a trick for tumble powder coating

[w0fms]

I have to agree that ESPC is going to give the best results with the most colors available.. but the HF Red in the Ziploc #5 round container with the "I got more than I paid for" cheapy airsofts covered a thicker coat all around... not as even, but more than acceptable. Look at my picture in the post. I further inspected the 60 I did and only one of them has a bit of a "scrape off" from the tweezers I used to pull them out. The up-down shake does seem to be necessary, and I did that SEVERAL times as I was pulling them out.

If I wanted 100% perfection in HF Red, I'd airsoft DT them first and then put a second on with the ESPC gun.. but.. boy either method is "good enough" and worked well.. but the ESPC always takes me longer and is much more messy... I do need to pick up some suitable hemostats though.. agreed... the tweezers were a PITA...

Fred

[bangerjim]

I have to agree that ESPC is going to give the best results with the most colors available.. but the HF Red in the Ziploc #5 round container with the "I got more than I paid for" cheapy airsofts covered a thicker coat all around... not as even, but more than acceptable. Look at my picture in the post. I further inspected the 60 I did and only one of them has a bit of a "scrape off" from the tweezers I used to pull them out. The up-down shake does seem to be necessary, and I did that SEVERAL times as I was pulling them out.

If I wanted 100% perfection in HF Red, I'd airsoft DT them first and then put a second on with the ESPC gun.. but.. boy either method is "good enough" and worked well.. but the ESPC always takes me longer and is much more messy... I do need to pick up some suitable hemostats though.. agreed... the tweezers were a PITA...

Fred

You got it my friend! Must be the water in Iowa! I am an olde Iowa boy.

You DO have to shake them up & down during your pick-up. I normally do it 2-3 times on a batch of 70 or so. It restores any divots that may pop up while you are picking.

Glad you mentioned it. I forgot!

banger

[el34]

If you DT first and cover the bases you might not get electrical contact for ES.

[bangerjim]

I have not tried or messed with it but............will the 11KV transfer thru the .001 coating of PC? HV potential can do strange things and that sure is not a very thick coat of potential insulation.

An interesting experiment?

May try it when I get the time.


banger

[el34]

will the 11KV transfer thru the .001 coating of PC? HV potential can do strange things and that sure is not a very thick coat of potential insulation.

banger

Many months ago I tried parchment paper over a grounded tray, under the bare boolits. The thought was that static doesn't rely on current flow to attract, it's more like magnetism. So therefore true conductivity wouldn't be necessary.

But it didn't work. Powder went everywhere.

I'm still hanging on for a eureka, either on my own or more likely from a physicist. I work with a girl with a PhD in physics but she didn't really have much to say about static charges.

[bangerjim]

You answered the question with hard proof.

Thanks!

banger

[el34]

You answered the question with hard proof.

Thanks!

banger

Results count. I'm picturing the two sides of a capacitor where an excess or absence of electrons on one side (grounded tray) attract the opposite polarity on the other side (powder through conductive boolits) with no DC continuity between tray and boolits.

Maybe I just forgot to step on the pedal.

[bangerjim]

Physics says it should work, but who knows! That 11KV is not true static electricity like you get from walking across the carpet in the winter and then get one ZAP.

I have several antique gold leaf electroscopes and those indicate true static charge. You can hold a "charged" plastic rod (or your body!) closer and closer to the top electrode and the gold leafs inside will spread apart gradually as you approach. Since the charge generated by the gun is a high tension continuous charge from a fly-back type of circuit, it behaves differently.

I will try it next time I use my ESPC gun.

banger

[el34]

You're right Jim, a collection of electrons stuck with nowhere to go isn't the same as just a high potential. So why is it called ElectroStatic? Sort of is, sort of isn't I guess.

[el34]

I coat rifle nose first then flip them over, ES works fine. Yea, Banger It's like the 2 George's, Washington & Custer.

That has inspired me to try ES on some nasty DT boolits I have. Even considered remelting them but it's a few hundred, it'd be good if ES fixes them. Maybe try today.

[bangerjim]

You're right Jim, a collection of electrons stuck with nowhere to go isn't the same as just a high potential. So why is it called ElectroStatic? Sort of is, sort of isn't I guess.

The "official" title of the process from what I have read is coronal discharge transfer. But the ES name seems easier to say!!!!!!

banger

[snuffy]

I hate being ignorant about some, well, most things. So I ordered this book from amazon;

http://www.amazon.com/dp/1885540043/...528360_TE_dp_1

It'll get to me on Monday. Knowledge cures ignorance pretty quick.

After reading it I hope to be a lot more able to figure out how to apply electrostatic to our applications.

I'm getting good coverage from my midway/frankford arsenal tumbler with white crossmen BB's and red HF powder. But I think the addition of ES during the tumbling would result in a more even coating, and avoiding the bare spots that seem to never get coated.

[bangerjim]

Excellent. We will be waiting to "go to school" on you!

thanks!


banger

[SniderBoomer]

I am keen to try PCing using this bb-tumbling method with some long 30-cal boolits.

Think getting them to stand up on their bases on the shaky trip to the oven is a challenge.

I wonder - do we have to use an oven? If we used a flat hotplate, could the freshly coated boolits be placed on the plate, with no need to walk them to an oven. At the right heat setting, would the induction of heat from the hotplate, up thru the base of each boolit, be enough to melt the coating? What about covering the hotplate with a thermal insulator (like a teapot cosy) so it acts like an oven, but without any shaking of the boolits?

If the melting powder would cause the heating boolits to slide around or move (and tip the boolit) then what about wiping off the pc from the base first before setting it down on the hotplate? The bare bases then gas-checked at the sizing step.

[Beagle333]

If you possibly could handle em enough to wipe the bases, you might as well stand them in some fender washers and then you can carry them wherever you want, easily. GC later, as you said.

[el34]

I wonder - do we have to use an oven?

There ya go, thinkin' outa da box. Got me doing it too. I picture the functional equivalent of a bottomless convection toaster oven that you set over your stationary pan of boolits. Oven comes to boolits instead of boolits come to oven.

[Beagle333]

There ya go, thinkin' outa da box. Got me doing it too. I picture the functional equivalent of a bottomless convection toaster oven that you set over your stationary pan of boolits. Oven comes to boolits instead of boolits come to oven.

I was thinking about that when I was gutting and hotwiring my latest convection oven for PID. The bottom already flips down and unlatches from my convection toaster. All I'd have to do is remove the bottom rods and it'd sit down over the tray perfectly and the air would circulate the heat from the top looping rod. 'Perhaps just elevate the tray on some fire bricks.... that should be about the same height as it would have sat anyway, and it would be directly adjacent to the convection fan..... and that sure would take the pucker factor out of moving any rifle boolits of any caliber! If you can stand em long enough to spray em.... you can bake em!


Now where did I put that phone number to my patent lawyer!?!?!?

[SniderBoomer]

Thinkin somethin like one of these below, just stand them base-up fresh out of the pc tumble, and let induction and convection heat do the 'oven' job.

Of course, it would still be like stacking dominoes, just one false move and the lot goes over... but I reckon it'd be easier than carrying a tray of a few hundred to an oven in scenes like those cowboy films where wide-eyed 'pokes are handing a tube of nitroglycerine...

[MacFan]

Physics says it should work, but who knows! That 11KV is not true static electricity like you get from walking across the carpet in the winter and then get one ZAP.

I have several antique gold leaf electroscopes and those indicate true static charge. You can hold a "charged" plastic rod (or your body!) closer and closer to the top electrode and the gold leafs inside will spread apart gradually as you approach. Since the charge generated by the gun is a high tension continuous charge from a fly-back type of circuit, it behaves differently.

I will try it next time I use my ESPC gun.

banger

Too cool Banger!

[bangerjim]

Thinkin somethin like one of these below, just stand them base-up fresh out of the pc tumble, and let induction and convection heat do the 'oven' job.

Of course, it would still be like stacking dominoes, just one false move and the lot goes over... but I reckon it'd be easier than carrying a tray of a few hundred to an oven in scenes like those cowboy films where wide-eyed 'pokes are handing a tube of nitroglycerine...

I have that EXACT dual hotplate. I started out using it but it took up way too much worke space and did not get hot enough for my pre-heating of my molds and ingots (~600f). The smaller flat aluminum surface lab hot plate I now use easily and rapidly gets to well over 700F!

It will get to 400, but remember that temp is on the base and NOT totally around the boolits as with a convection (or somewhat less a standard) toaster oven. Being surrounded with 400F moving air heats the boolits evenly and rapidly all around for an even consistant bake.

Relying on heat transfer from the base only AND thru the powder on the base to the entire boolit will proably cure them, but at a much slower rate of production. Right now I have "itchy fingers" waiting just 10 minutes!!!!!!!! And you would have to build a metal shell around it to stop even the slightest drafts from cooling the uppers of the boolits. In essence, you have built a toaster oven!!!!!!!

But try it. And let us know the time it takes to get a good cure on the entire boolit.

The unit I have is a pro food prep dual flat plate and cost FAAAAAAAR more than even a good convection oven at WM. And that's before the custom built shroud that will be needed.

Keep the new ideas commin!

I have found after playing with at lease 5 different ideas, the fender washers under NSAF for me are still the "bestest and fastest" way of doing tall skinny rifle boolits that do not fall over.

banger