Toaster Oven Capacity Rules?

[OTShooter]

I’m about to do my first powder coating. I have an 1100W toaster oven, and I’m going to be coating 230 grain .452” bullets with Smoke’s powder.

Assuming I don’t have to worry about spacing, (except that the bullets shouldn’t touch each other), what sort of rules should I observe for cooking my bullets?

Do folks load their ovens based on total number of grains of bullets, how much of the tray is covered, or something else?

Do I need to extend the baking time for some number of heavier bullets over the same number of lighter bullets? Does it really matter?

Thanks in advance!

[GBertolet]

I load the trays with as many bullets as will fit, if I have that many to treat, without having the tray bend under the weight. Generally bigger bullets are more weight, although there are fewer, than say 9mms filling the tray. Bigger diameter bullets are taller also, adding weight. I do a lot of 45 cal 230 gr bullets, with no issues. This criteria is my determining factor. I go 400 degrees for about 15 minutes after a preheat for a nominally filled tray, and up it to 20 minutes with a maximum filled tray. This works for me fine. My toaster oven works great. I have only used it on bake setting, and have never tried on broil. I don't know if it would make any difference or not. Heat from above or below?????

By the way, I use Smoke's powder also.

[Walks]

I'm picky, so I set every bullet on it's base, about 1/8" - 3/16" apart. Just keep going until the tray is full. You GET a lot more .356 - .358 bullets then you will .432 or .452 bullets.
I have 2 racks in my Oven, but only use one at a time. Fill one while the other is "cooking".
And .311 - .314, man you can get a lot off those on a tray.

[BNE]

I load one tray and only cook / fire one tray at a time. I tried 2’trays and had some under fires bullets. I have a decent little convection oven for this, but your mileage may vary.

I say try it and then do the smash test. If they are under done, put them back in. No loss other than your time.

BNE.

[Jhopson]

I put my bullets nose down in the used plastic Ammo trays and then flip them over onto the tray that way they are all standing up. I can do 400 9mm at the time this way. 20 minutes at 400 degrees with Smoke’s powder


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[charlie b]

It depends on your oven. FYI, broil setting is not a good idea. In some ovens it is not temperature controlled. Usually it turns on only the top element, which creates a more uneven heat on the bullets. For any oven it will take a while to get all the bullets up to temp. If you put them in a basket then you need to wait that much longer to make sure the bullets in the middle of the pack get up to temp for the proper length of time.

I do not bake very many bullets at one time in my little oven and I leave a lot of space between them so they all heat as fast and evenly as possible.

If you need to do more than 100 at a time then I would invest in a convection oven. Don't know if they are still on sale but this is the time of year to go find one.

[BamaNapper]

For me, how heavy I load the tray depends on what I'm using the bullet for. For the accuracy in rifles I shake/bake, stand them up on parchment paper, not touching, and run them through a convection toaster oven. They end up smooth and pretty. For pistol I'm typically shooting 7-10 yds and I get the same accuracy whether I get picky or just shake, dump, bake, and break them apart when they're cool enough to handle. I make trays out of 1/4" hardware cloth and try to limit my dump method to just a single layer. Not as pretty, and I end up with speckles of whatever colors I've used recently, but they shoot just fine with a lot less time involved. I estimated 1200 an hour with my toaster oven, running cooled batches through the sizer while another batch bakes. A roll of hardware cloth let me make a handful of trays to fit the oven. I can run batches through without waiting for them to cool. Yes, let the oven preheat before putting the bullets in and use an oven thermometer to find out where 400 is on your dial. Don't trust the numbers on the knob, it can easily be off either way by 50 degs. Smoke's here also.

[Conditor22]

1st use an oven thermometer and check the ovens temperature setting, adjust it until the thermometer reads 400°

2nd is the oven is not a convection oven, I wouldn't bake more than 50 - 100 boolits at a time centered in the middle of the tray for 25 min in a preheated oven. Manufacturers spec says to bake for XX min at XXX° after the objects surface temperature reaches XXX° or the PC starts flowing to achieve a full cure

due to the toaster oven not having a circulating fan like convection ovens they get hot spots and can melt lead you'll have to find out the capacity of your oven.

I like to line the bottom of my ovens with a heat-retaining media. I use ceramic BBAQ briquettes, some use fire brick, lava rocks ---- anything that will heat up and hold the heat. this greatly speeds up the oven's recovery time after the door has been opened to put the boolits in

[bmortell]

I guess ideally youd get a lazer themometer which are fairly cheap nowadays and start time from when the ones in the middle are up to temp. Or just start time a bit after the ones in the middle are melted. But it dont need to be exact science for time. Just cook 5 extra minutes if your worried

[cwlongshot]

I find that even heat is important.

I load my oven with lava rock made for outdoor grills. Then I preheat the over for a good 30minutes.

Then small or Large batches seem not to matter at all. I use baskets and try to stay wil single layer.

CW

[OTShooter]

I went for it this afternoon and, following Smoke's instructions, I coated and baked about 60 bullets.

The first 10 were a test of all the different steps, and I separated the bullets from the BBs with fine tweezers. 20 minutes at 400F (checked with an oven thermometer) turned out 10 beautiful bullets.

The only issue with this was that my fine tweezers don't open quite enough for these .452 bullets, so it was a hassle to get them around the bullets, and a hassle to let the bullets go.

While the first 10 were in the oven, I coated another 50. This time I wore a nitrile glove and just picked the bullets up out of the container I shook them in.

The first batch came out beautiful. The second batch had some thin spots, but nothing bare. I may do a second coat on them.

Overall, it worked well, and I appreciate everyone's input. That helped a lot.

[bmortell]

I use scissors to grab in the lube grove, since there sturdy and easy to open and close, grab all the ones that are on top without BB's on top of them. then the ones that are buried a bit if you pull them out of the bbs some paint will get knocked off, just shake it for another 10 seconds then up down a few times, then grab the ones on top again.

I haven't tried the gloves yet. people say it works, but it don't make sense to me that physically grabbing it don't knock anything off. plus I tap the scissors on the edge of the bowl to knock extra off

[Conditor22]

[Misery-Whip]

+1 for Blue nitrile glove. Put it on, get fingers in the powder start touching bullets. Works great. I run 2 ovens. One was 5.50 at the goodwill. Paid 3.00 for the other at a yardsale. Can get about 500 358-125rf coated in an hour.

[Dragonheart]

You asked a very good question and one most don’t have to worry about because they cook one or two hundred bullets at a time. In a case like that the dynamic load is small so if one monitors the temp and brings the oven up to 400 F degrees and then adds a few more minutes they will have achieved the typical powder cure of 10 minutes at 400 F. degrees.

Where this method can get into trouble is if you start really loading up an oven as I do. My all-time record for the number of 9 mm powder coated bullets cured in a single cook in my Hamilton Beach Countertop Toaster Oven. 621 bullets per rack times 4 racks = 2484 total.

The powder manufacturers specify 10 minutes at 400 F degrees, but that is when the substrate comes up to 400 F. In a case like mine the dynamic load is very high and looking at my thermometer is not going to give me the information I need because the thermometer is measuring air temperature in the oven and not the actual temperature of the load (the bullets substrate). If I used an arbitrary number like 15-20 minutes I can assure with a load of 2484 bullets the bullets will be well below the necessary cure temperature.

Some recommend start timing after the powder starts to flow and assigning a time. The reason this is a poor practice is powder typically starts to flow at 150 degrees. To achieve cure temperature the substrate has to come up another 250 degrees so setting an arbitrary number does not account for a high dynamic load or other variables.

Load can be calculated mathematically, but there are so many variables that would first have to be found and even so some would be a moving target, it would drive all of us crazier than we already are. Also trying to get an accurate temp reading using one of these handheld laser infrared thermometers is a waste of time as they are extremely inaccurate.

All the above is why. So to answer your question, what I do is I monitor the actual temperature of my bullets and then to be on the safe side I add some extra time because it is not going to hurt. I use a very inexpensive digital thermometer with a K type thermocouple. I embedded the thermocouple into a cast bullet and I place the bullet in the center of a middle tray because from previous sessions I know that is the place that comes up to cure temp last. Actually, I have two thermocouples monitoring the temp because when I cook in my 30” oven I am cooking over 5K bullets. I have not found a better or easier way to assure full cure regardless of the oven or the load.

The digital thermometers I use is a TM-902C digital LCD K-Type. These can be found on EBay and Amazon for under $7. They are amazingly accurate for such a cheap thermometer. If you go this route be sure and get extra thermocouples as they do go out. A metal K probe also is good to check the temp of your casting pot. If you cast one into a bullet get a bare wire thermocouple. Thermocouples can be purchased separately.

[OTShooter]

I think the thin spots in my second batch may have been due to not having enough powder in the container. I'm going to add powder and try the same number of bullets to see if that helps.

I ordered hemostats for manipulating bullets. I'm not much of a "tweezer guy", and finding needle nose pliers with long enough and fine enough jaws is pretty challenging (or expensive).

I'm also looking at "straining" the bullets out of the powder/BB mix with hardware cloth. I'm pretty sure .25" hardware cloth will pass the BBs without any issue, and I'm not looking at casting anything small enough to pass through a hole of less than .25" square.

[Dragonheart]

OT, bare spots are usually a sign of not adequate static charge, probably due to too high humidity. Moisture in the air kills the static charge. It can also be caused by contaminated bullets usually when a water drop was used and the water was not absolutely clean.

[OTShooter]

That may have had something to do with it. Smoke also tells me that heavier bullets can take longer shaking before they coat properly. I’m working on setting up for my next batch, and I’ll watch the humidity.

[OS OK]

Someone once posted this picture here when they were having trouble...I got a kick out of their honesty but this is what you can expect if you don't heed all the warnings offered up thus far...a thermometer is a must because these CheeePoChineeee Piece-O-junk ovens will lie about temperature like a democrat.

[OTShooter]

I have a dependably accurate oven thermometer. I made sure the oven was at really darn close to 400F before I started my first batch, and both batches baked quite well. I do NOT trust a cheap appliance to be calibrated or even repeatable at a given setting. I'm a longtime user of test and measurement equipment, so I measure, check and verify before I trust any important value/quantity.