Turns out 7075 takes longer than CPU heatsinks to etch to the same depth. Will increase etching time when we do the Fire/Safe markings. Overall I’m very pleased with the outcome.

First attempt at electro-etching my son\’s lower receiver. This setup has failed the leak test twice now and we may abandon the popsicle sticks + hot glue, and use polymer clay to create a well to retain the electrolyte (table salt and water, with a dash of vinegar) We did some tests on old computer CPU heatsinks with the Q-Tip method and while…Read More

Picked up an AR 15 Lower Parts Kit and buffer tube kit at the Hannibal Gun Show. Other than some trouble with the trigger guard and a floppy safety selector (80% lower, could be the maker) everything came together just fine.
Hope to see everyone Sunday, bring out your ambi safeties, and enhanced trigger guards.

Actual build photos