Which gun to buy

[ty1854]

Originally Posted by SolutionsAutomobile

Tried it!

First I coated a test pieces but that metal was more oily than i though, so I had holes in the finish. TOTALLY my fault, didnt want to start the compressor for blasting.

Second I took a pieces I had coated successfully with my old gun, same mirror white from ptbp (I want to make sure ive got the hang before coated 900+$ turntables)
I tried shooting my clear with flakes and pearl in it. It didnt want to stick to it all that well. It stuck to some place and not to others seemingly randomly.
The powder does not flow and stick like in the hypersmooth video.
Heres a pic of it before cure. I put in more pearl blue so we can see the difference.


See how it sticks in places, and not to others

A bigger pic is located here:
Photo: Second coat /clear uneven coverage | Powdercoat album | Veikra | Fotki.com

Im now wondering about ground surface area and also about Pbtp powders. Ive tried 2 mirror colors from them and they've been the hardest to get right (OP, bad attraction to part).
I did not have any luck with clears and second coats so far.

What pressure do you have it set at? What is your KV Setting? It sounds like a bad ground to me causing the charge to build up in the surface since it cant go to ground. This will cause the problem you are having. Also heat your parts to about 100-120*F before you shoot the powder as this seems to help with powder attraction no matter what gun you are using.

[SolutionsAutomobile]

I Agree it does look like a bad ground, but its still a 22 gauge wire thats firmly attached to the bare metal hole. Should I really need a large half inch by half inch square area to properly ground it.

Ive tested my power outlet with a ground fault tool and they ARE grounded. Did that when I was trying to do the same with my chicago gun.

Ive lowered kv to 15-25kv (<1/4)as stated on the gun. Shooting from from 5-8 inches, pressure tried between 5 and 12 psi.

I think Ill try with a OVERKILL ground. Like clip right on bare metal, shooting first coat, then die grinding to bare metal for second coat

[SolutionsAutomobile]

I Agree it does look like a bad ground, but its still a 22 gauge wire thats firmly attached to the bare metal hole. Should I really need a large half inch by half inch square area to properly ground it.

Ive tested my power outlet with a ground fault tool and they ARE grounded. Did that when I was trying to do the same with my chicago gun.

Ive lowered kv to 15-25kv (<1/4)as stated on the gun. Shooting from from 5-8 inches, pressure tried between 5 and 12 psi.

I think Ill try with a OVERKILL ground. Like clip right on bare metal, shooting first coat, then die grinding to bare metal for second coat

[FigureLLC]

1) the randomness... did anything touch the coated part? hands, masking tape, anything? contact with pretty much anything gives your part a funky field.

2) you should be grounded fine. turn the kv down as low as possible for second coats (first coat is usually good at around 55kv, and i've heard to hit it with 100kv or as much as the system can handle... i'd keep it to 55 if you're shooting anything with faraday cages), try to keep the gun at about 8" from the part, and adjust the air so you've got a nice cloud without too much velocity. if that doesn't work, bump the pressure up till you get a pretty heavy stream. if that doesn't work try moving the gun closer.

i haven't used that particular gun, but i'm still figuring out tricks with our nordson, usually accidentally. just keep at it and you'll learn how to get it to do what you want it to do. as someone else on here said, "it's not the wand, it's the wizard."

3) if none of that works, the suggestion to shoot hot works. i usually do it with the part at 225. 225 is the magic number for hot flocking for me. just enough heat to let the powder melt on contact, but not overbuild.

[SolutionsAutomobile]

I did manipulate the part after first coat. first coat was applied a week ago, Ive touched it with my fingers quite a lot. I do not think it could mess with anything before cure. Sure Id expect weird stuff after cure, like fish eyes, but static should still be attracted to it when shooting it cold. That's just my guess

Could it be that im using too little powder in the hopper? Maybe its not charging the powder enough because of it.

I refused to hot flock, Especially with a gun that shoud easily do 3 coat cold. Hot flocking is messy, and on a thin part like this it cools too quickly. Plus hotflock that pearl and metal flake would make it a paint to get a even consistant looks. Id end up with darker spots and uneven flakes .

[ty1854]

You don't have to hot flock ANYTHING if you do something is wrong somewhere. Take a new test panel and shoot it with a powder and cure it. After it cools apply a second coat to it I guarantee it will go on with no problems. You should have wiped down that part with denatured Alcohol before you shot it cause touching (bare hands) it before coating WILL cause attraction issues if the oil on your hand or some other contamination gets on the part. If you are going to try and trouble shoot you need to eliminate all the variables you can. That means you need to get a new panel and note your prep methods, gun settings, and cure schedule that you are using. This way if something happens on the test panel you can pin point the issue more easily. If I were a betting man I would say bad ground or surface contamination. Anyway shoot a blank test panel and get back with us, good luck!

[SolutionsAutomobile]

Ive just done another test. I tried with other powders not from pbtp, just in case.

Cleaned up and grounded straight with gun clip


First; Xtreme Chrome tgic shot at 80kv ,shot at 8-12 inches, came out great (slight OP as always)
fully covered:

[SolutionsAutomobile]

Cured:

Good enough

Second coat, Candy purple. Shot at 8-12 inches, 15 kv Partially covered the part. Notice the uncoated square with no chrome under.

[SolutionsAutomobile]

Next I tried 24-30 inches , with lots of powder, all the way down to barely any power and it went all the way to this.
juuuust slightly better.


Cured: Note the square again


You can see there wasnt enough candy purple everywhere there was chrome underneat.

I did not touch the part on any area but the pointed end where I grounded for the candy purple, a place im ignoring in the pics

Hope this helps you see whats going on.

[SolutionsAutomobile]

I just watched a video of the same gun doing a second coat, mine does not work as good with the exact same settings. It's like their 2nd coat goes on as easy as first coat, just with lower voltage.

Probably something wrong with my ground. My budget ground fault detector said its ok, but it does not give a value. I'll have to find an electrician with the proper equipment to read ground resistance, should be under 25 ohms, under 5ohms being perfect. I work with microcontrollers, I dont have any power diagnostic equipment such as these. Might have ground , but a high resistance one.

Im starting to get ****ed...