Powder Coating 101 - Electrostatic Method

[gimling]

I tried this method it worked for a short while. eventually buildup of powder and they will stick again.

I made these yesterday to deal with the "sticking" issue. I used JB Weld to attach to cookie sheets. JB Weld has a max temperature threshold of 600 degrees. I'm going to put the foil over this and push it down around each nut.
Attachment 84943

[el34]

I tried this method it worked for a short while. eventually buildup of powder and they will stick again.

The thing I made with flathead screws through nylon spacers died too. The nylon shrunk a little every time I baked so I had to kep tightening the nuts. After about 15 bakes the nylon started crumbling, assisted by my having to push hard sideways to snap the boolits off.

I first tried non-stick foil, then went to 6-32 nuts sitting on the foil. I had to use wire cutters to separate the nuts from the boolits but the JBweld might have prevented that, I'm gonna try it next.

Thanks 500MAG.

[500MAG]

I tried this method it worked for a short while. eventually buildup of powder and they will stick again.

It's something that takes 10 minutes to make. The pan comes from the dollar store. With nonstick foil if I can get 15 to 20 runs with it I'll be happy.

[Beagle333]

You are just using the nuts to make elevated bumps in the foil, aren't you? Wouldn't it last a really long time if it never gets paint on it, or am I missing the technique? (I'm hoping to try it!)

[Smoke4320]

I do the same thing .. nuts glued to a drip pan..
on rifle bullets where I want the base covered I just put nose down and push bullet thru the tin foil .
hex nut lets bullet stand base exposed..
Pistol bullets I just place base down on the nut covered with foil and coat away..
Done several thousand so far .. works very well..

[KYShooter73]

Re: W0fms.... I don't lube at all to resize. The PC will be fine.

[w0fms]

I used a little Lee case lube last night when I sized them since a couple were a little more effort than I felt comfortable with... however, you are right the PC itself is a pretty good lube itself and I could have pulled it off w/o lube... I tried it that way. Good to know about it sticking to the nuts..maybe that's not a "great" one step solution.

This is going to sound crazy, but has anyone tried a food grade spray, like Canola Oil (with soy lecithin in it?). Would it hurt the PC? I doubt it.. but.. the nuts on the sheet sounds nice for a ball-down tray.. and spraying it with food oil seems easier then then putting the non-stick foil on the nuts when "ball down".. if you get what I'm asking or leading into...

[w0fms]

Okay.. how about a Teflon sheet/pan, cut to fit into the toaster oven .. with holes drilled in it for the ball? It might work too... has anyone tried a Teflon cookie sheet instead of the non stick Reynolds wrap? Now to flip them over and do the other side the Reynolds is hard to beat....

[xacex]

You wont get the electrostatic charge to the boolits with the Teflon sheet.

[bangerjim]

NS foil is the easiest and cheapest way to do this guys. Why waste time with sheets of this and rolls of that. Cover the surface (with or without glued nuts) and spray away.

At $5.50/#, the HF powder is not worth trying to recover!!!!!!

banger

[KYShooter73]

This is going to sound crazy, but has anyone tried a food grade spray, like Canola Oil (with soy lecithin in it?). Would it hurt the PC? I doubt it.. but.. the nuts on the sheet sounds nice for a ball-down tray.. and spraying it with food oil seems easier then then putting the non-stick foil on the nuts when "ball down".. if you get what I'm asking or leading into...

I asked the same thing over in the main PC thread, no replies, so I sorta tried it. I used a bit of motor oil spread thin, but still too thick. I was very careful not to transfer any oil to the pc'd portion of the boolit. My results merit another test with an extremely light coat of something non-stick. Everything came up easily, including the overspray around the boolits, but some oil leeched up about 1/16" onto the boolit causing loss of PC adhesion.

[drysound]

I finally took another shot at powder coating. See the picture below for results from my second try. Red and Black is HF powder. I tried Bangerjim's method for other colors using pink and blue Krylon Fussion spray paint. I am painting the flat black PC boolits. My first paint try was with pink and I think I just sprayed it to light. After it came out of the oven the coverage was even but not as pink as I expected. I shot more blue paint in my next try and that worked much better. However both the pink and blue were harder to run through the size die than the powder coated red and flat black. Also, lost some pink paint on every one going through the size die. I am not coating the base and using non-stick foil to line my trays cut down from 92 cent Walmart cookie sheets.



Thanks again to everyone for the suggestions after my first try. I solved the clumping problem with the Black HF powder A little shake and rolling the jar seemed to break it up. I marked a dowel rod to use as a dip stick to be sure I had between and inch and inch and a half of powder in the sprayer jar. I tried el34's method and removed the diffuser tip from the spray gun. This worked great for me. I also constantly tapped the jar as I was spraying. Now I get a nice fog of powder over my tray. I think it worked better than using the diffuser tip. Someone posted a photo of their PC work area and had a spray booth made from a big cardboard box. I also made myself a spray booth from a large box. I am working on my back porch and the box/booth worked great to help deal with little breeze and kept the overspray concentrated in a small area that made for easier clean up. I am using a $5 toaster oven but may have to break down and buy a new one. I constantly had to tweak the temperature dial as the oven seemed to be running way hotter than the dial setting. Using a HF infrared thermometer reading off the black back of the oven. Any suggestion on good toaster ovens? Thanks again for all the great knowledge you all are sharing here. Great help for a newbie.

[el34]

Good lookin' boolits!
I agree with the tapping on the bottle. I wish it were clear so you could see what's going on in there. I wonder if the conical shape is significant, there might be a glass pickle jar that would fit.

I got my oven at Walmart, a B&D Convection. It was either $40 or $50, don't remember. It's thermostat is accurate according to my casting thermometer and the timer is handy. It has slots for 2 trays but only comes with 1 and I haven't yet tried to double the production rate.

With no lube I size before PC and so far haven't thought they need a post-PC sizing. Sooner or later we'll get good at this.

[w0fms]

Aldi's has Teflon sheets on sale this week for almost nothing (like less than Goodwill), and Wally World is across the street.. If non-Teflons are cheaper at Wally I'll go that way. I understand that Teflon is a hell of an insulator, as I'm an RF engineer... but so is the PC and I coated the ball tops with a coated flat base already. I think the big sheet being charged (obviously I'll scrape off where the alligator clip goes) is probably enough for the PC process to work.

I might not be talented with the spray gun, but if I don't go ball side down, I can't seem to get a good coat on the base of the boolit where the lube groove is. Even when I hung in mid air and sprayed through hardware cloth. To do the the base of the boolit side down is to just make it look good. My last batch looks pretty good but the process is not yet ideal.

I am starting to lean towards a cut up cookie sheet with a bunch of holes drilled into it and the non-stick foil just poked into the holes a bit. Flat base down on a flat sheet with the foil first, and then flip up ball side down to finish it off on the 2nd coat.. we will see...

[bangerjim]

Aldi's has Teflon sheets on sale this week for almost nothing (like less than Goodwill), and Wally World is across the street.. If non-Teflons are cheaper at Wally I'll go that way. I understand that Teflon is a hell of an insulator, as I'm an RF engineer... but so is the PC and I coated the ball tops with a coated flat base already. I think the big sheet being charged (obviously I'll scrape off where the alligator clip goes) is probably enough for the PC process to work.

I might not be talented with the spray gun, but if I don't go ball side down, I can't seem to get a good coat on the base of the boolit where the lube groove is. Even when I hung in mid air and sprayed through hardware cloth. To do the the base of the boolit side down is to just make it look good. My last batch looks pretty good but the process is not yet ideal.

I am starting to lean towards a cut up cookie sheet with a bunch of holes drilled into it and the non-stick foil just poked into the holes a bit. Flat base down on a flat sheet with the foil first, and then flip up ball side down to finish it off on the 2nd coat.. we will see...

I will be most interested to find out how those TFE sheets work. The sheet material in MANY times thicker than the powder coat, so there may not be enough EMF energy transferred thru it to make the powder stick as well. I have not disassembled the electronics box of the HF gun to see what method they are using to generate that high tension electrical potential. It is not really true static electricity, more like a hi-tension Tesla technology I think. Definitely not a neon sign xformer!!!!

banger

[bangerjim]

Teflon will prevent the ES from working. NS foil works best. The WW sheets are probably cheaper than HW store alum, if they are sturdy enough to hold 10# of boolits. Banger - it's like a BW TV horizontal generator.

Brings back memories of my childhood! B&W TV's with HV fly-back circuits! I never considered they would use that, but is works. Charge a pF cap and let 'er rip! I tore into many of those things. My first o-scope was an old 19" B&W TV I converted to use as a scope for a science fare presentation.

Can anybody say vacuum tubes????????

banger

[MacFan]

Not rocket science but here's the bullet lifter I use when one gets away after PC'ing. Harbor Freight small needle nose sharpened and bent.
I've tried ES PC'ing some bullets on plain sheet metal and then using the needle nose to transfer them to a NS foiled covered sheet. I'm starting to like this method. I can PC and transfer 100+ easily while I wait for a batch to cook. No excess at the base, no falling over, no rolling away, we'll see.

The flat handle return springs are Gooped in place to keep them out far enough to do their job

[bangerjim]

Not rocket science but here's the bullet lifter I use when one gets away after PC'ing. Harbor Freight small needle nose sharpened and bent.
I've tried ES PC'ing some bullets on plain sheet metal and then using the needle nose to transfer them to a NS foiled covered sheet. I'm starting to like this method. I can PC and transfer 100+ easily while I wait for a batch to cook. No excess at the base, no falling over, no rolling away, we'll see.

The flat handle return springs are Gooped in place to keep them out far enough to do their job

Wow......a nose picker AND boolit picker-upper! Nice. I'll have to make one.

banger

[el34]

Brings back memories of my childhood! B&W TV's with HV fly-back circuits! I never considered they would use that, but is works. Charge a pF cap and let 'er rip! I tore into many of those things. My first o-scope was an old 19" B&W TV I converted to use as a scope for a science fare presentation.

Can anybody say vacuum tubes????????

banger

My favorite vacuum tube is the el34.

I'm also an electrical engineer and have been scratching my head over the necessity for DC continuity from ground clip to the lead. A charge of one polarity is attracted to a charge of the opposite polarity even though there's a barrier between. But being poky I haven't yet set up an experiment, I want to try parchment paper under half the boolits and compare.

[drysound]

Hey MacFan, when you use the needle nose to transfer PC'd bullets from your sheet metal to the baking pan do you get any pin holes in the coating from the tips of the needle nose or does the powder coating fill in any pin hole as it melts and cures? This method would help me pass the time waiting for a batch to cure.