powdercoat cured too hot or too long.

[Scout800a]

Any risk in having cooked powder coat too long or too hot (aside from melted bollits)?

[Beagle333]

It can get brittle if you overdo it. Then it will crack or flake off when it hits the forcing cone and not do the job.
See if they still pass the smash test and if so, they'll shoot.
It should flex with the shape of the boolit and can't do that if it's brittle.

[popper]

I cook for an hour no problem. I've not gone above 400F for HF powder.

[Scout800a]

Thats good I would have hated to send what i've done so far back in to the pot

[Walter Laich]

Is there a reason you cook for a whole hour?
.
just wondering?

[bangerjim]

10 min is all that is needed!!!!!!!!!! I have left them in after timer went off for mabe another 15 minutes because I got busy doing something else.

Over heating is NOT good for them. Keep at 400F. But cook as long as you wish.......to waste electricity!!!!!!


banger

[prickett]

Is there a reason you cook for a whole hour?
.
just wondering?

He water drops when done to regain some of the hardness.

[sasquatch76]

I cook mine until they get the shiny glazed look (about 10 mins at 400), then turn the oven off and leave them in for 5 mins. I then open the door until they cool off enough to remove the tray for further cooling. Seems to work great.

[mdi]

As my experience progresses, I'm cooking shorter and shorter times. I am still at about 400 degrees, but last batch of bullets ran for 10-12 minutes. Results looked good...

[bangerjim]

Glad you posted that. As I have been saying for months now, all you need is 10min AFTER the stuff turns shiny in the oven. That "shine time" will depend on the quantity and the caliber (weight) of the load you put in the pre-heated oven.

Temp needs to be as close and constant to 400F as you can get.

Glad things are coming together for you! No need in wasting time and electricity on 20-30 minute bakes.........they are NOT needed.

I did not make this stuff up................MOST commercial powders state 400F for 10 min. The HF bottles (like many other things they print in Chinglish) are wrong at 20 minutes.

I do not let the oven cool off! I have another batch ready to go in, so I remove the hot boolits, put more racks in, and set the freshly baked hot batch in front of my outdoor evap cooler. (this IS Arizona!)

Have fun!

bangerjim

[popper]

If you don't need the hardness, do like Banger does. I use a low Sb/Cu/As alloy that gets really hard in a day - don't want to wait a couple months to get some hardness back, but this is for rifle. 400F for 10 min. works fine as Banger says.

[flyingmonkey35]

3 mins in a pre heated toaster oven they go glossy reset time back to 10 and water dropem right after

Color is HF red/yellow

[hanleyfan]

most brands say how long to bake, I know eastwood states to bake at 450 for 5 min. and than turn down to 400 and bake for 20 min. I know a lot of the others say 10 min. at 400, so what ever brand you use I would go with the manufacturers recommendations.

[Rushthezeppelin]

3 mins in a pre heated toaster oven they go glossy reset time back to 10 and water dropem right after

Color is HF red/yellow

Holy crizap you made University of Texas burnt orange bullets....me likey

[waksupi]

I have a question for the PC people. I haven't ventured into this yet, but have an idea I may want to test.
Do you think a longer heat time, at around 200 would cure the PC?

[popper]

Not with HF red. If I get time this week I want to test PC at different temps, 300-450F to see how it does and how it affects hardening. Also re-heat for WDing. The HF red is thermoplastic, not thermosetting & I noticed some minor problems on second coating. Kinda did this in the last year but didn't really record any data. Have to cast, coat & load 20# of 9 for the kid. She wants them RED.

[mechteacher]

My PC cure directions said 10 minutes 400 F. I shake by hand in a plastic storage container, dump into a metal strainer sitting on a 1 quart paint bucket. After a light shake dump them on oven toaster tray lined with parchment paper. No need to stand up etc. Bake in preheated oven. When done I pull and dump tray into a bucket with about 2 inches of water. Remove bullets and place on cloth to dry. I size with lee sizers, the first time I pickup each bullet.
I do .30 through .54 cal bullets.

[Willbird]

I have a question for the PC people. I haven't ventured into this yet, but have an idea I may want to test.
Do you think a longer heat time, at around 200 would cure the PC?

TIGER DRYLAC is one powder mfg that posts a time/temp chart, they are talking about the time at which the substrate reaches the specified temperature. 356F is the lowest that mfg is going.

This is for a gloss product...


This is for a matte product


I'm not sure anybody has done a study yet on placing a bullet in an oven, and charting when the surface reached oven ambient temperature. IMHO if the core is staying cooler it is acting as a heat sink until the full mass of the bullet reaches oven temperature. if we set them on a tray base first the tray is gathering heat and pumping it into the bullet via conduction maybe ??

IR temperature measurement can be messy due to how different colors and surface emit heat, if we slaked 10 different PC bullets in an oven for hours I would fully expect different colors to measure different temperaturs with IR measurement.

[Conditor22]

mechteacher
That is 10 min at 400° AFTER the substrate has reached 400° you're looking at an overall bake time of around 25 min


I've found 2 different bake schedules (which are actually similar with different stages where you start timing the bake cycle

EASTWOOD - Cure Time: 20 Minutes AFTER flowout/the PC melts

PBTP, CARDINAL - 10 minutes AFTER the boolits reach 400°

https://www.powderbuythepound.com/su...wet-black.html
• Cure Schedule = 400f/10 Min at Part Metal Temperature

http://www.cardinalpaint.com/assets/...9-T013-TDS.pdf
Cardinal paint CURE SCHEDULE: (METAL TEMPERATURE) 10 MINUTES @ 400 DEGREES F.
I guess the time is relevant to how/when you start gauging it


https://www.eastwood.com/hotcoat-pow...ight-blue.html
SPECIFICATIONS

Color: Ford Light Blue
Gloss Level: Gloss
Cure Temperature: 400 Degrees
Cure Time: 20 Minutes after flowout

[popper]

I stand my boolits up and cook on my hot plate (a ceramic tile on the H.P. to spread the heat). I put a cover over them for a while to speed up the heating - no fan. Cooking is mostly conduction.