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CASWELD Our new 'Welding' rods

Introducing our latest range of Welding and brazing rods, for the repair of Pot Metal, Aluminum, Stainless and much more.

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About to build my first setup, mind giving me a hand on a couple noob issues?

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  • #16
    The ramp time depends on the alloy and target current densities. If you are running a robust alloy (5xxx, 6xxx or 7xxx) at low current densities, you can probably get away with just setting the the power supply output directly. Having said that, I would probably still run an initial ramp for about a minute or 2. In commercial shops, we never see a run start without a 3-4 minute ramp. Maybe gardinhackle can chime in about how he ramps his stuff.Hes got more hands on experience than I do. I'm just a technical junkie.
    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 spread the love and LIKE the post
    _____________________________________________
    Last edited by kevinB: Now. Reason: superfluous typo's

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    • #17
      Originally posted by KevinB View Post
      Maybe gardinhackle can chime in about how he ramps his stuff.Hes got more hands on experience than I do. I'm just a technical junkie.
      I run CV as the big shops do and 30 secs is number I stick with.

      Comment


      • #18
        All is going great with the build Will post pics as soon as I have something worthy. Got my fist order from Caswell and I'm excited. Hope to start "cooking" Alu next week

        More on the noob questions.

        - Having trouble with electrolite bath. Internet information and math overload. Most from people using battery acid. I have access to 98,9% pure sulphuric acid. I don't have a scale to measure weight, but I measure by volume. How much acid do I need for a 50L bath?

        - I'll be working (de-burring, chamfering) and brushing the cut pieces right before anodising. So am I correct that I can skip de-oxing and desmutting? If so, just degrease thoroughly, rinse and straight into the acid bath be ok?

        - I also have access to used titanium rack. I was thinking of building a small rack, for better sustain and contact instead of hanging from titanium wires. My pieces are 1 to 2mm sheets only. Will the surface area of the titanium rack affect the anodising current density calculations? I was planning on a place holder style design to fit all different sizes, but I think maybe this is not the best option?

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        • #19
          If you are using 98+ % sulfuric, get some titration equipment and learn how to use it. It's the only way to know for sure what you have. Also, as you use your bath, you will need to make adds occasionally. That's when titration becomes really important.

          Will the surface area of the titanium rack affect the anodizing current density calculations?
          No, titanium does not pull any appreciable current compared to aluminium. Do not include any titanium in your area calcs.
          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 spread the love and LIKE the post
          _____________________________________________
          Last edited by kevinB: Now. Reason: superfluous typo's

          Comment


          • #20
            Originally posted by KevinB View Post
            If you are using 98+ % sulfuric, get some titration equipment and learn how to use it. It's the only way to know for sure what you have. Also, as you use your bath, you will need to make adds occasionally. That's when titration becomes really important.


            No, titanium does not pull any appreciable current compared to aluminium. Do not include any titanium in your area calcs.
            I do have such equipment at work, and I will be learning as I'll also be doing weekly titration for copper plating baths in the future. But right now I'd like to get started anodising and can't seem to figure out how many ml/L of sulphuric acid I need to add to de-ionized water. I've pondered on just getting battery acid and follow Caswell's guide, but since I can get the sulphuric for free and my tank being 50L… That would be a lot of money wasted on battery acid :/

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            • #21
              You need to be at 180-190g/L of H2SO4 in your bath
              The density of H2SO4 is 1.84g/cm3.
              There is 1 cm3 in 1 mL.
              There are 1000 mL in 1 L.
              I'll let you run the math.

              Don't forget to include the fact that you are using 98% H2SO4 (although if you assumed 100%, you would still be ok).

              Post back with the amount of H2SO4 you are going to use along with the bath size.
              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 spread the love and LIKE the post
              _____________________________________________
              Last edited by kevinB: Now. Reason: superfluous typo's

              Comment


              • #22
                Originally posted by KevinB View Post
                You need to be at 180-190g/L of H2SO4 in your bath
                The density of H2SO4 is 1.84g/cm3.
                There is 1 cm3 in 1 mL.
                There are 1000 mL in 1 L.
                I'll let you run the math.

                Don't forget to include the fact that you are using 98% H2SO4 (although if you assumed 100%, you would still be ok).

                Post back with the amount of H2SO4 you are going to use along with the bath size.

                Kevin, you’re gold mate. I can’t think of how to thank you for all your help! Very vey much appreciated!

                Yeah, I’ll calculate 100% for simplicity, and then extrapolate a “teaspoon” extra for “good measure”

                ok, so for 50L…
                185g x 50 = 9250g of H2SO4 needed.
                9250/1.84g = 5027ml of acid into 50L of water. Wow, that much?

                Think I'll do 45L, as I don’t want the tank so full.

                (185 x 45) / 1.84 = 4,524L (plus the teaspoon, lets say, 0.126ml) = 4,65 L of acid into 45 = total volume 49,65L …

                Sweet !

                BTW - if this assumption correct? -> I'll be working (de-burring, chamfering) and brushing the pieces right before anodising. So am I correct that I can skip de-oxing and desmutting? If so, just degrease thoroughly, rinse and straight into the acid bath be ok? These are 2D, 1mm regular aluminium sheets (5754) I'll be working with.
                Last edited by Pancrecio; 08-22-2016, 10:40 AM.

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                • #23
                  5L of H2SO4 seems about right. I think the bath should idealy be running in the 15-20% concentration range, but that's kind of a guess since I've never run the numbers to convert 180g/L to a percent by volume.

                  What are you brushing the parts with?

                  De-oxing and de-smutting are the same thing. The deox bath follows the etch. So I think you are asking if you can skip the etch and deox? If so, I would have to refer you to someone with a bit more hands on experience ( gardinhackle are you there?).

                  From a purely process control point of view, be consistent with the parts thought the entire manufacturing process. This include material handing before machining, though machining, after machining, cleaning, deburring, etc, etc. A consistent process will give you consistent quality. Once you have that you can then decide/determine if etching and deoxing is needed.
                  kevin
                  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 spread the love and LIKE the post
                  _____________________________________________
                  Last edited by kevinB: Now. Reason: superfluous typo's

                  Comment


                  • #24
                    Pancrecio,

                    If you are running 6061 you can skip the desmut stage although it doesn't hurt to do a 30 sec dip. The only reason to use the etch for 6000 series Al is to either put a matte finish on the parts or stripe them for redo so it's your call. Just a reminder that the electrolyte density you are working to is for the 12 ASF method, not the LCD method.

                    Comment


                    • #25
                      Originally posted by KevinB View Post
                      5L of H2SO4 seems about right. I think the bath should idealy be running in the 15-20% concentration range, but that's kind of a guess since I've never run the numbers to convert 180g/L to a percent by volume.

                      What are you brushing the parts with?

                      De-oxing and de-smutting are the same thing. The deox bath follows the etch. So I think you are asking if you can skip the etch and deox? If so, I would have to refer you to someone with a bit more hands on experience ( gardinhackle are you there?).

                      From a purely process control point of view, be consistent with the parts thought the entire manufacturing process. This include material handing before machining, though machining, after machining, cleaning, deburring, etc, etc. A consistent process will give you consistent quality. Once you have that you can then decide/determine if etching and deoxing is needed.
                      kevin
                      Originally posted by gardinhackle View Post
                      Pancrecio,

                      If you are running 6061 you can skip the desmut stage although it doesn't hurt to do a 30 sec dip. The only reason to use the etch for 6000 series Al is to either put a matte finish on the parts or stripe them for redo so it's your call. Just a reminder that the electrolyte density you are working to is for the 12 ASF method, not the LCD method.
                      I'm getting 5754 blanks, which are laser cut and one side still even comes with the factory laminated plastic protection.
                      From what I gather, I could use Caustic Soda for a quick dip etch. I'm not looking for matte finish right now, just to get it right from the get go.
                      So my protocol so far would be...

                      1 - Prepare part, remove plastic and glue residues, de-burr, bevel, etc
                      2 - Fixed to block of wood, brush with WD-40 and scotch brite, remove WD-40 with acetone (as seen on youtube, will refine with proper tools in the future)
                      3 - Degrease bath agitated at 110ºf, rinse very well.
                      4 - Caustic soda @ 10% for under 30 seconds (110ºF - 43ºC ) - rinse very well
                      5 - CC/LCD Anodise - Rinse well
                      6 - Dye bath - Rinse well
                      7 - Sealing.

                      So what would be the ideal electrolyte mix for me @gardinhackle?

                      Comment


                      • #26
                        First off de-grease at 140 deg minimum. The LCD method requires 3 to 1 (water to battery strength acid). I don't run LCD so don't quote me.

                        Comment


                        • #27
                          Originally posted by gardinhackle View Post
                          First off de-grease at 140 deg minimum. The LCD method requires 3 to 1 (water to battery strength acid). I don't run LCD so don't quote me.
                          That's where all the internet math got to me. I usually see references to mol/L, then also battery acid can vary from 30%-50% h2so4 concentration. This math is just way above me.

                          But I checked the Caswell manual page 16, and it reads

                          "Sulfuric Acid Concentration

                          Most conventional sulfuric acid anodizing is carried out using electrolyte concentrations ranging from 165-225 g/l free sulfuric acid. An increase in the sulfuric acid concentration intensifies re-dissolution of the coating, producing a pore structure of greater average diameter allowing dyeings of greater intensity. It is most important to maintain the free sulfuric acid concentration within narrow limits to ensure successive dyeings of equal intensity. "

                          So I'm assuming I'm good to go. It's very similar to copper sulphate baths we use, which is also a reassurance.

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                          • #28
                            Hello Pancrecio,
                            Can you post the source of that quote?

                            edit, nm, it came from the book (boot to the head)....

                            While higher dissolution will occur with higher concentrations, I think the the pore size is governed by the voltage applied. If you run 24ASF, your applied voltage is much higher than when you run 12ASF. Parts run at 24 ASF won't take dye.
                            Last edited by KevinB; 08-24-2016, 10:36 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 spread the love and LIKE the post
                            _____________________________________________
                            Last edited by kevinB: Now. Reason: superfluous typo's

                            Comment


                            • #29
                              Originally posted by KevinB View Post
                              Hello Pancrecio,
                              Can you post the source of that quote?

                              edit, nm, it came from the book (boot to the head)....

                              While higher dissolution will occur with higher concentrations, I think the the pore size is governed by the voltage applied. If you run 24ASF, your applied voltage is much higher than when you run 12ASF. Parts run at 24 ASF won't take dye.
                              But isn't the entire Caswell manual geared towards LCD ? There is no mention of 24ASF or 12ASF … I've been using the 720 calculator which is pre-set to 6ASF, and looking at 0.75mils, both of which I've seen references as being really great for small scale dye anodising. Caswell suggests 4.5 is best for dyeing. I'm good with whatever works best!

                              It suggests 1:3 battery acid to water ratio, which is a bit vague as commercial battery acid concentrations can vary from 30% to 50%.

                              I'm not sure if this math is correct, but here goes

                              1 : 3 of acid concentration in percents would mean the proportion of free acid in the 1 part (minus the water) divided by the 3 parts (plus the water volume of part 1)

                              50%/L concentration… at 1:3 that would be 500ml:3500ml = 14,2% sulphuric acid volume.
                              40%/L concentration… at 1:3 that would be 400ml:3600ml = 11,11% sulphuric acid volume.
                              30%/L concentration… at 1:3 that would be 300ml:3700ml = 8,1 % sulphuric acid volume

                              My previous calculations of 185g/L gave me 4.65L acid into 45L water, which is 10,3% volume.

                              Please correct me if I'm wrong but the ballpark numbers seems match up nicely.

                              Comment


                              • #30
                                Pancrecio, since you are running such a low current density the exact amount of acid to water ratio is not critical. If you are out by a few g/L it's not that big of a deal. The process will still work. If you have access to sulfuric acid in battery grade concentration then add 3 parts water. You will be in the range for what you want to do, especially for the tank size you intend to work with.
                                Last edited by gardinhackle; 08-30-2016, 11:13 AM.

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