Is this correct?

[mehavey]

Preheat oven to 450....

That's because the thermal mass (heat sink) of the cool bullets going in immediately sucks the oven temp down right at the start.
"Pre-Heating" at 450 -- then reducing to 400 when the bullets actually go in -- gives you a leg up on then coming back up to hit the req'd 400 for the duration.

as far as BB's go, don't skimp. Use as many necessary to "mostly" cover the bullets within the bowl
The BB's are your powder transfer mechanism and should completely cover themselves in powder ASAP


If they're doing their job, hand-swirling the combo for 90sec should be more than enough

[Traffer]

Didn't read the whole thread...First failed attempts prompted me to make this comment:
I harp this over and over and over.
Humidity is the key. When the humidity is 100% it seems impossible to get adhesion...When humidity is 50% it seems impossible to screw it up. It you have to PC in humid conditions (over 90%) do it in an air conditioned environment.

[Conditor22]

traffer, several friends and I on the west coat successfully PC boolits in the garage, with the big door open when it is raining outside.

keep your powder dry and boolits clean. I worst-case scenarios pre-warm the boolits

[Conditor22]

That's because the thermal mass (heat sink) of the cool bullets going in immediately sucks the oven temp down right at the start.
"Pre-Heating" at 450 -- then reducing to 400 when the bullets actually go in -- gives you a leg up on then coming back up to hit the req'd 400 for the duration.

as far as BB's go, don't skimp. Use as many necessary to "mostly" cover the bullets within the bowl
The BB's are your powder transfer mechanism and should completely cover themselves in powder ASAP


If they're doing their job, hand-swirling the combo for 90sec should be more than enough

I line the bottom of my ovens with ceramic BBQ briquettes (any heat retaining media will work) this help the over recover much faster when opened and brings the rest load of boolits up to temp faster.

I ran out on this one, testing the temperature, ended up setting it to 415° to get 400° (the first 2 are $15 thrift store convection ovens testing the temperature, ended up setting it to 415° to get 400°)





I've run thousands of pounds of boolits through this little guy



it's now hooked up to a PID set to 200° C, other PID is for my casting pot. (state of the art cardboard deflector screen )
I pulled the bottom knob and installed a switch to turn the convection fan on and off

[Traffer]

traffer, several friends and I on the west coat successfully PC boolits in the garage, with the big door open when it is raining outside.

keep your powder dry and boolits clean. I worst-case scenarios pre-warm the boolits

OK here we go again...Raining does not mean 100% humidity. Just as not raining does not mean 100% humidity. Check the relative humidity...Is is 100% Probably not...Especially on the coast it can be as low as about 40% when it rains.

https://weather.thefuntimesguide.com...when_the_humi/

[charlie b]

If using a tumbler you need a way to generate static electricity. Rotary tumblers tend to have rubber liners that will not do this. Vibratory can have grounded bowls, again not good. And the BBs are the only things generating static so you need a LOT more than when using a #5 container, besides making sure the container is not grounded.

[AlHunt]

I was doing some powder coating today and thought I'd document 1 of the cycles just to show it works for me.

This is Smoke's Translucent Copper. I didn't shake enough off so it's a little splotchy but it'll be fine.

• I put the bullets in HDPE5 container with just powder, no BB's.
• Shake up and down for 30 seconds.
• Swirl for 30 seconds.
• Repeat both up and down and swirl.
• Dump it onto my wire rack.
• In this case I used a knife blade and made 1 single layer.
  (Usually I don't but there's a lot of surface area on these bullets.)
• Bake for 20 minutes at 375F.
• Turn out into a waiting box.

I just wanted to show what I do and that it works. Hopefully OP gets his problem resolved.

[a.squibload]

I heat the boolits before shaking, seems to negate the humidity problem.
Have had great results in the open garage in a thunderstorm.
Small batches, less than 100, thermal mass not a problem.
Usually stand pistol boolits on bases on non stick foil, rifle boolits go in a screen basket.
Preheat unneccesary, I go 11 or 12 minutes in a $10 thrift store toaster oven
at 400°F, have tried 375°, still works. Harbor Freight red, cheap, works fine.
Sometimes drop them in water when done baking, might help break them apart
if using basket method. Not that hard to separate in any case.

Keep at it, at one point I was about to go back to lube
but reading here and trying different things got me a method that works.
No icky sticky lube, no leading, have shot over 2000fps. Found 'em in the berm
with PC still attached.

One time all they had at HF was yellow, wasn't as good (or was it just me?) but
mixed with red I get orange and it coats fine.

(A friend forgot a batch in his toaster, not sure how long they were in but
the boolits slumped! Unusable.)

[Petander]

One time all they had at HF was yellow, wasn't as good (or was it just me?) but
mixed with red I get orange and it coats fine.

My experience with yellow/red Ripol powders as well.

I come from Hi Tek, exact measurements. So I make notes of my PC experiments,I weigh powder, pellets, bullets etc.

I find it much easier to change something when I know how it was the last time. Instead of "a spoonful and half, a handful, some pellets in a bowl etc..."

[crackers]

"Dropped in clean water straight from the mold."
Try dropping on a cookie sheet/tin - suspended just enough to flex. The bullets won't deform. The water drop has no benefit since they are going in the oven but it is a huge uncontrolled contamination risk.

[mehavey]

I just drop onto a folded plush hand-towel right beside the lead furnace.
Same (unwashed) towel now for 20 years.
Somehow no "contamination" for PC'g.

Same with double-boiling old lube off and then PC'g
No problemmo

If the OP is having problems getting powder to stick, it's either
- Bad powder (But his Eastwood Mirror Blue is one of the best)
- Bad container. Any Tupperware will do (but the generic Safeway Signature quad-lock in Post 44 is exceptionally good
- Bad or insufficient Airsoft balls as static-producing transfer agent

[JohnSmiles]

Didn't read the whole thread...First failed attempts prompted me to make this comment:
I harp this over and over and over.
Humidity is the key. When the humidity is 100% it seems impossible to get adhesion...When humidity is 50% it seems impossible to screw it up. It you have to PC in humid conditions (over 90%) do it in an air conditioned environment.

Humidity is not the issue here.

[JohnSmiles]

I just drop onto a folded plush hand-towel right beside the lead furnace.
Same (unwashed) towel now for 20 years.
Somehow no "contamination" for PC'g.

Same with double-boiling old lube off and then PC'g
No problemmo

If the OP is having problems getting powder to stick, it's either
- Bad powder (But his Eastwood Mirror Blue is one of the best)
- Bad container. Any Tupperware will do (but the generic Safeway Signature quad-lock in Post 44 is exceptionally good
- Bad or insufficient Airsoft balls as static-producing transfer agent

Plenty of balls. Too many boolits and not enough powder seems to be the culprit. Will find out Sunday.

[JohnSmiles]

"Dropped in clean water straight from the mold."
Try dropping on a cookie sheet/tin - suspended just enough to flex. The bullets won't deform. The water drop has no benefit since they are going in the oven but it is a huge uncontrolled contamination risk.

There is no contamination risk in clean water.

[JohnSmiles]

That's because the thermal mass (heat sink) of the cool bullets going in immediately sucks the oven temp down right at the start.
"Pre-Heating" at 450 -- then reducing to 400 when the bullets actually go in -- gives you a leg up on then coming back up to hit the req'd 400 for the duration.

as far as BB's go, don't skimp. Use as many necessary to "mostly" cover the bullets within the bowl
The BB's are your powder transfer mechanism and should completely cover themselves in powder ASAP


If they're doing their job, hand-swirling the combo for 90sec should be more than enough

The directions on the bag itself say to run at 450 UNTIL there is good flow, then reduce to 400 for 20 minutes.

[reddog81]

Too little powder can be a problem and I've never had a problem using too much powder. Contamination has never been a problem and I've tested it by leaving bullets sitting outside for a month in my chicken coop and letting them get rained on. Humidity can be problem with some powders and others are not effected by it too much.

The bullets you posted in post number 21 look perfectly fine assuming they pass the smash test.

[mehavey]

The directions on the bag itself say to run at 450 UNTIL there is good flow, then reduce to 400 for 20 minutes.

True. But that is to ensure flowout gets a good start.

But I keep it simple. 400-degree set/leave it there
Once oven comes back up to temp* after bullet insertion,
set timer for 30 minutes and walk away.


Several thousand perfect bullets later . . .


Post #1
Looking back at things, however, you've hinted your problem is not so much powder cure in the oven.
Rtaher, it was getting the powders to stick/coat the bullets well before the oven.

That problem comes from either
_1. Bad powder (But Eastwood Mirror Blue is one of the absolute best)
_2. Bad container. Any Tupperware will do (but the generic Safeway Signature quad-lock in Post 44 is exceptionally good
_3. Bad or insufficient Airsoft balls as static-producing transfer agent (I suggest brown and/or black)
I recommend concentrating on #2 and #3

Post #2
What kind of thermometer/probe* are you using to gauge/control oven temp?

Post #3
I wouldn't invest in PC'g hundreds of bullets at a time until you have nailed down what works

[Petander]

Post #3
I wouldn't invest in PC'g hundreds of bullets at a time until you have nailed down what works

This is why I mentioned the overall weight of 200 310 grain bullets.

I use a 2000 watt wall convection oven and 9 lbs would be pushing it.

[charlie b]

FYI, there can be contamination in 'clean' water.

[JohnSmiles]

Too little powder can be a problem and I've never had a problem using too much powder. Contamination has never been a problem and I've tested it by leaving bullets sitting outside for a month in my chicken coop and letting them get rained on. Humidity can be problem with some powders and others are not effected by it too much.

The bullets you posted in post number 21 look perfectly fine assuming they pass the smash test.

Yes, they are quite useable I think, but not uniformly coated. I will try again tomorrow to get a better coat using more powder. I read time after time 'just a couple of tablespoons of pc', but never noticed that amount was for considerably fewer(and smaller) boolits than I started out with.