Most people ARE NOT baking PC long enough

[KenH]

While I'm sure 275 for 12 minutes will allow PC to cure "strong enough" to handle most shooting needs and pass the smash test, I'd prefer to follow manuf's instructions to cure the powder. They've spent a LOTS of money developing the powder, and figuring how best to cure the powder to max strength.

I use Smoke's powder, and I'm sure he uses the manuf's cure instructions, so I tend to follow Smoke's advice for curing PC.

[Grmps]

Ken, I researched the 3 major pc manufacturers and they had comparable bake times

This Test of your baked boolits will give you the answer to if you are baking them long enough.

Set a baked boolit in a small container covered with the gunpowder you will be using and see if there is a reaction in a couple days and a week.

In the end, only You can decide what you want to run through your gun.
I can only show you what the manufacturers recommend for their product.
Like others have said, when it comes to my guns, I ALWAYS proceed on the side of safety.



https://www.prismaticpowders.com/sho...3/gloss-black#
CURE TIME & TEMP: 10 min. @ 400°F
As always, the cure time starts when the substrate reaches temperature


https://www.thepowdercoatstore.com/c...ck-powder-coat
Polyester
Cure Schedule: 15 Minutes at 375F Degrees (Part Metal Temperature)


https://www.tcipowder.com/media/1086...r_coatings.pdf
Cure Schedule: 12 Minutes@ 375°F
Metal Temperature Minutes@ °F


http://www.columbiacoatings.com/stor...tructions.aspx
POWDER PAINTING

Be sure gun is properly changed to the color desired before coating.
Check that you have the proper air pressure set (Refer to your powder gun manual). If using our Hyper Smooth or Kool Koat Powder Systems, we recommend 60 psi to the control box. We highly recommend using an air regulator on the gun and not relying on a compressor to regulate the air because the actual pressure that builds up in the air hose is more than the gun requires and can cause bursing of powder at the end of the gun.
Make sure the part you are going to powder coat is properly grounded to a true earth ground.
Preheating parts at 375-400F for 10-25 minutes is highly recommended to help outgas parts and kill any material such as oils that could have been missed when cleaning parts.
Cool for 3-5 minutes or when the material reaches 175F. This will help with Faraday Cage Effect in the areas where powder has a hard time adhering such as cracks and creases in your parts plus shooting warm uses less powder. It is not required with our Hyper Smooth and Kool Koat Gun Systems but will help with other gun systems.

CURING
Light Parts: 385F for 20-25 minutes (ie. Pulleys, brackets and other small parts)
Heavy Parts: 385-400F for 25-30 minutes (ie. Wheels, intakes, manifolds) Heavier part=higher temperature
2. Multiple Coats

Chrome/Silver base coat with a translucent and/or clear top coat
Satin White base coat with Red Fluorescent
Primer base coat
Dormant base coat with a clear top coat
Solid Colors: Partial cure for 5-10 minutes.
Metallics: Full cure at 385-400F for 25-30 minutes. Let parts cool down to less than 100F before adding a top coat.


https://www.propowdersupply.com/product/mirror-blue/
Description
CURE SCHEDULE IS 10 MIN AT 400F *PART METAL TEMPERATURE*

INTERIOR OR EXTERIOR POLYESTER TGIC WEATHER RESISTANT POWDER COATING

95% GLOSS LEVEL WITH 60 DEGREE METER * RECOMMENDED MIL THICKNESS – 1.2 – 1.8 MILS *

[KenH]

Grmps, your info is about what I had found also which conforms nicely to Smoke's instructions of put pan of bullets (room temp) into preheated oven at 400⁰F for 20 minutes. That gives the bullets time to come to temp, and another 10 to 15 minutes for full cure. Is this an "exactly perfect" per manuf? Don't know, but bet it's pretty close.

It's those who talk about <300⁰F bake temp, and short times that concern me. Does that work? I suppose it does, but is it as strong as the coating could be if properly cured?

[Handloader109]

I've used several brands, but 20 min at 400 works for all.

[Walter Laich]

Since I have a PID on my oven I can tell when it reaches 400°

once there I bake for 10 minutes

all is fine here

[Mr_Sheesh]

The oven's air temperature isn't the boolit's temperature; I've thought of drilling a boolit and making it an interference fit over a thermistor probe, to get a better idea of boolit temperature. Could use a smaller boolit like a light 25 or 30 cal one, since we'd care about the outside temperature of the boolit, not the center of a .458" 350 grain boolit?

The surface of the boolit aka "substrate"'s temperature's going to be THE critical thing to get good bonding, I'd imagine.

[MaLar]

I place the boolits in the oven turn it on 400 and watch till the PC melts then twenty minutes and done.
Went and shot some today and if I'm wrong I'm a happy wrong.

[Traffer]

The oven's air temperature isn't the boolit's temperature; I've thought of drilling a boolit and making it an interference fit over a thermistor probe, to get a better idea of boolit temperature. Could use a smaller boolit like a light 25 or 30 cal one, since we'd care about the outside temperature of the boolit, not the center of a .458" 350 grain boolit?

The surface of the boolit aka "substrate"'s temperature's going to be THE critical thing to get good bonding, I'd imagine.

That sounds like a worthy experiment. You could do different sized bullets and come up with a formula for heat times according to the mass of the slug to be coated. The results would be interesting...a lot for work though.

[Grmps]

OK let's relate baking boolits to baking chicken or cooking steak.

the oven /pan can be X degrees but it takes 5, 10, 15 minutes for the chicken/steak to reach X degrees and be done.

The X degrees they are waiting for to start timing is not the oven temp but the temperature of the boolits

IF you open the oven door to test the boolits, you've just let all the hot air out and will need to wait until the inside temp gets back up to X degrees.

[Dragonheart]

OK let's relate baking boolits to baking chicken or cooking steak.

the oven /pan can be X degrees but it takes 5, 10, 15 minutes for the chicken/steak to reach X degrees and be done.

The X degrees they are waiting for to start timing is not the oven temp but the temperature of the boolits

Great analogy! Anyone that can't understand that has never bit into a piece of still raw chicken. Under cooked bullets is just like raw chicken, something I don't want, regardless of what these self proclaimed You Tube experts try to tell you. A thermoset polymer requires a specified heat and time for the full cross linking of the molecules to occur. When completely cured the polymer transforms into a new material with completely different properties, but it appears some must like raw chicken.

The idea of a probe inserted into an equal or slightly larger mass of alloy is very interesting and might be worth giving it a try. It would think the easy way would be to just insert into a casting?

[fredj338]

With several diff powders, my bake time is 13-14min once the oven is at 400, works fine.

[Dragonheart]

With several diff powders, my bake time is 13-14min once the oven is at 400, works fine.

Only problem is what if you have an oven like this? Even when the air temp of the oven is 400 and has been there for 14 minutes the temperature of the bullets is still not 400 and I usually only fill 4 of the 5 racks.

[dbmjr1]

A couple of observations:

I'm using Harbor Freight PC in a $20 Walmart toaster oven. I generally set the timer to 10 minutes, which actually is closer to 15 minutes, and pull them out when it goes 'ding'. I do not pre-heat the oven. This has given me good results, however, reading this I see no harm in trying to cook a batch twice as long. Experimentation is fun.

On the subject of high nitro powders, such as Bullseye and Titegroup. I am currently pulling a batch of .32/20 I loaded a couple of weeks ago using TG powder. I can see, on the bases of the bullets, where the powder grains have reacted with the PC. This does NOT seem to effect performance, or cause leading problems. It is, however a bit troublesome to me.

[slide]

This is what works for me. Go to wal-mart and buy a twenty dollar multi meter. Make sure it measures temp. Mine will go to 1200 degrees F. It comes with a thermocouple that has just a small wire on the end. Drill a hole in the one of the bullets you are baking. Secure the wire with high heat aluminum tape and you are ready to go. The wire is thin enough to go in with batch of bullets you are baking and won't effect the door closing. I have one made up for all the bullets I powdercoat. Even 22 caliber. I have one thermocouple that I have used for several years that has a 158 grain semi-wadcutter taped to it. This way you are measuring what the bullets are heating to and not the air. Sorry,no pictures, don't have a camera.

[Dragonheart]

Slide, that is a really good recommendation as everyone seems to post what works for them or at least what they think works for them, not taking into consideration all the ovens operate differently, mine included. Temperature & timing is all about the bullets and not the air temperature of the oven.

[farmerjim]

I use templaq 400 to indicate when the boolits in my convection oven get to 400. With the oven at 425, the lee 358-125-RF takes 6 minutes + or - 30 seconds to reach a 400 degree surface tempature . I have put it on several boolits scattered around the tray and found them all to indicate 400 within a few seconds of each other. Thus there are no hot or cold spots in the oven. All my trays are loaded the same so once I get a time to 400 for a boolit, I can use this time and save the templaq.

[Hickok]

The PC fairy said 15-20 minutes in a preheated oven is what she recommends!

Attachment 229566

[44MAG#1]

The bottom line is each person is going to do what works for them. Regardless what anyone else says or writes.
As long as it works for what a given person does that is what counts. If it isnt working I sincerely hope that individual has the knowledge to do something different.
I know I would. If I didnt then I would say something is badly wrong. Probably too wrong to correct.


Again I mean no hurt, harm, anguish or turmoil by my post I have posted on this posted subject. I am not baiting, trolling or calling out anyone. I am making a post based on my experience, knowledge and/or belief or opinion. That is all.

[Dragonheart]

We are not born knowing, we are ignorant until we learn. Knowing how to properly cure powder coating is learned and I have learned things from this website because others have taken the time to share their learned knowledge and experience, which I appreciate. I personally have no need to reinvent the wheel, unless there is no wheel. I think most here do consider and evaluate suggestions because sometimes someone else has come up with a better wheel. If we didn't do that and just continued on with what we have always done then why spend any time on this site at all? Yes, there will always be those that refuse change, but the fact that those here are into powder coating proves they are open to new ideas.

[44MAG#1]

We are not born knowing, we are ignorant until we learn. Knowing how to properly cure powder coating is learned and I have learned things from this website because others have taken the time to share their learned knowledge and experience, which I appreciate. I personally have no need to reinvent the wheel, unless there is no wheel. I think most here do consider and evaluate suggestions because sometimes someone else has come up with a better wheel. If we didn't do that and just continued on with what we have always done then why spend any time on this site at all? Yes, there will always be those that refuse change, but the fact that those here are into powder coating proves they are open to new ideas.

If people have experimented to find there are other methods that work well then they have gained knowledge through experimenting. They too have learned. Which reinforces the fact they are not resistant to change at all. These people go on to learn. Scientist learn that a lot of the things previously learned may or may not be right due to stepping out and realizing that nothing is written in stone. Even some of the most revered scientist have be in error at times.
Experimentation is what has kept knowledge from being stagnant. We all would be using matchlocks and blackpowder if experimentation wasnt used or maybe a spear or sharp stick. Now we can used blackpower or primitive firearms or archery only if we want too.
Experimentation is wonderful and I for one hope it never stops.

Again I mean no hurt, harm, anguish or turmoil by my post I have posted on this posted subject. I am not baiting, trolling or calling out anyone. I am making a post based on my experience, knowledge and/or belief or opinion. That is all.