need help with surface prep

[mkriegs]

I keep getting these little white marks all over my finished parts, it looks like dust but it's actually in the aluminum. And the strange part is that I don't remember getting those when I used to use a battery charger (I use CC now).










There's some more strange phenomena going on in my work but I'll have to get pictures of those later.

[sswee]

How are you prepping the parts?
SS

[mkriegs]

right now I'm not really doing much of anything, I use a spray degreaser and scrub with a sponge until the parts pass WB. I don't have (and can't afford) a beadblaster or polishing tools, so that's not an option yet.

[fourkbmx]

i need help too, i prep my piece by using scotch brite, then clean with thinner, then dip in caustic soda, rinse, muriatic acid, rinse and then ano tank. my problem is that after the ano tank it seems like it was dirty underneath the ano film, it looks like little black filaments.

[mkriegs]

duh, I can't believe I didn't realize it before, but I left these parts out overnight inbetween the acid bath and the dye baths because I didn't have enough time. Then the next day when I went to resume, there was what looked like a white-ish powder on the parts around the areas where the parts were hung. So I rinsed the powder off and continued business as usual but now I'm thinking I didn't rinse off all of that white-ish powder and it affected the dye process somehow.

[acidrain]

It's really important that you go directly from ano to dye. In fact, once the parts are preped, you really need to do the whole process.

[destroyer125]

Originally Posted by fourkbmx

i need help too, i prep my piece by using scotch brite, then clean with thinner, then dip in caustic soda, rinse, muriatic acid, rinse and then ano tank. my problem is that after the ano tank it seems like it was dirty underneath the ano film, it looks like little black filaments.

Do not use muratic acid or hydrochloric acid on aluminum.

[fourkbmx]

what should i use for prep and cleaning aluminium before dipin in ano tank

[destroyer125]

Caustic soda (Sodium Hydroxide A.k.a Lye) will work, just dip for a few seconds and wash very good. Hydrochloric acid reacts violently with aluminum and can dissolve stuff in minutes, lye also reacts quickly, but not anywhere the rate of hydrochloric

[fourkbmx]

lye turns aluminium black and te muriatic acid turn it back in a very light grey color ready for ano, that is what im using, could you please describe your prep process, because im trying to use something that isnt as reactive as these because im working with 7075 and it isnt as resistant as other alloy so i've screwed a couple of tries.