new fluxing thoughts.

[Lloyd Smale]

YOu guys that know me know i do alot of casting. Ive noticed lately that ive had more and more trouble making good bullets. I about know the problem. Its zinc wws. Those evil little sobs that the liberals are shoving down our throats. I smelt way to much ww to have the time to pick out individual weights or to smelt at a low enough temp to have them float out. Now i can add 5 percent tin (2 percent isnt enough with zinc contamination) and it helps or cut them with lynotype (which is getting about impossible for me to find anymore. I did some testing the last couple weeks and came up with something i think might help. Ive never really have been a big fan of fluxing. I flux when i clean wws and flux when i alloy but rarely flux the pot. Maybe once or twice in a 4 hour session. What i did this time was cast a pile of 300 grain lyman swc 44s and 340 bc lfngc 44s. I first casted with lead i fluxed when smelting and then fluxed again alloying it into both 5050 ww/lynotype and ww/5percent tin. I then casted as i usually do fluxing occasionaly but not alot. I then switched to the same batch of wws and alloyed them the same with the exception that instead of fluxing i just skimmed off the top. I did both alloys again and casted with them but again did not flux at all and just skimmed and scaped the pot about evey half an hour. With the 5050 it cut my variations in bullet weights in half and by over 3/4s in the ww 2 percent alloy. I went from an avearage of about 9 grains to 4 with the ww 2 alloy and from 5 to 1.5 with the 5050 alloy. Now this isnt a controled test as it was only one batch of wws but it was about typical in casting character and bullet weights. I guess the conclusion i came to is that fluxing for the most part is going to be a thing of the past for me as its not making any sense to flux in the zinc as i cast. To be honest i did a simular test years ago and found that overfluxing hurt more then not fluxing at all but i never got the dramatic effects i got this time and havent had the problem with bullet fillout that ive had lately either. Where i really notice it is between the cavitys of 2 cavity large molds. The hot spots seem to be much more prevelent with contaminated alloy. I also noticed in testing that my best bullet were comming when i ran my pot as cool as i could for the alloy. My thoughts on that are that the cooler the alloy the more of the zinc that seperated. Any thoughts?

[hunter64]

Since lead melts at 621F and zinc is at 787F if you get the lead to 640 or so and stir the heck out of it, the zinc should rise to the surface and skim it off. There was another post going right now by 44man and that is what he did, as soon as it melted he skimmed the surface and he had success.

[Junior1942]

LLoyd, simply use a thermometer and keep your melt to around 650 degrees, and the zinc wws are easy to pick out. They'll be floating on top along with the metal tabs and crud. BUT you have to use a thermometer.

[1Shirt]

Just another reason other than to get frosted boolits that seem to hold lube better (at least for me). The pretty shiny ones do look great, but have never found them to shoot any better than the frosted ones, and weight variance between the two never seemed appreciable.
1Shirt!:coffee:

[Lloyd Smale]

problem with that is i use a turkey fryer or an open fire in the pit to smelt. I just dont have time to fool around with small batches and trying to maintain a low temp. I think the lowering of casting temp and the changing fluxing habits are going to be the trick to dealing with zinc.
LLoyd, simply use a thermometer and keep your melt to around 650 degrees, and the zinc wws are easy to pick out. They'll be floating on top along with the metal tabs and crud. BUT you have to use a thermometer.

[44man]

1shirt, frosted boolits are good but they are a lot different then zinc contaminated galvanized ones.

[ron brooks]

Junior,

So you load up the smelting pot with wheel weights and put the thermometer in the pot and watch the temperature and keep it around 650 degrees?

Thanks,

Ron

[Lloyd Smale]

heres a little update. I remelted the batch of #2 that was giving me the problem and allowed it to cool and then skimed it and repeated it 3 times. No fluxing just skimming and casted some out of the lead and the weight variations were more then cut in half so it does do some good and it does get some of the zinc out. I think thats about it for me fluxing other then when smelting wws. I even tried the old contaminated lead today and casted a pot just skimming every couple minutes and keeping the heat as low as possible and it made a big improvement in bullet quality. Never did see the use in fluxing with a bottom pour anyway. Fluxing is mostly to remove dirt and if your lead is in clean ingots you shouldnt have a problem with dirt. Ive been told over and over by people that know metals better then me that once an alloy of tin lead and antimony is an alloy it can never seperate anyway so fluxing to keep an alloy consistant is just an old wives tale anyway. About all your doing when fluxing anymore is forcing the zinc back into the mix. Im not scientist but my casting has proven this over and over. If you think fluxing helps just try a batch out of the same alloy and flux every 10 minutes and then do a batch just running a pot till its empty without fluxing and ill about bet your bullets are more consistant without fluxing.

[Dale53]

Lloyd;
I am "somewhat" in your corner. I flux when I start my pot. I do not flux until I am finished and starting another pot full (RCBS 22 lb pot). I normally cast until the pot is empty, then stop (no more all day sessions for me). Of course, if I am casting BIG bullets, I might do TWO pots:mrgreen:. Big Bullets meaning anything over 400 grains.

I DO believe that fluxing helps me to keep my bottom pour pot free of dirt. That enables me to cast with a minimum of dripping.

The biggest danger of zinc contamination, however, comes when you are smelting. I practice the 650 degree smelting temperature faithfully. I have recently found a few zinc wheelweights and just remove them floating on top of the melted WW's with the clips. That is the safest way of protecting my metal supply. It really doesn't take that much longer to melt. Higher temps are really not needed IMHO. My metal supply is older and there are few zinc weights. However, they are only going to get more numerous (thank you, tree huggers...)

FWIW
Dale53

[SharpsShooter]

I DO believe that fluxing helps me to keep my bottom pour pot free of dirt. That enables me to cast with a minimum of dripping.

I have to agree entirely. I clean the smelted metals with great attention to detail, but still stir and skim my 20 pound bottom pour. I usually do not get much in the way of impurities, but since my pot is a LEE, why take the chance of creating a drip-a-matic. Once per fill-up is all that is required and it is easier to do than stripping the pot down for a cleaning.

SS

[tomf52]

Lately I have found my best results are obtained by stirring the pot vigorously with a rounded end wooden stick and skimming the top (ladle pouring here) frequently. Stopped using all the "magic" fluxes. Only suggest the wooden dowel tool because it scrapes the bottom better than a stainless steel spoon.

[cbrick]

Lloyd,

I have always fluxed at the beginning of a casting session and when adding alloy, never at any other time (This is for the casting pot, not smelting, I flux well when smelting).

I add 3% tin to my wheel weights and once I start casting nothing goes into the pot, not sprues, rejects, flux . . . nothing.

With 3% tin my wheel weights run a pretty consistent 11 BHN checked with an LBT tester, without the tin wheel weights on my tester are 9 BHN so the tin does add a bit of hardness but not much.

With my normal (3% tin) alloy my SAECO # 073 mould, 7mm 160 gr SPGC casts 163 gr bullets.

I tried your not fluxing, just skimming method over the weekend and got some interesting (educational) results. I heated up the pot and skimmed, let it cool and heated it up again, did this three times. What I was skimming off looked like the tin, shiny, not dull. After it was hot (700 degrees) and skimmed the third time I cast some SAECO 073 bullets. They weigh 168 gr and are 9 BHN.

when I was done casting I left the pot on for two hours and the surface of the melt was still bright and shiny without any oxidation at all. This all tells me that what oxidation I was getting (not much, but a little) was simply the tin.

Seems as if tin can be removed from the alloy and all I skimmed off was the tin. I had always thought as you did, that once its an alloy its an alloy. Period. I have read that the tin does oxidize with contact with air on the surface of the melt and this it seems is what I skimmed off.

I think the practice of smelting at 650 - 675 degrees is a good one and because of this there probably wasn't any zinc in the alloy. For the price of a little tin it was an interesting experiment but I think I'll have to continue fluxing at the beginning of a casting session and flux the tin back in and smelting at 650 degrees.

Rick

[Lloyd Smale]

Do you think its even possible that you took enough tin out in weight even it if could come out to vary bullet weight by that much. I dont think it would be possible. Even the guys that preach that you can take tin out by skimming the top of the melt will tell you that the ammount your taking out is very very small.

[cbrick]

Well, best answer that I can come up with is: I dunno. It was only one experiment and 3% tin is a bit more than most people use.

There was no oxidation on the surface of the melt from the time I skimmed it, cast 100 bullets and then let it sit for two hours, there normally is a bit.

The bullets cast during this session mirror the results in weight and BHN of the rare times that I cast without tin.

My pot is the Magma 40 pounder and each time I skimmed the alloy I got nearly a full serving spoon (the stainless spoon that I flux with) of whatever was skimmed off. I just looked in the coffee can that I dumped it into and its still shiny, must be the tin.

Not being a metallurgist the best I can come up with is the SWAG that it was the tin I skimmed off and that's how much of a difference it made.

But then its all a SWAG cause I really don't know, its just what it seems to me to be.

Rick

[GSM]

cbrick:

If you use the same method, try saving the skimmings in a separate can - after accummulating a fair amount, re-melt it (not in a bottom pour).

I had about a 1/2 coffee can built up from my RCBS pot (I tend to skim heavily) and just out of curiosity threw it into a Lee pot the other day. To my surprise, I came out with about 4 lbs of clean metal.

Fluxing with a dowel has signifcantly reduced the amount I take out now.

[jar-wv]

Lloyd. So does the zinc "alloy" with the mix during smelting or not? I have been under the impression that it does, and can't be undone, so I use a thermometer when fluxing. I'm also wondering about how much you smelt at once. I can smelt 100 lbs at once using a coleman stove and large stainless stock pot. It does take a bit of time per batch. I was worried about the batches I smelted before I got the thermometer, but found the setup I have will only get a batch to 600 degrees so I don't have to worry about the zinc ones and skim em out. I have found a few but not a whole lot of them.

[truckjohn]

Some of the zinc dissolves, but most of it just floats unless you mix the heck out of it.
Kinda like mixing up a Black and Tan -- you can pour the Stout in 2nd, but it still sinks to the bottom unless you stir it up good.

Then, when the alloy hardens back up -- you get different mixtures of solids as the the alloy cures -- typically a mish mash of Zinc rich alloy solid + a lead rich alloy solid.

If you re-melt it at a low temperature -- some of the high-zinc alloy may float out.

Good luck.
John

[Mr Peabody]

I quit fluxing a few years back after noticing how much more uniform my weights were by not doing it. Everyone has always been so adamant about it I didn't want the arguement of saying so.
Glad to hear some things change.

[Lloyd Smale]

one more thing i did that helped today. I got the alloy straightened around and was casting with 3 differnt molds. Two of them were casting perfectly and my 44 320 lyman swcgc mold was still not filling out in the lube grove perfectly. I took a brass wire brush and scrubbed the mold gently and it casted perfectly after that. Im guessing the zinc contamination was holding on in the mold cavity where the hot spots were. Once removed the mold worked fine.

[cbrick]

Diddo the brass brush Lloyd, I always start a casting session with each mould used with break cleaner or alcohol and the brass brush no matter how clean I think the mould may be.

I had never thought about it being zinc contamination but it could well be I guess. When I get incomplete fillout on the driving bands or inside the lube groove I have long thought that it looked much like a "hot spot". I even nick-named it "heat shrinkage". You might have hit the nail on the head here Lloyd.

Rick

[Lloyd Smale]

I wish i could answer you question but if i tried id be a bs'er I know that it seems to flux in and then if you reheat it seems to seperate at least somewhat
Lloyd. So does the zinc "alloy" with the mix during smelting or not? I have been under the impression that it does, and can't be undone, so I use a thermometer when fluxing. I'm also wondering about how much you smelt at once. I can smelt 100 lbs at once using a coleman stove and large stainless stock pot. It does take a bit of time per batch. I was worried about the batches I smelted before I got the thermometer, but found the setup I have will only get a batch to 600 degrees so I don't have to worry about the zinc ones and skim em out. I have found a few but not a whole lot of them.

[truckjohn]

one more thing i did that helped today. I got the alloy straightened around and was casting with 3 differnt molds. Two of them were casting perfectly and my 44 320 lyman swcgc mold was still not filling out in the lube grove perfectly. I took a brass wire brush and scrubbed the mold gently and it casted perfectly after that. Im guessing the zinc contamination was holding on in the mold cavity where the hot spots were. Once removed the mold worked fine.

Brushing/scrubbing the surface of a mold is a good practice and especially the vents -- as trash builds up in the vents -- that will cause a mold to not fill out correctly. You will see the effects most in the corners and sharp edges. In our little scratch vents, a few specks of oxide dust or lead can clog them up till they won't vent right.

Best regards

John