lead under my sprue plate

[happyhunter]

I did my first casting session on Monday. Fun. Used a 2 cavity 358477 and a ladle.

When I hold the ladle against the sprue plate I get lead under the sprue plate. Makes a funny looking bullet, to be remelted.

When I hold the ladle up a bit and pour it thru the hole I do not get the lead under the sprue plate.

I had tried tightening the sprue screw while I was working but it still did it. The mold is used. Is the plate possibly bent? I understand the plate is a replaceable item, when does it get replaced? Any suggestions?

Thanks,
HH

[scrapcan]

if you have a flat plate and fine sand paper you can easily check for a warped sprue plate. take the plate off, remember to loosen the grub screw that locks the top sprue plate screw, and gently rub it on the flat plate and sand paper. I will save the straightening option if it is dished or warped until you know it has those issues.

another thing to look at is if the wave washer is on the sprue plate screw and on top of sprue plate. That should help with even tension on the plate.

[scrapcan]

opps forgot to mention what you are seeing has been referred to me as flashing. You might also see finning between the mould blocks.

[Marlin Junky]

Could be your sprue plate is too tight. Loosen the pivot screw until the plate will just barely open under it's own weight and hold the mold up to the light to see if the sprue plate is mating well with the block. No light should be visible between the plate and block. Sprue plate screw tightness should be set so a gentle flip of the wrist will open the plate on a cold mold.

MJ

[44man]

Plates are a pain!
Is there flashing or is it lead smears from cutting too soon?
I have as much trouble as anyone when I make a mold. I have tried the sanding and lapping stuff but it always takes a plate out of flat, edges cut sooner then the centers.
I make 1/4" stainless plates and once in a while I have trouble but I have found milling the plate again will fix it. End mill marks on the mold top and plate does a great job, less friction, better use of lube, less galling, better air venting, etc.
I will never make either dead smooth.
Some thin plates move up from the cavities when the screw is too tight. Even the wave washer as it turns can change the plate fit. Lap a plate and the point of contact at the screw can be lapped too much and tilt the plate.
I have never found a way to lap anything flat and keep it flat. A good mill file does better.
Try it, take a piece of precision ground tool steel and lap it with any motion you choose. Then put a straight edge on it towards the light. You will make a rocker!
Have more fun, put the steel on a belt sander!
The truth is that if you take a warped plate, put it in a padded vise and smack it with a mallet to straighten it, you do better.

[scrapcan]

You guys have it right, lapping is a pain.

The test with the flat plate and fine sand paper is just to see if there is a problem.

I should have stated that, sorry it was not meant to be the fix. If there is an issue with a warped plate, then the members here can help you fix it.

I think it is a problem with the pivot screw also, but the only way to know is as MJ and 44man suggest. Try out different tension settings.

[44man]

You guys have it right, lapping is a pain.

The test with the flat plate and fine sand paper is just to see if there is a problem.

I should have stated that, sorry it was not meant to be the fix. If there is an issue with a warped plate, then the members here can help you fix it.

I think it is a problem with the pivot screw also, but the only way to know is as MJ and 44man suggest. Try out different tension settings.

You have knowledge!
I use a few strokes to de-burr the cutters since the stainless demands I cut the tapered holes with a lathe cutter. This stuff EATS countersinks! (But I got it FREE!)
I also round off all edges or anything that can gouge a mold top.
The very best has been when I take a tiny mill cut to the mold top before putting in the cherry and a milled plate. I do love those marks!

[MtGun44]

So don't "pressure cast" - just pour it in!

Bill

[happyhunter]

I looked the mold over. The plate was lifted up, very stiff to open. I played with the screw some and got it sitting pretty flat. I'll try it this way and see how it goes. As I looked at it the plate does appear to have a slight curve to it.

MtGun44,
I will just pour it in if I continue to have probs.

Thanks,
HH

[Sonnypie]

I get lead under my sprew plate too.
It's a bullet.

[MikeS]

As you're using a 2 cavity Lyman mould, you might want to consider just buying a new sprue plate. Lyman sells a 'mould rebuild kit' and along with a new sprue plate it has all the screws used in the mould as well, so if your mould has any screws that are messed up from people using the wrong screwdriver on them, you can replace them with nice new ones! An added benefit of doing this is that the new sprue plates Lyman makes are thicker than the earlier ones, which makes them easier to use, and easier to keep at the proper casting temp. Midway sells the kit for under $10.00 I believe, and I'm sure it can be bought from other sellers as well.

[boltons75]

Looked up the sprue kit, 6.99 shipped from optics planet.

http://m.opticsplanet.net/lyman-mould-rebuild-kits.html

[beagle]

It sounds to me like your sprue plate hardware isn't right.

I've found over the years that you should have the sprueplate, a bellville washer flate side down, a lockwasher and then the screw. Bellville washers and lock washers are available from Lyman's customer service for $.25 a throw.

The bellville washer places evem bearing pressure on the plate. The lock washer applies even, adjustable pressure on the bellville washer and allows you to adjust the swing of the plate to your desires.

Clean the plate and mould top. Spray with moly spray if you have it, let dry and cast. If the plate is in any way warped, under heat it will straighten up and lie flat. Until this condition exists, drop lead instead of feeding from the spout.

I have never warped a sprue plate to the point where it was not recoverable and I've covered alot of ground in bullet casting./beagle

[gwpercle]

Just get the new mould rebuild kit , in fact go ahead and order 2 or 3 extra just to have on hand for when you get another used mould. Much easier than sanding , filing or milling...after all that the plate is now even thinner. I get better boolits when placing dipper spout up against the hole so I like my plates flat.

Another thing to try is after adjusting the looseness / tightness of plate... and thats hard to explain cause there's a fine line between too tight and not tight enough... hold a little pressure on the plate with the pouring spout pressed to the hole as you pour the lead in. Some times this helps but if plate is warped / bent nothing works..........gary