Lyman Mag 20 disassembly/cleaning?

[jason280]

I'm slowly getting stuff together to start casting, and just snagged a Lyman Mag 20. It had just a little surface rust in the top of the pot, so I started disassembling to clean up the pot. I have the bolts out, but can't get the rod lever stud out...I believe it's screwed in from under the pot lip. Main thing is, I can't get the pot out of the housing...I can get it about an inch or so lifted, but that's it. The drain is also clogged, won't let the shut off rod all the way down.

Any suggestions on how to get the pot all the way out and drain cleaned out?

[Kraschenbirn]

You've disassembled about as much as needed for simple cleaning. So far as the inside of the pot, soaking with penetrating oil followed by a wire brush and a rinse with brake cleaner spray should be adequate. That 'blocked' drain is most likely just some hardened alloy from the last time the pot was used and you may be able to melt it out with the careful application of a propane torch. If not, you can remove the base (three bolts on the bottom) and the mold guide and drill the blockage out from the bottom side (don't recall, off-hand, the correct drill size). Finally, you may want to lap the valve stem/seat but beyond that, you should be good to go.

Bill

[jason280]

The seat is likely the culprit, I'll have to likely brush it out. I hit it a little while with propane, may have to heat it a little more. I thought about simply turning it on and letting it heat for a while, but wasn't sure how long you could run them empty (or if it even matters).

As far as the bolts, I'm still not sure how the pot itself bolts into the frame/housing. I'm afraid the nuts that hold them in place have fallen inside the frame, which may be an issue...I pulled the cover off just a bit, and its packed tight with some sort of heat resistant insulation. Not sure I really want to have to repack it all, but I may have to!

[Kraschenbirn]

1) Not good for heating elements to run an empty pot for any length of time. When casting, I try to keep pot at least 1/4 full and when changing from one alloy to another I unplug pot before draining whatever is left into an ingot mold.

2) If you (absolutely!) have to remove the top cover, take care to disturb the insulation as little as possible otherwise you risk disarranging the heating element.

And, don't ask how I know about these things 'cause I've been there, done that, got the T-shirt maintaining/repairing an old Saeco 24 for twenty years.

Bill

[jason280]

Ok, this thing has just about defeated me. I have the drain cleaned out the best I can, and have heated it with propane & MAPP. Whatever is left, must have alloyed to the point I can't easily melt it. The shut off rod stem still won't slide all the way through, so the drain will have to be drilled out. What I can't figure out, and I couldn't get Lyman to answer, is the diameter of the drain hole (and whether it's that same diameter the entire length of the spout). I can't tell is the drain is angled/needled like the end of the shut off, or if it's simply one size all the way through. Basically, is the seat portion that seals just the larger shoulder of the rod? The diameter of the shaft is 3/16 just below the shoulder, if course it tapers to a sharp point.

Any ideas?

[Ranger 7]

On the Lee 20 pound bottom pour pots, the hole is 5/64".
get a hand vise, insert drill bit and using the weight of the vise, rotate till through.
Then get some valve grinding compound, put a dab on the end of the shaft and again using the weight of the vise, rotate.
Clean out with pipe cleaners, water.
Should sole your problems, including dripping.

[Kraschenbirn]

Drain diameter is NOT full diameter all the way through!! From your pic (Post #5) that valve is clean as mine has ever been since it left the factory. Bevel on the stem seats onto a corresponding taper inside the valve body...just like a intake/exhaust valves of a 4-stroke engine. Major diameter of the valve stem is a few thousandth smaller than the inlet side of the valve body; minor diameter (needle portion) should be just a slip fit into the outlet. When needle is fully seated, it should NOT protrude below outlet.

Bill

[jason280]

Makes sense, but I swear I remember it going all the way through...guess it could have been some old stuff. I've tried calling Lyman, but the tech guys are out this week with the Shot Show.