Powder Coating 101 - Electrostatic Method

[bangerjim]

First stumble in the learning process... The sheet metal is plenty strong and hardly bows when picked up with the weight of the bullets on it. But it does slightly bow and bullets balancing on hex nuts glide right across non stick foil. Go figure. I need to do something to brace the sheet metal so it is solid enough to not bend at all. And the rack of freshly sprayed bullets needs to be right next to the oven or as close as possible to not risk bullets falling over or sliding. I need to find a way of mounting small handles on each side to pick it up careful enough to not tilt it at all. And then it needs to be easy enough to slide into the oven. Enough about the stupid rack...

Second stumble in the learning process... The spray gun is rated at 10 - 30 PSI and with the regulator set at 25# I had some intermittent flow issues. One second it was coating too thick and then not at all. This first batch isn't going to be perfect but once again this is the learning phase. It may just be the pressure being lost from the tank to the gun and the gun isn't really getting 25# to work with. I will dial up the pressure to 30# next time. But enough talking, we want pictures of results, right???

This is them freshly sprayed:


I wore a dust mask and that isn't going to cut it. I need to open the garage door and buy a real mask before I do this again. This stuff really hangs in the air. Once I get the powder flow just right there will be less waste but this time there was a red cloud. Yuck.

This is them fresh from the oven:


It's already a night and day difference in the quality of coating. They lose the dull sheen and it's finally a glossy coating. They feel so much more slick to the touch. With this method the bases aren't coated or at least not with this tray but I'm not worried about that. I'm just in this to avoid bullet lube and bullet lube smoke. The cleaner bore is just an added bonus. The low cost of the HF powder is what drew me back to this and the much better results with the ES spray gun is what made me break down and try this method. I know with this first trial run I used way more powder than I should have but I know I will get better at it and use less. That's the only way I will really be able to tell about cost effectiveness of this method for sure. I also need to try this method with rifle bullets since the finish is so much more even than any other method including the epoxy paint tumble. But for this being the very first trial run I still think these look awesome enough that I will continue to work at this.

This would be the reason for the hex nuts. This one fell off the nut and sat on the tray with the excess powder:


This is a dry tumble vs. ES comparison with the ES in front:


I cannot express enough how good these look and feel compared to anything else I've tried so far. The finish comes out so perfect!!!

You are getting a LOT of overspray in that picture above. I get hardly any. Mabe a light coat (<1/8 tsp) on the Workmate after spraying 6-7 batches.

A trick to keep the flow going:

1. do NOT use a full bottle on the gun. Pour ONLY about 2 inches of powder in the bottle that came with the gun.
2. As you are spraying keep tapping/bumping the bottle against your palm to keep the powder in there stirred up. Remember you are crating a fluidized bed in the bottle, so you need to keep it "liquid" at all times.
3. The powder flow out the gun should be a light mist, not a heavy dense flow! Control that by reg pressure and the brass FLOW control knob on the gun. The tapping above will allow you to run lower pressures.

Your coats look just like mine do every time ......PEFECT! I have not had any luck with the dry fumble method. Thin coats, multiple coat/bake process, lumps and flat spots where the slugs lay on the oven rack lead me Everytime to the ES gun method. It only takes me a couple minutes or less to get the rig out and be coating boolits! About the time it takes the little HF compressor to charge up to 125#.

I have been using lately the fender washer method as shared with another member. The GC shanks fit perfectly in the holes in the correct washer and the NS foil prevents the powder from getting to the washers. You do NOT need to glue the washers down. At ~$11/100.....not a bad method for 223 and 30 cal GC's

Keep up the good work!!!!!!!!!!

banger

[sparky45]

Fantastic first try with the ES Gun Bob.

[Beagle333]

Excellent coating Bob! I keep about 1-1/2" of powder in the gun, I definitely agree no more than 2", it has to fly around in there and make it up to the hooked tube. Like Banger, I also use the tapping or a quick flip occasionally from one side to the other to keep the powder fluffed up. You might also try varying the tip, or not even using it. I find a better flow with no dispersion tip on the electrode. You should not see a "fogging up" of the area, I can barely see the paint coming out, if at all. I just notice the boolits turning color as I move slowly down the row, like weedeating a fence line. If they stop turning from lead-colored to paint color as I pass, I'll tap or flip the jar to get it stirred up again.

Again, great looking boolits!!!!

[slim1836]

Bangerjim,

Where did you get those "fender washers"? I drilled 19/64 holes in a homemade tray, covered w/non stick foil, and ok with the results. May want to try your washers out.

Slim

[Maximumbob54]

The over spray and fog cloud came from the powder not flowing and then flooding out. I only put an inch in the cup and I think the pressure may have been too low. Next time I will both add more powder and slightly increase the pressure. But I'm still glad I joined this club. I forget who it was that was saying they look like candy bullets but they were right.

[el34]

Bob, I'll bet you're right on schedule with the short learning curve thing.

+1 on 1.5 - 2" powder.
+1 on tapping and reduced pressure.

Just after spraying I set my tray on the grate that slides into the oven to minimize the distance traveled while bowed. Haven't done it yet but I plan to add stiffeners someday.

Them's are great lookin' boolits! Good job! Kinda fun eh?

[bangerjim]

Bangerjim,

Where did you get those "fender washers"? I drilled 19/64 holes in a homemade tray, covered w/non stick foil, and ok with the results. May want to try your washers out.

Slim

Home Despot or Lowe's has them in 100 count boxes. MUCH cheaper than buying them in those stupid little plastic bags! Big Ace stores should have them also, but probably at a higher $$.

My HD has them for ~$11 a box.

You can also use standard washers but will have to glue them down as they are much smaller OD and will be much too close to allow to get the boolits in there! I just put the fenders back-to-back and cover the Al sheet then press NS foil over the whole mess to hold them in place.

banger

[Beagle333]

The fender washer method.... illustrated:
http://castboolits.gunloads.com/show...fically-30-cal

[slim1836]

Bangerjim,

I got Lowes 1.5 miles from me, will pick some up.

Thanks,

Slim

[Maximumbob54]

Think I will try that trick as well.

[Tech2]

Maxbob I suspect that your high voltage isn't working very well.
I used my dads gun and it made a mess like you have there. I bought my own and it worked drastically better.
Same techniques you describe.
Differences were mostly temperature teens vs 40's on mine.
Same red jar of HF powder. Same foil, same tray.
My gun sparks with ease and the yellow box has a hum.
His didn't hum and it never sparked but I didn't try to make it either.
Mine draws everything to the tinfoil and boolits. almost nothing hits the table.

Some form of standoff washer/nut is probably a good idea. My 308's fall over with ease and some of my 9's get a ring around the bottom that makes them difficult to start in the shell.
I just put powder under my first batch.

[el34]

Tech2 might be onto something. Bob, any chance you didn't hook up the ground clip or forgot the foot pedal? It can happen, I speaketh from experience. I see the cloud, I know what I forgot.

My gun sparks about an inch, inch and a half, maybe a good test of the HV generator.

[Beagle333]

+1 on an inch and a half. 'Scares the heck out of me every time I get too close. I'm all bent over it close and focused on getting a nice even coat, but not too thick, and BZZTTT!

[Tech2]

He has the ground clamp on you can see it in the picture.
The foot pedal now that is a different question.

[Maximumbob54]

I'm stepping on the foot pedal only while I'm spraying but I'm mindful to step on it a second before I spray and stop spraying before I step off. However, now that it has been said, my box does not hum. The red light turns green when I step on the pedal. A second issue may be that I have it plugged into an extension cord. I didn't figure that it would need much current and it's not that long of a cord. I'm out of outlets at the end of the garage but I guess I can unplug the freezer for the few minutes I need to spray. That might change things if I'm direct in the wall. I will try that later.

[Faret]

Maybe check the fuse?

[Beagle333]

A second issue may be that I have it plugged into an extension cord. I didn't figure that it would need much current and it's not that long of a cord.

I doubt that's it. I use mine on a 100' cord and it's fine.
You might not have any problem with it.... does it arc about an inch+ from the electrode to a boolit when you get too close? If so... all is well.

[el34]

I'd go for the spark test, that's the bottom line indicator.
Maybe to the foil so you don't electrocute boolits.

[Maximumbob54]

Sparky spark spark. Bigger zap than I was expecting. Made me jump.

[bangerjim]

The fender washer method.... illustrated:
http://castboolits.gunloads.com/show...fically-30-cal

Kudos to you, sir! I just could not remember who posted the idea or where but I, for one, like it!

Thanks for posting it!

banger