Rsrguy3 wrote:Don't know that I've had a burned alodine part yet I generally don't leave it exposed for more than 3 minutes.
You can burn the Aluminum very easily watch your dwel times its critical!!!!
You really cant see the burning but beware it is worse than not using Alodine at all.
It will actually cause the Aluminum to start the corrosion process faster regardless of Top coat, Also causes loss of Top coat Adhesion.
When Burnt it leaves a Powdery dust on the surface, When done correctly no dust.
Wipe with clean dry white cloth if it is clean your good if its coming back golden in color you got problems.
We use fairly Large Tanks to treat parts in Alumiprep first then a quick timed dunk in Alodine Tank. Using Tanks is the best ensures nice even etch its the only way to go.
Spray bottle method will get you in trouble burning parts fast, Its fine for small spots and small parts but something like that Nose Cowl I would definitely use a Tank for.