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First Anodizing bench setup, few Q's

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  • First Anodizing bench setup, few Q's

    Hey guys,

    Been reading a bunch over the last few weeks waiting for some parts to trickle in for the completion of my bench. I purchased the 20gal Kit from Caswell and just have a couple of questions that I wonder if the answer even matters.

    1) For the ano tank itself, is it beneficial to be able to move the cathodes closer to the anode when the parts are not utilizing the whole tank or should I just stick two sheets of lead material at either end and call it good? Secondly to this question, if it doesn't much matter, will having "less" distance for the current to travel allow for lower voltage use?

    2) Is there a solution mixture that would allow for faster anodizing times using the caswell 30 amp power supply? Reason I ask is because I have a spare 30gal (20gal effective volume) tank that would be handy to set up as a secondary bath for our production runs. For the most part we will be anodizing custom colors to order but there are a couple times a year where we run 2500 smaller pieces at a time. I could have two normal speed baths but was curious if a stronger concentration with higher amperage would yield faster cycle times through the bath.

    3) On the bigger production run stuff, a chiller would most likely be necessary as the surface area of a full rack would be 443"^2 and if I wanted any sort of "normal" time I assume the amps/volt level would require a cooler. I read some stuff about titanium cores rotting out and one person mentioned to remove the ground from the chiller. Are we talking the ground that would be connected to a core and attached to the chassis of the unit OR are we talking the ground on the 3 prong wall plug? If it matters, I have a little giant 14.2gpm MD-HC4 pump in transit to me. That alone is probably not enough flow to stay cool on large batch sizes, correct?

    4)short of bringing the power supply into a store with me, does anyone know what size banana plugs the back of the 30amp unit uses? I want to make a nice harness but I can't find the specs of what size the plug is for the main + and -

    I will post some pictures of the bench thus far once my phone finished charging.

  • #2
    Bringing the goods home from my shipping/receiving location...

    RO/DI filtration setup so I don't run out of pure water, ever... The funniest thing is, our city water is insanely clean right out of the tap. Less than 10ppm TDS. I thought the TDS meter was wrong so I went to the city website to find the water report and it even lists the TDS as <10! These filters will last many many thousands of gallons.

    Mock up of tank placement so I can figure out where the electrical needed to go...

    Subpanel and individual 20 amp circuits for all my anodizing needs...

    Tanks back on the rack after wiring complete. The gap on the second shelf is for some smaller cylindrical tanks (4 at a time) coming from ChemTainer. 7.5 gallon puppies for the custom color stuff I will be doing. The parts that get custom colored to order don't need a huge tank like the first 30gal tank on the middle rack which will be for the production stuff I have to do and always be black. Far short rack is for storage of other color tanks and a photo station for the custom parts people will want pics of.

    Closing it off with "quick release" panels so it looks nice... Also put a wood floor down on the shelves. Will be painting it red to match the walls when I am done building everyting.

    This was the first part of my agitation plumbing. At this point I only had the "in tank" runs started as I was waiting for the little giant to arrive. I hadn't dealt with what the spray bar along the bottom would be like yet.

    Little giant and water filtration system booster pump. Booster pump will have a more permanent location shortly.

    Just water to test the plumbing for leaks as well as play with agitation spray bar designs. I found what worked best in terms of turbulence was to have two outlets. Each is a 1/2" elbow with a cap and a 9/64" hole drilled in each cap. I tried a single 1/2' pipe with about 7 holes drilled in it spanning length of the tank and there just wasn't enough agitation going on. Good flow, but nothing vigorous. The picture below give an Idea of how agitated the solution will be.

    Last edited by blacktusk; 02-28-2017, 01:36 AM.


    • #3
      1) Theoretically having less distance between the anode and cathode will result in less bath resistance. Just how much of a difference would have to be determined experimentally. The trade off is potential shadowing. The closer the cathode is to the parts to more chance you have of uneven coating thickness in the part.

      2) If you are running constant current, there is little to nothing you can do to speed up the process except turn the current up higher. 6 electrons are required for each 1 molecule of Aluminum oxide. That is the basis of the 720 rule and you can't change that. Now about the solutions. Sulfuric acid is at its peak conductivity at 30% v/v. Any more or less than that and the conductivity drops fairly quickly. So the obvious question is why not run at 30% concentration? Because it destroys the coating is why. The higher the concentration, the quicker it dissolves the coating plain and simple. More is not better in this case.

      3) All I can say here is that if you are doing production runs, get a chiller. Has far as how big it should be depends on how much power is going into the tank and how efficient your heat exchanger is.

      4) I don't know. Maybe someone who has one can chime in.
      Last edited by KevinB; 02-27-2017, 08:19 AM.
      Process control doesn't give you good quality, it gives you consistent quality.
      Good quality comes from consistently doing the right things.

      Process control systems for Anodizers
      If a post helps you out LIKE the post
      I'm not an Amateur Metal Finisher. I've just been around the industry for a dozen years or so helping and consulting when and where I can.


      • #4
        Thanks Kevin. I figure that the most heat that could technically dump into the tank is 900 watts worth, 30v*30amps. However I doubt the power supply would ever run at max volts and amps simply because there would be no room left for its operation. That being said, I found a 1/4 HP culled that can handle 3000btu/hr. Which would be more than enough up to peak operating range. If I'm wrong, say so, just sharing my thoughts basically.

        should be running some test parts through the line by Wednesday! Pump showed up Saturday and got that all plumbed in, just need to fab up some hangers for the tank heaters.


        • #5
          The only time you should be seeing 30V in an anodizing tank is if you are running Type III at 18-24 ASF. I really couldn't speak to whether 3000btu/hr is enough or overkill. I tend to live in the world of electrons and ohms; that is a long way from thermodynamics.
          Process control doesn't give you good quality, it gives you consistent quality.
          Good quality comes from consistently doing the right things.

          Process control systems for Anodizers
          If a post helps you out LIKE the post
          I'm not an Amateur Metal Finisher. I've just been around the industry for a dozen years or so helping and consulting when and where I can.


          • #6
            Pictures added to second post!


            • #7
              So I'm filling up my tanks tonight. It's slow as the filtration system is a 75gpd setup. Anyway figuring out my measurements for all the solutions... the manual calls for 36oz of degreaser for every 4.5 gal. Then on the very next page it says 36 for 4. I have the 20 gal kit. I was only sent 10lbs of degreaser which means my mixture will be on the softer side. Should I order more or will being shy 1.25lbs of degreaser be OK?


              • #8
                I really can't answer as to whether your cleaner is concentrated enough, but I'll add this. The chemistry will deplete over time and you will need to make adds eventually to bring the concentration back up. Therefore, you will eventually have to buy more.

                There are 3 thing that govern a chemical reaction; concentration, temperature and time. To an extent, a reduction in one can be compensated for by increase one or both of the other two. If your concentration is weak, elevating the temperature and/or increasing the time should (but not always) yield the same results. This is simply a rule of thumb and does not apply to all chemistry.
                Process control doesn't give you good quality, it gives you consistent quality.
                Good quality comes from consistently doing the right things.

                Process control systems for Anodizers
                If a post helps you out LIKE the post
                I'm not an Amateur Metal Finisher. I've just been around the industry for a dozen years or so helping and consulting when and where I can.


                • #9
                  So I did my first test part. Everything was great, up until the very end. It degreased and passed the water brake test perfect, came out of the desmut beautifully brighter, anodized well, dyed well, rinsed from the dye and looked even better but as soon as I went to seal it almost all the black ran out. Instantly. It was disappointing and crazy lol.

                  info: 32in^2 SA, 6061, 9A/sqft, 80 minutes in the ano bath, 20 minutes in the dye. Tank temp for ano never went about 65, actually stayed around 63.5 to 64 the whole time. Dye was a little cold, 125 to 130 at first so I left it in for 20 minutes and it was back up to 140 proper by the end.

                  when I pulled it out of dye, I rinsed it in cold water and nothing bled. My Caswell sealant bath was not ready so I simply boiled water on the stove and the split second the plate went in the pot, the dye ran out.

                  the edges of the part stayed black as black, the front and rear of the part.... see the pictures. The anode wire also dyed and held color great during and after boil sealing.

                  any advice? Maybe the simple boil in water technique doesn't work with the Caswell system/dye? I have no way of measuring the anodize thickness right now but there is zero continuity on the part so I know there is an anodized layer.

                  Added: also to note, I added the black dye to 140° water. I didn't see the 180° requirement when adding the dye solution, could that have been a problem?
                  Last edited by blacktusk; 03-03-2017, 11:25 PM.


                  • #10
                    So I have made some progress. I called Caswell today and the friendly help was very much appreciated. The fellow suggested I must have lost continuity as the anodizing progressed. The aluminum wire had taken color great as well as the edges of the part. Used some titanium wire on another part and actually had the part take and retain color through the sealing stage.

                    I need some more practice as this part, even though it dyed well, lost all amperage with 45 minutes still to go according to what the 720 rule said it should take. It either lost connection again OR is an alloy that I wasn't expecting. What would you guys say?

                    Here is the part out of desumt...

                    Here is is after dying for 6 minutes roughly. Had to hurry up so I would be on time for picking up my Daughter from school.... Not sure why it is upside down either!

                    Then I pickled my racks. Not sure if I am supposed to wait longer but amps seemed to stop falling at 3.5... Do I add that to all my amp settings from the 720 calc when I use these?

                    Now I have some parts in the ano tank on the racks. Here they are in the desmut and then out out of desmut

                    Once these are dyed and sealed I will post some results.
                    Last edited by blacktusk; 03-04-2017, 11:27 AM.


                    • #11
                      Grrrreat success, alright.

                      Last edited by blacktusk; 03-03-2017, 08:56 PM.


                      • #12
                        So, just pondering some things with this first successful anodizing run.

                        1) the voltage slowly increased, it went past the maximum voltage the 720 calculator said I would see. It said I should see 15v, it ended up rising very slowly and settled on 16.1v. Amps were rock solid at 2.7a the whole time. I had 40 minutes to go but I wasn't seeing any change in voltage or amps for about 15 minutes. I pulled it out early and used the last 40 minutes on the timer to send it through the dye and sealant. So my question is when the power supply stabilizes like that and voltage no longer climbs or fluctuates, have I hit PAR? Should voltage keep rising? Does amperage start falling all of a sudden at the end?

                        I haven't finished insulating my tanks. The degreaser and desmut as well as the dye tanks don't have a problem keeping temp and barely cycle the heaters once up to temp. However, the sealant tank was taking forever and by the time I was ready to seal it was only at 180° I let it sit in the sealant tank a little longer but it seems to have sealed fine. I rinse, coated in gun oil (didn't have any WD laying around) and just now ( 4 hours later) I threw one of the wheels in bleach and nothing leaked out, rubbed out or changed finish wise. Obviously once I have my bench sealed and insulated, getting to 210 won't be an issue but just curious how good of a seal job was accomplished at 180 for 20 minutes? Does it HAVE to get to 210°?

                        Finally, I did not account for the surface area of the titanium racking. I figured I would do this test run without worrying to see what happens. Seems to have been fine, but maybe that is why voltage became unresponsive after 80 minutes? I read different things on these forums, Yes take account the SA of your Ti racking and I have also been told no, because it doesn't anodize.

                        Anyway, I am excited to start playing with this. We have 2500 small pieces that need to be done in a couple weeks and I am looking forward to doing it in house this time. We will now be 100% MFG'd in house which is an awesome feeling!

                        One more thing, the temperature is perfect right now! I actually have to use a small glass heater to keep the tank at 65°! I didn't run it with the parts in my last photo post and noticed the temps were dropping down to 59° and voltage was increasing. After heating the tank back to 65° votlage slowed down.
                        Last edited by blacktusk; 03-04-2017, 11:32 AM.


                        • #13
                          So I am a few hundred parts into production and jumping right in has been awesome. Learning lots fast in terms of how I want to optimize my ano line. As with my fresh status with all this, I have come up with more questions.

                          1) The ano bath seems to be way more "fizzy" now than it was when I started. I am running 532"^2 worth of parts at a time. The first two batches I could see the parts the whole time in the bath quite clearly. Now, there is so much fizz I can't see the parts much past 2.5" of the solution surface. Normal? What is the cause?

                          2)What is the most area people have run successfully with the caswell supplied 30/30 rectifier? I'd hate to load up 100 pieces to find out the rectifier actually decides it's too much half way through. If amps are set to 27 for example, and voltage is 22, there is no chance of it somehow getting to 30+ on volts OR amps unless I run into connection problems correct? I would definitely need a chiller at that part load. That would be almost 300 watts dumping into the tank. Right now, sans chiller I am getting away with 250 to 275 watts with a couple hour cool down between batches.

                          Here are some production pictures!

                          Last edited by blacktusk; 03-06-2017, 07:08 PM.


                          • #14
                            I was getting away with multiple pictures per post, but now it's not letting me get around the 2 picture max LOL.

                            Some weirdness after anodizing. Can't see this once dyed. After paying attention, I notice the lines only AFTER desmut. Not sure what it is, but it isn't affecting the parts and I guess its some weird machine finish side effect.

                            Weird build up in the bottom of the tank. Crusties from the Sulphuric acid and dissolved/chunked lead I think. Need to worry?


                            • #15