Re: Small tank anodizing
Good questions just up my alley.
My current tank - until I get the new 6gallon one finished - is about two gallons maybe. I've always done it indoors. I set up a platform to sit on a table (workmate actually) with a back panel. To this I attached a standard range hood - a cheap one from your local Home Depot will do. I put it down to max about a foot above the tank to be sure it attracts the fumes. It works out nice because it has a light as well. I attached a flexible dryer vent hose to it and I send it out the basement window. (works good for small spray painting jobs too)
I can't compare to large anodizing set ups since I've never been there. The largest I've done is maybe 200sqin. I used to anodize at higher currrents than I do know and bath temperature was a problem, but since I keep things down to maybe twice to 3x the LCD settings there have been no problems. The bath gets a fog of small bubbles - hence the range hood. I've nver used automatic agitation. I just carefully move the parts or stir the bath avery 5 minutes or so. I usually try to adjust current to achieve maximum of 120mins (because I'm impatient), but keeping within the 720 rule if you use that method is recommended.
Although I'm not 100% sure of my acid strength I measured specific gravity and it is suspected to be between 2:1 and 3:1 - a bit stronger than LCD.
I put my dye (about 2 quarts) in an enameled kitched pot heated on a single burner electric hot plate in the basement too. The dyeing seems to take about 1/2 hour at 120degF normally and the dye does not ssem to cool too quickly so I remove it from the burner after I put the parts in and use the burner to boil the water while the dying is going on. I manually swish the parts aroundin the dye as well. It's a bit of a juggling act and ocasionally I have to rush up and use the kitched stove becasue the parts are getting to the colour I want and the water isn't boiling yet so I have to get out the big guns.
I always empty the acid tank out after use becasue I don't do it too oftenand I don't like leaving acid out to evaporate near my lathe and milling machne. I put the acid into a 5 gal sealed plastic container - the kind with a pouring spout with the screw cap.
Maybe 15 years now. Never had any problems always had good results.
PS> I'll continue using my bigger tank in the basement in exactly the same fashion. I would expect a bit more circuit resistance and therefore higher required voltage but we'll see. I may have to rebuild my CC (24v) supply for a bit higher voltage output.
Anything I've left out?
Sage
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