Anyone else using Cerakote? Tips?

Discussion in 'Shop Talk - BladeSmith Questions and Answers' started by aarongough, Dec 12, 2013.

  1. PT Doc

    PT Doc

    Dec 24, 2011
    Could it be related to the auto body shop? Things in the air or that have settled? I have read about this with issues with other applications in similar settings. Try in another setting and I would guess you will not have this problem.
     
  2. Brian Avila

    Brian Avila

    Jan 2, 2011
    So I work with a custom gun smith for my Cerakoting. What we do is almost the same thing you do. But there are a couple of differences.

    I take my blades to 120 - 220 grit: flats, bevels, spine, etc,
    Soak in acetone.
    Sand blast with 120 grit media.
    Use compressor to get rid of all the sand.
    Coat the blades, try to do it not to thick and even. ( Blades are hung when sprayed and hung while curing )

    Cure temps we use is 250F, we have had good success with 200F as well.

    I really think taking the blade to a higher grit, and sandblasting with a higher grit media as well as using acetone will help you a lot. A pictures of your problem would help some too.

    Here is the outcome of some of the cerakoting we have done. Just for reference to see if you see anything different or same problems.

    [​IMG]

    [​IMG]

    [​IMG]

    There are a couple of times that we have had to take the knives to a higher grit in the grinding which is why I say 220 to get the sandblast to even out and get a smooth finish. I think it is really important to take the knife to a higher girt and sandblast with 120.

    But you are right, take the time and do it right the first time. It isn't excessive.
     
  3. woodwrkr221

    woodwrkr221

    393
    Jan 28, 2011
    Before I spray any finish, though it's usually varnish or lacquer, I always wipe the piece off with a painters "tack rag" which is just sticky cheese cloth that picks up all the last pieces of trash left on the piece. This is the last step before spaying, but should come before the preheat the others mentioned.

    Also you may need to make sure the pressure is adjusted correctly on the compressor. If the pressure is too low spray guns will sometimes spit.

    I've lots of good reports on Cerakote. I hope you get the bugs worked out.
     
  4. htony1

    htony1

    26
    Nov 18, 2013
    In my experience (on guns) it's tough To work with. I used a fine light mist at about 30-31psi with a moisture trap. It is certainly tougher than most coatings but tricky to work with
     
  5. A Justice

    A Justice

    763
    Oct 29, 2013
    Oven cured Cerakote just has much better wear resistance than Gun Kote. Gun kote is fine for knives, I have a CRK fixed blade with Gun Kote, but on firearms Cerakote significantly outperforms Gunkote. I would only assume that it would be that much better on knives as well. Both are great coatings on brand new knives, but after pulling a knife in and out of a sheath 1,000 times and abusing it, I would bet that the Cerakote will look better.

    Like I mentioned, I haven't seen many knives at all Cerakoted, and I was really interested in it. Good luck Aaron, it does seem like moisture or gas could be the culprit, and also light coats are helpful. I don't have enough reference to say if you're coating too thick, but that is a concern with oven cured coatings. Is the deficiencies random or do they seem to occur in certain areas of the blades each time?

    If you haven't nailed down a color scheme yet, the best non-reflective all terrain solid color is a slightly dark gray - you can get it by using the Tungsten Cerakote as a base and darkening it with a small amount of black (I wouldn't do more than 1 part black to 6 parts Tungsten). Black actually stands out more than most colors in daylight.
     
  6. aarongough

    aarongough

    Mar 12, 2013
    Yes. Sometimes naivety and assumptions get the better of me and I will admit that I wasn't gassing off as instructed... Turns out Cerakote doesn't tolerate that kind of tomfoolery.

    That being said I might have found part of the culprit at the shop tonight. I headed there with the new air filters and such intending to spend an hour or so performing maintenance on the compressor. However when I removed the old water/oil filter I was surprised at what I found:

    [​IMG]

    A few months ago the compressor got left on overnight accidentally, on that same night the air-hose in the sandblaster failed and the compressor ended up running for many hours straight. It cooked itself a bit in the process, but after changing the oil and stuff it seemed to run ok so we continued using it. What you see above is something we missed... Seems the compressor vaporized and burned a lot of oil, and that oil got into the air-hoses where it condensed leaving this delicious 'compressor butter'...

    The water/oil filter, regulator, and the manifold were all full of this stuff. About 1/8" thick on the walls of all the piping. I drained the tank and took the large bolt out of the side of it. There's some of the condensed oil at the bottom of the tank but it's otherwise remarkably clean... I'll be replacing all the piping and components as I think it would be a fools errand to try to clean them.

    Wouldn't be surprised if that was causing part of the issue given that I didn't have a filter on my HVLP gun!
     
  7. aarongough

    aarongough

    Mar 12, 2013
    I've closely inspected the blades under good light and it doesn't seem that there's any foreign matter stuck to the paint... It could be, but others are spraying different finishes in our shop with no issues so I think it's likely to be a problem with the prep...

    Nice job on those knives! I would like to switch to 100 grit media I think, but I've had real problems finding it near me. i will have to look harder and swap out the media in my sandblaster.

    I had been thinking about using a tack cloth, but I wasn't sure if the wax would get grabbed by the rough sandblasted surface. I will give it a go on a test piece soon and see how it works. I'm sure I'll get it worked out (especially with all this help) I'm pretty stubborn about this kind of stuff! :D

    Thanks, I just got a good dessicant drier that will be attached directly to my gun, hopefully that will help things!

    I haven't tried the other finishes personally, but from what I've read on gun forums most people seem to agree that Cerakote is one of the most (if not the most) durable finishes around, that was why I ended up wanting to try it out...

    To be honest most people ask for black. If I was asked to recommend a color for a soldier's knife it would likely be coyote brown or flat dark earth, similar colors are fairly common in nature and will blend in with the majority of camo schemes... I agree about black not being the ideal color. I may well end up getting a pot of coyote brown just for military customers, other customers seem to mainly want black so far.

    For reference guys this is what the black Cerakote looks like when I manage to get it right. The fact that it comes out so nice is the only reason I'm still willing to fiddle with it! It really doesn't look like paint in person, looks like the blade itself is just made from some black material almost.

    [​IMG]

    Here's hoping I can start getting it right more often! The knife above had to be re-coated 3 times before the finish came out well.
     
  8. Brian Avila

    Brian Avila

    Jan 2, 2011
    When you figure it out let us know. I am curious.
     
  9. aarongough

    aarongough

    Mar 12, 2013
    I haven't yet had the chance to try again. I'll be taking all the advice given so far and coating some blades this weekend... If that doesn't give the desired results then will definitely take you up on your kind offer!

    Will do!
     
  10. jforbush

    jforbush

    Sep 29, 2007
    I am trying really hard not to get myself kicked out of this forum right now...........
     
  11. Brian Avila

    Brian Avila

    Jan 2, 2011
    ? what ?
     
  12. PT Doc

    PT Doc

    Dec 24, 2011
    Hehehe...compressor butter...hehehe.

    Did you finish the black blade in the same shop? Before the compressor butter fiasco of 2013?
     
  13. jforbush

    jforbush

    Sep 29, 2007
    I posted up a simple post about the OP calling me and I get a policy violation for "selling"! All I did was post that I am a applicator and have worked with Cerakote for a while and could provide assistance if the OP wanted it. Left my email address and cell number but I guess that is "selling". The Mods on this forum drive me up a wall sometimes.....that is why I let my maker subscription go and rarely post anything anymore.

    Sorry to the group that I was willing to assist a fellow craftsman.....it won't happen again in a open forum.
     
  14. bbuford

    bbuford

    3
    Dec 9, 2013
    I do auto restoration work, I also paint (cerakote) guns for a couple of spec ops guys. Your tactics sound good and I will add that a clean gun makes a painter happy, tack rags are designed to brush against the surface lightly not scrubbing hard to prevent contamination from the rag. When you open up a new tack cloth it should be completely unfolded and hung up for a few minutes before you use it the first time so the resin will flash off, then make a loose ball and lightly wipe your surface. Preheat to prevent outgassing is a required step, I spray medium coats with about four to six inch gun distance with a minute or two between coats so that I do not build up solvent in the film. One trick I learned about the air source was to take a blow gun and hold it into a white towel and hold the trigger down for a couple of minutes and then look for contamination in the towel.
     
  15. mccandmatt

    mccandmatt

    358
    Oct 29, 2013
    you said you have water and oil traps, most shop compressors will have a water trap but what you might be thinking is an oil trap is actually oiler that oils pneumatic tools. You might actually be spraying oil into your ceracote and when heating it, it is causing your issue.


    Nevermind this was already addressed, that you're using a filter system. My mistake.
     
    Last edited: Dec 13, 2013
  16. 12345678910

    12345678910

    Jul 13, 2009
    How about just using compressed nitrogen or argon ?

    That should be a head start over compressed air
     
  17. aarongough

    aarongough

    Mar 12, 2013
    Yep, black blade was finished in the same shop, same compressor and after the 'butter fiasco'... I think I just got lucky. We bought $500 in new parts today to replace all of the lines/parts that are attached to the compressor, hopefully that (in addition to the dessicant drier that I have added to my gun) will help keep the finish nice.

    Sorry to hear that. I took it in the manner which you intended i believe. If I have issues after the compressor if overhauled I will get in touch!

    Sounds like good tips all around! Thanks, I will keep those in mind!

    Yeah, it was definitely a filter as opposed to an oiler.. However it was all full of gunk. We've bought all new parts and I will be rebuilding everything tomorrow.. We'll see how it goes!

    Always with the fancy solutions :D

    That woud definitely work! I'll try the compressed air from the overhauled compressor with the new filters and all that jazz, plus the off-gas and stuff. If that doesn't work then alternative pressure sources might be something to look into for sure...
     
  18. aarongough

    aarongough

    Mar 12, 2013
    Ok, so yesterday I spent the day re-building the compressed air system at the shop. New pipes and hoses, new manifold and couplers, new regulator and 2 new filters. Everything was replaced except the compressor itself.

    [​IMG]

    Also got an inline drier/filter which is setup to attach straight to my HVLP gun:

    [​IMG]

    I then prepped the blades and applied a new batch of the coating. Here was the process:

    • Degrease blades in ethanol
    • Blast blades with 80-90 grit sand at 115PSI
    • Blow any excess grit off blades with compressed air
    • Brush down blades with clean (new) paintbrush to make sure all grit is gone
    • Gas-off blades at 300ºF for 60 minutes
    • Mix Cerakote (27ml of graphite black, with 1.5ml of hardener), thoroughly mix, strain through fine automotive paint strainer.
    • Spray light coats onto blades while they're still warm. Coats were lightly sprayed from 3-4" away from the parts.
    • Bake at 250ºF for 2 hours.

    Unfortunately even with the extra prep steps the coating still has defects. Below are some pictures of the defects. The spots feel rough and scratchy when you run your fingers over them, like little pieces of sand or something. Very few of these defects could be seen on the blades before they were baked. The coating seemed to go on a little thicker than usual this time, normally there is a bit less texture to it.

    [​IMG]

    [​IMG]

    [​IMG]

    This batch has been ready to go for over 2 weeks except for this coating issue. It's starting to be a real pain.
     
  19. Karda

    Karda Banned BANNED

    Jun 1, 2007
    Imagine how the moderators must feel, with members not reading or understanding the clearly posted rules.....or blatantly disregarding them.
    As in your homepage. You do not have a knifemaker/craftsman/service provider membership, yet you feel it's ok to help yourself to free advertisement..... that others pay for?
     
  20. J-siah

    J-siah

    Jan 28, 2008
    What psi are you using on the paint gun?
     

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