Lead in mould vent lines

Tasmanian Rebel · Post by **Tasmanian Rebel** » Thu May 27, 2004 12:24 pm

I have been having trouble recently with lead specks setting up shop in the vent lines on my moulds. This has started to become a problem with my pet Lyman postell mould and recently reared its head with a new Steve Brooks mould. I'm starting to wonder if my use of mould prep(Rapine) is the cause of this. I noticed with the reading info I got with a Paul Jones mould where Paul says NOT to put any mould prep inside his mould or one will get vent line obstructions.
These specks are seen in the nose portion of the moulds. I'm using 30:1 alloy poured at about 825 degrees. I must be doing most things right however as I'm getting very good bullets generally with only .5 gr variance. My pouring sessions are being cut short however because these lead specks build up to the point the mould halves start incompletely closing. I'm thinking of just putting the mould prep on the outside only on all my moulds like PJ says. Has anyone out there had this problem or does anyone know if this is what is causing this?
This leads to another question-what is the best way to remove this lead which seems to be practically baked on the mould like enamel? The best thing I have come up with is a small brass rod ground down like a chisel and scrape this stuff off- however I have had to resort to a dremel brush in the past to VERY CAREFULLY "tickle" this stuff off with magnification without damaging the mould. Can anyone out there give me some guidance or suggest what is happening and what to do about this?

powderburner · Post by **powderburner** » Thu May 27, 2004 1:13 pm

it sounds as if your mould may be overheating a bit. lymans are good for that with the big bullets ( no PJ experiance yet)

a carpenters pencil sharpened to a chisel point will take off hot lead and a lead wipeaway cloth will clean a cold one I degrease really good after using the wipeaway cloth. I never had any luck with mould prep but have solved the problem of a hot spru plate smearing under the plate by cooling it on a damp towel for a few seconds each bullet ( makes for a real clean base when the spru is cut as well)
and have also set the mould nose on the DAMP towel as well when it shows signs of overheating ( usually really shiny almost wet looking noses)....perhaps these may help , you may also try smoking the mould cavity with a bic lighter instead of mould prep but only necessary if the mould refuses to release these are my findings .........Dean

Tasmanian Rebel · Post by **Tasmanian Rebel** » Thu May 27, 2004 5:32 pm

Thanks Dean, that helps. I'm getting a good, easy release with these bullets so will go without the mould prep on the inside to see how this does. I've never put mould release on the inside of my PJ moulds and (surprise) have not had lead in the vent lines with this mould. Do you know where I can get a lead wipeaway cloth?

Halfcock · Post by **Halfcock** » Thu May 27, 2004 5:53 pm

Taz: I have had the same problem. I use a welders stainless steel scratch brush. welder supply stores have them for a couple of $. The slang term is a ss tooth brush. The lead wipe cloths are available at most of the gun shops here (MT).

Paul

Tasmanian Rebel · Post by **Tasmanian Rebel** » Thu May 27, 2004 8:10 pm

Thanks Halfcock, will look this at our welding shop here. Hey man, I'm going to be in your neck of the woods in a little over 2 weeks at Quigley! Really looking forward to seeing that part of the country. I hunted in the states all around it in the 80's and 90's but never went across the border to MT. I'm getting there on the Tuesday before the match even to hopefully get some sightseeing in along with some practice on the targets. Hope to see you and some others who lurk on this board. Got me a real beaver fur cowboy hat yesterday to look like I belong out there but the jig will be up when I open my mouth and this southern slaaaang comes out.

Bill C. · Post by **Bill C.** » Tue Jun 01, 2004 7:39 am

Ooo...I'd be careful with a Stainless Scratch Brush!

You can get the same thing with Bronze Bristles...I'd go with that! The Bronze is harder than the Lead but not nearly as hard as the Stainless.

You can even find them at a Home Depot in the Tool Dept.

Jimilner4570 · Post by **Jimilner4570** » Thu Jun 03, 2004 8:52 pm

high percentage of tin and a low percentage of Antimony will cause the alloy to flow into the vent lines. The easiest way that I have found to remove this lead, is to heat the mould to casting temp, and using a soft cotton cloth, simply wipe the lead out following the vent lines.
Jim Milner

Tasmanian Rebel · Post by **Tasmanian Rebel** » Fri Jun 04, 2004 7:07 am

Thanks Jim. Will try this the next time. This stuff has been real hard in the past to get off-seems like it's nearly baked on. Interestingly, the problem has disappeared with a slower rate of pour and turning the mould upright slower. I'm not sure whats happening exactly but can't argue with the results.

RD146 · Post by **RD146** » Fri Jun 04, 2004 7:21 pm

Tasmanian Reble:

I'm betting I have your solution. When I began casting the Lyman Postell for my #3 45-90, the same thing was happening. It only got worse untill I discovered that I wasn't opening the mold blocks wide enough when dumping that big bullet. When it would tumble from the mold, the base of the bullet would strike the inside of the opposite mold half leaving a speck of lead. When I made an effort to open the blocks more, no lead on the inside. Hope this is helpfull.

Regards
From the Land of the Yankton Sioux
R. Dupraz

Tasmanian Rebel · Post by **Tasmanian Rebel** » Fri Jun 04, 2004 7:47 pm

Thanks RD, it is helpful. I have not thought of that and will check on this this weekend during another casting session.