Powder coat problem.

[CWLONGSHOT]

I have had zero issues sizing my PC past .003 large. If I find it offers resistance Hormady one shot in a bag then mixed around solves that. (NOT a one shot fan but I keep as a release agent and PC bullet lube. Albeit only used on rare occasions) Then wash it off.
The coatings thickness or rather its possible uneven thickness is a non issue since my extra sifting maneuver. The coatings are quite uniform and thinner.

Thanks for the kudos. "Seeing" I find better for most then just reading. But now you have both!!

CW

 

[STIHL]

Well I found my issue. Powder did not cure long enough for these large bullets. I washed the cracking PC off with acetone. It disolved 98% within a few minutes. I was left with some funny looking bullets. Did a test and beat one flat no issue. Got the rest cooking now.
Bumped my fire time to 25 minutes after good glassy flow. Which is taking them 35-40 minutes total to bake off. Here’s you guys some pictures to see what I’m did. I’ll show off the finished product in a little while. Sized the others out of my test run and had no issue, things are looking good.

 

[STIHL]

Finished product, I got lucky. They are far from the prettiest I’ve coated, but I think this powder has gotten older or just doesn’t do as well as I want anymore. Ive got some coming from smoke in the next week or two. Will see how that does.

 

[Spindrift]

Those should do the trick, glad you solved your problem!

 

[Ian]

For this very reason I used a contact thermocouple probe and very accurate volt meter to determine the actual temperature of a bullet in the oven and did so with various calibers and weights until I got familiar with my oven. Convection makes a huge difference to how they cure and also how they harden if you quench.

My cook times are based on MY oven with MY bullets trayed up in the mass load that I've actually tested. Time for the bullets to reach the cure temperature plus recommended cure time plus a couple minutes extra for a fudge factor is how I arrived at my times. Most are good to go in 20-25 minutes from a cold start. The powder flows about 4-7 minutes before the bullets are at cure temperature, so never go by that.

 

[CWLONGSHOT]

Yup, As we have seen, under cooking is bad. But conversely "over cooking" hasnt shown to creat problems. So when in doubt aire on the safe side and cook a lil longer!
CW

 

[Joshua]

The industry literature that I have read indicates that longer bake times will affect color, but will not harm the coatings functional nature.

With clear coats you will get a yellow tint from overcooking.

 

[CWLONGSHOT]

The industry literature that I have read indicates that longer bake times will affect color, but will not harm the coatings functional nature.

With clear coats you will get a yellow tint from overcooking.

I have baked off 20+ pounds of powder coat.. Believe me the few extra minutes Im advising is not hoing to produce a noticeably different color.
CW

 

[STIHL]

I see no difference in the color. If you want to know the truth, I think the color looks a hair dull, but it is thin and the lead surface bleeds through, where it is thick, it’s the color of the dry powder at 40 minutes. At the plant we bake everything 30 minutes in a 425 degree natural gas fired oven. It doenst take sheet metal long to come up to temp in a forced air oven, bakes like a convection oven does. But with 100 times the air moving. Parts come out the same color as the finish paint does. I promise it is not as critical as a few seconds, if it was I’m sure they could screw it up. I would much rather over cook it than undercook it ever again, not worth my time and effort on the learning curve, but 1 time.

 

[Joshua]

I have baked off 20+ pounds of powder coat.. Believe me the few extra minutes Im advising is not hoing to produce a noticeably different color.
CW

I tend to agree with you. The difference in color will be almost imperceptible to us as bullet casters.

In industry where multiple items of an assembly may be powder coated at different times, small differences in color will be perceived. I remember when I worked at the Harley Davidson dealership, we had a Buell get returned because the tank had turned a different shade then the rest of the bike. In that case color differences did matter. Hopefully none of us are going to be comparing our colors batch to batch and loosing sleep over any perceived differences.

What is more important was the second thing that I mentioned. That the manufacturer’s acknowledge that a limited amount of over baking will not have a detrimental effect on the physical quality of the PC.

The advantage of a plastic jacket is why I have begun to use PC. I really could care less what color they end up.

Cure time starts when the bullet has hit “part temp” of 400°F. You will see the powder liquify, that happens at a lower temp than 400°F, I guess it liquifies at around 325°F. I wait five minutes after it liquifies and then start my 20 minute timer. I end up with a 30 minute overall cook time.

You weren’t the only one advocating a longer bake time. That was me in post No. 2.

 

[fiver]

I'm good at making cookies and Bread and syuff like that.
all I done was apply the same baking techniques,,,,, I.E. it's done when it's done there ain't really a set time.
12-15 minutes is all subjective to the oven temp, humidity, proof, and insulation qualities.
I've browned off bread in under 15 minutes and 2 days later it took 22 minutes with a butter brush and a return for 4-5 more to get the same finish.

 

[RBHarter]

In fresh paint 50% won't see a noticable difference in a full shade if it's broken on a line . 25% will notice but won't know what they're seeing . 20% will be able to identify the color change but not consistently which is lighter or darker without light changes , those that remain see likely are among the tiny portion that can readily distinguish over 400 shades of of a particular color .
White is the single most mismatched color on the planet and most of us can't tell blue from grey from green . Then there's red/orange/yellow . In shades of white that is .

Personally I loathe that whole turquoise/aqua/teal mess .

 

[Ian]

12-15 minutes is all subjective to the oven temp, humidity, proof, and insulation qualities.

I bet altitude makes a difference, too.

 

[fiver]

it definitely does.
just boiling water is a lesson in air pressure [you go from 212 to 220 pretty quick]
and when baking simple stuff [like a box cake] you have to modify their recipe by adding in more flour.

 

[STIHL]

Either way it’s cut, done is better than raw in this instance. I’m not picky about my color I get tired of looking at a particular color and I want a change. Orange is my color I’m tired of at the moment. I’ve got some green and blue and clear coming, just to change up a little. If it works well I’ll order 5 different colors and be set for a while on powder.

 

[RBHarter]

Boiling water , same as horse power loss , round numbers , simple math , 3%/1000 ft . Standard day 3300 ft water boils at 191° at 8000ft it's takes 45 minutes to boil eggs soft after the water boils with a tblsp salt per qt of water .

 

[Wolfman]

This is what Ian is talking about. It takes a lot of the gueswork out of the process. I was real hesitant about posting this but I thought maybe it might help somebody. When I posted over on the other site I acutally had a guy post my exact same post about a month later using my words claiming he came up with the idea. From then it was a running battle with different guys about credit. One of them claimed his Grandmother did this. Never thought there were those knids of people in the reloading and casting camps. Anyway, you can buy these digital thermometers off of ebay for abourd $20.00 last I checked. Drill a hole in a the bottom of a bullet similar to the one you are baking. Be careful! That little sucker will get hot. Lay your t-couple bullet in with your baking bullets. When your t-couple hits the manufacters temp start a timer. For instance if your powder calls for 400F for 10 minutes,when your t-couple bullet hits 400F start a countdown timer.

 

[Wolfman]

After reading the post I didn't do a very good job of getting most of the info out. I can't take all the credit for this. One of the aussies on the hi-tek thread made a joke about putting a thermometer up the bum of a bullet. For some reason that stuck in my head and got me to expermenting. When you put your drilled bullet on the t-couple you can squeeze it down( a fella called Hossfly came up with the squeeze). For a long time I used high heat aluminum tape and still have several that are still taped after quite awhile. I always use a coated bullet for the t-couple. Supposedly it absorbs heat at a different speed than bare lead. In the end I doubt it will make any difference. This just another option. Use whatever works for you. I like fooling with stuff like this.

 

[STIHL]

@Wolfman that actually ain’t a bad idea. I have so many other projects going im just going to wing it and keep on trucking like I’m going right now it’s working so I’m not going to try to over complicate this one, for once.

 

[L Ross]

it definitely does.
just boiling water is a lesson in air pressure [you go from 212 to 220 pretty quick]
and when baking simple stuff [like a box cake] you have to modify their recipe by adding in more flour.

Ha! We tried boiling dried beans at 11,000 ft. in a mountain mule deer camp and the water kept boiling away and the beans never did cook.