Heat treating???

[tomme boy]

OK, I need some ?'s answered about doing this.

1) How critical is the temp? I know you can go too high and the lead will start to melt and the bullets will slump.

2) How low can you go on the temp and still heat treat them to a higher #?

3) What are you lubing the bullets with to size and check them before heat treating them?

4) How long do you let them sit after HT'ing them? I normally like to let my WD bullets sit for a couple of weeks if I can.

5) do you have to stand them up? Especially if you know you are going to use a lower temp.

[dubber123]

I like to keep temp swings to a minimum, and you won't believe how far the swings can go even with a good quality oven. It took a good bit of fooling around with tray placement, and a blocker tray over the lower element to get my temp variations within 10 degrees or so. Get a good thermometer and experiment before putting 3 hours worth of casting in the oven. Ask me how I know this.

I keep my temps at 450 degrees to give me a buffer zone before slumping. It's not worth it to me to press my luck and ruin a whole batch of boolits to gain MAYBE 1/2 Bhn.

I keep them in the oven for a full hour. You might get away with less, but 1 hour has always worked for me.

Standing up Vs. lying down doesn't seem to matter, as long as you are under slump temp. Lying down is much easier, especially with long, thin boolits.

I lube and size right away in a Lyman 450. Waiting even a day makes sizing MUCH harder, and you are wiping away some of your hardness.

I try to wait a week before shooting. I find heat treated WW's make Bhn in the high 20"s after 3-4 days.

[Mike W1]

Without a doubt the best article I ever read about heat treating was by Dennis Marshall in the RCBS Cast Bullet Manual number one. If you can't get hold of it PM me.

[Yodogsandman]

Spot on dubber123!

Temperatures over 300F will HT your boolits. The higher the temperature, the higher the BHN potential. A full hour at the desired temperature is necessary, start the one hour time when the oven temperature is reached or pre-heat your oven. I also shoot for 450F degrees to HT.

Quench boolits immediately from the oven using the coldest water possible for best results.

If you size prior to HT'ing, no lube at all or clean it off first before HT'ing. If you size and lube after HT'ing do it ASAP. I broke my table when I waited too long and had to use a 3' pipe for leverage due to a boolit stuck in the sizer.

I like to size boolits bare first prior to HT'ing. I clean my sizer die first before sizing. I lube and apply gas checks after HT'ing.

My $5 yard sale convection oven runs 50F degrees hotter than the set temperature. Get a cheap oven thermometer to check your oven.

I always just dump my boolits on a pan, laying on their sides and separated a bit to HT.

HT'd boolits will reach their full BHN potential at different lengths of time depending on oven temperature. The highest temperature heated boolits that are then quenched in the coldest water is about 5 days. Lower temps take longer. Using warmer water to quench slows the process too.

Only alloys with antimony and/or arsenic are heat treatable. I'm unsure but, maybe sulpher too.

[35 shooter]

I ht ww @ 465* for 1 hr., then dump in cold tap water. I size and apply checks after ht within 24 hrs. You can hardly make a mark on them with a fingernail after 12 hrs. I've shot them within 48 hrs. and didn't notice any decrease in accuracy as compared to waiting a week or two.
The only time they were tested for bhn was after about 2 weeks and they were 27 bhn.
You can lay them down on the tray for ht. as long as you don't approach slump temps.

[waco]

"Cast bullet notes from Lasc.us" at the bottom of this page. There is a great and very informative article on heat treating cast boolits.

[btroj]

I run them thru a sizer dry if I want to hear treat them later.
You NEED to go a full hour in a preheated oven.
Temp doesn't matter, you can reheat them later to any temp you want. I have taken stuff I heat treated earlier, redid them, and they came out where I expected.
I did not stand them up. I wasn't near slump temp and I didn't do that many at one time.

Dont overthink it. Try some, see what happens. Play with temps to see what temp gives what hardness.

Any questions, ask Cbrick, the resident heat treat guru.

[tomme boy]

[Bjornb]

There's a very interesting thread in the stickies from 2008 about toughness of alloys. It also goes deep into heat treating.
Wiljen's LASC article on arsenic brings up a different angle: he quenches in an antifreeze/dry ice mix, achieving 19 degree liquid. This "water" drop also achieves the hardest BHN value.

[tomme boy]

Well I tried to HT some bullets a couple of nights ago. They started off as 1 year aged bullets. They were about 17 for hardness from having a friend test them. These should have hardened up somewhat, but I could dig my fingernail right into them.

So I have them in the oven again right now. I increased the temp to about 450* I have small bucket with ice in the water waiting to drop them into.

Am I rushing this or should it show some hardness after a couple days?

[btroj]

Test tonight, tomorrow, and the next day. They will max out, or close to it, in a few days.

[35 shooter]

With straight ww ht @ 450 to 465*, my fingernail will slide across it like on glass after 12 hrs.
I don't know what alloy you used, but ww hardens fast!

[Shuz]

I heat treat to 475 deg in an old toaster oven, using the flat edged pan that came with it. I kept playing with the thermostat on the oven until my separate oven thermometer, placed inside, got no higher than 475 deg. Once I determined what that setting was, I now turn the oven off, by simply "pulling the plug". I have a 5 gallon bucket of room temperature water underneath the place where I heat treat, and simply use a pair of Channel Locks to take the tray out and dump the boolits after at least 1/2 hour of having the boolits @ 475 deg. WW+1% tin alloy boolits harden to Bhn 22 within hours after this treatment.

[cbrick]

Well I tried to HT some bullets a couple of nights ago. They started off as 1 year aged bullets. They were about 17 for hardness from having a friend test them. These should have hardened up somewhat, but I could dig my fingernail right into them.

So I have them in the oven again right now. I increased the temp to about 450* I have small bucket with ice in the water waiting to drop them into.

Am I rushing this or should it show some hardness after a couple days?

How hard they are before HT is simply a matter of what alloy it is. If they were quenched for hardness that is gone as soon as you heat them and how you cool them will determine their hardness assuming a Sb alloy. They should show increased hardness after a couple of days assuming a Sb alloy and what temp you had them in the oven and for how long.

The percentage of Sb will determine how they hard they get and how fast they get there. The percentage of Sn will also limit the amount of hardening and age softening but this would take plus 5%.

A half hour won't do it, you'll get both limited and erratic results. It takes a minimum 1 hour at temp. btroj recently experimented with this and is now a believer in 1 hour.

I don't recommend dumping them out of the tray into the water. At this temp they are as putty soft as it's possible to get them without melting them. I've never done that simply because I can't imagine not dinging them up, after spending the time and effort to make quality bullets why risk the bases and driving bands by dumping them?

No, you don't have to stand them up but I do because they will be so soft I don't want the weight of one on top of another.

Rick

[cbrick]

There's a very interesting thread in the stickies from 2008 about toughness of alloys. It also goes deep into heat treating.
Wiljen's LASC article on arsenic brings up a different angle: he quenches in an antifreeze/dry ice mix, achieving 19 degree liquid. This "water" drop also achieves the hardest BHN value.

I should probably re-read Wiljen's article to make sure I remember correcty but I don't think he's using antifreeze, but rather he experimented with that to see results/differences. I could be wrong bout that though.

Rick

[cbrick]

3) What are you lubing the bullets with to size and check them before heat treating them?

I use Unique.

No, not the powder. Hornady case lube, a little tub and just a very little on your finger tips as you handle the bullets to place them in the sizer is all it takes.

Rick

[shooter93]

I like them standing so I have various sized 'pans" with holes drilled all through them. They range in size from a coffee percolator....the part you put the grounds in....to a metal pie plate that drops into my bucket. Depending on the number I'm doing they all fit so they won't topple going into or out of the oven.

[leadman]

I use a pid to control my oven temperature. A good device for checking oven temperature without the pid is the $20 DVOM from Walmart that comes with a thermocouple. This is the yellow one in the auto section. Very useful around the house and vehicles also.

[tomme boy]

This was just a test to see what would happen with my alloy I have been using. These were rejects that I had already sized and checked. They are as hard as glass now. It took almost a week. I think I may need to change what I am using.

I called my old ladies father last night and talked to him. He is an old farmer. He bought a little over 2000 lbs of pure Lino in pigs a long time ago at an auction. He bought it to use as weight for one of his tractors. He gives me some of these every now and then. Well next week I have to go pick up 2 bars. I think each weighs around 30 something pounds. I want to use this to make up something that will get me into the mid to higher 20's heat treating. Or should I just use it straight and air cool or water drop? I used to use it 3 parts range lead to 1 lino.

[btroj]

My straight range scrap will give 24 BHn if heat treated.

Try your range scrap by itself and see what it does if heat treated. Mine does well by itself but I do know I can mix it 10/1 with monotype and get closer to 30 BHn with heat treating.

What matters most is learning where the break point is for a certain load/gun combination. Increasing hardness helps accuracy but only to a point then it becomes a factor in decreasing accuracy.