Molds not closing properly?

[xxRosenbaum126]

Hey everyone! Brand new to casting and made my first attempt earlier today and nothing went smoothly 😂. I started to figure things out and ran into an issue I've yet to resolve. The lead appears to be leaking all the way down to the guide pins making them unusable. Any help is greatly appreciated. Using lee 2 cavity 230gr rn

[kevin c]

So you know already that the “fins” are there because molten lead is getting between the mold halves.

With the mold closed, hold it up to the light and look into the cavities. Do you see any light coming through a gap between the mold faces?

Not closing could be from several causes: lead, dirt or other damage on the mold faces, proud or dirty alignment pins, binding handles, warped blocks. Sometimes there can be progressive lead build up once a gap is present, which, with enough time, can turn a little issue into a big one.

I’ve also overheated the mold or alloy; in that situation, unless you really clamp the mold halves together tight until the alloy hardens, even if the mold halves close without a gap, lead will leak out through the vent lines. What you have, though, looks like more than an overheating or underclamping problem.

ETA: Welcome to the forums!

[xxRosenbaum126]

I'll take another look tomorrow morning. There is a bit of light coming through the center of the block. I did clean the mold faces earlier and inspected the pins. Everything looked clean and without damage. However these are old used molds that were just given to me by a friend, so its possible theyre warped.

[243winxb]

If warped, this will not help.

Lee has tip & helpful info. https://support.leeprecision.net/en/knowledgebase

[Dusty Bannister]

If this is an old used mold, then you may find that the blocks are pretty loose on the handles. Lee has no adjustment feature for that. It will be helpful to follow the suggestions of 243win and be sure the mating surfaces are clean and smooth and lightly lubricated. It might be beneficial to set the blocks lightly on a clean flat surface and then close the blocks so all alignment surfaces can easily move into their correct position as you firmly close the molds. What I am seeing is that the blocks are being held apart by either some debris in the mold, or you have not correctly lubricated the contact points so they can slip into position. Use care and the proper lube on those surfaces because excessive lube or the wrong lube can create even more problems.

Many different casters use different lubricants so expect others to make suggestions. I have no CLP on the bench, so have never used it. I use a synthetic 2 stroke oil, very sparingly to avoid getting oil in the cavities. The application should create a shine on the surface, not a wet surface or the oil will run and #%@ results. Good luck.

[Rickf1985]

I have a Lee two cavity that will do the same thing for the reason Dusty mentioned. There is a LOT of play between the molds and the handles and they do not line up very well when you close them. What I do is to just set the front edge of the mold on the table as I close it and this lines up the blocks as they close. If you have a metal table then get a short section of wood and use that to touch down on and you will not loose much heat. It does not take much, all you need is to touch the front edge on the wood to align the blocks when they come together and the alignment pins will do the rest.

[lastditch]

Check to see if you have old dry lube around alignment pins base. Look for a burr along mold edge.