Toaster ovens and their accuracy

[prs]

My oven is a little optimistic too, but the temps within are stable regarding one area to another. There is some variation between on and off cycles too. So I marked the dial for a peak of 400F and added a little time like Smoke described to make up for the lower temps around the off cycles. Like Gremlin noted, the "load" of lead in the oven gets hot on the outside first and it must take some time to warm all through. So I do not pre-heat, but let the oven and boolits warm-up together figuring to get a more thorough heating. Then, when the powder is all melted, I give it a good 15 to 20 minutes. Seems to work well with 7+ pounds of boolits on two trays in a little convection toaster.

[bangerjim]

Hey all - I've been struggling with PCing though I have persevered because it's the only way I'll be able to shoot lead through my suppressors without excess buildup. I got a cheapo Rival TO at the Mart that Wal built, but never could get a decent cure according to the smash test. I finally got a round over thermometer, and sure enough, the thing is all over the place. The dial sets all the way to 450, but was shutting off and maintaining 350...if I put it on "bake", it stays on and will eventually get over 400.

Would one of you kind gents mind walking me through how to apply a PID to the situation? The way this one works, the timer runs whether or not it has power; I'm unfamiliar with how a PID works but if it could allow power to the TO when it's under 400 and shut it down when it gets to 400, seems like that would work.

OR - should I just buy a better toaster oven?

I just did one batch; it took about 20 minutes to get the thing up to 400 with the tray of boolits in it, so then I ran it another 20 minutes according to the instructions that came with the PC. So 40-45 minutes for one tray! But it seemed to do OK with the smash test; I could see little bits of lead through the PC after smashing, but it wasn't like it was flaking off, so hopefully it's doing OK.

Many thanks for ALL the help - this is THE most helpful place on the net!!

If you have a controller, just get another TC and stick it in the side of the oven and plug your oven in the controlled power plug. Remember, the TC only senses temp at ONE spot in your oven so if is a standard oven, it might not be the cure-all. A convection (circulating fan) style, the air moves all the time and the TC will sense a better over-all temp. And remember to watch the power consumption rating of the oven vs the rating of the controller SSR. My oven draws 1800 watts. And if a convection style, you need to power the fan separtely from the elements.

My convection oven maintains within 8 degrees with it's own control. No controller needed.

I only bake at 400F for 10 min. No more is needed from my tons and tons of experimenting. Start timimg AFTER ALL the powder has turned shiny. My boolits pass my "smash into a cube" test with flying colors.......not a bit of PC come off.


Have fun!
banger

[prs]

The variations in how we do and what we do is pretty much to be expected given we are in the pioneer stage of all of this. Banger, with your 10 minutes of bake post paint melt as compared to my 15 to 20 (all at about 400F); how does your bake load compare to mine? I am baking two closely packed shelves at once with 200gr .454 diameter boolits, about 250 boolits per tray and that seems to be about 17+# per bake. Maybe I can trim my bake time and get another batch in sooner.

prs

[kryogen]

I have a cheap convection oven, and I use the Frozone PID with a thermocouple through the side wall, at the back.
Fan is always on (direct to wall outlet), and 4 elements to PID.
Keeps temps +-2 degrees.
The standard thermostat on the oven is totally useless, like 50-100 degrees off and varies too much.

I put 2 large lead ingots at the bottom of the oven and a large metal plate, so it accumulates heat and varies less when I insert the boolits.

[bangerjim]

The variations in how we do and what we do is pretty much to be expected given we are in the pioneer stage of all of this. Banger, with your 10 minutes of bake post paint melt as compared to my 15 to 20 (all at about 400F); how does your bake load compare to mine? I am baking two closely packed shelves at once with 200gr .454 diameter boolits, about 250 boolits per tray and that seems to be about 17+# per bake. Maybe I can trim my bake time and get another batch in sooner.

prs

I mainly ESPC so with the 3/4" spacing, I get around 150 boolits per tray (depending on cal) x 3 trays max. The key I have found is not the number of boolits but the liquifying of the powder, indicating proper cure temp has been achieved. That appears to me to be the most important factor rather than the exact temp the oven cavity (PID or not) or the # of boolits. If the powder is shiny on ALL of your boolits, irregardless of the number, then your boolits ( not just the oven internal temp) are at the correct bake temp. 400F works for me every time. Only then do I start my 10 min timing.

banger

[Chunky Monkey]

I just upgraded from a toaster oven to a connection oven. I would also like to install a PID. Can anyone suggest a good reasonably priced one front Amazon? Also is where can I find info such as installing PID for dummies?

[Beagle333]

There are a lot of threads in the Casting Equipment section on building PIDs. Just read a few and learn what you can, and then when you get your parts collected, start your own new thread on your build and everybody will help walk you right through it! Easy!

[Chunky Monkey]

There are a lot of threads in the Casting Equipment section on building PIDs. Just read a few and learn what you can, and then when you get your parts collected, start your own new thread on your build and everybody will help walk you right through it! Easy!

I'll take a look-

thanks

[Dragonheart]

Actually my Hamilton Beach convection oven is pretty accurate, but I have a Taylor glass oven thermometer placed inside the glass door.

[firefly1957]

My old toaster oven was used in the RV when i did not want to use the gas oven for small things it burned more then baked so i replaced it with a new one . I found that set at 450 degrees it can run as hot as 650 degrees and the 220 setting is about 450 degrees . It worked well for bullet paint curing for me .

[mongoose33]

I just did my first powder coating tonite--and even though the dial was set at 400, some of the bullets melted!

Got an oven thermometer, tried again--imagine my amazement when it read 550 degrees!

Here's a pic showing my first try--using a tumble method--and note how different they look color-wise from the last boolit on the right, which was done using teh electrostatic method. Clearly the higher temp creates a browner color, if not a burned color.

Live and learn.

[Dragonheart]

I just did my first powder coating tonite--and even though the dial was set at 400, some of the bullets melted!

Got an oven thermometer, tried again--imagine my amazement when it read 550 degrees!



Here's a pic showing my first try--using a tumble method--and note how different they look color-wise from the last boolit on the right, which was done using teh electrostatic method. Clearly the higher temp creates a browner color, if not a burned color.

Live and learn.

Wow, That was one hot oven!
I use a Taylor Oven Thermometer, which has a glass vile mounted on a metal angle so it will sit or it can be hung from a rack. Taylor is known for making accurate thermometers and this one works well for me. I have my thermometer on a lower rack so I can see it through the glass door. I live on the Gulf Coast where the humidity is high, so I preheat my bullets to 200 degrees to get a good single coating of powder in my tumbler. At 250 degrees you will end up with a sticky mess, so a good thermometer is a must. I also check the pan of bullets with an infrared thermometer before dumping into the tumbler. I use Prismatic Powders and the cook temperature is 400 degrees for 10 minutes, but the powder rep has said if it's a little of don't worry about it. But I do make sure I am at 400 or slightly above and for at least 10 minutes at that temp.

[Case Stuffer]

I purchased a $18 Rival at Wally World just to try Powder Coating. A decent dial thermometer showed the setting dial was off by over 50F and that it was not very consistant. Built a PID and it was very useable but I wanted a larger oven that was also convection capable . I ran across a $30 deal on a like new Faberware ,one that is $40 at Wally World .
I am now able to use 10-1/2 square trays versus the 7 X 9 that I was using , I wired convection fan to a seperate power cord for full time fan and moved PID to this one. This new one comes up to temperature much faster, holds a lot more Boolits, recovers much faster and temperature is a lot more even everywhere in it.

FYI I bent up a simple L shaped bracket to hold the temp. probe which threads thru.(between) the original oven rack's support rods which means I can place it directly under the mesh trays I made so it is only 1/2" from the actual Boolits.

[matrixcs]

A friend of mine brought over his newly purchased toaster oven because some of his pc did not melt. I checked it out and set at 450 it barely maintained 400... on disassembling the box a couple of things were noticeable, the thermostat and temp dial are the same and count on the heat passing thru the wall of the oven and there is no insulation anywhere so if it is cold on the outside or breezy the accuracy will be terrible... not ideal since we as a group are probably never going to use these in a temperature controlled environment. On this box it was easy enough to remove the stop at 450 to allow more heat but my friend has decided to build a pid to really fix the issue.

[Case Stuffer]

Post here explains this well and has a very good photo also.

http://castboolits.gunloads.com/show...=1#post3262412

[fishingsetx]

My flea market toaster oven would barely make 350 set on 450. A home built temp controller did the trick along with bypassing the thermostat! Now it maintains 400 +-5

[Walter Laich]

once I got the temp stabilized with a PID I went ahead and took out the timer. Simple operation: two wires going into the timer, cut the timer out and joined the wires. Now stays on all the time until I unplug it.
.
It's getting more user friendly as I go along

[Markbo]

Couldn't I just drill a small hole in the side to insert a thermometer? That way I don't have to worry about the case or glass or anything else breaking.

[Markbo]

Not a good idea or nobody knows?

[RobS]

Yep..........I drilled a hole in the top of mine but all the same.