cast 230gr bullets breaking in toaster oven

[NATJAC]

Hi,
This is my first post, i just signed up. I am just getting into casting and have been following your forum for a few weeks now.. I really thank all of you for your knowledge and experience!!
I have encountered a problem, I recently casted up a couple hundred bullets (lee 230 gr for 300 blackout) and I did the powder coating thing.. but when i put them in the oven i drilled holes in a piece of metal and tried to stand the boolits up-nose down in the holes. After cooking at 400 degrees for 15-20 minutes, i pulled them out and i noticed that some of the tips of the bullets actually broke off, and some were bent. At the break off point the bullets' interior looked "frosted" and not melted (see attached picture), what did i do wrong??
NOTE: While casting, my pot did get over 900 degrees and some of those boolits may did come from that temp.. but with the boolits looking good i decided to keep them and not recycle.. After I cast the boolits i did notice frosting.

[dahermit]

What kind of a casting pot do you have that would take the alloy to 900 degrees? How did you measure that temperature? Have you put an oven thermometer inside you oven and checked that actual temperature that is achieved when it is set to 400 degrees? What bullet alloy are you using?

Just off hand, I would say lower the temperature in your pot so that it is closer to just over the melting temperature of your alloy, check the oven temperature. Also, it would appears that from the crystalline structure, there is too much antimony in your alloy try diluting it with more pure lead.

On the other hand, your powder coating job looks really good.

[runfiverun]

900 degrees holy cow, I woulda flipped out.
that would have over heated the mold and the alloy both the sprue never would have hardened.
throw them back and get that pot temp down to about 725 where it belongs, that's plenty warm enough to pour frosty boolits.
your mold temp should be monitored as well for good consistent boolits in fact the mold temp is the critical temperature here.

over 900 man. you changed the crystalline structure of the alloy at that point.

[LAGS]

900 degrees ?
I hope you were wearing a Gas Mask.
That is up to the point where Lead Boils and becomes really Toxic.

[NATJAC]

RE: dahermit: I was using a lee 20lb pot. and i did use a thermometer. I put it on high heat to melt the ingots and once they melted I changed the setting to #7, the temp was around 650 so i started to run a few casts to warm up the mold... after a few casts the boolits started to come out really good so i thought i was good to go... but after about 20 or so casts i checked the temp again and it was over 900! I gradually turned the dial down (while continuing to flux) until I got to #2!! and the temp finally went down to ~700 so i made a few more casts and then called it a night.

The lead is "isolead". I have no clue on how to determine the tin/antimony in it, i just used this for a reference: http://www.fellingfamily.net/isolead/

I didn't have a thermo for the oven... i guess i should do that next time!

[NATJAC]

RE: LAGS: no kidding! i was using a shade tree mechanic ventilation system i put together... worked really good! (windows/fans/etc)

[NATJAC]

900 degrees holy cow, I woulda flipped out.
that would have over heated the mold and the alloy both the sprue never would have hardened.
throw them back and get that pot temp down to about 725 where it belongs, that's plenty warm enough to pour frosty boolits.
your mold temp should be monitored as well for good consistent boolits in fact the mold temp is the critical temperature here.

over 900 man. you changed the crystalline structure of the alloy at that point.

I thought my thermometer was broken... i was freaking! especially casting for the 1st time!

[Smoke4320]

put them all back in the pot.. remelt at no more than 750 and add 1-2% tin ..
Make sure your Powder coating oven is at an actual 400 degrees.. preheat oven then add bullets for 15 minutes and all should be good

[NATJAC]

put them all back in the pot.. remelt at no more than 750 and add 1-2% tin ..
Make sure your Powder coating oven is at an actual 400 degrees.. preheat oven then add bullets for 15 minutes and all should be good

Thanks Smoke4320! btw, what's the easiest/cheapest way to add tin?

[Taylor]

Pewter,check your local flea markets.

[dahermit]

The lead is "isolead". Isolead as in "Medical Isotope Shielding". Here is some info on those types of alloys. http://fellingfamily.net/isolead/

[leeggen]

We all have screwed up once or twice some of us more but who cares it is in the learning curve to casting.
Welcome to the sight, and read, read and read.
CD

[NATJAC]

Thanks all!

[Smoke4320]

For tin you can also visit the swap & sell section.
One vendor is imashooter. He sells pewter ingots in small coins . easy to add to lead.

I get hi speed billet for the added copper as i do mostly rifle bullets and like speed.
We will be waiting for good bullet pics

[Hickok]

If you can't find any tin/pewter locally, go to the hardware store, look for tin solder, read the label, and get a roll with the highest tin %. Pricey, but it will work.

[ryokox3]

I have cast with that same mould and found it is very easy to bend the tips after casting. It just did not cool fast enough and the shape helped it bend when I dropped them onto a cotton towel on my workbench. Going forward water quenching with that mould for me.

[ffries61]

900 degrees ?
I hope you were wearing a Gas Mask.
That is up to the point where Lead Boils and becomes really Toxic.

Not really, boiling point of lead is much higher than that.

[11B-101ABN]

When I get broken boolits like your photo, it is usually because I dumped them from the mold before they were sufficiently cool. How long did it take for the sprue to cool with your "hot" boolits? This is not an exact science, and probably no two people use the exact same alloy. If you let the alloy level in your pot get too low it will cause the temp to rise. I keep the level in my casting pot within an inch of the top by returning sprues back into pot immediately, also have toaster oven set to 375 preheating my ingots to keep level up. You might check into a PID controller to keep temp under control. Lastly, put your location in your name box, maybe someone that is located close to you will offer hands on help.

[rototerrier]

One thing I'd like to throw out there is to make sure you have the thermometer calibrated. I have a nice TelTru that I cast with for about a year before realizing it was off by 100 degrees. Of course, I didn't much care what the temperature was as long as I was getting consistent and desirable casting results from the alloy. I typically shot for around 780. After calibrating the thing, turns out I was casting at 680. It all really became evident when I built a PID and set the PID for 650 just to start and my thermometer was telling me I was at 750.

Anyway, could be possible that your thermometer is a little off and you didn't really go over 900 since that's a very high overshoot. Just want to throw that out there as something to look into.

[fredj338]

Not sure a full Lee pot will get to 900deg, maybe. I would also verify the oven temp, cook less time, cool 100% before removing the bullets from the plate. I've been casting on & off for 35yrs, never "broken" a bullet.

[NATJAC]

When I get broken boolits like your photo, it is usually because I dumped them from the mold before they were sufficiently cool. How long did it take for the sprue to cool with your "hot" boolits? This is not an exact science, and probably no two people use the exact same alloy. If you let the alloy level in your pot get too low it will cause the temp to rise. I keep the level in my casting pot within an inch of the top by returning sprues back into pot immediately, also have toaster oven set to 375 preheating my ingots to keep level up. You might check into a PID controller to keep temp under control. Lastly, put your location in your name box, maybe someone that is located close to you will offer hands on help.

The sprue would glaze over in about 5 or 6 seconds, as soon as it glazed i used my hand to turn the sprue plate.. seems to produce cleaner bases. I think i was dropping about 5-6 castings per minute, i read i should only be doing about 3.

Re: Fred: "Not sure a full Lee pot will get to 900deg" I had to put my pot on setting #2 to get down to 600 degrees.. most people use #7.. i think my pot is a little HOT.

Thanks all for the advice!

[Smoke4320]

With that long bullet it needs to be a little cooler and drop on nice soft cloth or into water
3 casts at 715-730 would be plenty and possibly a little to fast

[reddog81]

I wouldn't be surprised if my Lee 4 20 could get to 900. I once turned it on and walked away with it turned all the way up and when I came back a while later the lead was glowing red hot.

I usually set it on 6 to warm up, and turn it down to 4 once it's fully melted and I start casting. Then once I've got a good rhythm going I turn it down to 2 or 3.

i used a thermometer a couple of times but once I got the hang of casting and reading the bullets, the mold, and the sprue it seemed like an extraneous part of the whole process.

[Motor]

How do you use your hand to turn the sprue plate? I cut my sprue with a wooden mallet. In fact the mallet stays in my right hand (I'm right handed) the whole time. I only set it down to open the bottom pour valve.

The wooden mallet is awesome. I use it to rap on the mould to make sure it's closed, then close the sprue plate, then cut the sprue, then to tap the open mould which makes the boolits drop out.

I have experienced the deformation of hot boolits too. I cast a .501" 440gr. It can fall through 6 inches of water and hit another boolit and come out deformed.

Like everyone else said, nice thing about casting is mistakes simply go back in the pot.:)

Motor

[dikman]

My first PID had a bypass switch that I would use during the initial heating of the pot (Lee Pro 20). It seemed like a good idea when I built the PID, but is actually pretty pointless. Anyhow, the first time I used it I left the pot for awhile and when I checked the temp (the PID was still capable of reading temp) it was over 900! So yes, it can do it.

Motor, I do like you with the mallet, except I still hold it while operating the lever.

[Walter Laich]

You can find a stand along oven thermometer at Wally World for about $6. I used it before I built my PID for the oven. It's in cooking section. On a metal bracket that lets the gauge sit up so it's easy to see.

Another great thing about this part of shooting is all the mistakes disappear back into the casting pot

[Echd]

Not sure a full Lee pot will get to 900deg, maybe. I would also verify the oven temp, cook less time, cool 100% before removing the bullets from the plate. I've been casting on & off for 35yrs, never "broken" a bullet.

I have broken them, but they were extremely hard and water dropped, so odds are the extreme temp shift had fractured them already.

[NATJAC]

RE: Motor: "How do you use your hand to turn the sprue plate?" when the sprue glazes over i grab the mold with my hand and use my thumb to turn the plate. it's just a two bullet mold.

Reddog81: I cast a few more bullets a couple of nights ago and my setting was around 2 or 3 as well.. that setting maintained a temp of just shy of 700 degrees... i'm REALLY glad i bought a thermometer!! if i didn't, i would have some pretty HOT lead on setting #7 !! This time the bullets turned out GREAT!! not completely frosted over...

smoke4320: i slowed way down this time on this last casting session, counted to 10 seconds before dropping and counting to 15 seconds before closing the mold to pour again. Fine looking bullets, i almost feel bad shooting them.


I have another question though, when i turn the sprue plate, the base seems to have a small smear/jagged edge of lead that is left of the base of the boolit, do i need to trim that off? i'm just thinking they would be more susceptible to the flame from burning powder thus leaving lead in the barrel.

[.30 Rem]

It sounds to me like you are opening the sprue too soon. Boolits should have a flat base.

[NATJAC]

It sounds to me like you are opening the sprue too soon. Boolits should have a flat base.

The bases are flat, but the edges are a little jagged. do you think if i wait a little longer to open the sprue they will turn out better?

[dahermit]

I suspect that the alloy you were using had way too much Anitmony in it, which caused an extended "mushy" (crystiline, grainy condition), which caused the bullets to fall apart in the oven. I would suggest diluting your alloy with pure lead, or add a whole lot of tin...which is prohibitively expensive.

In any event, here is a post (see dahermit), I did on the subject some years ago: http://thefiringline.com/forums/archive/index.php?t-454208.html

[John Boy]

NATJAC: Many good responses to your issues. But the main one is your casting of the bullets:
* Heat the pot & mold to a temperature so with a 5 second pour, the sprue puddle frosts in 5 - 8 seconds. And with the radiation lead, the pot temperature will frost the sprue puddle at 750F or less
* When the puddle frosts ... Then cut the sprue plate and dump the bullet
* Hold the pot temperature constant (yes, a thermometer is a must cast tool)
Shake & Baking the bullets - your on your own ... just follow the advice given.
BTW - put your cast thermometer in the oven to determine the temp and HOLD IT THERE

[dahermit]

NATJAC: Many good responses to your issues. But the main one is your casting of the bullets:
* Heat the pot & mold to a temperature so with a 5 second pour, the sprue puddle frosts in 5 - 8 seconds. And with the radiation lead, the pot temperature will frost the sprue puddle at 750F or less
* When the puddle frosts ... Then cut the sprue plate and dump the bullet
* Hold the pot temperature constant (yes, a thermometer is a must cast tool)
Shake & Baking the bullets - your on your own ... just follow the advice given.
BTW - put your cast thermometer in the oven to determine the temp and HOLD IT THERE
His problem is not the temperature he at which he is casting, it is heat at which the bullet "slumping"/beating in the oven. The oven is too hot for that alloy. See my post (and the others at that site), above that pertains to the mushy stage of high-antimony bullet alloys.

[robertbank]

One often overlooked source of tin are radiator shops. The slag/drippings they get off the floor is 50-50 lead tin. I get it for free at our local radiator shop. You get a lot of waste with it but I would guess the ratio would be 75% alloy.

Take Care

Bob

[NATJAC]

Hey guys, thanks for all of the replies! I turned the oven down to 350 and no breaking or bent bullets.. so we are good to go.
here's what they look like.. the coverage is pretty thin but, for the most part, the rings and base fairly covered! do i really need to do another coating?157935
The way i baked them was i drilled a hole in a piece of thin metal and stuck them all nose down. I'm not sure if i like that because the bullets were really sticking in the holes and even scratching the lead as i pulled them out.. and the excessive handling of them knocked off powder from the bullets as i was trying to stand them into the holes. Next time, I am going to just pile them in a wire mesh tray and see if they come out better.

[RP]

Not bad at all just need to fine tune you method and you will be fine.

[GabbyM]

Don't feel to bad. About five years ago. I put about 2,200 bullets of 22 caliber in a kitchen gas oven to heat treat. Found out those little 22's heat up quick and maybe my oven was to hot. When I dumped them in the cold water they crystalized. Many broke and all were junk. Simply got those little things to hot.

Upside is there weren't undetected flaws that may of shown up after I'd loaded up 500 rounds. Since then I always hammer test heat treated bullets. Just a few out of a batch. Plus I'll never place over 2,000 bullets in an oven at one time again.

[NATJAC]

Thanks for all the help!