mold is suddenly finning

I have a Lee 6 CAV 358-158-RF bullet mold that I've had for several years now that is suddenly casting bullets with fins mostly on the nose. I'm at my wits end with this problem. I've inspected this mold using magnification looking for lead or minute specks of lead, the mold seems to be very clean. I've checked the blocks for warping, don't find any warping. I changed mold handles, I've changed how I hold the mold while I'm pouring lead, careful to avoid the sprue cam lever while pouring lead. Nothing seems to matter, the mold is still, sporadically casting bullets with fins. I've cast single bullets to isolate which bullet cavity is the culprit, but the finning problem migrates after I identify one or two cavities as being the 'problem' cavity. Before I junk this thing, what am I missing? Oh, I also clamped the blocks together in a heavy vise with as much pressure as I could leverage for 24 hours to see if that would help. It didn't. Open to suggestion. This is really puzzling. This mold has in the past worked well, casting very nice bullets. Initially I did find lead in the mold preventing the mold blocks from closing properly. That's what started the problem. That lead contamination on the mold blocks is long gone, but the problem remains. Don't know what else to do, what else to check...JJ

Attachment 206642

There is either a price of Lead you are missing or the mold got too hot and warped.

Check in the alignment pin holes and around the pins.

Have you dropped the mold recently?

Quote:

---

Originally Posted by jeepguy242

Have you dropped the mold recently?

---

No, never. That said, I did carefully hone one of the corners of the mold that looked like it might have got banged a bit. Took a file to the face at that corner, but didn't seem to remove little, if any material. Nor can I see any light in the bullet cavities with the mold blocks lightly clamped together. JJ

Check pin alighnment. Check in the pin holes carefully for lead or crud build up making pins sticky or bind. Also run a q-tip around edges of cavity and blocks, pulled fibers will show burrs that may have came up. Set the block with female holes on a piece of glass and look for areas not touching. A good straight edge ( 6' steel ruler) may also show the low spots.

Are the boolits out of round? If so, then something is holding them open pins, handles off, lead stuck somewhere. Try to set the mold on a flat surface to close when casting see if that helps. What temp are you casting? If over 750 back it off. Try to cool the mold down about every third cast with a wet towel on the side Try to ladle pour, if top poring or don't pressure pour. Good luck to you.

Suspecting there is contact that you are not seeing, remove the blocks from the handles. Smoke the mate surface of both blocks with a butane lighter. Swing the sprue plate out of the way. Put the blocks together in the correct casting position with the sprue plate out of the way. First see if the blocks tend to "teeter" when pressure is applied to the top of the mold half and then the bottom of the mold half. That would indicate an obstruction that you need to find. Slide the two blocks in opposite directions a couple of times. Then try to rotate the blocks in opposite directions. Pull the blocks apart and inspect for any spot where the smoke has worn away and you will have found the high spot. If you do have block movement while doing this, then the pins might have moved and you need to look further. I have to wonder what you were trying to fix by smashing the blocks in a vise without knowing there was a need to do that. These are soft aluminum blocks and can distort under that kind of pressure. Let us know what you find from this procedure.

I have one that the sprue plate cam likes to try and hold open a bit if I don't watch out. Check to make sure you are not putting any pressure on that sprue plate handle and that the blocks stay closed when the sprue plate is closed.

also check for wear where the sprue handle goes against the mold it might be 'over camming' and pushing the blocks apart when closed.

Quote:

---

Originally Posted by texassako

I have one that the sprue plate cam likes to try and hold open a bit if I don't watch out. Check to make sure you are not putting any pressure on that sprue plate handle and that the blocks stay closed when the sprue plate is closed.

---

second this
when holding the mold closed for the pour use just the two handle that are on the mold. If you put any pressure on the sprue plate handle it will open the mold and you will get finning.

also had a lee that had an alignment pin come loose and keep the mold open

here is a question no one has asked...

have you used a dremil to polish the mold halves?

Quote:

---

Originally Posted by mozeppa

here is a question no one has asked...

have you used a dremil to polish the mold halves?

---

No, what would I polish?

Would you post some close-up pictures of the mold halves

Also, check the leading edge of the sprue plate where is fits around the stop pin for any burs that might be keeping it from closing properly.

Occasionally I will gently tap the handle (with a small leather mallet) where it contacts the mold with the mold fully closed to assure complete seating of the alignment pins/closing

Melt and Mould together got too hot.

You say you can't see daylight when they are closed with a firm grip on the handles...not touching the sprue handle?

This is my story and I'm sticking to it...
Melt and Mould together got too hot.

Been there...done that!

I'm guessing you have a loose alignment pin since you say it migrates from cavity to cavity, guess could be handles interfering with blocks also? I sure wouldn't clamp them in a vise and reef on it though, just doesn't sound right.:o

I dunno I have had some LEE molds in the past that putting them in a vice and hammering them into shape sure made me feel better about things.

Quote:

---

Originally Posted by runfiverun

I dunno I have had some LEE molds in the past that putting them in a vice and hammering them into shape sure made me feel better about things.

---

+1^^^^^

Had the same lee 6-cavity mold start to do the same thing the op pictured above. Got the mold extremely hot and put it in a vise and and tightened the vise up tight leaving the mold to cool. Doing so ended the finning. Used that mold for a couple years after that and ended up giving it away to a friend that bought a lever action rifle chambered in 357.

The only thing that can be happening is either you have some lead attached to the mold, lead in a alignment pin hole or the mold is warped all to heck.

This is why I don't buy and or use aluminum molds or sorry Lee molds.

I had the same problem with a .32-40 mold. I was using the LEE drip can for years and never had a problem...suddenly fins. I did the mold clean-up ritual and nothing helped. Started using the ladle and I have not had a problem since. I don't know what caused the problem but it's solved now.

Quote:

---

Originally Posted by jeff100

No, what would I polish?

---

sometimes people will polish the cavities with a dremil in hopes of getting better release on molded boolits when they stick in the mold halves....so they polish.

and when the buffing point spins near the edges where the 2 halves come together a tiny bit of metal can easily be
buffed away ...now you have finning.

I have one Lee mold that will fin unless I invert it and smack it with a wooden dowel every so often. I can't find any lead stuck anywhere and it drops great boolits so I don't care.

Sent from my SAMSUNG-SM-G930A using Tapatalk

"I have one Lee mold that will fin unless I invert it and smack it with a wooden dowel every so often" what he said!

My NOE moulds tend to be stiff at closing due (I think) to the blunt alignment pins so the moulds do not close easily even when sprue plate lube is applied to the pins. I just give the edge of the handle a gentle tap as I close the mould and that does it.

Could be that when you are working with the mould it starts binding a bit on a pin so the blocks don't quite fully close. Try sprue plate lube on the alignment pins and if that doesn't do it then try a gentle tap just as you close the mould halves.

Longbow

PS: I love my NOE moulds so don't misunderstand. It is just a quirk I solved and continue to do. The moulds cast perfectly as long as they are closed.

Quote:

---

Originally Posted by longbow

"I have one Lee mold that will fin unless I invert it and smack it with a wooden dowel every so often" what he said!

My NOE moulds tend to be stiff at closing due (I think) to the blunt alignment pins so the moulds do not close easily even when sprue plate lube is applied to the pins. I just give the edge of the handle a gentle tap as I close the mould and that does it.

Could be that when you are working with the mould it starts binding a bit on a pin so the blocks don't quite fully close. Try sprue plate lube on the alignment pins and if that doesn't do it then try a gentle tap just as you close the mould halves.

Longbow

PS: I love my NOE moulds so don't misunderstand. It is just a quirk I solved and continue to do. The moulds cast perfectly as long as they are closed.

---

Yes, I've lubed my alignment pins and sockets. The mold seems to close with no effort. I also have NOE molds, I love them, they cast excellent boolits. That said, I find them difficult to open, usually taking several cycles of opening pressure, closing pressure until I finally get it worked open. I lube the heck out of this alignment hardware too. They close fine, just the opening that is difficult. I think it's the boolits themselves causing the binding when trying to open and I just live with it since the mold casts such perfect boolits. JJ

Quote:

---

Originally Posted by Grmps

Would you post some close-up pictures of the mold halves

Also, check the leading edge of the sprue plate where is fits around the stop pin for any burs that might be keeping it from closing properly.

Occasionally I will gently tap the handle (with a small leather mallet) where it contacts the mold with the mold fully closed to assure complete seating of the alignment pins/closing

---

Here you go, dang if I didn't notice a small piece of lead near one of the alignment pins as I was prepping the photo. JJ

Attachment 206841

Quote:

---

Originally Posted by runfiverun

I dunno I have had some LEE molds in the past that putting them in a vice and hammering them into shape sure made me feel better about things.

---

Ditto done the same thing and it trued them.

Have you held the empty mold up to a light with the halves closed and been able to see light anywhere they meet?

Quote:

---

Originally Posted by vzerone

Ditto done the same thing and it trued them.

Have you held the empty mold up to a light with the halves closed and been able to see light anywhere they meet?

---

Yes, I have inspected the mold under strong light and do not see any light breaking through. When I posted the picture of the mold I thought I saw a small amount of lead near one of the alignment pins. I looked at the molds to clean off that lead and found no lead, just a small area near the pin that was marred from a deposit of lead that had been previously cleaned off, scarring the mold face in the process. I took another close careful look at the mold faces under good light and high magnification and I now believe that there is some damage to the face of one of the mold blocks at the nose of a couple of the bullet forms where lead would probably flow no matter how tightly the blocks are held together. The damage is very slight, but it's there. In the past I did find some lead splatter on the mold faces that I had cleaned off with a dental pick. The finning started some time after that. I now believe the mold has been damaged by casting with that lead spatter on the faces and what's done is done, I will have to either live with trimming off the fins (done that, don't like it) or replace this mold. Many thanks to everyone who took the time to help me, I learned a lot about molds and inspecting molds and what to look for. Although it seems I'm not going to be able to fix this mold, this thread has been really helpful to me. Lesson learned, don't keep casting when you know you have lead splatters on the face of the mold blocks. - JJ

Quote:

---

Originally Posted by jeff100

Yes, I have inspected the mold under strong light and do not see any light breaking through. When I posted the picture of the mold I thought I saw a small amount of lead near one of the alignment pins. I looked at the molds to clean off that lead and found no lead, just a small area near the pin that was marred from a deposit of lead that had been previously cleaned off, scarring the mold face in the process. I took another close careful look at the mold faces under good light and high magnification and I now believe that there is some damage to the face of one of the mold blocks at the nose of a couple of the bullet forms where lead would probably flow no matter how tightly the blocks are held together. The damage is very slight, but it's there. In the past I did find some lead splatter on the mold faces that I had cleaned off with a dental pick. The finning started some time after that. I now believe the mold has been damaged by casting with that lead spatter on the faces and what's done is done, I will have to either live with trimming off the fins (done that, don't like it) or replace this mold. Many thanks to everyone who took the time to help me, I learned a lot about molds and inspecting molds and what to look for. Although it seems I'm not going to be able to fix this mold, this thread has been really helpful to me. Lesson learned, don't keep casting when you know you have lead splatters on the face of the mold blocks. - JJ

---

You know if you feel it's that far gone, you might warm it up a little and clamp it in a vise. Nothing lost if you're going to replace it.

You know I've had a number of the Lee molds over the years and even though I say they are the softest aluminum I've ever seen, I've gotten some of the most accurate bullets from them. They are very affordable and once you doctored them up and take care of them they can las a long time.

I wish you luck with whatever you do.

Quote:

---

Originally Posted by vzerone

You know if you feel it's that far gone, you might warm it up a little and clamp it in a vise. Nothing lost if you're going to replace it.

You know I've had a number of the Lee molds over the years and even though I say they are the softest aluminum I've ever seen, I've gotten some of the most accurate bullets from them. They are very affordable and once you doctored them up and take care of them they can las a long time.

I wish you luck with whatever you do.

---

I love my Lee molds. They usually work great for me. This one is a problem because I abused it through my ignorance. Not the fault of Lee or the mold. Just saying...JJ

Quote:

---

also check for wear where the sprue handle goes against the mold it might be 'over camming' and pushing the blocks apart when closed.

---

Then for starters, close the mold block and with a tight squeeze and plate out of the way, hold the mold up to a bright light to determine where any light can be seen in the cavities

Those are some clean blocks. if the faces are clean I'd suspect an alignment pin.

clean and dry the mold. hold it together and hold it up to a light pinching it together. rotate it around at all angles to see if you can see light through it

If you can't tap the offending pin back a smidgen, clamp the mold halves together between two flat solid blocks of wood might re-seat the pin(s),.

.

Any new developments on this post yet? OP...what have you done to correct the problem thus far?

How do you monitor the pot temperature? Where do you try to keep it?

Do you hold a medium firm grip on the mould handles as you fill the cavities?
Do you incorporate the sprue handle in your grip as you fill the cavities?...You should not...

Quote:

---

Originally Posted by OS OK

Any new developments on this post yet? OP...what have you done to correct the problem thus far?

How do you monitor the pot temperature? Where do you try to keep it?

Do you hold a medium firm grip on the mould handles as you fill the cavities?
Do you incorporate the sprue handle in your grip as you fill the cavities?...You should not...

---

No light can be seen through the mold using very bright LED light and rotating the mold blocks as I inspect them under the light. I do not hold the sprue handle as I fill the mold, I use moderate pressure on the two mold handles as I pour. I DO use a thermometer in my pot and of late have been casting at 600-650 degrees F.. I used to cast hotter but once I started really paying attention to my alloy composition, I've been able to dial back the temperature of my melt and cast at cooler temps and still get good fill out. Nice shiny boolits are the result. I did clamp the blocks together for a 24 hour period but I did not preheat the blocks before clamping.

My last ditch effort here will be to try ladle casting with this mold. If I still get finning while ladle casting, I'll try heating my mold and clamping under pressure again and then try ladle casting one last time. If that fails to fix this, I'm DUN.

I had a Lee mold that won't close completely--sliver of light between the halves

Each time I would close the mold I would turn it 90° and tap the mold sides together which would close the mold completely.

After doing this 20 or so times the mold came back into specs and has worked without problems from then.

another quick possible fix came to mind:
remove the handles and flip them over, reinstall. Could be they are canting a bit when closing.

or try another pair of handles. If mold was dropped could have twisted them


and there is always the option of sending it to another caster and letting them see what results they get. Cost of postage would be about it

Quote:

---

Originally Posted by jeff100

Yes, I've lubed my alignment pins and sockets. The mold seems to close with no effort. I also have NOE molds, I love them, they cast excellent boolits. That said, I find them difficult to open, usually taking several cycles of opening pressure, closing pressure until I finally get it worked open. I lube the heck out of this alignment hardware too. They close fine, just the opening that is difficult. I think it's the boolits themselves causing the binding when trying to open and I just live with it since the mold casts such perfect boolits. JJ

---

I had that problem, bad, with an NOE mold, so I called, and Swede suggested using a chamfer reamer to touch to alignment inserts. Did, no joy. But I had another reamer from my electronics days that has a sharper included angle, and tried it. Worked. Mold opens and closes like a champ, no play when closed.
My take on your problem is some kind of obstruction in the locator holes/inserts...

No light can be seen through the mold using very bright LED light and rotating the mold blocks as I inspect them under the light.
------------
You may be doing it right, but not saying it right. Close the blocks, and hold them between you and a light source. Maybe just hold them in front of a window and then look to see if there is any light coming through between the block halves. Also, it was suggested that you check to be sure the handles are not damaged. I have had the hinge bolt loosen up which will allow the blocks to be misaligned when closing.

You are checking for a warp at room temp that might appear at casting temps. I am of the opinion that Lee molds are as great as BIC lighters. They are useful, inexpensive and we should not be overly concerned when they are dead.