Vent lines

[cigg52]

Just bought my first mould. It is a Lyman 40 cal. I notice that the two top (base of bullet) vent lines stop short of the edge of the block. I have not had a chance to cast yet and just wondering if this could a problem ? Thanks

[grouch]

It could be, but unlikely - many molds were made with no vent lines, just depending on leakage for ventilation. Some of them worked fine. I doubt that 1 or 2 missing vent lines will make any difference. Suggest you try it.

Grouch

[cigg52]

grouch thanks for the reply, hope to cast this weekend.

[sundog]

Every Lyman, RCBS and SAECO mould I own has been 'worked over'. Not a doubt in my 'lil ole pea pickin' mind' that it helps. Each edge of both halves are carefully dragged across a fine stone one or two strokes. It removes unseen burrs which could prevent proper closure. Plus one the top, facing edges, it produces another vent line under the sprue plate. Too clean vent line on a block, I use a single edge blade with a corner broke off and carefully swipe the line with pointy, broke edge. Redo as necessary. The bottom side of the sprue plate is lightly honed after running a reamer in the sprue hole (from the top) by hand. Also, chamfer the spru plate edges. All of this takes only a few minutes, and as far as I'm concerned improves performance leaps and bounds. Also, the thicker sprue plates work better on Lyman moulds that the older thin ones.

Is it necessary to do all that? NO. I enjoy casting so, I don't mind spending a little time working on my tools. I also enjoy cutting fire wood. One of my latest projects has been hanging a new handle a very vintage double bitter and reshaping and sharpening it (all by hand). Also worked over a couple of vintage chain saws back to operational status.

Point is, having good tools makes enjoyable past times even more so. sundog

[Bent Ramrod]

cigg,

Many of my Lyman molds have a vent line that stops 1/16" or so ahead of the alignment pins or holes. Sometimes this is no problem, sometimes I have to extend the line on the one side to the alignment hole with an engraving tool or a triangular file. Each mold is a law unto itself; so some casting and then see what is needed.

[cigg52]

Thanks guys, I just recieved my first lead melter in the mail today, it's a Lee 20lb magnum dipper. I had some sheet lead that I smelted a while back and some tin , well I think it was tin from the scrapyard. Mixed 10lb. of lead to 1/2lb of tin. Heated it to 800+ deg. and casted 5 or 6 bullets just to try it out. the bullets were a little wrinkled, and the bases were a little rounded. this is a single cav. mould. How many bullets do I need to cast before the mould is up to temp. ?

[MT Chambers]

For an iron mould....keep casting, for an alum. mould it should be ready...I use a hot plate to preheat my moulds.

[cigg52]

MT CHAMBERS- I know this might sound dumb, but how do you heat your mould on a hot plate ? do you just sit the bottom of the mould on the hot plate and for how long ? or put some kind cover over it to heat it like it was in a oven?

[grouch]

Try scrubbing your mold with dish detergent ,hot water & an old toothbrush. Make sure it's dry, and 10 - 15 bullets should start to get you results. It'll be a lot easier in subsequent casting sessions. The common problem with a new mold is oil in the cavity, which vaporizes and causes most of the wrinkles you're experiencing.

Good luck,
Grouch

[cigg52]

grouch- Thats sounds like a good idea, Iwill give it a try Thanks,cigg52

[martinibelgian]

Ditto on preheating on a hot plate - with a bit of experimenting, you'll need just 1-2 rejects before you are producing. I do it all the time....

[cigg52]

How long do you keep the mould on the hot plate ?

[threett1]

cigg-just leave it on for a few minutes. No set science to it. I leave a corner of my molds in the melt to heat them up. Most pots you can prop them in there some way and go putter around for a few minutes. Aluminum doesn't take long. Iron or steel a little longer. Usually the alum ones 5 or so minutes with the corner in the melt.