Powder coating fail.....
- Thread starter Shadow9mm
- Start date
This site https://www.americanelements.com/meltingpoint.html shows some allows of Lead-Antimony at 477F and Lead-Tin at 369F
This isn't a PC fail.
It's an oven Temp fail.
What thermometer ? (The mechanical one in the pic?)
Was the oven on "Bake", or "Broil" ?
And how long was the Oven allowed to equilibrate ?
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It's an oven Temp fail.
What thermometer ? (The mechanical one in the pic?)
Was the oven on "Bake", or "Broil" ?
And how long was the Oven allowed to equilibrate ?
$34 at Amazon
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More of a failed attempt at PC, but not due to any fault in the PC itself you are correct.
yes, the mechanical oven thermometer in the picture.
oven goes from 450 to bake, then broil. Turned it up to bake for about 2min.
Pre-heated the oven for about 15min, was at a steady 250 before I put the pan in.
yes, the mechanical oven thermometer in the picture.
oven goes from 450 to bake, then broil. Turned it up to bake for about 2min.
Pre-heated the oven for about 15min, was at a steady 250 before I put the pan in.
IME, toaster ovens usually have poor thermal coupling to their thermostats. You probably experienced a bad case of control point overshoot on the hot side. What you want to do is get an inexpensive thermocouple-based thermostat that will respond quickly and have good absolute precision. You put the thermocouple (tc) probe in the air at the height of your bullets. Set the oven's thermostat to maximum but plug the oven into the tc thermostat. This combination let's the tc thermostat have full control and prevents it entering a competition with the built-in thermostat for control.
If you want really tight control, move up to a PID controller. They can be found cheaply on line, too.
If you want really tight control, move up to a PID controller. They can be found cheaply on line, too.
See:
https://thefiringline.com/forums/showpost.php?p=6809137&postcount=10
https://thefiringline.com/forums/showpost.php?p=6809213&postcount=12
https://thefiringline.com/forums/showpost.php?p=6809282&postcount=13
That Temp Probe made all the difference in he world in monitoring what was really happening.
(The I PID'd it and never looked back -- 405° ± 1° all day )
-- Then I discovered Eastwood
https://thefiringline.com/forums/showpost.php?p=6809137&postcount=10
https://thefiringline.com/forums/showpost.php?p=6809213&postcount=12
https://thefiringline.com/forums/showpost.php?p=6809282&postcount=13
That Temp Probe made all the difference in he world in monitoring what was really happening.
(The I PID'd it and never looked back -- 405° ± 1° all day )
-- Then I discovered Eastwood
I would not ignore the idea bullet metal may melt at a lower temp than pure lead. A quick search revealed lead/tin solder and lead/ antimony alloy melted under 500 deg f . Of course,that will vary with percentages.
When you get your thermometer check the lead melting in your pot for melt temp.of your alloy.
My knowledge of the topic is not strong, but couldn't the radiant infrared heat from the heating elements heat the objects...the bullets, hotter than the air temp?
Might your thermostat depend on air heat?
I'm not sure how that works
When you get your thermometer check the lead melting in your pot for melt temp.of your alloy.
My knowledge of the topic is not strong, but couldn't the radiant infrared heat from the heating elements heat the objects...the bullets, hotter than the air temp?
Might your thermostat depend on air heat?
I'm not sure how that works
That's why to BAKE from the bottom (not Broil from the top)
...and on/in pan that further shields/separates the bullet from the bottom element's direct radiation.
Note that even that slight separation prevents the like of parchment paper from burning (451) from that direct heat.
...and on/in pan that further shields/separates the bullet from the bottom element's direct radiation.
Note that even that slight separation prevents the like of parchment paper from burning (451) from that direct heat.
Highly recommend looking up the plans for and building yourself a PID controller. It will not only dial in your oven temp but also keep your lead pot at a steady temp.
I use one for my lube heater, lead pots, and my toaster oven for coating. They are easy to cobble together a d can be had for under a hundred bucks.
I use one for my lube heater, lead pots, and my toaster oven for coating. They are easy to cobble together a d can be had for under a hundred bucks.
armoredman
New member
Great Scott, go to Goodwill and get a cheap toaster over, replace the tray with a metal one. set to Toast. Run your boolits there for 20 minutes. I have been doing this with a $5 toaster over for years, specifically an Elite oven with three settings, Bake/Toast/Broil. Don't over think it.
2wheelwander
New member
I had a small but very successful powder coating business for 5/6 years out of my garage. So I'm coming at this from a powder coaters perspective.
You should not have to preheat an oven than size for 15 minutes. I'd expect up to temp within 5 minutes. Keep in mind when you throw in your parts and tray they are at room temp so it'll take a few minutes after having the door open to get back up to temp.
1st, I don't know what powder you are using, but unless you are using high temp powder (highly unlikely) you are baking too hot. 90% of powders cure at no more than 400' part temp. So, if your powder cures at 400' @ 10 minutes, your cure time starts when the part reaches 400', then the timer starts. This isn't a do or die rule, bake at 15-17 minutes and you'll be good. You won't hurt the powder by cooking at 450, but you're just running up your electric bill for no reason and obviously heating your material beyond its abilities.
2nd, others are right, your oven may indicate 450 degrees, but it may be off by 50 degrees. Get a laser temp gun from harbor freight and an oven thermometer to get a better idea where you are actually at inside the oven.
3rd, you can bake your powder at lower temps than indicated on the powder container. For instance if it says 400 degrees for 10 minutes (remember, this is after the part has reached 400 degrees, not from when you put it in the oven), you can lower the temp and bake for longer. Say you want to bake at 350 degrees, the run the cure time out to 20 or 25 minutes. With most powders you can do this down to around 275 or 300 IIRC. Time to temp scales can usually be had by powder manufacturers.
You will know when your powder has begun to bake when it flows out - or looks shiny and no longer like a powder. Don't worry about over baking your powder. Unless your are getting carried away and setting it under a 500 degree broiler for 30 minutes you aren't going to hurt it.
Free tip - baking on foil can create a cured bond between the part and the foil requiring you to trim off the foil. You can bake on corrugated cardboard just as easily. It will smell like straw burning. Keep an eye on it so you don't combust. I've never had cardboard combust when doing 400 @ 10 minute bakes. I used this primarily when doing bolt heads and other hardware. Just keep an eye on it until you get a feel for things.
HTH.
You should not have to preheat an oven than size for 15 minutes. I'd expect up to temp within 5 minutes. Keep in mind when you throw in your parts and tray they are at room temp so it'll take a few minutes after having the door open to get back up to temp.
1st, I don't know what powder you are using, but unless you are using high temp powder (highly unlikely) you are baking too hot. 90% of powders cure at no more than 400' part temp. So, if your powder cures at 400' @ 10 minutes, your cure time starts when the part reaches 400', then the timer starts. This isn't a do or die rule, bake at 15-17 minutes and you'll be good. You won't hurt the powder by cooking at 450, but you're just running up your electric bill for no reason and obviously heating your material beyond its abilities.
2nd, others are right, your oven may indicate 450 degrees, but it may be off by 50 degrees. Get a laser temp gun from harbor freight and an oven thermometer to get a better idea where you are actually at inside the oven.
3rd, you can bake your powder at lower temps than indicated on the powder container. For instance if it says 400 degrees for 10 minutes (remember, this is after the part has reached 400 degrees, not from when you put it in the oven), you can lower the temp and bake for longer. Say you want to bake at 350 degrees, the run the cure time out to 20 or 25 minutes. With most powders you can do this down to around 275 or 300 IIRC. Time to temp scales can usually be had by powder manufacturers.
You will know when your powder has begun to bake when it flows out - or looks shiny and no longer like a powder. Don't worry about over baking your powder. Unless your are getting carried away and setting it under a 500 degree broiler for 30 minutes you aren't going to hurt it.
Free tip - baking on foil can create a cured bond between the part and the foil requiring you to trim off the foil. You can bake on corrugated cardboard just as easily. It will smell like straw burning. Keep an eye on it so you don't combust. I've never had cardboard combust when doing 400 @ 10 minute bakes. I used this primarily when doing bolt heads and other hardware. Just keep an eye on it until you get a feel for things.
HTH.
If you do not test the toaster oven heat setting against a reliable thermometer, you are courting more melted bullets. Cheap toaster ovens are notorious for incorrect heat settings... they are pure fiction. Ask me how I know.
using eastwoods hotcoat in ford light blue. instructions state pre-heat to 450. I was outside in about 38F weather so it took a bit. I was advised not to do it inside. I went by the gauge in the oven. says to put the items in and once it has flowed out to drop to 400F and set the timer for 20min.
I am guessing they recommend 20min, in addition to the 450 pre heat, to allow the item to come up to temp and guarantee a full cure.
I had not heard about the bonding issue, but I had been told to buy non stick aluminum foil, which is what I was using. No ripping or tearing, pulled free. saw a guy on youtube who had a bunch of bullets with foil stuck to the bottom.
Lastly, I do have a cheap oven thermometer, but I have not checked it against my infared (laser) thermometer yet. Infared thermometers can be great however they have some sneaky tricks they can play on you as well. heres a short and not too dry article. basically metal surfaces generally reflect the air temperature, not the temperature of the object. My dad took a class in infared thermography (thermal cameras) and I got the practical version from him in high school.
https://www.flir.com/discover/professional-tools/how-does-emissivity-affect-thermal-imaging/
I am guessing they recommend 20min, in addition to the 450 pre heat, to allow the item to come up to temp and guarantee a full cure.
I had not heard about the bonding issue, but I had been told to buy non stick aluminum foil, which is what I was using. No ripping or tearing, pulled free. saw a guy on youtube who had a bunch of bullets with foil stuck to the bottom.
Lastly, I do have a cheap oven thermometer, but I have not checked it against my infared (laser) thermometer yet. Infared thermometers can be great however they have some sneaky tricks they can play on you as well. heres a short and not too dry article. basically metal surfaces generally reflect the air temperature, not the temperature of the object. My dad took a class in infared thermography (thermal cameras) and I got the practical version from him in high school.
https://www.flir.com/discover/professional-tools/how-does-emissivity-affect-thermal-imaging/
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Unlike lead casting, no problems PC'g inside.
(Might as well stay warm
)The best of the best.
(Stick with it.
)'Parchment' paper in same grocery section.
(You'll never look back)
Once you get that ThermoPro for continuous monitoring....
(you'll see where things went south)
Once you get the wireless... & Pre-heat for steady 410 (it'll wander ±10°) and time 30 minutes.
(Walk away... but keep the wireless unit w/ you to watch things)
so I did some basic testing today. did it inside instead of outside. at 450 the over thermometer was reading 550. Dropped it down to 350 and it read 450 until I opened the door to put the bullets in. Then it dropped. have it just above 350 now for a consistant 390-400.
Based on how cold it was the other day I'm guessing the oven was staying on to get hot enough and the direct heat melted the bullets.
Got 2 bullets in now with my ford light blue and some PBTB glass clear. The bullets were lubed and I cleaned them, but not well enough. Glass clear looks amazing. Blue is looking rough. Fun test run though,
Based on how cold it was the other day I'm guessing the oven was staying on to get hot enough and the direct heat melted the bullets.
Got 2 bullets in now with my ford light blue and some PBTB glass clear. The bullets were lubed and I cleaned them, but not well enough. Glass clear looks amazing. Blue is looking rough. Fun test run though,