Most people ARE NOT baking PC long enough

[Lloyd Smale]

I can see where lava rocks would make the range cycle less but its still going to swing from cut in to cut out temps. So your not only going to be at proper temps longer but lower temps longer too.

CW has a good point here. A good heat sink (material on the bottom of your oven that retains heat) goes a long way on stabilizing temperatures and helping the oven return to 400° faster after opening the door.

CW used lava rock, I use ceramic BBQ briquettes, others use fire brick. You need to make sure the material you use does not interfere with the heating elements or the convection fan.

"So how can you cure powder with heat? The short answer is “however you want”. Powder doesn’t care how you heat it as long as the surface gets to the temperature that is necessary to cure the powder and stays there for the cure time necessary."

https://www.eastwood.com/hotcoat-pow...-articles.html

Eastwood States: when the surface of the part reaches 400° (checked with an IR thermometer)(or "once the powder flows out and appears to be smooth" {11 min into the video}), bake/cure for 20 min

What this tells me (and I always suspected) is you bake your boolits for 20 min (Eastwood) or XX minutes after the PC flows seeing the PC flowing indicates that the surface of the boolits' have reached the proper temperature.

According to Eastwood: Don't touch part/boolit with bare hands

Dang, there sweeping up enough powder from the floor to do tons of boolits {12 min into the video}

[Willbird]

I can see where lava rocks would make the range cycle less but its still going to swing from cut in to cut out temps. So your not only going to be at proper temps longer but lower temps longer too.

I would think something with more thermal mass than lava rock might be better. Plain old cast iron or steel maybe. If the mass in the oven reaches a stable temperature, and the mass is say 4x the mass of the room temperature bullets...the temperature drop from starting a batch would not be as extreme ?? I ordered a new Igrill mini, should be here Friday, might be interesting to have a look at some stuff. The calculations of BTU per grain to raise a bullet to some temperature should be fairly simple to get a rough idea on. We can easily run some tests on our lead pot to get a ROUGH idea about how many KW per hour are required to raise X lbs of lead Y number of degrees. The numbers for heating bullets in an oven will be different, but IMHO not exponentially different. Dragon has the best setup right now to plot KW hours per grain of bullet really . If we had a rough idea. There is lots of heat lost from the outside of an oven though, but from steady state....load in 25,000 grains of bullets....to steady state should give us an idea of exactly how much energy was required. The public library here (I bet most do) have the Kill O Watt devices you can sign out like a book, they measure KWH exactly for stuff that can plug into them.



Bill

[Dragonheart]

Ditto, What Lioyd said: "I can see where lava rocks would make the range cycle less but its still going to swing from cut in to cut out temps. So your not only going to be at proper temps longer but lower temps longer too."

When you increase the thermal mass whether it be rocks, copper or bullets it is going to take a limited power output more time to bring a "Load" to temperature. Once the temperature of the Load is stabilized the extra mass will retain the stored energy (heat) longer, but this extra mass doesn't have the ability to produce more heat (power) only the elements can do this. Extra mass can help on the recovery of temperature when a door is quickly opened and closed or swapping out a tray, but it is a detriment in the initial heating as it increased the time to come to temperature. Adding more load to fix wild thermostat swings or bringing the temperature of the load up faster, just will not work. Nothing is going to fix the thermostat swings other than a thermostat with closer tolerances or better thermocouple; this is the reason so many have gone to PID's. To bring the oven up to temperature faster requires more BTU input (power).

[Willbird]

The BBQ PID controllers have sometimes had added programming to sense “pit open” which can cause a temperature runaway....they are pretty amazing (PID on a bbq pit in general) once you close the lid and start running steady state. They will hold +-1-2 degrees by controlling a fan on-off feeding air to a basket full of charcoal literally just inside a 55 gallon drum with 6 holes drilled in the lid.

Bill

[Onebad06vtx]

I us a regular spare oven.
I just make sure its preheated.
Powder cooks for 20 minutes and never had a problem.

[Stars & Bars]

There are now a few Youtube videos showing how double base gunpowder [containing nitroglycerin] reacts with and melts the powder coat, fouling the gunpowder too whereas a single base gunpowder [not containing nitroglycerin] does not react with powder coat and the gunpowder stays 'dry'. I found this information useful. I now clean the powdercoat off the base of 100gr 380ACP bullets when using a double base gunpowder Bullseye. I also use gas checks on bullets [that allow for gas checks] to shield the powder coat from the gunpowder. Gunpowder manufactures post on their websites whether a powder is single or double base powders.

[Conditor22]

There are SOOOOOOO MANY PEOPLE who have NEVER read the manufacturer's requirements for baking their powdercoating.

most people on Youtube showing PC failing don't tell the manufacturer and the way, the length, and temperature they baked at

I agree many manufacturers don't make it easy to find or understand their baking requirements.

It's always XX minutes at XXX° after a certain condition has been reached.

[slide]

This is still only another option. If what you are doing is working keep doing it. All my powders are 10 minutes at 400f PMT. This means part metal temperature. The item that you have coated must reach 400f and stay there for 10 minutes. If you will get a digital thermometer with a thermocouple,drill a hole in the base of a coated bullet,secure it with high temp aluminum tape,you will know exactly what temp your bullets are at. Just put it in with your bullets when baking. These instructions are on the powder for a reason. I tried the low temp cure, it didn't work for me,got leading. You can check out the thermometers and thermocouples on amazon. They are not expensive. Carry on gentlemen! Conditor22 this a very good point. Thank you for bringing it up!

[Tripplebeards]

I know conditioner22 replied to my other post. I have not tumbled coated for a good year and a half and know my oven temp is off so I set it at 455 instead of 400. Well had a brain fart and I set it at 355 for 20 minutes. I did a smash test and had a couple of cracks in my PC exposing the lead. So I got paranoid and re heated at 400 for another 20 minutes.

Here’s the smash test at 355 degrees for 20 minutes. You can see the little chips missing. I think it was just from the lead expanding and cracking off? Anyways made me paranoid enough to re bake at 400 degrees fo 20 minutes. If an improperly cured boolit has a GC on it to place a barrier between the PC and powder you think it would be alright? Don’t plan on doing it again on in the future and will blast my 355 degree rounds out in the next couple of days anyways.






Here is the smash test after re baking at 400 for another 20 minutes.






So what happens when it’s not cured? Dose it come off or smear off? Or is it just to make sure it’s impervious to gun powder and has nothing to do with it coming off and leading in your gun if improperly cured?


I do bounce off the excess PC after tumble coating and if I don’t I get a lot thicker coating but it’s even. It seems the thicker uneven coating looks better after the hammer smash test and holds up better with the rifling on recovered boolots but the thinner, bounced off excess coating groups tighter and still doesn’t lead my barrel.


I did load up some of the 355 degree batch before I realized what I did. I have them loaded in a ladder test all the way up to max 35 Rem jacketed velocities so I’ll find out out it the 355 degree bake holds up or leads. I never leaded a barrel yet...knock on wood. My bore slugs at .357 and they are sized at 3595”, PCd and GCd.



I played with my heat temps in my conventional oven and at 455 degrees at 20 minutes I had the most even results on smokes red PC. I even tried at 5 degree increments all the way to 475 but it was uneven at higher and lower temps.


Here are the 455 degree tumble coated boolits.






I think I just got lucky because I can never duplicate how pretty and smooth they are to this day. Smokes clear goes on like this all the time for me. The PC went on a lot thicker as well. I believe the cold, dry winter day helped.

Here’s some of the recovered slugs with minimum charge of trail boss.

[Tripplebeards]

I finally got out and shot my 355° bullets today. I have zero leading. They were loaded to max jacketed velocities with Varget. I used soft 16 to 1 pure lead and pewter at 7.8 Bh from 38.5 grains to 40 grains. I did the same with 50/50 alloy at 10.4 Bh.

The harder 50/50 was the Clear winner with just a hair over an inch group at 100 yards.



The bottom group was with properly baked PC using a 200 grain lee.

[prs]

My little Black&Decker convection oven has two typical sized toaster over trays. I stand about 110 of my 200 to 250 grain bullets on each tray and load both trays into the cool to warm oven set at 400F on the dial and I bake 40 minutes. I notice all the coating is melted within 5 minutes and flowing to an even coat by 10 minutes, so I bake that other 30 minutes for good measure. That may be over doing it, but no harm. I figure that is a lot of lead to bring up to temp. And, it takes me almost that long to stand up bullets on the next two trays.

I use unique, bullseye, red dot, green dot double based powders and shoot some PC ammo I loaded years ago. As long as the round goes BANG and the steel goes CLANG I don't give a DANG!

prs

[Conditor22]

prs I agree with you, we take great care in the other aspects of reloading, baking the PC isn't a place to skimp on the manufacturers specifications

[gnappi]

From what I'm reading, whatever works is what to do.

I've just started and with my little oven set to 410 and let it soak for 20 minutes, then I put 100 to 110 bullets in, set the timer to 25 minutes and they have come out perfect every time. I kinda dread changing brands of paint because it's working so well.

[Conditor22]

1) confirm with thermometer the oven is actually reaching 400°
2) preheat the oven to 400°
3) place coated boolits in oven
4) Bake for 25 min to ensure cure for all powders

****Don't overload non-convection ovens****

Most Countertop ovens temperature settings will change depending on the surrounding temperature due to the location and type of thermostat

[Dragonheart]

Conditioner22 is absolutely correct about confirming your oven. Just because the oven dial say 400 it does not mean the oven is stabalized at 400 or even will ever get to 400 degrees. i have a BlacK & Decker oven that will not reach 400 degrees even when the thermostat is set at maxium! In addition it has temperature swings of as much as 50 degrees. How do I know this? Because I have tested it with a Taylor Oven Guide Thermometer and I monitor my temperature when cooking with the thermometer. Your oven needs to reach 400 and be able to hold 400 or very close. if you don't use an accurate thermometer you are just guessing and your end results are anybody's guess.

[dangitgriff]

Connecting a PIF to whatever oven you’re using sounds like a great idea.
I’ll add that idea to my engineering tinker list.
R/Griff

[Dragonheart]

Connecting a PIF to whatever oven you’re using sounds like a great idea.
I’ll add that idea to my engineering tinker list.
R/Griff

Problem is by the time you add the cost of buying or building a PID you could have just bought a Hamilton Beach Countertop Convection Oven and been done with it. I have two, one has been cooking bullets since 2012 and still going strong and both work perfectly.

[dangitgriff]

Right, and a relatively inexpensive IR thermometer would also be a great alternative.

[Doughty]

Also, just because you test the oven once, doesn't mean it will stay that way. I was gifted a convection oven which when loaded with bullets would only reach a measured temperature of about 375. I was making bullets for .45 auto and everything worked out good. A month or so later I was experimenting with high velocity rifle bullets and things weren't going so good. The barrel would quickly crud up and was difficult to clean. I decided to re-evaluate my entire process and discovered that the same oven would now only reach a mass temperature of about 325, with an empty oven. I switched to another oven and began having happy experiments with rifle bullets.

[Slingin'Lead]

I've been using Eastwood powders and baking for 20 minutes in a thermometer verified oven.

Yesterday evening I recovered some boolits from my trap. (Lee 356-120 TC coated with Ford Lite Blue) Lead was showing through on some of the rifling marks on the boolit bases but when I cleaned my pistols after firing them I had no leading so I'm confused about what is going on.