Anyone else using Cerakote? Tips?

[aarongough]

Hey guys!
I've been using Cerakote for a bit now, but I'm finding that it's very finicky and labor intensive to get it to work right. On both my current batch of knives and the last batch I've had to re-do the coating several times in order to get an acceptable finish, and it's still not 100% in my estimation. I'm all too aware that the type of knives I make are going to start getting beat up the minute the customer receives them, but I still want them to be as perfect as I can make them when they leave my hands.

The predominant issue I'm having is that little gritty clumps of something keep showing up in the finish. I have been unable to work out whether this is grit leftover from the sandblasting process, or whether it's clumps of pigment or something else. It doesn't look like this is stuff settling on the finish, instead it's either something in or under the finish.

For reference my current process is:

• Heat-treat blades
• Fit scales to tang with temporary pins
• Shape scales and tang to final shape
• Removes scales
• Degrease blade with simple green, then wash in Ethanol
• Add hanging fixture made of mechanics wire to blade through tang
• Sandblast blade at 115PSI with 80-90 grit aluminum oxide
• Blow any grit off blade with 115PSI compressed air
• Mix Cerakote, strain through fine automotive-paint type cone strainer
• Spray on Cerakote with mini HVLP spray gun, 2 light passes from about 8 inches away, round spray pattern
• Hang for 10 minutes in clean area to dry
• Flash cure at 250ºF for 10 minutes
• Once the batch (~6 blades) is done I cure the lot of them for 2 hours at 200ºF

I'm going to read through the application manual again to see if there's something I'm doing wrong, and I'll probably also contact Cerakote for advice, but I was curious in the meantime if anyone else was using Cerakote and what your process/results were like.

At the moment I find the process frustrating because the results don't seem to relate to how careful I am with the prep. I'm not exaggerating at all when I say it would be much easier and less time consuming to do a 800-1000 grit hand-rubbed satin finish (because I keep having to re-do the Cerakote)... I hope other people have had better luck.

Thanks!
-Aaron

 

[drop of a hat]

I've had it done as a modification on my watches, and it comes out smooth. All it has is the Cerakote texture, which can feel gritty to some.

 

[aarongough]

I've had it done as a modification on my watches, and it comes out smooth. All it has is the Cerakote texture, which can feel gritty to some.

When it comes out right it's really nice, very silky smooth finish. Unfortunately I'm getting distinct bits of 'grit' or something in the finish... It's not all over the surface, just maybe 5-6 spots per side when it comes out bad. I'll have to see if I can get some photos.

 

[Teter09]

Do you have any sort of moisture removal on your compressor lines? I'm unsure since you use a sandblaster which usually requires a very large capacity compressor and most folks have something to remove moisture on a 60 gallon or more compressor, but also these could be done in a small enough enclosure you might not be using a large compressor...and I've seen lots of folks try to use small compressors with no thought to the moisture being pumped out. You would need to make sure the moisture is removed prior to going through the HVLP gun as well as when you spray off any residue from Sandblasting. Not sure of your background so covering the bases.

IF not moisture...are your hanging wires clean? I've seen where they might have 'dust' from being used previously and it can fall onto what you are spraying.

You said it looks like it is in or under the finish, so I'm leaning towards moisture...or perhaps the cerakote 'dust' from the wires since it would blend in perfectly.

Do you by chance have pictures?

 

[A Justice]

I have never used Cerakote on a knife, and I noticed that there aren't many people that do. Even though it's the best coating for guns, better than Gunkote.

Try heating the knives to the curing temperature before applying the coating. I always had to heat gun parts to take care of the oil that degreaser wouldn't. It takes excessive preparation to get good results with Cerakote.

 

[aarongough]

Do you have any sort of moisture removal on your compressor lines? I'm unsure since you use a sandblaster which usually requires a very large capacity compressor and most folks have something to remove moisture on a 60 gallon or more compressor, but also these could be done in a small enough enclosure you might not be using a large compressor...and I've seen lots of folks try to use small compressors with no thought to the moisture being pumped out. You would need to make sure the moisture is removed prior to going through the HVLP gun as well as when you spray off any residue from Sandblasting. Not sure of your background so covering the bases.

IF not moisture...are your hanging wires clean? I've seen where they might have 'dust' from being used previously and it can fall onto what you are spraying.

You said it looks like it is in or under the finish, so I'm leaning towards moisture...or perhaps the cerakote 'dust' from the wires since it would blend in perfectly.

Do you by chance have pictures?

Skepticism of my experience is always a good thing! I've done some spraying before but it was always stuff where sanding back was an option. That's not on the table with Cerakote...

We have a moisture/oil trap on the compressor, but I should double-check that it's working properly. I will admit that maintaing the compressor is not something that I've taken responsibility for personally, as others in our shared shop use it for spraying nitro and I *assumed* that they maintained it properly. Perhaps that is not the case... I will double-check the moisture trap. I also have some disposable dessicant air-dryers on the way that I can attach to my HVLP gun to make doubly sure.

The hanging wires I use are only single-use. I make them from thin galvanized wire and just toss them each time as they have to be cut in order to get them off the knives.

Interesting that you think the 'grit' might be moisture related, I will admit I hadn't thought of that as a possibility.

I don't have pictures right now unfortunately. I will have to take some next time I get a bad batch.

 

[aarongough]

I have never used Cerakote on a knife, and I noticed that there aren't many people that do. Even though it's the best coating for guns, better than Gunkote.

Try heating the knives to the curing temperature before applying the coating. I always had to heat gun parts to take care of the oil that degreaser wouldn't. It takes excessive preparation to get good results with Cerakote.

'It takes excessive preparation to get good results with Cerakote.'

As I am finding out! Normally most people would consider the prep I do on just about anything (glue-ups, etc..) to be excessive, it's a strange feeling to run up against something where it's not enough! That being said I've never worked in an automotive paint shop or anything so perhaps I'm just unused to the standards that need to be kept for high-quality spraying.

I will use a pre-heat next time I do an application.

When the Cerakote goes on right it's really, really, nice looking stuff. Doesn't look much like 'paint' as it's so thin. If I can get to the point where I'm getting it right first time every time I think I'll be very happy with it.

 

[Theiskell]

Is it in the finish before you heat it to cure the coating? If not the metal could be gassing out causing you imperfections.

 

[Blackhat3]

I don't have any personal experience with it, but a friend of mine does it on guns. My understanding of the process, and perhaps a step you may be leaving out, is that after blowing off the grit after bead blasting you should wipe the blades down with denatured alcohol or something similar to remove any final traces of grit or residue from the compressed air. I hope you get it figured out.

 

[Omega Leather Works]

I'm not a fan of the stuff on the knives I buy, but I'm feeling an appreciation for it more as I read this thread.

I just stripped a blade of a factory coating and the stuff is a pretty serious one at that. An excellent choice imo for guys that like such a thing.

 

[aarongough]

Is it in the finish before you heat it to cure the coating? If not the metal could be gassing out causing you imperfections.

Interesting thought! The coating changes a bit during the baking, it usually looks clean before the bake so maybe you're onto something there!

 

[J-siah]

Ive been using it for a few years. It is probably the best stuff on the market that is economical enough for most knife making operations. I get pretty good results, way better than I ever got with KG-gunkote. make sure you have a good water separator and filter on your air supply. also make sure you disassemble your gun and clean it every time you use it, little flakes of paint will dry on the walls and the next time you use it you will get little flecks on your knife. I also run my air purifier and kick up all the dust in my shop with an air hose a few hours before I paint just so I know that nothing will get kicked up while Im painting. Also preheating is a good Idea, I heat to 150-200 and then let them cool down for a minute and spray them. try not to spray heavy enough that the knife looks wet, if it looks wet you are spraying to heavy. I do light dusting passes and I do it slowly so that the knife can stay dry.

-Josiah

 

[aarongough]

I don't have any personal experience with it, but a friend of mine does it on guns. My understanding of the process, and perhaps a step you may be leaving out, is that after blowing off the grit after bead blasting you should wipe the blades down with denatured alcohol or something similar to remove any final traces of grit or residue from the compressed air. I hope you get it figured out.

I tried wiping it down after the sandblast on my last attempt, I ended up with a bunch of fluff stuck to the blade as the sandblasted surface is kinda rough...

Thanks, me too!

I'm not a fan of the stuff on the knives I buy, but I'm feeling an appreciation for it more as I read this thread.

I just stripped a blade of a factory coating and the stuff is a pretty serious one at that. An excellent choice imo for guys that like such a thing.

The main reason I'm using it is because my military customers need a non-reflective blade coating. Becuase I don't use stainless I hesitate to sand/bead-blast the blades as it will make them prone to corrosion, so a coating is the only other option. I tried acid-etching for a while but it wears off much too quickly and is prone to corrosion as well...

 

[J-siah]

when you wipe it down are you using lint-free rags?

 

[aarongough]

Ive been using it for a few years. It is probably the best stuff on the market that is economical enough for most knife making operations. I get pretty good results, way better than I ever got with KG-gunkote. make sure you have a good water separator and filter on your air supply. also make sure you disassemble your gun and clean it every time you use it, little flakes of paint will dry on the walls and the next time you use it you will get little flecks on your knife. I also run my air purifier and kick up all the dust in my shop with an air hose a few hours before I paint just so I know that nothing will get kicked up while Im painting. Also preheating is a good Idea, I heat to 150-200 and then let them cool down for a minute and spray them. try not to spray heavy enough that the knife looks wet, if it looks wet you are spraying to heavy. I do light dusting passes and I do it slowly so that the knife can stay dry.

-Josiah

I have been cleaning the gun thoroughly with acetone between uses. I actually do the same thing as you with the air hose. I hose down the shop with high pressure air (with our air-extractor fan going) before I spray.

Interesting what you say about doing really light passes. I have been doing my passes heavier than that. They go on wet but dry within 10 seconds or so. I will have to try your method.

when you wipe it down are you using lint-free rags?

I was yes, but the rough surface of the sand-blasted blade pulled fibres out of the cloth...

 

[J-siah]

yeah I would try lighter passes, that's one thing I've learned is that it should look dry almost as soon as it hits its warm target. you might have your psi set to high for your blaster too. I normally blast at around 60-70 psi.

 

[aarongough]

yeah I would try lighter passes, that's one thing I've learned is that it should look dry almost as soon as it hits its warm target. you might have your psi set to high for your blaster too. I normally blast at around 60-70 psi.

Thanks for taking the time to share your experience! I will try the lighter passes and lower blasting pressure.

I just hit my machinery supply place and grabbed a new moisture/oil filter as well as a dessicant line drier that will attach directly to my HVLP gun.

I will try again either tonight or on Saturday, hopefully the drier air, lower blasting PSI and the outgas step will fix the issue.

 

[Theiskell]

Interesting thought! The coating changes a bit during the baking, it usually looks clean before the bake so maybe you're onto something there!

In my day time job I have to deal with all sorts of materials gassing out from finger prints even after they have been wiped with acetone and methanol. If the other ideas you have been given do not work for you. Try taking the parts up about 50* above your cure temperature and let them soak there for 30 minutes or so. That should ensure you are not gassing out. I have done quite a few different coatings and just began making a pre-heat standard practice. It's absolutely necessary when you do powder coating.

I don't want to hijack the thread, but what problems are you all seeing with the KG guncoat???? I love the stuff and it's way easier to apply IMO. I have not tried it on a knife yet but have used it on several guns with good results.

 

[aarongough]

In my day time job I have to deal with all sorts of materials gassing out from finger prints even after they have been wiped with acetone and methanol. If the other ideas you have been given do not work for you. Try taking the parts up about 50* above your cure temperature and let them soak there for 30 minutes or so. That should ensure you are not gassing out. I have done quite a few different coatings and just began making a pre-heat standard practice. It's absolutely necessary when you do powder coating.

I don't want to hijack the thread, but what problems are you all seeing with the KG guncoat???? I love the stuff and it's way easier to apply IMO. I have not tried it on a knife yet but have used it on several guns with good results.

Good point about gassing out at a higher temperature than the baking temp. I will definitely do that!

 

[Teter09]

Good point about gassing out at a higher temperature than the baking temp. I will definitely do that!

Reading through the literature...it specifically says to do so at 250 degrees for 30 minutes. Granted, this is for their H series which is more firearm related, but I think its a solid bet.

I'm also glad you grabbed the new filter AND dessicant filter. I get moisture through my system still and run 2 DeVilbiss filters, which led me to add a dessicant dryer to it when I paint things.

Definitely post pics once you spray this weekend! :thumbup: