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  1. #31
    JOGARA's Avatar
    Lives in Derby, United Kingdom. Last Activity: 14 Hours Ago Has been a member for 1-2 years. Has a total post count of 293. Received thanks 11 times, giving thanks to others 54 times.
    https://youtu.be/6zoH5OUDsAo

    Not sure what is wrong. It looks like it is anodising but just doesn't want to take the ink.





  2. #32
    How long are you actually leaving it in the dye for? In the videos it seems you are just doing a very quick dip, I was of the understanding that itís more like 15mins.

    Are you going straight from anodising to dying after a rinse with distilled water?

    If it isnít accepting the dye, in my very limited knowledge I would say it can only be a few things - either the anodised layer isnít sufficient (poor connection/insuffficient power supply/not long enough in the run), or the pores are too small

    The size of the pore will depend on:
    Solution Concentration
    Solution Temperature
    Current Density
    Higher solution concentrations and temperatures give higher pore sizes, which are good for dyes
    Lower concentrations and temperatures give smaller pore sizes and thicker harder coatings. Higher current densities give thicker films and cooling is necessary to keep the temperature constant.
    .

    What solution strength have you got and at what current per square foot are you doing it?

  3. #33
    I did a lot of home anodising a few years ago but now get my parts done at a local shop.

    To get expected,repeatable & consistent results you need to follow a system using proven techniques. By far the easiest & cheapest is Caswell's LCD method & the 720 rule, you need to have a constant current power source where you control the amps going in. Don't buy anything/everything from Caswell, it can all be sourced cheaper if you look.

    I used to get excellent results but you MUST stick to the method or diagnosis of any problems is very difficult. Caswell's anodizing forum is very helpful & can sort out any problems as long as you are following a proven method & not just 'experimenting'.

    For dyeing you need to dip the parts for at least 10mins, I used to dip black for 15mins for repeatable results. If the dye isn't taking then either the part is not anodised or the anodised layer hasn't 'grown' the correct pore size.

    Unless you follow a method & unless you can control the amps entering the bath then every attempt is going to be an experiment with variable results which often means failure.

    Tip No'1. Use as big an acid bath as you can, helps massively with keeping the temp stable.

    Tip No'2. Use titanium to connect the part. Using ally wires was always hit n miss, I ended up screwing in titanium bolts to the part & connecting with titanium wire . . . never had a failed connection.

  4. #34
    JOGARA's Avatar
    Lives in Derby, United Kingdom. Last Activity: 14 Hours Ago Has been a member for 1-2 years. Has a total post count of 293. Received thanks 11 times, giving thanks to others 54 times.
    Quote Originally Posted by Zeeflyboy View Post
    How long are you actually leaving it in the dye for? In the videos it seems you are just doing a very quick dip, I was of the understanding that it’s more like 15mins.

    Are you going straight from anodising to dying after a rinse with distilled water?

    If it isn’t accepting the dye, in my very limited knowledge I would say it can only be a few things - either the anodised layer isn’t sufficient (poor connection/insuffficient power supply/not long enough in the run), or the pores are too small

    .

    What solution strength have you got and at what current per square foot are you doing it?
    I have left it in for 20-30 mins and even an hour. Same result as putting it in for 20 seconds.
    Yep Anodizing > Rinse > Dye > Seal
    Have not got to seal yet though...

    I have directly connected my alligator clips to the part and it still didn't accept the dye. The power supply is 48V 5A so plenty and I have left it in for 2+ hours yesterday.

    I believe my solution is around 20-25% acid to water.
    My acid was only 85% though so I might add some more.

    Calculated for my part 25V max, 2.7A for 72 mins.

  5. #35
    Quote Originally Posted by JOGARA View Post
    I have left it in for 20-30 mins and even an hour. Same result as putting it in for 20 seconds.
    Yep Anodizing > Rinse > Dye > Seal
    Have not got to seal yet though...

    I have directly connected my alligator clips to the part and it still didn't accept the dye. The power supply is 48V 5A so plenty and I have left it in for 2+ hours yesterday.

    I believe my solution is around 20-25% acid to water.
    My acid was only 85% though so I might add some more.

    Calculated for my part 25V max, 2.7A for 72 mins.
    Is your part electrically conductive across its surface after anodising?

  6. #36
    When you say your power supply is 48v 5a . . . . Exactly what power supply is it?

    You MUST use a power supply where YOU set the amps it's putting out.

  7. #37
    Quote Originally Posted by JOGARA View Post

    Calculated for my part 25V max, 2.7A for 72 mins.

    Sounds like he is using a constant current supply if he is able to set 2.7 amps... I assume you are using 6 asf and then using your cad program to determine surface area of the part multiplied by the number of parts being done at once to arrive at the result?

    From my research I've seen suggested that for 6 ASF you are looking at something around 1:15 acid to water ratio (6.7%), so actually if anything yours sounds significantly too strong. Caswell only mention battery acid (usually around 32%) at 3:1 with their 4.5 ASF, so unless my maths fails me that would be an actual acid/water ratio of around 1:11 or roughly 9%, again making your mixture far too strong if using their 4.5asf method. Oddly enough that should result in a larger pore size however... perhaps you actually end up with pores too large to hold on to the dye? Conversely the excess acid concentration may mean that it is breaking down as fast as it builds up, leaving you with an insufficient anodised layer.

    I would suggest you adjust your solution to the correct strength and see how it goes.

    Also don't submerge crocodile clips into the bath, no metals other than the lead/alu cathodes and alu/titanium wires/rods should be in contact with the acid solution. Other than potentially contaminating the bath, the current will try to flow through the steel clips instead of the aluminium and your anodising will stop.
    Last edited by Zeeflyboy; 15-10-2017 at 10:28 AM. Reason: ratios back to front!

  8. #38
    JOGARA's Avatar
    Lives in Derby, United Kingdom. Last Activity: 14 Hours Ago Has been a member for 1-2 years. Has a total post count of 293. Received thanks 11 times, giving thanks to others 54 times.
    I have a DPS5015 so yes can set max current and voltage.

    I had use use STL to surface area calculator http://preview.codecanyon.net/item/3...762.1508073459
    Then metric to imperial and used this 720 calculator http://www.ndhsubmersiblescience.com/ano/720rule.html

    Worked out to the 25V max, 2.7A at 72 mins for my parts.

    My clips are not in the bath, I read about the problems with contamination.

    I think ill split my tank in 2. Then add 1L to one of them and see if that is okay.

  9. #39
    What cad program are you designing in? I can't imagine you need to use an STL to surface area calculator, should be able to pull that info straight from the CAD program.

    How big is your bath? Will splitting in two and diluting with 1L bring you to something under 10%?

  10. #40
    JOGARA's Avatar
    Lives in Derby, United Kingdom. Last Activity: 14 Hours Ago Has been a member for 1-2 years. Has a total post count of 293. Received thanks 11 times, giving thanks to others 54 times.
    Quote Originally Posted by Zeeflyboy View Post
    What cad program are you designing in? I can't imagine you need to use an STL to surface area calculator, should be able to pull that info straight from the CAD program.

    How big is your bath? Will splitting in two and diluting with 1L bring you to something under 10%?

    Fusion 360 but can't work out surface area for some reason.

    I have 5L tubs. Only 3L of water plus added ingredients.
    By weight I have 3000g of water and 400g of 85% acid. So that is 7.5% of 85% acid?

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