Powder Coating 101 - Electrostatic Method

[Beagle333]

I am spraying on one tray and then transferring to a tray that is already in the oven as well. I get lots more boolits per tray and also I don't knock over the taller 30 and 270 cal boolits by trying to move a tray full of them.
The only trick is that if you don't have a PID controlled oven, you have to ramp up the heat slowly so it doesn't overshoot.... since it is much easier and safer to work in a cool oven, the preheating really didn't work well (for me) for transferring. It isn't hard to walk the temp up slowly though in 3-4 increments if you don't have a controlled oven.

[RP]

I also spray on one tray then move to another for baking on everything besides my HPs. I prefer to PC HPs for that reason. I have several trays and seem to have winded up with three little ovens so when I spray I keep everything going like a factory. First I start with some HPs a batch in the ovens and trays waiting to go in then I spray my other style bullets and do the transfer to the cooking tray. I get several trays of HPs done before I have one of the transferred trays ready for the oven which has a lot more bullets ready. Doing it this way a few hours of PC yields a lot of bullets then I pack it up and start casting for my next batch. I also have a supply of bullets that can age to hardness before they are loaded up for shooting.

[robertbank]

OK I have done several hundred bullets now and I find I am running into a problem. When I use non stick tin foil and place bullets on the file and coat, when they come out of the oven I am dealing with flashing. The flashing is a pain to deal with, does not come off completely when run through my Lee push through sizers. Is there a secret to preventing the flashing. I initially tried the nuts under the foil and probably gave up on them to quickly. I has a devil of a time keeping the bullets on the nuts.

Ideas ? Suggestions?

Take Care

Bob

[Beagle333]

You will either have to lighten up on your coat and/or work on your spray angles so you get your coat without so much powder built up around the base of the boolits, which will reduce, but not eliminate the flashing. Or figure out the trick with the nuts.... perhaps square ones will work better than hex ones for you and help with your balancing? I ran out of the hex ones and had to use some square ones and found they worked pretty well. Or...... get some smooth-jawed needlenose pliers or forceps and transfer the sprayed boolits to clean foil. I have gotten pretty good at moving them to a clean tray. This allows you to have zero flashing and also stack them much tighter than you can spray them and allows for a much larger load to bake. I believe the time spent transferring them to another tray is regained by the reduced number of trays you have to bake, since they are loaded heavier.

[MostlyOnThePaper]

I've had some luck with one of these:
http://noebulletmolds.com/NV/product...mttjo1m8ofidn2

The powered version might be better.
Having to handle every bullet is indeed a pain in the behind.

Loading less bullets per tray and changing spray angle pretty much fixes it.

[ipijohn]

OK I have done several hundred bullets now and I find I am running into a problem. When I use non stick tin foil and place bullets on the file and coat, when they come out of the oven I am dealing with flashing. The flashing is a pain to deal with, does not come off completely when run through my Lee push through sizers. Is there a secret to preventing the flashing. I initially tried the nuts under the foil and probably gave up on them to quickly. I has a devil of a time keeping the bullets on the nuts.


Ideas ? Suggestions?

Take Care

Bob

I switched to Hollow Point molds and PC them with their HP's down on a bed of nails. Or I stick the nose of rifle boolits in unusable cases and paint them nose down.

[robertbank]

I am going to try the nuts again and see if I can get the hang of it. My principle reason for moving to PC bullets is to reduce the smoke cloud one can get shooting IDPA/IPSC with lead cast bullets. PC bullets do just that but unless I can manage a better method to deal with the flashing and I am sure with some effort on my part the nuts should do the trick PCing will take a back seat to the traditional lube method. I go through about 10K bullets a year and I don't have the time to mess with trimming flashing off of 9MM/38spl bullets. Life is to short.

Take Care

Bob

[Beagle333]

The nuts will work for 9mm/38 boolits. I have no trouble eliminating flashing and also keeping that caliber boolits on the tray when moving to the oven. If you can't keep them on 6-32, try some small square ones and see if that little bit of extra "edge" helps with the balance while moving the tray.

My rifle boolits are the ones that really show a benefit from swapping trays after spraying.

[robertbank]

I am going to make an effort to make them work. I know I can chew gum and pat my belly at the same time, surely I can master moving trays.

Take Care

Bob

[Smoke4320]

to get the majority of the flashing off before sizing I just transfer coated bullets back and forth 3 or 4 times between containers .. the light tumbling and mixing gets the vast majority off

Thanks

[Beagle333]

If you can figure out how to use the nuts on the tray, the end result of the tray looks like this:






And the .38 cal boolits look like this:








And if you don't get them centered exactly up on the nut, you will get just a tiny bit of flashing where the nut was exposed, like this:

[robertbank]

Thanks those photos really help. I have a small test tray I will get set up for 50+ nuts. I have to watch the Vancouver Canucks play Buffalo tonight so gluing the nuts down will be a nice diversion.

Take Care

Bob

[Gunslingerdoc]

Coat on hardware cloth....no flashing, powder falls thru the mesh, works just fine for 45, 9, 40 cals. Tad unstable for long 30 cal. For 223 or long 30 cal boolits you just poke the tip on the boolit thru the mesh and coat base up. After a couple of uses, you'll need to sand off the built up PC with a sander...takes about 30 seconds per rack.

[Beagle333]

If on a previously used rack.... how does the electrostatic part work then? If you sanded the entire tray down to bare metal every time, I could understand....

[robertbank]

Sorry but what is ``Hardware Cloth``.

Take Care

Bob

[Beagle333]

It is the wire mesh like you would put in the bottom of a rabbit cage. It comes in 1/2" and 1/4" (and maybe 1/8") grids.
Looks like this:
http://www.lowes.com/pd_90-16418-122...ductId=3160773

click "additional images" in the link to see larger photos of product.

[robertbank]

Thanks Chuck. When I was looking into options for getting started I ran into some screening at a body shop. It has 1/8th inch spacing much like a screen door. I thought at the time the powder would simply clog the screening. I see where the hardware cloth might work. I am committed to the nut method for now. Thanks to you I think I have it figured out. I will do a test tray later this morning. I am going to let the neighbours sleep in. My air compressor is capable of waking the dead.

Take Care

Bob

[Beagle333]

The hardware cloth will work.... once. What I'm curious about is how a user will get an electrical charge through his boolits after the first use. They won't be sitting on a bare metal screen anymore, unless the surface of it gets sanded completely every time. The boolits must be sitting on clean bare metal for the static charge to get from the ground clip to the boolit, or it isn't ESPC... it's just gravity spray.
It would be great if somebody has a technique, but I haven't seen it detailed yet.

[robertbank]

Incidentally I found one answer for any bullets you might tip over on the way to the oven. I have an old wire stripper/crimper tool. I use the crimping part to pick the bullets up in the lube groove. The tool only touches the crimping groove on the bullet and then on very little of the surface. Works better than needle nose pliers for me.

Would spraying your bullets first then transferring them to the Hardware Cloth work and leave less powder on the wire mesh. If you used that method the Cloth would last a lot longer before needing sanding I would think.

Take Care

Bob

[Beagle333]

Would spraying your bullets first then transferring them to the Hardware Cloth work and leave less powder on the wire mesh. If you used that method the Cloth would last a lot longer before needing sanding I would think.

If you transfer them to anything, it will leave the excess powder behind and remove any flashing. The tray of nuts works because the excess power falls away from the elevated boolits, but you can just also spray them on any flat metallic surface, even just some foil over your workbench and then transfer them to another tray (of mesh, metal, or anything that will withstand baking), whether already in your oven (for tall rifle boolits) or just an extra tray with foil/parchment paper on it and bake them that way and the excess powder that would have caused flashing would be left behind, and you can even recover the powder from the foil where you sprayed the boolits. (there seems to be some interest in recovering overspray). Only the spraying surface needs to be conductive.