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  • Another newbie joins the ranks

    Greetings Earthlings,

    Well, here I am... another "wannabe anodizer" looking to get his act together so he can make cool stuff...

    My main interest is as a "hobbiest/artist" doing small to mid sized pieces, from a couple square inches up to maybe as large as 4 sq. ft surface area.

    I'm still working my way through all the old messages, but I think I've got a pretty good handle on the basics of the process, and I (think I) understand the 720 rule and most of that good stuff pretty well

    I'm looking towards starting with about 8 gallon dye tank capacity, but would like to be able to easily upgrade to maybe 20 gallons or so if things work out well.

    I'll build my own CC power supply, probably about 25 amps at 20 volts max (based on some of the parts I've got lounging around) and if I'm feeling ambitious when I build it, I may build in some data logging capacity to record voltage and current periodically so it can be coughed up (along with temperature data) into an excel spredsheet later for examination. I'm a pretty firm believer in keeping good records on time, temperature, etc in order to be able to fine tune (or troubleshoot) a process...

    Anyhoo... I've got MOST of my equipment figured out I think, except for the problem of cooling my anodizing tank. Here in CA in the summer it can be triple digit hot in the shop, so I can't just rely on having a large tank with a lot of thermal mass to keep temperature rise at bay. I will need a more active form of cooling to bring the acid temp down before I start anodizing, and to keep it down during anodizing.
    I've got a nice magnetic drive Little Giant pump that's rated for "Nasty Duty", and I will use that to provide circulation in the acid tank and hopefully be able to come up with a clever (?) heat exchanger to use with it. My best cooling options are probably a heat exchanger that uses well water to cool it (about 55°F) to cool the tank, or else use an old window style air conditioner to do the job some how.

    If anyone has any good (and cheap) cooling methods they'd like to share, I'd love to hear from you! I'm afraid a nice slick titanium heat exchanger is out of my budget.

    Also, somewhere liked to this site (I think),I found a good chart that rates how "worthy" different materials are in different nasty (acid) solutions. I can't find it now to save my butt... can someone gently steer me to it please?

    Once I select my tanks (gotta go to Wal-Mart and Home Depot this week and look at plastic tubs and sinks) I'll know exactly what my fluid capacities will be and I'll be able to order a few dyes and some chemicals (strippers, desmut, etc) from Caswell. I'll probably have to invest in an RO filter also.

    Thanks for any good advise you've got for me, and for all the good stuff that's already archived in this forum. It looks like there's a very impressive knowledge base here!

  • #2
    Hello, and Welcome!
    I have some experience rigging up an economical heating/cooling system.
    First, let me qualify my system... I ano paintball markers, and rarely go over 1.5 sq. ft. of surface area. My target CD is 6 amps per sq. ft., so I'm not generating that much heat. I live in the Seattle area, and rarely have to worry about cooling, so here is how I heat, and occasionaly cool my modest 40 gal. tank:
    Circulation is from a 140gph saltwater aquarium pump purchaced on ebay for $20. It is not rated for acid, but features a ceramic shaft, and has been in my tank for about a year now with no problems.
    I built a welded aluminum tank that has about 10gal capacity to use as the heating/cooling heat exchanger. The top is open, and the bottom has a valve for easy draining. I have a 3500 watt hot water tank heating element mounted in the side of this tank, along with an appropriate thermostat. It keeps the tank heated to 100F.
    From inside the ano tank, the aquarium pump circulates acid through about 30ft. of 3/4in. PVC pipe, (using about 50 elbows) through the heat exchanger tank, and back into the ano tank. I have a second thermostat glued to the outside of my ano tank, which controls the circulating pump. I have it dialed in to maintain 68F.
    To cool the acid, I would simply turn off the heating element, drain the water, and replace it with cold water, and opperate it manually until the ano tank get's down to the correct temperature.
    Both my ano tank, and my heat exchanger tank sit side-by-side inside of a sturdy plywood box with a lid. The entire box is lined with 1-1/2in. rigid foam insulation.
    I turn the power off when not actually anodizing (or getting ready to anodize), and close the lid. The system retains it's heat for days. I can usually bring the tank up to temperature in a couple hours from in the 50 degs. range.
    Rigid PVC work well in acid, but flexible vinyl hose does not.
    I hope this gives you some ideas.
    I do things.


    • #3
      Thanks acidrain!
      The PVC heat exchanger is intriguing...
      Have you ever had any leak problems wiht all those elbows? The glue
      holds up OK?

      Did you use sghedule 40 PVC or the thinner schedule 80 or 120?
      I'm thinking the schedule 120 might give the best heat rransfer with it's thinner walls.

      I have a pump thats rated for about 400GPH with a 6 foot head and around 240 GPH with a 12 foot head, so it should be sufficient to push juice through quite a bit of tubing and still have plenty of flow for good agitation I hope...

      I was hoping to find some kind of tubing that would work for the acid and not have to glue a lot of (potentially leaky) fittings, but I haven't found anything good yet and the PVC pipe is starting to look better all the time. especially if someone else is already using it with good success.

      Thanks for the ideas, that'll give me something to think about tonight while I should be sleeping!


      • #4
        Hello luminous,
        I thought I would let you know what I've gotten to work for myself. After 3 tank upsizes, I'm using a cheap ($17.95) Home Depot utility sink.It's made of HDPE, 20 gal and about 21" square, 13" Dp. Cooling here is a problem too. I have the smallest 110V window unit Home Depot had. I built a cooler box around the tank out of 2" white foam. It will maintain the tank to 60 degrees. If you have a Little Giant pump, your set there. I am changing from aeration to agitation here shortly. Heating the DeOx and dyes I use the Caswell 300W heaters with thermostats. After hot plates, crock pots and an assortment of other items they have been the best and easiest. RO is the way to go. I keep a few extra buckets just to put RO water in for when I have alot to do because it only does 10 gal a day. The only thing you didn't mention and I highly recommend is a sput welder for electrical connections. I log all my data also. I use 5 min intervals for voltage readings. After a few runs, you can definitly tell if something isn't going as planned. Best of luck. SS


        • #5
          just a quick note luminous in piping, schedule 40 is the thinest wall compared to 80 and 120. the schedule rating is the wall thickness compared to diameter.(i used to be a pipe welder)
          when in doubt polish it out/ why replace it when you can refinish it
          G2 Polishing and Powdercoating


          • #6

            Thanks for the heads up on the Home Depot utility sink! That sounds perfect, complete with a drain on the bottom to hook up the circulation pump...
            I'll probably get one of those.

            No problem on containers to store RO water, I still have a lot of 5 and 15 gallon stainless kegs left over from my brewing days.

            Are you using the Caswell RO unit? If so, how do you like it? How long have you been using it? Any trouble?

            I'm still thinking about the sput welder. I have a nice TIG welder, so I can use that to make my connections, but the sput welder does sound very convenient. I may build one, or I may just cough up the $150 for the small Caswell unit and save myself a day of soldering. I'll probably just use the TIG welder for a while...

            I'll buy Caswell heaters and thermostats for the dye and DeOx buckets.
            Can the heaters easily be rinsed off and transfered from one color dye to another, or do I need a dedicated heater for each dye color? I was thinking about just buying 1 heater for DeOx and 3 for dye buckets, although I'll probably have at least 8 dye colors.

            Errr.. thanks for the refresher course on pipe schedule. I'm not quite sure what I was thinking... I *thought* I remembered that larger numbers were smaller sizes... but my memory ain't what it used to ne and it's been a LONG time since I played with pipe. I used to have a piece of 1/2" PVC that had very thin walls on it. I wonder what it was..? Schedule 20?
            Anyway, thanks for straightening my head on that one!

            I appreciate your help guys! I'm really excited about the prospect of being able to anodize my own parts. And the process itself appeals to me too... Past "hobbies" have included brewing beer, color photography darkroom, and bending and processing glass for neon art, so I'm pretty comfortable with processes that require strict control over parameters like remperature, time, pH, etc. I'm pretty sure I can do this if I can get the equipment together without busting my wallet....



            • #7
              My brother is a plumber. He got the RO unit for me. It has been in use for 7 months with no problems. Sure beats the running to the grocery store.

              Tigs are nice, the sput welder is a big convenience.

              I rinse the heaters over the tank and wipe them off with a paper towel to go to the next color. If you go the 8 gal. dye tanks, you probably need two heaters per tank to heat quicker. 1 heater will work but will take a little while to get there. I use 2 heaters with no thermostat in my sealer tank. If you boil to seal, a camp stove or propane fish fryer with a stainless pot works good. Watch out on the dyes, the colors on the dye page are not all very accurate. I have all the colors and chips made, if you have a question about one.


              • #8
                Thanks sswee,

                I guess I better figure on a couple extra heaters if it takes 2 to get 8 gallons up to speed quickly. I guess I should do the BTU calculations so I can figure out how long it's likely to take...

                I've got a couple of 15" diameter stainless kettles (actually cut down beer kegs), that work great over a propane burner, so I'll probably use one of those to boil small parts for sealing until I can come up with something larger.

                Thanks again!