Anodizing Question

[Zamble]

I got my anodized lowers from Colfax yesterday. But I realized, I should have got the unanodized ones. What can I do to strip them? I want to have them engraved and lettered. I realized they will probably turn out like crap if I do.

Any suggestions? I plan on machining it out on Tuesday, so I hope I can do it before then.

[kcstott]

My suggestion will be to ship then back and get the correct ones you need.
Bead blasting is usually best if you have a set up or know someone that has one.

If that is not possible follow the instructions below very carefully

Two gallons of water and one to two tablespoons of Lye
A heavy pair of rubber gloves like chemical gloves. Lye will burn your skin just like battery acid will. this is nasty stuff so be careful.

This can be found at the home depot or lowes in the plumbing section. it is drain opener.
Look for a package that only contains "sodium hydroxide".
Don't use the drano or other type drain openers as they have ground chunks of aluminum in it that speed up the reaction. Not good.

Mix it up and only use at a max one tablespoons per gallons of water. It will mix up a very concentrated alkaline solution. Let the part soak for a few minutes to at the most a half hour.
Check the part frequently what you are doing is etching the metal and initially it will look as though nothing is happening, Once the anodize starts to break down it goes quick.

Have a bucket of clean water near by to rinse the part off and stop the etch. It's also there to rinse your gloves off to. do not drip or spill the solution as it will react just like mild battery acid and corrode metal or eat holes in your clothes

If you let the part sit too long it will pit the part and pit it randomly and deep rendering it useless.

[GSwain]

Why not sell the ano'd lowers and just buy the un-anno'd ones, or ship em back as kcstott suggested? Stripping a commercial ano job seems like a shame!

[kcstott]

It is only if he was not going to have them redone.

All aluminum should be anodized even after engraving

[Zamble]

I plan to have them hard anodized, but I want them engraved. I mean, if I engraved them and they get scrathed a bit from the process (assuming I left them anodized), would the anodizing be uniform when I hard anodize them?

Thanks.

[more1911]

If it's been anodize (type 2), you could have it engrave then strip and replate
with hard anodize (type 3)

[Zamble]

Yes they were type 2 anodized. If I engrave as is, then type 3 them, will it look good or like crap?

[freonr22]

I had eagle arms lowers forever ago stripped and redone, and they were totally loose tolerance, and that was having the "factory" do it. I know nothing if type 2 or 3 would make any difference, maybe the type 2 is a different thickness, process

[kcstott]

Yes the type has a little to do with the thickness build up but in reality it's the stripping part the open up all the tolerances.

[Zamble]

Anyone else? When I bought them anodized, I figured that I would not need to have to have them anodized when I completed them. But it look now as my thought process was wrong. They were soft anodized, but I now know that they will need to be hard anodized.

Anyone live near Stockton want to possibly trade 2 for two un-anodized? I figure that I might as well start off where I have them engraved and finished, then type 3 anodize them.

Unless someone has a better suggestion?

[kcstott]

See you didn't say they were type two anodized.
I'd go ahead and strip as type two is a very thin layer and so long as you monitor the bath is would be fine.

The other thing you can do is go ahead and have them engraved and let the hard anodize shop deal with the old coating they will bead blast that stuff right off with little dimensional change and mean millionths of an inch dimensional change.

Type three Hard anodizing being as thick as it typically is causes problems with critical dimensions when stripped. You should have no issues

[jmpgnr24k]

Why not sell the ano'd lowers and just buy the un-anno'd ones, or ship em back as kcstott suggested? Stripping a commercial ano job seems like a shame!

That right there^^^^^^