- Number of parts, dimensions and amperage
- Surface preparation steps
- Electrolyte pH
- Solution temperatures and times in solution for degreaser, muriatic acid, electrolyte, blue and yellow chromates