Beginner with questions

[SpiritFlyer]

I'm new to powder coating and have been trying some things and having some problems.

Background:
I built my own oven. I haven't done a temp. calibration yet.
I have the Redline 250 gun.
I've added a ground wire from my spray rack to a ground rod outside my garage.

Successes:
Black on bare steel - looks great
Lollypop Purple on bare steel and bare aluminum - looks great

Failures:

1. Extreme chrome on bare steel and bare aluminum - color separates in places - See picture. Do I need thicker powder, lower temp, longer cook?
My oven has an old house oven temp controller - the powder says 392 for 30 - 60 minutes. I set the dial at very slightly under 400 and cooked for 35 minutes.

2. Illusion Amethyst and Illusion Aquamarine over black. I couldn't get an even coat of powder to stick. Tried different settings on the gun, didn't seem to matter

3. Lollypop Purple over Extreme chrome. Had the same problem with powder not sticking evenly. Tried with over Extreme chrome hot right out of curing oven - that's the dark one. - seemed to get a more even coat of powder on, but then the chrome seemed to lift up and mix with the purple in the oven.
Tried it on Extreme Chrome cold. - very poor powder adherance and some lifting of the chrome into the purple in the oven as well. That's the light colored one.

Hopefully the picture helps explain my situation. Please advise to what things I should do to correct my problems.


Thank you so much.


Spirit Flyer Creations

Daniel Gilbertson
Readstown, WI

[SCOTTRODS]

I'm new to powder coating and have been trying some things and having some problems.

Background:
I built my own oven. I haven't done a temp. calibration yet.
I have the Redline 250 gun.
I've added a ground wire from my spray rack to a ground rod outside my garage.

Successes:
Black on bare steel - looks great
Lollypop Purple on bare steel and bare aluminum - looks great

Failures:

1. Extreme chrome on bare steel and bare aluminum - color separates in places - See picture. Do I need thicker powder, lower temp, longer cook?
My oven has an old house oven temp controller - the powder says 392 for 30 - 60 minutes. I set the dial at very slightly under 400 and cooked for 35 minutes.

2. Illusion Amethyst and Illusion Aquamarine over black. I couldn't get an even coat of powder to stick. Tried different settings on the gun, didn't seem to matter

3. Lollypop Purple over Extreme chrome. Had the same problem with powder not sticking evenly. Tried with over Extreme chrome hot right out of curing oven - that's the dark one. - seemed to get a more even coat of powder on, but then the chrome seemed to lift up and mix with the purple in the oven.
Tried it on Extreme Chrome cold. - very poor powder adherance and some lifting of the chrome into the purple in the oven as well. That's the light colored one.

Hopefully the picture helps explain my situation. Please advise to what things I should do to correct my problems.


Thank you so much.


Spirit Flyer Creations

Daniel Gilbertson
Readstown, WI

Top to bottom:
top one looks ok,.... can't tell mcuh about it but I'll bet, even though it's not visible in the picture, it suffers from similar problems the others have.
next one down, looks to have a good coat of powder. Appears to have some prep issues. Otherwise it looks OK.... may also suffer from undercure just a little.... not really clear in the picture.

next one down is the extreme chrome..... That piece appears to have a pretty bad case of substrate contamination. Wasn't prepped properly maybe. It also has the same undercure appearance the "good" purple part shows, but much more severe. There is a possibility there's some overtemp also. I'm not as familiar with the results achieved by overtemp, so that could be what causes the pieces to look poorly prepped.

The last one looks to have a case of Back-Ionization on the second coat. The little "pock marks" are evidence of that. Basically the part is not well grounded and the excess charge is not draining off any, or enough during the second coat. Typically due to a weak ground. Usually caused by the first coat, covering the part where it is hanging.

Temp control is vital to the curing process, so getting that part addressed is paramount to getting your coating to be uniform.

Prep is the heart of all coatings, be it wet paint, ceramic, powder, chrome plating, etc.... Once the part is celaned, stripped, celaned again with compressed air, run a torch over it for dust bunnies,.... Should not be touched with human skin again before the coating process.... It doesn't look like any of these suffer from handling issues. They appear to have Prep, and curing issues.

Once you get the base coat cured properly, the second coat will not affect the first coat so much. It certain ly shouldn't "lift".

Once you get the basics down, the custom colors will be much easier. I have one color that beats me to death with issues almost everytime I use it. And I love the color. It's a good thing no one is asking for it on their stuff as customers. Jollipop Copper Orange. If I ever master that one, the rest will be silly simple.

I've been coating for just under 2 years now, and I'm by no means THE authority, but the above is a reflection of my experience, and is just my opinion. Others may chime in and disagree.

[SpiritFlyer]

Thanks ScottRod,

I take your comments to heart.

First I'll calibrate my oven and make sure I'm not under curing and have the right temp.

Next I improve my prep. So far I sand to bare metal, blow with air, wipe with a clean cloth, wipe with rubbing alcohol, let dry then spray. Maybe I should wipe with another solvent instead of alcohol? Wipe with water, blow with air, dry in the oven? I'm a little unsure which path to take.

On second coats, I'll use a new wire to hang the item and make sure the hole is clean of the first coat.

Thanks for the prompt response.

Spirit Flyer
Daniel Gilbertson
Readstown WI

[SCOTTRODS]

Thanks ScottRod,

I take your comments to heart.

First I'll calibrate my oven and make sure I'm not under curing and have the right temp.

Next I improve my prep. So far I sand to bare metal, blow with air, wipe with a clean cloth, wipe with rubbing alcohol, let dry then spray. Maybe I should wipe with another solvent instead of alcohol? Wipe with water, blow with air, dry in the oven? I'm a little unsure which path to take.

On second coats, I'll use a new wire to hang the item and make sure the hole is clean of the first coat.

Thanks for the prompt response.

Spirit Flyer
Daniel Gilbertson
Readstown WI

Your comments made me remember yet another important item. When curing the coating, the temperatures suggested on the powder, are curing times at Part Metal Temp. That is to say, once the part reaches the suggested temperature, start your timer and cure for the time required, at least. Most powders are over-cure stable, up to 100% in time. If your curing schedule is 10 minutes @ 400 degrees, then your part must be very close to the 400 degree mark, and be cured for a minumum of 10 minutes. You can cure a little longer (as I do), or even double with most powders, to make sure you do not undercure. Undercure seems to be one of the most common errors in the coating process, just behind poor preperation. The colors to be careul with will be the light ones, like Yellow and white (some clears will yellow if cured too long also).

Now on the Prep process, Rubbing alcohol has a small amount of water in it, and may be an issue if you do not dry the part thoroughly after wiping down with it. Using Denatured alcohol should be a better cleaner. I also use plain ol' Dishwashing liquid soap, and water to clean up anything that is not steel. I use it on steel parts that have been coated already too, when adding a second or subsequent coat. Making sure they are dry is the important part when using soap and water. I usually just put the part in the oven for a few minutes to dry after a wash like that.

To add a twist to the never ending possibilities, there are times you may experience moisture on parts after applying the powder, when introdicing a COLD part to the oven, as condensation can occur. In cases when you are working in the extreme cold, make sure you keep the work area warm, or maybe even pre-heat the parts to try and avoid that condensation. You can watch coindesation form and dry, if you use a propane torch to burn off lint and fuzzies, prior to shooting the powder also. As part of the combustion process, there is always a bi-product of water, if warmed sufficiently, it will evaporate quickly. The torch is one of those items you need to have in your tool arsenal for powder coating. It has a few really good uses, one of which is scratch removal on cured powder coat. Just a quick pass with the flame, will elimnate surface scrathes, but not deep gouges.

On second coats, there is no need to change the hook as long as it does not move between coats. It usually already has a good ground. If you are having trouble getting the second coat to stick, then change the hook by all means, and clean the part to bare metal at the hanging point.

Hope these items are useful.

[SolutionsAutomobile]

Im also having problems, but with second coat, I have a hyper smooth 2. Im suspecting Ambient air humidity for my problems (got a easy 3rd coat once with same setup). Maybe you could provide readings of air temp and humidity in you shop when you coat.

[SpiritFlyer]

Thanks for the comment on humidity, it was a cool humid evening when I did the problem pieces.

Finally got a good oven thermometer to calibrate my oven. Was definately over temping my pieces. 50 degress too hot on the upper end and 25 too hot on the lower end. If the powder is sensitive to over temping, that might fix some problems (extreme chrome color separation)? I will also start curing longer. I had been allowing 5 minutes for the part to reach temperature but will start allowing at least 10.

Thanks for all you help.

SpiritFlyer
Daniel Gilbertson
Readstown, WI

[FigureLLC]

for what it's worth, i've never had a positive experience with extreme chrome. i've got a couple cans of it sitting in my cabinet that i haven't considered using for a loooong time.

[SpiritFlyer]

Did some samples of extreme chrome on aluminum tubing yesterday. I don't have pictures of them but they're much better than before. Here's what I did:

1. Sanded to bare metal
2. Sprayed with air
3. Wiped with clean cloth
4. Wiped with clean cloth and acetone wearing nitrile gloves
5. Put in oven 150 degrees for 10 minutes.
6. Pulled out and let cool
7. Sprayed with extreme chrome - a good thick coat
8. Put in preheated -calibrated oven at 390 degrees for 50 minutes
9. Turned off and let cool
10. Result - most of it looks very good but there are a few tiny pimples or popped pimples. I've seen something about metals outgassing - could this be what's going on? I thought the thicker powder amount would look thick but it doesn't. Except for these few little spots the finish looks great.

Thought I'd post this update with the question. I now need to research outgassing and possibly add a pre heating step to my process or heat hotter after the cleaning.

I haven't tried the second coat yet but will when I get this figured out. I really don't know how I could get them any cleaner. I really think my problem initially was over temping for too short of a total time.

Thanks so much for all of your help,

SpiritFlyer
Daniel Gilbertson
Readstown,WI

[SpiritFlyer]

Thanks Len for your response about extreme chrome. If you have problems with that powder and don't use it, what do use use as a base coat under a candy color top coat?

I'd like to use candy purple, blue and red, but need a consistent reflective color underneath those. I've tried those over bare aluminum and they look good, but I need a good base to cover welds and brazing on steel.

Thanks much for your comments

Spirit Flyer
Daniel Gilbertson
Readstown, WI