Powder Coating Questions

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rwehavinfunyet
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Powder Coating Questions

Post by rwehavinfunyet »

If You have any powder coating questions let me know. I run a full service powder coating business in Port Clinton OH and i might be able to help you.

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Re: Powder Coating Questions

Post by jimjimmac »

Lisa,

When you powder coat hot rolled steel with the mill scale still on, do you do any preparation to the metal prior to coating? A friend of mine thinks I should be applying some sort of etching solution ahead of time like they do in professional shops for better adhesion of the powder during curing which is also a rust inhibitor.

If true, what is it, and how is it applied?

Thanks

Jim
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Re: Powder Coating Questions

Post by jmsrbrt »

2nd question....have you ever powder coated something with a torch? Like, apply the powder then melt it on with a hand held torch, maybe propane? I was thinking of bigger items you might want to treat, but your oven isn't big enough. What would be the solution?
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Zippo
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Re: Powder Coating Questions

Post by Zippo »

Anyone ever get an gritty area, almost like sandpaper? It seems to only happen on my mirror black and gloss clear finishes. Tried cold, pre warmed 270F, and hot. Just happens at random, and of course right in eyes view on the part. Believe have an good 2-3m coverage, correct timing and temp after flow, metal been prep prior. Just not seeing why it is showing up now and again, Has appeared on single coat and some second coats Any ideals as to why....
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Re: Powder Coating Questions

Post by kb3gun »

Zippo wrote:Anyone ever get an gritty area, almost like sandpaper? It seems to only happen on my mirror black and gloss clear finishes. Tried cold, pre warmed 270F, and hot. Just happens at random, and of course right in eyes view on the part. Believe have an good 2-3m coverage, correct timing and temp after flow, metal been prep prior. Just not seeing why it is showing up now and again, Has appeared on single coat and some second coats Any ideals as to why....
I've had this happen and it's been for two primary reasons. Either I failed to completely clean the item (or the cleaning pretreat wasn't completely dry) or from the material out-gassing. I've actually had it happen after the part came out of the oven. It could also be caused by contaminated powder.
jmsrbrt wrote:2nd question....have you ever powder coated something with a torch? Like, apply the powder then melt it on with a hand held torch, maybe propane? I was thinking of bigger items you might want to treat, but your oven isn't big enough. What would be the solution?
For larger items that won't fit in an oven, I use heat-lamps (Eastwood has a good selection). I would never use an open flame. Raw powder is very flammable.
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rwehavinfunyet
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Re: Powder Coating Questions

Post by rwehavinfunyet »

Jim,

with the mill scale you can use a product called GF acid clean 72. Galaxy sells it. It will acid etch and add a phosphate to it. makes a great prep solution.

question 2,

I dont recommend doing it this way. the problem is not a even cure. most powders need 350 to 400 deg for 15 to 20 min. That is the part temp and time. If you under cure it will not hold.
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Re: Powder Coating Questions

Post by plain ol Bill »

Lisa I tried to find the GF acid clean 72 you mentioned and could not find it using Google. You mentioned Galaxy - could you give me a little more info about the product and where? I have been looking for a treatment I could use with a pressure spray rig (garden sprayer).
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rwehavinfunyet
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Re: Powder Coating Questions

Post by rwehavinfunyet »

yes get a hold of this lady... her name is lori and she is my sales rep. she can point you in the right direction 419-496-8396
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Re: Powder Coating Questions

Post by tirediron »

Does powder have a shelf life? Where do you store your powder? Thank you in advance for your help in this matter!
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Re: Powder Coating Questions

Post by jimjimmac »

Lisa,

Regarding your answer about metal prep:
With the mill scale you can use a product called GF acid clean 72. Galaxy sells it. It will acid etch and add a phosphate to it. makes a great prep solution.

I attached a pic of a product I found on the internet at Home Depot. I assume it is similar to the product you described which will etch and add a phospate. I haven't had a chance to go to the store and read the label, which will have instructions, but from your experience, once you apply it do you have to rinse it off or just leave it on.

Some times I remove the mill scale soaking the metal in vinegar then grind to a shiny silver then powder coat with a clear coat. The reason I ask about preping the metal is because there were times I coated with a color or just black and have been doing it without removing mill scale. Now with the etching process, does the chemical get applied over the mill scale, or do I still have to remove it then apply the etching solutiom to bare metal.

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rwehavinfunyet
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Re: Powder Coating Questions

Post by rwehavinfunyet »

If you want a smooth surface you have to get the mill scale off. I use muriatic acid and grinding. To get the powder to adhere the 72 will etch and prep. It will not take off the mill scale.

Powder does have a shelve life? Yes. Do i follow the guides on it... no I have 10 year old powder that works just fine.

Moisture is powders worst enemy. Try to keep it in a dry area.

the galaxy 72 is the best i have found and you have to mix it with water to use 95% water to 5% acid. i use a yard sprayer and spray on and pressure wash off. If your part turns white add more water. I also use degreaser.
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Re: Powder Coating Questions

Post by Largemouthlou »

Lisa, what gun do you use?? I have an Encore and not completely happy with my settings..
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