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Thread: Powder coat thickness

  1. #1
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    Powder coat thickness

    I’m casting my own bullets (.45-70 350 gn @.458) and I’m wondering how much the powder coating will increase the bullet diameter before I size them.

    Thank you
    CZ455 American .22LR, Marlin 1894 .357 and 1935 8mm Mauser K98k S42/G (RC), Remy .308 AICS, RPR 6.5 creedmoor, no4 1* LB 1943, NRA RCO

  2. #2
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    This is going to sound really flippant, but it depends on how thick you coat them.

    I cast to throat size and then coat, leave a week and then size and lube.

  3. #3
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    Quote Originally Posted by lightning22 View Post
    This is going to sound really flippant, but it depends on how thick you coat them.

    I cast to throat size and then coat, leave a week and then size and lube.
    I just wondered if the increase to diameter was in the region of .005-.008” per coat.
    I think its a weekend project in the man cave.
    CZ455 American .22LR, Marlin 1894 .357 and 1935 8mm Mauser K98k S42/G (RC), Remy .308 AICS, RPR 6.5 creedmoor, no4 1* LB 1943, NRA RCO

  4. #4
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    When I powder coat for shooting a light coat usually gives 2-3 thou increase , So after casting I size then powder coat and then resize to final diameter.

  5. #5
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    Quote Originally Posted by acmsarh View Post
    When I powder coat for shooting a light coat usually gives 2-3 thou increase , So after casting I size then powder coat and then resize to final diameter.
    Excellent, just the sort of info I’m looking for.
    Thank you
    CZ455 American .22LR, Marlin 1894 .357 and 1935 8mm Mauser K98k S42/G (RC), Remy .308 AICS, RPR 6.5 creedmoor, no4 1* LB 1943, NRA RCO

  6. #6
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    Could I ask where you get your powder coating powder from?

    Thanks

    Bill

  7. #7
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    on the bay about £10 a kg

  8. #8
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    I bought the gun from Electrostaticmagic and asked them the same question. They said thickness should only be 7-9 microns (1000ths of a mm) and this has been borne out from my testing.

    They also supply the powder.

    I looked at the "Wet" methods online and decided against it. From what I saw you often end up coating them twice and messing around with acetone didn't appeal either.

    The gun works really well and produced perfect results first time of use. Of course you need a small compressor but definately worthwhile.

    https://www.electrostaticmagic.co.uk/

  9. #9
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    And the bullets look SO cool. I use red or Nato green

  10. #10
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    Just been out and measured some 44-40 bullets uncoated and sized v coated unsized.
    Uncoated sized .4291".
    Coated unsized .4318".
    Total size increase from a light powder coat is an increase in diameter of .0027" , 2.7 thousanths of an inch or 68.58 microns.
    I have tried the wet coating method using Acetone and powder , What a mess that was and when baked it looked like it had been applied by spitting it on.

  11. #11
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    Quote Originally Posted by markH View Post
    And the bullets look SO cool. I use red or Nato green
    What method do you use to paint and cure the bullets? Do you place them on a tray pointing up, spray, then bake?

  12. #12
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    I use a piece of perforated steel. I pre bake to 140 degreed so the bullets are hot when I spray. Then I spray, turn up to 180 degrees and bake for 20 mins.

    I use perforated steel because sometimes the bullets are stuck to the tray and they're easier to break off.

    Apparently some people use a non-stick baking sheet but I don't really see how the earth connection is maintained.

  13. #13
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    Quote Originally Posted by acmsarh View Post
    Just been out and measured some 44-40 bullets uncoated and sized v coated unsized.
    Uncoated sized .4291".
    Coated unsized .4318".
    Total size increase from a light powder coat is an increase in diameter of .0027" , 2.7 thousanths of an inch or 68.58 microns.
    I have tried the wet coating method using Acetone and powder , What a mess that was and when baked it looked like it had been applied by spitting it on.
    But you're comparing sized uncoated bullets with unsized coated bullets The sized uncoated have already been reduced by the sizing process whereas unsized coated are as cast diameter and then coated.

  14. #14
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    The coated unsized only the coating has not been through the .429" die the bare bullet's have already beed sized to .429 before powder coating , The reason for 2 step resizing is that just to cast then powder coat before the sizing can be to big a step in size reduction , It can cause the bullet to smear going through the die so you size in stages.

  15. #15
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    Quote Originally Posted by markH View Post
    I bought the gun from Electrostaticmagic and asked them the same question. They said thickness should only be 7-9 microns (1000ths of a mm) and this has been borne out from my testing.

    They also supply the powder.

    I looked at the "Wet" methods online and decided against it. From what I saw you often end up coating them twice and messing around with acetone didn't appeal either.

    The gun works really well and produced perfect results first time of use. Of course you need a small compressor but definately worthwhile.

    https://www.electrostaticmagic.co.uk/
    I use this same kit, it's excellent.

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