Sprue Plate Shape of Lee Molds

Cleaning up some Lee Molds that's been setting in my shop for several years. I didnt clean them up like I should have last time using them or while using. Wont happen again. But I found a small amount of lead and small fragments had stuck to the sprue plate and scoured the tops of the mold while in use, luckily not over the cavities. But the worse part is scoured is toward the end and its from the sprue plate shape and the way its rubbing against the mold when closing. It has a bow or arch to it. When closed I can hold it up and see light under the center portion between the mold and the plate slightly. When closing it closes easy until the end part of the plate is covering the mold, where the scour marks are.
Is this normal?
Also found one of the locating pins on the 2 cav pushed back into the mold a bit. I set it flush on a vice and tapped the pin back to where it should be with a punch when mold was hot. But I'll mostly be using the 6 cav anyway but trying to save the mold if I can.
I have a newer (not used as much) Lee 6 cav mold and it has a slight bow as well.
I heated them up with the pot last night and tried to wipe off any lead fragments I seen. Removed the plate from the 2 cavity and will clean them up with brake cleaner and a virgin rag, Reapply anti seize to the appropriate locations hope for the best.

I recently trued up the sprue plate on one of my Lee molds by polishing on a flat surface with oiled 400 grit wet or dry. It improved significantly. Also, (as described in a previous thread) silicon dielectric grease from the auto parts store really keeps the lead from sticking.

Wayne

I’ve sanded several sprue plates, even new ones. If sanding won’t do it you may have to try and straighten it by force. Perhaps a new one is available from Lee.

What's going on isn't normal . You MUST keep the underside of the sprue plate and the top of the blocks CLEAN ... just a small amount of lead will score deep grooves in the soft aluminum blocks and the buildup distorts the shape of the sprue plate ...bows it up .
When ever you see the first sign of smeared lead on underside of sprue plate or top of blocks ... STOP ... clean off all the lead smears and coat the clean surfaces with synthetic two stroke oil (apply a thin film with a Q-Tip) ... this will help keep the build up away .
The lead smears will keep building up and can ruin a mould ... much easier to deal with when first noticed , steel wool will remove it when thin ... wait and it will ruin a mould .
Gary

I added a few replacement Lee 6 cavity sprue plates to get a Midway order over $49 for free shipping. They also use to have Lyman replacements but that's been a few years back that I needed them.

Bill

I keep small Popsicle sticks cut square with diagonal cutters at end. When you see a booger build, dump mold and get mold good and hot and wipe scrape free. Then a touch of your chosen lube and get back to it.

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Originally Posted by gwpercle

What's going on isn't normal . You MUST keep the underside of the sprue plate and the top of the blocks CLEAN ... just a small amount of lead will score deep grooves in the soft aluminum blocks and the buildup distorts the shape of the sprue plate ...bows it up .
When ever you see the first sign of smeared lead on underside of sprue plate or top of blocks ... STOP ... clean off all the lead smears and coat the clean surfaces with synthetic two stroke oil (apply a thin film with a Q-Tip) ... this will help keep the build up away .
The lead smears will keep building up and can ruin a mould ... much easier to deal with when first noticed , steel wool will remove it when thin ... wait and it will ruin a mould .
Gary

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Ok I think that's what was happening, I will follow your advice to a T. I wasn't aware you put any lubricant on the top of the mold or bottom of the sprue plate?

Your saying a thin film of the aforementioned?
I called Lee today and explained the 6 cavity had very light use, only maybe 1 or 2 light sessions. They are going to send me another sprue plate for the 6 cavity. I told them the 2 cavity has had quite a bit of use and that's on me. Will primarily use the 6 cavity anyway, same casting.
It doesn't look bad but there is thin line that scoured on the 6 cavity, luckily not near the cavities, it looks like a small particle of lead imbedded in the aluminum that is rubbing on the plate for sure, I can feel resistance when I try to close the sprue plate so Ive been very gentle until I clean it. I heated the mold up to full temp and that small fragment does not flake off or melt. I even fanned it with a torch being careful. I'm gonna have to lightly sand it flush with fine paper or something.

I would think the lubricant on top of the mold or bottom of the sprue plate would transfer to the bullet castings...but I guess if its a very thin film it would not affect a thing. Will definitely do this, greta tips and info from everyone. Very much appreciated! Love this site!

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Originally Posted by Gtek

I keep small Popsicle sticks cut square with diagonal cutters at end. When you see a booger build, dump mold and get mold good and hot and wipe scrape free. Then a touch of your chosen lube and get back to it.

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Awesome tip right here, will take advantage. Thank You, great idea.

With respect to the lube on the sprue plate; the key is (as you note) a VERY thin coating! Using a "Q" tip, get just a tiny drop of two-stroke oil on one end. Wipe that over the plate and then wipe it off with a cloth etc. Some recommend using "never-seize" instead of oil.

Replacement parts from Lee are usually free, except for the shipping.

https://leeprecision.com/double-spru-plate.html

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Originally Posted by blackthorn

With respect to the lube on the sprue plate; the key is (as you note) a VERY thin coating! Using a "Q" tip, get just a tiny drop of two-stroke oil on one end. Wipe that over the plate and then wipe it off with a cloth etc. Some recommend using "never-seize" instead of oil.

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Ya I will do this for sure, makes sense in needs a touch of lubricant.

If you are concerned about lubricant getting into the cavities, don’t be. During casting, as soon as I swing the sprue plate to cut the sprues, I wipe the top of the mold (cavities are full) and the bottom of the sprue plate with the lubricant of choice. I recently switched from 2 cycle oil to copper Neverseize. I keep a bit of a rag damp with Neverseize and wipe it on. Works well and doesn’t take much. Just enough to see.

Sam Sackett

I lightly sanded down 2 small fragments of lead look like was imbedded into the top of the mold Tonight then clean them up put on a new sprue plate. Heated up the mold on a hot plate as well as a lead pot. Used antisieze on the pins and the pivot points. Then I did the suggested wipe down with two cycle oil. I cast about 10 to 15 rounds a lot of them were naturally no good from what I could tell from quick glance While dropping them out. I was out of time so tomorrow I will clean out the cavities really well and smoke the molds have another go with it. I appreciate everyone’s input.

It’s been a little bit so it will take me a while to get a temperature that is working well and to get back in the rhythm but it’s all part of the fun isn’t it…
I got my powder from Eastwood and I picked up a couple toaster ovens will give my go that that as well once I get some good drops.

I plug the cavities and lightly spray mold release on the top of the mold and bottom of the sprue plate.