Heat Treating from the mold

[FAsmus]

Gentlemen;

Yesterday I stepped out to my unheated casting shed to run off some RCBS 30-180-SPs. I need to build inventory for the shooting season of 2013.

It was cold, but that is good since my casting outfit generates enough heat to keep me warm.

The quench-bucket was iced over so I broke it up - there being only about 1/2 inch of ice I didn't bother washing it out, figuring it would soon melt off when the hot bullets were dropped into it.

I lit-off the burner and was soon casting away, dropping the hot bullets into the water just like normal. ~ Then I noticed that the pieces of ice were not melting in my stainless steel bucket. I kept on casting until I estimated that I had 200 bullets done, the ice still didn't show any signs of melting.

It was quite stormy outside by now, the wind serious enough that snow began blowing into the shed. The temperature was dropping too, I could tell because my feet were getting cold. ~ I kept on casting.

By the time my pot ran out - some 330 bullets - the ice I'd left in the bucket was still there and around the edges of the water's surface new ice was beginning to form on the steel of the bucket. It was semi-painful on my bare hands to drain off the freezing water in order to dump the bullets onto my drying pad.

I was amazed that this casting session didn't result in the water heating up - at least enough to melt the ice and prevent new ice from forming.

How could this happen?

Good afternoon,
Forresty

[blikseme300]

Maybe you being so far north and it being so cold? I see you are in Wyoming, or as we here in deep south Texas say, the great frozen north.

Wow, I can only imagine being that cold. Here we are still sweating some days as the temperatures are still in the mid eighties.


Bliksem
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[41 mag fan]

Could it be from an altitude perspective?? I'd like to know the answer on this one......

[canyon-ghost]

It was semi-painful on my bare hands to drain off the freezing water in order to dump the bullets onto my drying pad.



Ever thought it might be cheaper to get some hardware fabric (wire screen) and build a screen that you lift out of the bucket? My hands aren't so great either, hate the thought of getting them really cold.

[41 mag fan]

You sure it wasn't so cold out those boolits were freezing in the space from mold to bucket?? :kidding:

[garandsrus]

It takes a lot of energy to heat water. Not enough in a couple hundred bullets to do much.

[dragonrider]

I use two buckets one inside the other. The inner one has a couple of hundred small holes drilled in it to allow the water from the outer bucket in. After casting I just lift the inner bucket allow it to drain, and presto no reaching into the cold water.

[cbrick]

Probably the quantity of water and the length of time hot bullets were entering the water.

When I was doing a lot of heat treat testing I was using the kitchen sink with just enough water depth to cover a tray of about 100 boolits. 100 hot boolits hitting that much water all at the same time did warm the water. Slightly. When I installed a laundry room sink in my loading room and used many times the quantity of water even 300 boolits going in at once changed the water temp only a couple of degrees.

Based on this it doesn't sound surprising to me that a couple of boolits at a time over the length of the casting session did not warm the water enough to melt the ice or even at all.

Rick

[FAsmus]

Gentlemen;

Roger the explanations about the high heat-index of water ~ I should have known that.

Another question comes to mind since we're talking about casting and heat-treating in the cold;

Have any of you ever cast and quenched from the mold in cold enough conditions to require anti-freeze be added to the quench medium?

If so, did the heat treatment result in harder bullets than, say, dropping them into typical room temperature water?

Good morning,
Forrest

[cbrick]

Not anti freeze cold but I had an interesting outcome when I was doing all that HT. When I started I was using a gas fired propane kitchen oven and the kitchen sink. I experimented with the water temp by adding ice and I did get somewhat harder bullets the colder the water. Here's the rub to that, when I switched to using an electric convection oven the difference in final hardness disappeared. I was (and still am) perplexed by that so I did some more in the gas oven and it did seem to be true, colder water harder bullets. Then going back to the convection oven the difference seemed to be gone. I have threatened myself with re-doing these tests to try and figure it out but haven't. Yet.

Rick

[williamwaco]

It takes a lot of energy to heat water. Not enough in a couple hundred bullets to do much.



I think this is the answer.

I tried water cooling some a few months ago just for testing.
It was not cold, around 90 degrees.

I was using a small plastic pail, held only about one gallon of water.
This was tap water. I didn't measure the temperature but probably around 75 to 80 degrees.

Dropped directly from the mold into the bucket. After about 200 bullets, the water was not even warm. It felt no warmer than when I started.


.

[FAsmus]

Rick;

Thanks for the post.

That was an interesting report ~ If you do get around to running a test run a few bullets through a Brinnel hardness tester, or perhaps put one bullet each into a vise and squeeze them together and see which indents more .. Then let us know!

Good morning,
Forrest

[Mal Paso]

I think some of the heat escapes with the bit of steam created when the boolit hits the water.

I've put over 50 lbs of very hot boolits in 2 gal of water over casting sessions and if the water ever gets warmer it's just barely.

[Any Cal.]

I have gotten water warmer by dropping boolits in it, but they were 265g and my melt was plenty hot, and were dropping out of a 6 banger mold. That was in a big washtub, maybe 5 gallons of water, say 350 or so boolits... looks like over 13lbs of hot lead in 40 pounds of water, no choice but for the temp to go up. I was surprised the ice wasn't melting in the first post, but if the boolits were small or it was a 2 banger mold it would make sense.