Quote:
Originally Posted by acidrain
You have de-smut and de-grease reversed... it would go:
Strip or etch
de-smut
Degrease
ano
dye
seal
Since your parts are not etched or stripped, you really don't need the de-smut step at all.
If your "blotches" are well defined ovals or long stripes, it's the grain of the aluminum showing through.
If they are hazy random blotches, I suspect your beadblast method is too heavy.
Try 60psi at some distance (3 or 4 inches) and just a quick back-and-forth dusting. With beadblasting, less is better.
As for your PH levels, the only thing you have to worry about is the dyes. There is a sticky with all the different colors and their respective PH levels.
As for sealer, I suggest the high-temp sealer for non-food related parts, but many have had equal success just steem sealing. For food related parts always use steem sealing.
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I am doing the degrease and de-smut in the order that is in the caswell book.
I am using 7075 alum.
What is steem sealing?
When I take the part out of bucket #5 (before the final sealer) the areas that become blotches are white, almost like a chalkie look to it. I will get a pic of the blotches.