Curing the 30 Caliber Blues... Part II

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Re: Curing the 30 Caliber Blues... Part II

Post by Ranch Dog »

GasGuzzler wrote:Sounds like my experiences. Don't waste your time but I would like to know what the softies do if dropped on concrete....the ones that look like they're close to melting at 400-450. Do they splat or do they explode?
I'm not sure what you mean. As soon as they solidify the are solid, hard bullets of 19 BHN. When struck with a 5# mallet they compress but do not fail. What I'm looking for with this process is a bullet that will survive 50.0K PSI for the 300 Sav, 308 Win, and that matter, my 454 Casull. You cannot pull that off with 19 BHN.
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Re: Curing the 30 Caliber Blues... Part II

Post by Ranch Dog »

The oven heat does help find a lot of rejects rather than sending them down range. Here, you can see a couple that have spit off their gas checks for one reason or another but look at the identified bullet. A cavity, an air pocket near one side, melted through. This is something you would never have seen and would have been one of those unexplained flyers.
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Re: Curing the 30 Caliber Blues... Part II

Post by GasGuzzler »

Ranch Dog wrote: Will it keep the temperature within 10°? At this point for any additional time or money it would need to keep the entire oven, front, back, and sides with 10°
Nope. Won't do that without an oven that could already do so itself. The PID might make it stay within 10 degrees if it learns properly but it won't be within 10 degrees in every nook of the oven.
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Re: Curing the 30 Caliber Blues... Part II

Post by DaveInGA »

62chevy wrote:RD that cheap Black and Decker is never going to do what you want without a PID. Dave has a wonderful thread on here on how to make one. Maybe if you ask nice he will make you one.
RD, as I've been reading your posts I and II today with great interest, I began to realize you've exceeded the capabilities of your oven's thermostat. I have all the parts for my PID here at the house ready to build. I can have it finished and ready to ship by Monday at the latest, perhaps Friday.

The oven you have, with convection capability, is going to get as close a you're going to get with consistent heat dispersion with an added PID to keep the temperature in a much more narrow range than you think. But beyond that, you'll have to make adjustments for heat dispersion using your thermostat you have. Keep bullets out of the extreme hot/cold areas. Temperature control is always kind of a slippery thing. I have a good bit of experience with it from back in my R&D days. It's very fluid in it's properties, hence hard to chase absolutely down. The PID will help much more than you realize.

To go further using that oven, you are going to need a PID. You can use my build to confirm and to control your oven, you'll need to rewire the oven to bypass the internal thermostat and drill a hole to insert the K thermocouple in. Not difficult for a farmer/rancher, who's used to fixing or building things to do a job. (I grew up on and around my Grandfather's farms, one cattle, one tobacco/cotton/wheat.)

PM me your address and I'll get busy and send it when I'm done.
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Re: Curing the 30 Caliber Blues... Part II

Post by Ranch Dog »

I appreciate the offer Dave, I really do, but after spending an evening trying to catch up with my farming over the headlights of a tractor, I think this has gone beyond even my level of interest.

To keep the total oven temperature with 445° to 455°, the PID would need to maintain it's temperature within 5° or less. Most of these ovens are operating at max to begin with, 450°, and from hours of watching the elements respond, I don't think it could get any better. From observation, if this oven's sole purpose was for heat treating cast bullets, it seems to me the four heating elements would need to be staged in response to thermostat control. At this high output end, I suspect one heating element responding on its own would cause the total oven temperature to be a bit more constant. I'd even go further and say the lower rear element acting alone when the temperature exceeds 455°. I really believe all four elements responding is creating the small temperature swing. I looked at some maintenance manuals online and it seems that 20° is considered quite good.

The pans used also influence the overall temperature flow, something Dave kind of hit on. I used a flat pan and then a pan with sides. With the flat pan the melt occurred on the back side but with the sided pan the melt occurred on the left and right. I saw the airflow with the flat pan when I melted the wax and it was just a cyclone through the oven and out the exhaust with a little leakage on the top of the door which the gloves on it cured. I didn't melt any wax in the sided pan but if I didn't I think the airflow would indicate some kind of hotspots without airflow or heck, maybe it's too much airflow, around the sides.

The cheap way to go further, time is money at this time of year, would be to use the flat pan and a smaller, tighter group of bullets in the center of the pan. A fellow that hunts here is going to spell me for three or four hours around lunch and I might try that.

Dave, I really don't like looking a "gift horse in the mouth" but let me see if the above will cure it. The other consideration is that even after all this background noise, the bullets might not perform anyway as I want jacketed performance from cast in these high pressure cartridge. In that 300 Sav and 308 Win are sub-MOA performers, I'd say there is at least a 60% of the previous statement being true.

Well, time to hit it.
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Re: Curing the 30 Caliber Blues... Part II

Post by Ranch Dog »

While the tractor warms up...

What I've learned is the oven will be helpful with my normal, Lyman #2 clone. The oven can be used to control the quality of the BHN down to a single digit, no variation, which helps with the downrange MOA performance. This alloy has a much greater melt temperature so the I'm not sitting on the alloy's limit during the bake at 440°.

I also have a recipe similar to Lyman #2 that will produce a 30 BHN for a somewhat limited life of several years. That's kind of back on the subject of Part I of this topic. That's okay too as I'm not going to cast large lots of bullets anymore. Just enough for two years at most.
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Re: Curing the 30 Caliber Blues... Part II

Post by 62chevy »

RD have you considered using 1% copper in your alloy? Read about it on CB but never tried it and a couple of the poster on that thread seamed suspect at best. So that may be a no go and just wishful thinking as some say copper is a contaminant. Just a thought.
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Re: Curing the 30 Caliber Blues... Part II

Post by GasGuzzler »

Unless you have a fancy PID and multiple thermocouples and rewire the elements I doubt the 5 degree threshold can be maintained throughout the entire oven. You'd hardly be able to tell without multiple sensors.
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Re: Curing the 30 Caliber Blues... Part II

Post by DaveInGA »

RD, in red in the quote:
Ranch Dog wrote:I appreciate the offer Dave, I really do, but after spending an evening trying to catch up with my farming over the headlights of a tractor, I think this has gone beyond even my level of interest.
Okay, but I'll toss this out there to keep you entertained with something to chew on mentally while you're ploughing. :D

To keep the total oven temperature with 445° to 455°, the PID would need to maintain it's temperature within 5° or less.PID's actually are capable of maintaining a variance of a single degree, because it's the reaction time of the control, not the oven's (or casting pot's) coils that keep the temperature in a tight range once the PID is calibrated.

Most of these ovens are operating at max to begin with, 450°, and from hours of watching the elements respond, I don't think it could get any better. What you're seeing is the inexpensive oven's bi-metallic thermostat control reacting. It's plenty effective for baking at and around 350 degrees, as most women will not notice the temperature swings and generally adjust the temperature up/down to suit their baking, but it is not adequate if you're looking to hold the temperature too a tight range and prevent overshoots like you're getting. It simply reacts too slow.

From observation, if this oven's sole purpose was for heat treating cast bullets, it seems to me the four heating elements would need to be staged in response to thermostat control. At this high output end, I suspect one heating element responding on its own would cause the total oven temperature to be a bit more constant. Based on this description, I'd say you may have more than one thermostat, perhaps one for each element. Your biggest issue here is insuring the PID controller solid state switch can out put the needed amps. A math calculation or a simple clamp on current meter across the 120V wire while running at time of highest current demand will answer that. You may need a 40Amp instead of a 25 Amp SS switch.

I'd even go further and say the lower rear element acting alone when the temperature exceeds 455°. I really believe all four elements responding is creating the small temperature swing. I looked at some maintenance manuals online and it seems that 20° is considered quite good. That's about right for bi-metallic thermostats.

The pans used also influence the overall temperature flow, something Dave kind of hit on. I used a flat pan and then a pan with sides. With the flat pan the melt occurred on the back side but with the sided pan the melt occurred on the left and right. I saw the airflow with the flat pan when I melted the wax and it was just a cyclone through the oven and out the exhaust with a little leakage on the top of the door which the gloves on it cured. I didn't melt any wax in the sided pan but if I didn't I think the airflow would indicate some kind of hotspots without airflow or heck, maybe it's too much airflow, around the sides. One thing the air flow cannot do is cause the temperature go over what the heating elements are heating it up. Their only purpose is to move the heated air through the oven. As you block certain areas and leave others open, air, which can have laminar flow, will move the air up/over and obstacle and back down into a lower area. For illustration, look at how air flows over airplanes, jets and automobiles.

The cheap way to go further, time is money at this time of year, would be to use the flat pan and a smaller, tighter group of bullets in the center of the pan. A fellow that hunts here is going to spell me for three or four hours around lunch and I might try that.I think that's a good start.

Dave, I really don't like looking a "gift horse in the mouth" but let me see if the above will cure it. The other consideration is that even after all this background noise, the bullets might not perform anyway as I want jacketed performance from cast in these high pressure cartridge. In that 300 Sav and 308 Win are sub-MOA performers, I'd say there is at least a 60% of the previous statement being true. Yes, you could possibly be chasing the elusive "unicorn," but perhaps not so much. My reading on other a couple of other forums suggest you may be doing better than you are thinking right now and a little bit more experimentation will get you close, if not there. If it gets you there, then a different coating will perhaps get you past the speed barrier you're looking at into the range you want. Here's a thought on some reading to look at: Modern coated lead bullets at high velocities. If you can get close with the lead hardness, then add a coating to help the lead survive the initial violence of cartride ignition, you are likely going to be there. I would already be there myself, but I lack two things. A range of my own close by to shoot at and my health issues slow me down. So I'm rooting for you to get there. +guns

Well, time to hit it.
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Heck, we made it to the moon, what's a deer at 500 yards with a lead bullet? Couldn't be that hard now could it?
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Re: Curing the 30 Caliber Blues... Part II

Post by Ranch Dog »

Thanks Dave, really got busy out back and never came back to the house until dark.
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