Powder Coating 101 - Electrostatic Method

[boltons75]

Ok, quick question that's not specifically casting related. I'm helping out a high school robotics team, and we are getting ready to convert an old filing cabinet into a make shift powder coating oven, using 110v burners from old hot plates, gutting the drawers and just using their faces as doors.

My question, would r13 foil faced fiberglass insulation work ok for insulation? Looking for a low cost, yet still safe solution.

[hanleyfan]

Okay, I been playing around with a powder coating gun for a couple of weeks and I am having trouble getting the boolits to coat completely, only about half of them coat completely and the others won't coat completely, the more powder I shoot at them they just won't coat, I have tried aluminium foil, metal trays and galvenzied wire with all the same results, The problem is the ground wire don't seem to have enough juice to effect all the boolits, If I ground my hemostats and pick each one up at the tip and shoot powder at them the cover immediately no trouble, but on a tray forget it. any suggestions? the only reason I bought this power coating gun is I have some powders that won't tumble and I wanted to use them. the gun I bought off amazon.

[StromBusa]

Okay, I been playing around with a powder coating gun for a couple of weeks and I am having trouble getting the boolits to coat completely, only about half of them coat completely and the others won't coat completely, the more powder I shoot at them they just won't coat, I have tried aluminium foil, metal trays and galvenzied wire with all the same results, The problem is the ground wire don't seem to have enough juice to effect all the boolits, If I ground my hemostats and pick each one up at the tip and shoot powder at them the cover immediately no trouble, but on a tray forget it. any suggestions? the only reason I bought this power coating gun is I have some powders that won't tumble and I wanted to use them. the gun I bought off amazon.

That sure sounds odd, if you ground the aluminum foil, everything that's conductive and is in contact should ground. Try a different extension cord, make sure the system is getting full power.

[bangerjim]

Are you spacing them at 3/4"????????????????? VERY important. Otherwise the charge will not suck the powder down in between the tightly packed boolits. Many people on here that have been used to BBDT tend to pack the boolits as tight when ESPC and it WILL NOT WORK.

BTY..........the "juice" is in the tip of the gun. The ground wire is just that, a return for the electrons.

I get perfect coats with my Amazon and HF gun every time..........spacing at 3/4".


banger

[bangerjim]

I walk all around my trays when spraying. And popper is right. I use fender washers on my 30's and they probably end up more towards 1½" spacing. 9/38/40/45 work great at ¾".

All get perfect coats......first time.......every time.

banger

[hanleyfan]

The boolits are spaced right around 2 in. apart, There is good charge at the tip, I found that the hard way, I have shot them at all angles, side, top, I turned the tray and sprayed from all angles, but some just won't take a coat, but if I pick them up and ground the hemostats and they take a coat no problem, I have took all the suggestion I have gotten on here and nothing works.

[Beagle333]

I don't have the Amazon gun, mine is the HF gun, but I do know that I have to have somewhere between 1/2 and 3/4" of spark jumping ability from the boolit to the electrode on the gun, or I don't have a great connection somewhere. It'll sometimes zap a little 1/4" spark but that won't cut it and if I wiggle the clamp (usually happens on used foil) it'll get a good bite again. And if you have a good spark going, the only other thing is if you are either spraying too close or with too much pressure and are actually sandblasting the previous grains of powder off with the next ones out of the gun. Are you far enough back that the powder has time to slow down and stick to the boolits as it goes whizzing by?
Those are about the only reasons that will cause a less-than-perfect coat for me.

[boltons75]

boltons75 I removed the outer case from my convection toaster and just throw an old towel over it for insulation. Even a newspaper works. So R13 should work also, you only go to 400F. Biggest trick will be to get the convection housing part with remote motor. IMHO, I'd use calrod from ovens, check your local repair shop for proper size. The solid heater hot plate heat and cool slower than the rods. Don't know how big of parts you want to PC, but it is a school sponsored project so liability will be a 'liability'. Put appropriate labels on it, high volts, hot - do not touch, etc. Probably need a lic. elec. to do wiring, etc.

This was one I did with another team last year, I moved onto another and have a couple kids that want powder. This is really just a project were doing that has to run on 110v, i have old oven heating rods, but not sure if they can be run off 110v. But my hot plates are really old with the same style elements, and are 110v.

[robertbank]

I have my trays for my oven and I am about to glue the nuts on the tray. My tray's usable surface grids out tp 10 x 15 for 150- bullets per tray with grid lines spaced 3/4". BangerJim is this what you recommend? I have three trays that will fit in the oven at a time ...I think. I won't know for sure until I get the nuts on and see how tall the bullets will be standing on the nuts.

Take Care

Bob

[bangerjim]

I have my trays for my oven and I am about to glue the nuts on the tray. My tray's usable surface grids out tp 10 x 15 for 150- bullets per tray with grid lines spaced 3/4". BangerJim is this what you recommend? I have three trays that will fit in the oven at a time ...I think. I won't know for sure until I get the nuts on and see how tall the bullets will be standing on the nuts.

Take Care

Bob

I have good luck with ¾" spacing on 9/38/40/45. On 30's I use fender washers that the GC shank fits down into and they end up around 1½" apart. All coat 100%.

I do not use nuts or any kind of elevation. Just put the bases on the NSAF.

An idea came up recently on here (apologies to the poster as I do not remember his name) to crumple the foil tightly in a ball, open up carefully leaving the small wrinkles in there, and put your bullets on that. Have not tried it, but the poster said it worked perfectly without any flash.

Too busy with Christmas & New Year's to mess with boolits now.

bangerjim

[Beagle333]

http://castboolits.gunloads.com/show...82-Tray-Ideals

Here are 6 pages of tray ideas we discussed one time.....
Good luck!

[Gerald C]

This is my setup for doing large boolits, these are from a BA mold,459 dia, 546 grains, I use in my 45/90 bp rifle, I shot out to 1280 yds. the first pic. is the oven in use, the second pic. is the pid controller I use to control temp. next pic. is of the boolits coming out of oven. next pic id a close up. next pic. is one of my paint racks to get this effect on the boolits. now you ask why? well why waste paint when that part of the boolit don't touch the bore,










Gerald C

[robertbank]

Now that is a slick idea. It should work for any caliber of bullet as well.

Take Care
Bob

[ipijohn]

Now that is a slick idea. It should work for any caliber of bullet as well.

Take Care
Bob

I use the same technique for 30 cal, 270's and .225's. This technique keeps the bore rider section from getting too large to chamber easily in semi-auto rifles.

[RP]

Those PID controls sure look handy, I tell myself I need one then say well you have to many things going on now. Then I see a post that makes me want one again. I was looking at mounting mine on the wall like Gerald C has done and use it on my casting pot lube sizer and now my oven. Nice set up you have there Sir.

[robertbank]

I was thinking about soldering sized 9MM cases on a steel sheet. Two thoughts. One would be to just powder paint the tray and not use aluminum foil at all. Place the ground clip on the underside of the tray to make the connection. The other is to solder the cases to the tray and place the tine foil over the cases.

For those who are experienced in this, would the first idea work? I still am waiting for the powder gun so my hands are tied until it arrives.

Take Care

Bob

[RP]

Robert before I did a lot of soldering you may want to look at pop rivet. drill the plate and use the primer pockets to hold the brass. No worries about the cleaning fluxing and with my skill level getting it to hot and melting the one beside it lose or warping the plate.

[robertbank]

Robert before I did a lot of soldering you may want to look at pop rivet. drill the plate and use the primer pockets to hold the brass. No worries about the cleaning fluxing and with my skill level getting it to hot and melting the one beside it lose or warping the plate.

Man this site just keeps giving and giving. Great idea and I am on it. What do you think about not using tin foil but just painting in the top of the tray and using the untounched bottom of the tray to attache the ground?

Bob

[Gerald C]

what I did was use some 1/8 alum. plate, I spaced and staggered the rows 3 case widths apart, so my 45's are wider
than the 38s are. I drilled the primer holes on my lathe and taped them 6-32. I then belled the mouths to fit to the boolit shape. I layed out the plate and drilled them on the mill. ( dro ). I use the foil to keep build up of paint. I also take a Q tip and use baby oil to lightly coat the mouth and outer part of the case. this keeps the paint line thin on the boolits. It was a pia to cut each hole out used a very sharp deburring tool to do this. I tried to just poke the boolits in the holes. looked great until they came out ! looked like they were on heavy seas very wavy and thick paint line.

Gerald C

[ipijohn]

what I did was use some 1/8 alum. plate, I spaced and staggered the rows 3 case widths apart, so my 45's are wider
than the 38s are. I drilled the primer holes on my lathe and taped them 6-32. I then belled the mouths to fit to the boolit shape. I layed out the plate and drilled them on the mill. ( dro ). I use the foil to keep build up of paint. I also take a Q tip and use baby oil to lightly coat the mouth and outer part of the case. this keeps the paint line thin on the boolits. It was a pia to cut each hole out used a very sharp deburring tool to do this. I tried to just poke the boolits in the holes. looked great until they came out ! looked like they were on heavy seas very wavy and thick paint line.

Gerald C

I coat using the same technique and get the paint fillet also. I have found that an old school hand pencil sharpener is the rignt size to trim it off nicely on .225 up to 30 cal painted projectiles. Or if money doesn't matter Rigid makes a pipe OD/ID trimmer that you can do 1/4 up to 1 1/4 inch... cost is about $40. http://www.ebay.com/itm/381090795723