What did we do wrong?

[blackcote]

Can an anodizer do anything to cause marks like these? The customer claims these were perfect when they left his hands. So I'm looking to find out what we done wrong if anything.

[blackcote]

Here's two more.

[mkriegs]

what are you using for stripper? I've gotten similar marks from stripping too long in the lye bath, although I've never seen anything like that second picture.

[destroyer125]

Looks like hardcore pitting.

[blackcote]

no stripper used, these are new parts.

pitting from what though? can too long in cleaner do it? and if so, why does it happen on only 2 out of 17 parts all processed at the same time,

[destroyer125]

Sometime embedded impurities will do it. I can do 50-60 parts, and 2-3 will come out with small pitting, nothing like that though.

[Z]

pitting occurs do to impurities in the the tanks. Chlorides in the sulfuric acid tank causes pitting also stray currents. If you use a metal for your sealer tank and use metal for your load bar it can cause pitting when chlorides are present.

[blackcote]

What's considered a chloride? and how does it get to my tanks? Can a black oxide line contribute to this? We run a large hot black oxide line in the same building, but not at the same time and we keep lids on all the tanks containing anodizing chemicals when not in use. Not air tight but fully covered. Edit: I guess this is where it could be as we use sodium chloride for blackening. Is there anyway I could check for chloride levels to know when to change it out... as building another building is not an option. Edit: My bad, we actually use sodium hydroxide.

Although we're using a plastic tank for all tanks, can you explain your thoughts or facts on chlorides in the sealer causing pitting?

Can I rule out leaving it in the cleaner too long? We use the sp degreaser.

[fourkbmx]

chrorides are present in tap water, you should check out you are using destilled water, i've some similar problems before becasuse i didnt used destilled water. use only tap water after the sealing

[blackcote]

in tap private well water?