2nd solo attempt at casting - low yield

[bcr]

I made my second attempt at casting today, using my Mihec H&G 68 clone. I started with about 2% tin, and eventually added ~2 lbs of straight COWWs. I have a little Lee 10 lb pot which doesn't last too long loading this large mould.

I got 122 boolits that I kept, but my yield was very low, probably 15-20% of all the boolits I cast were keepers. The boolits I threw back mostly had poor fillout, rounded driving band, or a deformed base because I was getting some lead under the sprue plate.

My sense is that my main problem was keeping my mould hot, because the boolits seemed to come out prettier after I had been casting a while, but every time I really got going I would have to stop and refill the pot. Also, with such a small pot and having to keep adding to it, I think I was having a hard time keeping the melt a steady temperature.

Do I just have too small a pot for too big a mould, or are there some things I can do to make this work? It would be a lot more fun if I could end up with 500 boolits in a casting session instead of 100.

[wellfedirishman]

I have the same 10lb Lee pot and can cast tons of 200 grain 44-magnum bullets using a 6-cavity mold without hardly any bullet loss. I use mostly straight WW alloy.

The main thing is keeping your mold nice and hot. Is the temperature dial on your mold turned up to top or close to it? Run a few 'warm up' pours through the mold before your start casting for keeper bullets.

Once the mold is hot, bullets tend to fill out just fine and drop freely. If the mold is cold, the bullets are wrinkly and misformed.

Also, for plinking or casual pistol target shooting the bullets don't all have to be perfect, in my experience.

[MtGun44]

Mold and/or metal too cool. Heat the metal up and cast VERY fast, do NOT inspect, to get
the mold up to temp. Once you are at temp and they are dropping well, slow the rate to keep
the mold temp from rising.

Bill

[geargnasher]

Bill's got it right, that brass mould is soaking up a lot of heat and you'll need to preheat it and cast fast to keep it hot.

Let me put it in perspective, as I have one of those moulds: Once you get the mould hot, cast at a rate of three full cycles a minute (TIME IT!) and don't look at the boolits, just focus on filling, cutting the sprue while it's firm but still soft enough to cut by hand, and dumping the boolits and carefully closing the mould and sprue plate as quickly as possible to conserve heat in the mould. Mould heat=good fillout.

I'm guessing you don't have a lead thermometer yet, but I'd suggest getting one to help you out with eliminating a common variable with casting. Most alloys like to work at about 100 degrees over the point that the alloy is fully liquid and all grainy-ness is gone from the metal. If you add tin to assist fillout, keep your alloy under 750 degrees or you'll negate the fillout effect of tin.

To help get the mould hot and keep it hot during pot refills, make one of these "mould ovens" with an electrical work box or a skilsaw blade and large steel coffee or bean can with an opening cut in it, and drill a hole in the top for a BBQ thermometer (available in the grille dept. of any home improvement store). A 1000 watt, open coil hotplate (got mine at Walgreens for $10) will keep the mould at 450 if you leave it in there for about 20 minutes, and will keep the mould at casting temperature if you need to stop and tend the pot, or visit the other pot, or whatever.

http://castboolits.gunloads.com/imagehosting/thum_89094e5ad65ae2e31.jpg (http://castboolits.gunloads.com/vbimghost.php?do=displayimg&imgid=1966)

Gear

[darkroommike]

Quote: The boolits I threw back mostly had poor fillout, rounded driving band, or a deformed base because I was getting some lead under the sprue plate.

Just a guess, but are you adding back your reject bullets and sprue trimmings as you cast? If so, just put them to one side and run the pot. If you are stopping to add stuff back into the pot your mould has a chance to cool and adding even hot lead back to the pot is causing the lead temp to fluctuate.

[KCcactus]

I had the same issues with my Mihec .432 HBWC 4 cavity. By the time I got the mold up to a temperature it likes, my 10lb pot was getting low. I bought a 20lb pot, which helps you keep going when the mold gets hot. But, I still get a lot of rejects to start. For my next try, I'm going to get a hot plate and put together an oven like mentioned above.

[montana_charlie]

The main thing is keeping your mold nice and hot. Is the temperature dial on your mold turned up to top or close to it?
I need to see that mould ... the one with the temperature control on it.

CM

[mooman76]

I keep adding the sprue cuttings and bad boolits back to the pot to keep the level up longer. I add them while I am waiting for the sprue to cool so I'm not wasting time. I cast with a little 4# pot and can keep it going without to much trouble so a 10# pot should work fine. Yes you could get a 20# pot and that would make things easier, I have one of those too. I don't wait for the pot to get real low either as I add ingots, I keep the level up and add as soon as it gets low enough that I can add without raising the level too high. You will get better with practice and you develop a working pace that works best for you. The good thing is you waist nothing but time as you can remelt the bad boolits.

[bobthenailer]

IMO set temp of pot at 700 degrees , add sprues / defective bullets imediatly back into pot while there still hot , preheat mould to about 400 to 450 degrees, keep pot as full as possible and add extra preheated ingots to the pot when needed to keep it full. these recomendations should fix your problem !

[Colorado4wheel]

Small lee pot, big mold. Don't know how you would cast many good bullets with the mold constantly cooling off.

[10x]

snip
I got 122 boolits that I kept, but my yield was very low, probably 15-20% of all the boolits I cast were keepers. The boolits I threw back mostly had poor fillout, rounded driving band, or a deformed base because I was getting some lead under the sprue plate.

snip.

Make sure you leave a large sprue on the sprue plate. A large sprue acts as a reservoir and adds weight to fill the mold.
I watched a friend casting 45 caliber 500 grainers - many wrinkles and rounded bottoms. His sprue was smaller than a dime - told him to get as much lead on top of the sprue plate as possible fill out improved dramatically with rejects going to almost zero.

[GaryN]

I run my brass hollow point mold hot. In the neighborhood of 725 degrees. It seems to fill out better. I also have to run it fast. A minimum of three pours per minute. Usually closer to four. I noticed when I got it that brass loses heat a lot faster than steel. Yesterday I was heating up a pot full of lead. It had about 1/8 pound of solder in it. I have a twenty pound pot. I left it a while and went out to get my stuff set up to cast. I checked the lead thermometer. It was a little over 750. It could have been that hot for as long as an hour. I turned it down some and started to cast. I noticed the bullets looked kinda rough. I put in some more tin and they cleaned right up. I think I oxidized my tin off by having it too hot. I usually run my solid boolit mold at about 675. My ten pound Lee pot would have to be turned up to about 9 1/2 to be hot enough to run right. NOE has a real good lead thermometer for a good price. That's where I got mine.


p.s. I run the lead at 725 in the brass hollow point mold not the mold itself.

[bcr]

Thanks, these are some great ideas!

I do have a lead thermometer.

[Bullet Caster]

I ain't got no thermometer, but if I keep my coleman stove pumped up occassionally it keeps the lead at the proper temp for casting. I use Lee molds which are aluminum and heat up rather quickly. I cast pretty fast with a lot of lead on the sprue plate and as soon as it solidifies I whack it with my stick. I have a metal pan which i cut the sprues into and then add them back when I have to add pb to my little pot. I started out on the side burner of my grill and after a lot of black smoke and little lead melted, I gave it up. I got on the forums and found out the my coleman camp stove would work for melting pb. I'm casting 124 grain rnd nose .356 for my 9mm and 255 graine rnfp for my colt .45 clone. So far I've had two casting sessions and have rejected more 255's than 124's. I noticed the small boolit mold casts differently than my large 255 one--I cast at a different speed with it than the 124. I know the mold's hot when my old leather gloves start to smoke when I close the sprue plate after casting enough to get my mold hot. Doggone it, I think I'm getting the hang of it. I've cast 400 .45's and nearly 400 9mm's. If I knew how to post a pic I'd show ya what they look like.

My quality control is sitting in front of the TV and inspecting my days worth of casting. Seems like I'm gettin' pretty good at that 2!