Thread: zinc boolits range report
Retrieved: 01/17/2015
Last Post: 09/14/2014
Bad news, good news. They shoot just like the 429421 Lyman boolits. No it's not the rifle as I put 5 shots of 240gr Win jacketed boolits and it shot those fine. It will shoot 5 shot group with all touching when I do my part.
These jacketed boolits was shot without cleaning the barrel between zinc trials. No fouling in the barrel at all. I'm 100% sure that I will never get any copper or lead fouling from zinc boolits. Just kidding. The good news is I now know the problem. I'm convinced that these boolits should shoot as good as my Win 240gr jacketed boolits. the problem is shrink voids.
I'm going to play with keeping the mould cold while casting and get a good electric hot plate so I can regulate the temp better. It was mind boggling that the boolits with the visible hole weighed the same as the solid ones. after I cut a bunch up, ah-ha, it was an optical illusion. Every one of the boolits held to the light and wiggled, you can see the the circle shadow if you can call it that. I'm to close to giving up now. I like the no lube, no barrel fouling, push as fast as you want.
battle.
PICTURE 404
In this pic, you look closely at the 4 middle boolits and you can see a shadow of a circle. The 4 boolits on the right are obvious. The ones I cut with the circle shadow are the 3 on the left.
There are other zinc boolit casters in this group. How do your boolits shoot and do you have any suggestions.
PICTURE 404
sagacious
08-01-2010
The central void is called 'pipe.' I have had problems with the same phenomenon occasionally when casting zinc in metal molds, but never plaster lost-wax molds... more on that later. Often the pipe extends through much of the casting, and for castings that I was to use for later machining, it would ruin most of the usable metal.
The cause and solution are probably not immediately intuitively obvious. The causes are: 1) wetted oxide inclusions within the zinc melt, and 2) shinkage caused by an almost pure zinc alloy.
Here's what happens. As the zinc cools radially inwards from its contact with the metal mold surface, the pure metal solidifies first, and any oxide contaminants become dragged along with, and concentrated within, the unsolidified zinc towards the center of the casting. That leaves low-density contaminants at the center of the casting. As well, as the casting freezes, the center pipe area forms a generally vertical void as the pure zinc shinks from it's volume in the melted state. I didn't have pipe problems with lost wax molds, as plaster is an insulator, so the zinc casting did not cool in the same manner as when using a metal mold.
The solution (worked for me anyway) is to use pure anode zinc, and a good flux, and take pains to always maintain a clean melt. I also routinely added about 1 or 2% aluminum to the melt (it will dissolve readily in molten zinc) to help combat thermal shinkage. You'll never notice that small amount of Al in your finished bullets, but it will help reduce drossing/oxidation and give a more solid casting. A mold design that uses a large gate and sprue design also helps reduce pipe.
Your bullets looks good, and you should be able to get the kinks worked out. Good luck.
jbunny
08-01-2010
Sagacious, a big thank you. what kind of flux do you use?
What kind of temp do you cast at?
This 1-2% Al you add, by weight, volume, or grandma's cooking method, a handful?
Any paticular alloy of Al, like roof flashing, strong Al like in engine pistons?
docone31
08-01-2010
Wow, being an high temp caster, I find that interesting.
At any rate. I modify my zinc with a little plumb lead. The lead will absorb about 2% zinc. It will also go the other way. Zinc will absorb a high percentage of lead!
What I do, is to cast with zinc modified with lead. I have found, if I do not stir, I get clumping of either the lead, or zinc. Both metals have to thin with the other. None the less, I have found much reliability with zinc castings. I paper patch them, and for my target use, they function real well.
In all cases, with zinc, it takes heat to keep the metal fluid. Not enough to smoke the metal, but high enough to keep it fluid into the mold. I prefer aluminum molds. They do real well with the zinc castings I make.
When I did injection castings, it was different. I got prealloyed metal. I never did lost wax with zinc. I would have to keep the mold too low in temp and that would make mold warts, or cracking. Foam casting is an alternative with the investment casting, however burn out would leave residue.
Those castings look good. Nose pour would reduce the effort to eliminate the sprue.
sagacious
08-01-2010
The anode zinc I use does not require fluxing as often and as intensively as most lead alloys. I use a 3:1 mix of borax and zinc chloride. I've used pure borax at times too. I flux at the beginning of the session, and usually dispense with fluxing after that, unless a problem arises. I pour at around 850*F or so-- but I've been doing it for so long that I don't check the temp any more. It's hot enough to pour when there's no excess freeze-buildup on the ladle. Your situation and temp may vary. Be advised that zinc chloride will absorb water during storage (like Marvelux will), and be sure to do the fluxing outside or with very good ventilation, as the chloride flux will give off ammonia fumes.
I stir the melt with a 1/4" aluminum rod or very thick Al wire. I'm not sure of the exact alloy content, but to my knowledge, extruded/drawn Al is usually fairly pure. I doubt that the exact composition is critical, but one does want to use bright, uncorroded aluminum. While stirring, the Al rod will thin and sharpen at the end while it dissolves. It doesn't take much, a percent is adequate, and you can measure out the weight in Al wire before a casting session, and use it up as you progress through the casting session.
1-2% tin, antimony, and even lead may reduce pipe. I haven't tested them for that. As far as I am aware, any alloy content in zinc will reduce shrinkage, which should help. I save my lead-free solder for lead alloying, but you may wish to give 1% of that a try and see how it goes. There's a lot of room for experimentation, but I burned-up a ton of tin doing experiments a long time ago, and now usually just stick with what I know works for my application. Good luck.
jbunny
08-01-2010
Sagacious, dacone, thanks for the help. i have experimented with tin in zinc. Lead will redily mix in then but my oh my, what a sticky mess in the ladle. That is a recipe for galvanizing. I have one nice stainless ladle that I made and I was using it for the melting pot for experimenting and I can't get it of the ladle. It would't stick to the mould, thank heavens. Lots more experimenting to be done. BTW, I wear a welding respirator while casting and have a big exhaust fan going. One of these days, it's going to work!
jbunny
08-03-2010
Sagacious; your advice was bang on. I looked at all the Zamak alloys and there characteristics and then looked at the various aluminum alloy charts and 6061 being the most common and I have lots of scrap pieces of 100 thou checker plate. i took a peice 1.5 in wide 6in long and weighed it on my postal scale and 2 ounces. I had 8 lbs zinc in my pot which is 128 ounces. 1.2 ounces would be 1% so 2 ounces looked right. Well about as fast as saying abra-cadabra, it was didsolved. It made the melt flow better and pour easier. It is a lot harder than pure zinc as I really have to grunt to cut the sprues. I thought to myself, boy this is going to be hell to size. WRONG. The boolits are harder but they are wayyyyy slipperyier. They go through the sizer way easier.
I started with a cold mould and the boolits from the first 2 pours looked good on the outside, had tiny pipes. All the others, no more pipes. Yahoo. My next major challenge will be loading these as I will have my finngers, arms, legs and eyes crossed. Oh- I forgot my toes. LOL it will be ineresting to see the chrony readings.
sagacious
08-03-2010
Fantastic! Glad to hear of your success. Yes, it does make the alloy a little 'slipperier' and does reduce sizing effort. It's a win/win.
You may wish to add a sturdy handle to your sprue plate to assist in cutting the sprues (somewhat like the sprue handle on LEE 6-cav molds). A handle on a steel sprue plate with sharp cutting edges can make the casting session go much smoother and faster.
Remember that zinc is a different ball game than lead, so don't fret if you're not hitting them out of the ballpark just yet. Just keep moving forward with your progress, and you'll keep adding to your successes. Good luck.
Doby45
08-03-2010
He is nose pouring these and cutting the sprues with side cutters or something like that. Ain't ya?
lwknight
08-03-2010
Well... waddaya know!! Instead of hunting pewter, we can just recycle the beer cans.
On a more serious note: The pop rings are a different alloy than the rest of the can or so I hear. Anyone know whats up with that?
sagacious
08-03-2010
On a more serious note: The pop rings are a different alloy than the rest of the can or so I hear. Anyone know whats up with that?
The rings and tops are not extruded, like the body of the can is, so they use a stiffer alloy that allows the use of less material by weight. They add a very small amount of lithium to the aluminum in the tops/tabs to harden it-- but a web search can probably turn up the exact alloy they're using. Even a teeny-tiny weight savings per can is a big deal, since the factories produce millions of cans a day. This is also why aluminum can tops have become smaller in diam over the years-- uses less of the aluminum lithium alloy.
jbunny
08-05-2010
Another range report. The one positive thing about yesterday's outing is I learned something. Only got 3 shots on the paper at 100 yds. This 2 ounces aluminum in 128 ounces of pure zinc made beutiful bullits with no pipe voids, worked beautiful in the sizer. However it zinced the whole length of the barrel.
I soaked it all night in Hoppes #9 and a few strokes this morning and clean barrel again. I poured out the alloy and remelted 7 lbs pure zinc and added 2 lbs of the alloyed zinc and cast a bunch of boolits. Yes back to shrink voids. I grabbed a handful, turns out it was 13, loaded them up and back to the range, all 13 shots stayed on the paper this time with a fouling near the muzzle at the end. This fouling didn't look like your typical fouling that a couple of little streaks on top of the land and a couple in the middle of the groove.
I'm puzzled by noteing that shooting the Win jacketed boolits the barrel is shiny clean with just a few tiny speck of soot and same powder with zinc, no shine and black soot from end to end. Anyhow, pursuing this shrink void problem, I started cutting the sprue, the little part and the big part. I knew better and should of done that long time ago. No voids in those parts. I thought that by having a big sprue would eliminate the voids. wrong. Just like scotch, a drink is good, a bottle is no good. I have to redesign my mould. Never a dull moment around here.
sagacious
08-05-2010
Are you using lube on your zinc bullets? I lube mine conventionally, with no fouling. A friend and I have been shooting zinc bullets for years, with excellent results and no fouling. Have you tried alox or something similar?
jbunny
08-05-2010
No I haven't. Never had any fouling before. One of the reasons I'm casting zinc is I thought I would not need lube. This is the first time that I've had fouling. Zinc fouling in your barrel is not the end of the world. LOL.
I will be making another mould and that will solve my shrink voids, I hope. I tested my wild idea for a new type of sprue cuter just for zinc and it looks like it's going to work. Just call me stubburn. LOL
sagacious
08-05-2010
Sounds good! I think you just need to keep at it with your materials, and you'll get them to work.
I run the zinc bullets though my lubrisizer to size them, same as lead bullets-- so I just lubed them during sizing with my standard wax lube. I haven't tested unlubed zinc bullets, so you'll have to keep us posted on your progress with that. Keep on keepin' on!
oldtoolsniper
08-06-2010
There is an article and hand loaders digest, the 12th addition starting on page 128, titled shooting zink in big bores. It states that zink was first used by the Germans for antitank shells during World War II. It also references Veral Smith of lead bullets technology, Cornville, Arizona, stating that he is currently is state-of-the-art in this field. At the end of the article he gives basically the 12 rules that he applies to casting zinc. He enlarges the standard sprue holes 25 to 50% over the normal size used for lead, stating that zinc alloy is much lighter and thicker so it pours more sluggishly. The article also states that you should not attempt to size zinc alloy bullets as distortion and inaccuracy will result. The article also states that lubrication is not necessary, and gas checks are not required.
For what it's worth, the article is pretty interesting.
Changeling
08-06-2010
quote
I run the zinc bullets though my lubrisizer to size them, same as lead bullets-- so I just lubed them during sizing with my standard wax lube. I haven't tested unlubed zinc bullets, so you'll have to keep us posted on your progress with that. Keep on keepin' on!
Hello. If you and the other guys who are experimenting need a really high grade of aluminum, go to the speed shops, hot rod clubs, etc. It is not too unusual for these guys to blow a piston or just retire a set after so many runs. I'm sure they would be glad to give them to you. Quality is of the highest grade!!
geargnasher
08-06-2010
"Aluminum" pistons are a high-grade hypereutectic silicon alloy formulated expecially for casting, or an alloy designed to be forged. They are NOT pure aluminum.
sagacious
08-06-2010
Originally Posted by oldtoolsniper
He enlarges the standard sprue holes 25 to 50% over the normal size used
for lead, stating that zinc alloy is much lighter and thicker so it pours more
sluggishly.
I modify my zinc molds this way. It makes the sprue even harder to cut, but it can make for much greater consistency in as-cast weight.
I have also found that a lead-bullet mold that suffers from slow pours or inconsistent fill-out can be corrected by enlarging the sprue hole by a couple hundredths. Makes a much digger difference than it would seem, and the lead will 'swirl' in rapidly. Some old Lyman molds have very small sprue holes, and really benefit from this small modification.
jbunny
08-15-2010
Turbo 1889; thanks for sharing, good info there. I'm new at this zinc game and it's been one hurdle after another. I will try your copper alloy.
In case you didn't know, I use a casting vibrator that I made from a junk box hair clipper. Works like a hot damm. I started out with a steel pot and some scrap Zamak alloy and it was good at first but every time I cast my boolits got harder and harder. The zinc melt was dissolving the metal and getting harder. I now use a heavy enamel cook pot. It seems to be standing up good so far. I told the wife that I dropped it and broke the handle. He he he. All's fair in love and war and casting boolits.
I don't like beating on sprue plates so I used to cut them with flush sided side cutters. The hour glass bottle neck was causeing shrink voids in my boolits. I have now modified my mould and there is no room for side cutters. another hurdle. I now twist the sprue off and much cleaner and easier.
BAGTIC
08-24-2010
One of the recommended fluxes for zinc is salicylic acid (aspirin).
whisler
08-24-2010
I believe that aspirin is acetylsalicylic acid.
a.squibload
08-25-2010
...i now twist the sprue off and much cleaner and easier.
Just curious, how do you grab the boolit when twisting off the sprue? They don't look damaged at all.
I was thinking pliers might leave a mark!
jbunny
08-25-2010
A rat tail file on a cheap pair of pliers followed by Dremel sanding drum.
jbunny
10-24-2010
Originally Posted by Chainsaw2
So, other than zinc WW, what is your source of zinc for casting?
Jim, scrap yards and I bit the bullet and bought some new pure zinc. it pays to shop around. A while back I had fouled the barrel shooting thinking it was zinc fouling. Wrong. As I was heating the pot up for a casting session I noticed little molten puddles. The zinc hadn't started to melt yet. I suspect I put some lead bullets in the pot thinking they were zinc. That was the first time in about a 1000 rounds that I ever had any fouling. My .44 Mag rifle still shoots cloverleaves with j-boolits so the zinc has not hurt the barrel any.
chris in va
10-25-2010
I just thought of something. Any possibility zinc projectiles may be regulated as they are harder than both copper and lead? As in... armor piercing?
Also what composition are pennies these days? I understand they are mostly zinc, don't know the legality of melting them down.
rogsir
04-19-2011
When I collect ww here in Norway, it is separated in 3 parts - Lead, zinc and iron. I have only used the lead till now, but I want to give the zinc a try in my Glock 22. If anyone have tried that before, I would like to be directed to a link or something.
HighHook
04-20-2011
The guys that clean the bottoms of boats in the marinas replace zincs every day and throw them away. The zincs keep the electrolysis from ruining other stuff in the boat.
I wonder if they could be used? That is for someday in the future. Thoughts?
luvtn
04-20-2011
quote
Be advised that zinc chloride will absorb water during storage (like
Marvelux will), and be sure to do the fluxing outside or with very good
ventilation, as the chloride flux will give off ammonia fumes.
I don't understand the comment regarding giving off ammonia fumes since neither the zinc or borax contain nitrogen. Ammonia=NH4 perhaps it should read chlorine fumes?
Borax=Na2B4O5(OH)4•8(H2O)
Composition:
Molecular Weight = 381.37 gm
Sodium 12.06 % Na 16.25 % Na2O
Boron 11.34 % B 36.51 % B2O3
Hydrogen 5.29 % H 47.24 % H2O
Oxygen 71.32 %
recycledelectrons
04-21-2011
Originally Posted by chris in va
I just thought of something. Any possibility zinc projectiles may be
regulated as they are harder than both copper and lead? As in... armor
piercing?
http://www.recguns.com/Sources/IIG1.html
pointed me to
http://frwebgate3.access.gpo.gov/cgi-bin/TEXTgate.cgi?WAISdocID=XO0Mya/0/1/0&WAISaction=retrieve
(B) The term "armor piercing ammunition" means--
(i) a projectile or projectile core which may be used in a handgun and which is constructed entirely (excluding the presence of traces of other substances) from one or a combination of tungsten alloys, steel, iron, brass, bronze, beryllium copper, or depleted uranium; or
(ii) a full jacketed projectile larger than. 22 caliber designed and intended for use in a handgun and whose jacket has a weight of more than 25 percent of the total weight of the projectile.
Zinc is not mentioned.
Originally Posted by chris in va
Also what composition are pennies these days? I understand they are mostly
zinc, don't know the legality of melting them down.
Pennies have MOSTLY zinc cores, not pure zinc. Impurities like copper might have significant effects on melting points.
BOOM BOOM
04-21-2011
IIRC from my research, Zn falls 1/2 way between Pb and Cu. No way it could be considered a armor piercing bullet.
a.squibload
04-21-2011
Originally Posted by recycledelectrons
(ii) a full jacketed projectile larger than .22 caliber designed and
intended for use in a handgun and whose jacket has a weight of more than 25
percent of the total weight of the projectile.
So if someone swaged a jacket and filled it with cotton fiber it would qualify as "armor piercing". Gov. also has a definition for "assault rifle". Sometimes they lie.
Nice to know that if we have to start using zinc it's not automatically verboten. Yet.
Longwood
04-21-2011
I know many carburetors were made from zinc. I wonder if throttle bodies are now.
lwknight
04-22-2011
I don't understand the comment regarding giving off ammonia fumes since neither the zinc or borax contain nitrogen. Ammonia=NH4.
Perhaps it should read chlorine fumes?
Is there not plenty of nitrogen in the air that we breathe to react with the process?
jonp
09-08-2013
Aspirin is acetylsalicylic acid. It can be purified to get salicylic acid but an easier way to get salicylic acid in its pure form is to buy it.
It is used as a cosmetic wart remover and a main ingredient in acne medications.
It can be bought on Ebay and does not cost that much. http://www.ebay.com/itm/Pure-Salicylic-Acid-100-9gm-Cosmetic-Warts-Acne-/150751831804
Centaur 1
09-15-2013
Originally Posted by xacex
So it seems steel molds are the best to use out of the arsenal that we have
at our disposal right now. That got me thinking. One of the Lyman molds I have
is the 12 gauge Lyman slug. I think I might have to try it out with zinc since
it is already sized to what it needs to be, and it takes a ride in a shot cup.
That mold uses a ton of my lead too. It weighs in at 525 grains out of lead,
but I am curious what it would weigh out of zinc?
Now this sounds interesting. I believe that pure zinc is just too light to be used successfully in a conventional bullet. Shotgun slugs are anything but conventional when compared with a rifle bullet. They're extremely light for caliber, have the aerodynamic stability of a shuttlecock, and the trajectory of a rainbow. A zinc slug should weigh a little more than 60% of one cast from lead. I'm thinking that someone with the proper knowledge and equipment could get enough extra velocity to give a flatter trajectory, and enough energy to punch through a deer at 125 yards.
luvtn
09-16-2013
Originally Posted by lwknight
Is there not plenty of nitrogen in the air that we breathe to react with
the process?
After re-reading my comment I don't see how chlorine is a factor either. The nitrogen in the air is inert (or so little reaction as to be considered inert) during the smelting process IMO. If I am wrong show me the chemistry please. Thanks.
NYBushBro
09-14-2014
Stumbled across this thread today...
I've been reading "Practical Dope on the Big Bores" by Fred Ness.
He mentioned casting and shooting Zn boolits in this book... and it was written in the 1940s.