Stripper?

[00_buckshot]

I bought some of the Caswell chrome/anodizing stripper and have a question/concern. I have some aluminum parts that have anodize in some areas and raw aluminum in others. When I submerge the part into the stripper (5.5oz/gl distilled water) the raw aluminum begins to form thousands of bubbles turning into a white foam after about 15-20 seconds in the stripper. My question is, is this the aluminum being attacked or is it the inhibitors slowing the attack on the aluminum. There appears to be no pitting after the part removed from the stripper and rinsed so I don't know if any damage is being done or not. The reason I ask this is because when I was using a lye-based solution to do my stripping the exposed raw aluminum would not create any bubbles. The aluminum is 7075 if that makes any difference. Thanks for the help.

[dropride]

i am using the caswell stripper as well. mine does the same thing with it bubbling after a few seconds. the stripper will eat away at the aluminum if left to long, trust me i left a part in for a few hours after i forgot about it and it was alot smaller than when i had put it in.

[mcaswell]

Notes from our Stripper Supplier:

Stripper AND common lye, when used at the same alkalinity concentration will both equally attack (bubble) bare aluminum before it cuts thru the light anodizing. The only difference you have noticed has been that then lye was used at a lower concentration and/or a lower temperature. There are no inhibitors in the product. The aluminum flakes in the lye will very slightly slow down its reaction with bare aluminum but not enough you could tell it - again you were at lower concentration and/or lower temperature.

You do not need distilled water. In job shop production I like to use the the product at 6 oz/gal, 140 F, 5 minutes.

[00_buckshot]

I place my part in for only 15 seconds at a time and then rinse in water before doing it again. The stripper is left at room temp. Is this helping to slow the stripping down or speed it up? Does it really make any difference? After a few dips in the stripper I bead blast the part to get as much off as possible and then place back in stripper if there is still anodizing left on the part and repeat process.

P.S. - Caswell, I suggest you take this out of your desription of the product, "Anodize & Chrome Stripper is a super fast commercial grade stripper. It outperforms all others in speed and quality. Does not attack the aluminum." That's the whole reason I bought the product. I realize that all stripper will attack the aluminum but I was under the impression that this product had an inhibator in it.

[Fibergeek]

Using any stripper (including lye) at a lower temperature slows the process. The way 00_Buckshot is using stripper is the safe way, both to him and to the part being stripped.

Also be advised, a lye solution liberates very noxious and corrosive fumes when it comes in contact with bare aluminum. This is really serious at higher temperatures. Commercial strippers will also fume, but its nowhere near as bad.