Water Drop Temp make a diff in BHN?

[smallshot13]

Can the temperature of the water I drop in make a difference in the final BHN?

I've have cooked up an alloy from super soft sheet and sinker lead with a BHN of 6.7 (Lee Tester). I alloyed it with some super hard mono-type (high in antimony, etc.) at a ratio of 82%/18%, to come up with an air drop BHN of around 14. While testing for a hardness bump via water drop, I came up with two different values, a 19.5 and a 22.5+, from different sessions. For the harder alloy I iced the drop water to cool it down. Has anyone heard of this, or did I just mess up some how?

I use the 14 BHN for my .45 acp 200 grn LSWC, and I'm now cooking a pill for my new Rossi 44 mag carbine (20").

[cbrick]

First, the 14 BHN boolit (I don't shoot medicine) should work very well in your 44 Mag. Don't get wrapped around the axle from hearing the misleading term "hardcast".

I used to do a lot of testing with oven heat treated Pb/Sb alloy, when I first started out I was using a gas fired conventional cook oven. I did discover an increase in both final BHN and the time curve it took to get them there so I used ice in water to chill it. Somehow when I switched to an electric convection oven that difference in BHN from water temp disappeared. I don't know how or if that would translate to quenching from the mold but it could be interesting if someone wanted to do some serious testing/experimenting.

Anyway, don't be so sure you need to quench your 14 BHN boolits, odds are they will be just fine as is, shootem & see.

Rick

[runfiverun]

14 is already quite a bit harder than I use in either my acp or my plain base 44 mags.
I do push the 44's to a click over 1650 sometimes in my 44 mag lever guns, I haven't tried any faster so I don't know if I need more than the 10-11 hardness I use now or not.

[oldandslow]

ss, 10/30/13

When I was experimenting with different alloys for my rifles I water dropped loads into different temperature water and measured their BHN. When using 2.2% Antimony, 0.4% Tin and the rest lead and oven-heated to 465 degrees for 60 minutes and then dropped into 70 degree tap water the BHN was 15. When doing the same with ice-water the BHN was 21. So yes, the temperature of the water (and also the oven, but that's a different story) can affect BHN. One thing to remember, as many others have said before me, is that a harder boolit doesn't mean it will work better than a softer boolit or a tougher boolit. Good luck.

best wishes- oldandslow

[geargnasher]

I haven't found much difference due to water temperature, but my water-quenched, low-antimony alloys get more consistent the longer they age. Sometimes it's six months before they settle down. The trend seems to be that given enough time, the bell curve of hardness consistency in a given lot of water-dropped boolits gets narrower and less tall. My experience, anyway. I rarely oven-treat, probably because results from my conventional oven are no better or more consistent than a Homer bucket full of rain water an a squirt of Palmolive combined with ruthless attention to casting cadence.

Gear

[AlaskanGuy]

Whats the palmolive soap do for ya geargnasher? My wife loves Palmolive so i have a lifetime supply to do the dishes with... She buys me a new bottle every week so i don't forget how she likes em cleaned.... :kidding:

But even with all of the testing with super hard stuff for bear defense i did earlier this year, i gotta agree with the others here, super hard is not super better, even for our big alaskan types. The hardest i work with these days is running between 15 - 18 Bhn MAX. I tried the other hard stuff, and i am back to just slightly harder then i used to cast. Holds together nice if i just cold water drop my normal alloy stuff if i need something harder...

Alaskan

[imashooter2]

Raising the boiling point of the quench medium will increase hardness.

[Dusty Bannister]

The detergent might be to reduce surface tension to improve the full contact of the cooling agent on all surfaces of a bullet. Aid in the quench without little air bubbles insulating the surface of the bullet from the coolant.

Ima shooter, please explain why raiseing the boiling point of the quench medium will increase hardness. I am under the impression that it is not so much the temp of the coolant, but the difference between the temperature of the casting and the coolant, when the casting is placed in the coolant. Is this experience or is there a reference? TIA Dusty

[runfiverun]

it's the speed at which the boolit cools that influences it getting harder.
you can air quench and change the bhn too.
it will all pretty much settle down into a small range over time, if you keep things close.
dumping some boolits from a 375-f mold into 75-f water and then changing the temps up to 425 and down to 40-f will change the outer bhn because of the speed of the cooling.
2-3 bhn really isn't that big of a deal to me, so I try for consistency.
this means using tap water I keep in a container in my casting area which is heated to 60-65f almost all the time.
I want consistency not total bhn.

[Dusty Bannister]

I can certainly agree with consistancy. That is why I only remove the bullets from the broiler oven at the exact end of the heat cycle and immediately plunge the basket into room temp water. Since I HT&Q in the shed, I suspect some variation could occur at different times of the year because the shed is unheated. Some heating does occur during the baking operation but still not up to 68 degrees ambient air temp. Much depends upon the actual alloy as well, and we all know that WW are not consistant. It is surprising how accurately we can get without certified pure ingredients. I will HT for some applications, but being mostly a pistol shooter, most is just AC and go have some fun. Thanks for the reply. Dusty

[imashooter2]

The detergent might be to reduce surface tension to improve the full contact of the cooling agent on all surfaces of a bullet. Aid in the quench without little air bubbles insulating the surface of the bullet from the coolant.

Ima shooter, please explain why raiseing the boiling point of the quench medium will increase hardness. I am under the impression that it is not so much the temp of the coolant, but the difference between the temperature of the casting and the coolant, when the casting is placed in the coolant. Is this experience or is there a reference? TIA Dusty

The water boils at 212 (ish) degrees and encases the boolit in steam. The gaseous state does not transfer heat as efficiently as liquid, so the boolits cool slower. Dump the same boolits into ethylene glycol and they will cool faster because the ethylene glycol boils at 387 (ish) degrees. Steam forms later and dissipates sooner and liquid is in contact with the metal for more of the cooling cycle.

ETA, this is standard heat treating practice. There are many engineering references available online.

[Dusty Bannister]

Seems to make sense, but we went from detergent to anti freeze without any indication so I missed the curve. I was just trying to figure out why adding a detergent would raise the boiling point. Thanks for the reply and clarification of what you meant. Dusty

[runfiverun]

I missed it too..
anyway it looks like we are pretty much striving for the same thing only using minor differences in how we go about getting there.
i'm amazed also at how close things stay over time with the way ww alloy changes.

I do take my yearly smeltings and blend them equally into one big batch at the end of the year, and will generally melt that into one humongous batch with what I already have.
this will usually give me about 2-k pounds of one huge intermixed batch of ww alloy to work with.

[imashooter2]

You stated it correctly r5r... it is all about how fast you cool the metal.

[geargnasher]

I see where it might have been assumed that the dish soap was to raise boiling point for a harder quench, but I said "a squirt", which does nothing to raise the boiling point of three-four gallons of mineral-free water.

The soap leaves a microscopic film on the boolits when they dry off, which helps prevent discoloration and eventual corrosion common to the water-dropping process. It's a trick Waksupi shared with me years ago when I was complaining about WD boolits corroding when stored as-cast.

Gear

[NuJudge]

My Metallurgy professors used to tell me that the best thing you could do to increase the severity of the quench was to add a lot of salt to the water. They described this as inhibiting bubble formation.

I've noticed no difference in bullet hardness between cold water in Winter and rather warm water in Summer.