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Mold Problem

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Had a custom lead jig mold made. The jig has a double barb. Received the mold three weeks ago and right out of the box could not get anything below the head to come out or it only partially came out. Spoke with the man that made the mold and he couldn't understand it as he poured a sample to mail me and that was just fine. Told me to return the mold and he would look at it. He made a new mold which tells me that it didn't work for him either. Just received the new mold with a sample already poured inside the mold. Looked great. Fired up the lead pot and immediately poured two good jigs but then everything went down hill after that. Again I can't get the bottom, or portion below the head to come out. I poured a couple of my do-it molds just to be sure my lead temp and volume was good and no problem. Anyone have any suggestions. I really want this jig. Thanks, Pop

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OK, I smoked the mold. Used a kitchen match because you get more soot. Smoked both sides twice, my mold was real hot. Still doesn't work. I am using a 4/0 hook, which is what I sent with the jig sample and which I was able to pour two good jigs on. However after smoking the mold I could use a 3/0 hook and the part below the head came out most times, but another problem came up in that I got alot of flashing in and around the hook eye. This tells me that the hook eye is for a 4/0 hook but the shaft portion of the mold is not quite wide enough. I don't want to use the 3/0 hook because in our experience you get alot of short strikes on the 3/0 and the 4/0 is quite noticably longer. The original manufacturer (OH yes I am copying) did use 4/0 hooks and recently went to 3/0 and that is why I am doing the mold. We couldn't figure at first why we were getting the short strikes and then we had two jigs together, an older one and a newer one and we finally realized why. When others experience the same thing, I think there will be a market for my jig with the 4/0 hook. Do you think I am right about the mold or might there be something else. Thanks, Pop

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It may be in the type of melting pot you are using? When first starting out i owned two of the Lee Pro Pot IV. They are good dependable pots.

Then i switched to the RCBS Pro Melt Pots i couldnt believe the difference in the temperature control of the lead and the pouring characteristics.

I use certain procedure when i am pouring jigs:

(1) Start with the room temperature. You need to control the temp of the air so that the room is as warm as you can get it while also keeping in mind you need ventilation. You can use a kerosene fueled blower type heater. Locate your bench in a corner somewhere so that the ventilation air from outside wont directly affect the area you are pouring in. Direct the heater towards that corner.

(DO NOT ALLOW PERSPIRATION TO GET NEAR THE POT.....cut the bands off a pair of socks and put them around your wrists just to be safe).

(2) Determine if you need a softer or harder type of lead alloy for the particular mold you are using.

(3) Get the mold hot by pouring multiple blank shots and allowing them to sit in the mold. This should heat the mold and also allow you to have something to check the hardness of the lead.

(4) Hold the mold under the discharge barrel of the pot in such a manner that you are "injecting" the lead into the mold as opposed to pouring it. This will hold heat around the barrel and the opening of the mold cavity as the lead enters the mold. The less air contact and travel distance between the barrel and mold opening the better it will pour.

(5) Set the plunger adjustment screw so that as much lead as possible will enter the mold just short of splashing out. The faster flow will force the material down into the collar area of the mold cavity. Also keep as much material in the pot as possible so that the weight will help push the lead into the mold cavity. This is the advantage to having a larger 20 lb. capacity pot as opposed to a 10 lb. capacity pot.

(6) If im still having problems i will empty a third of the pot and add much softer lead. Very seldom do i ever smoke a mold.

SORRY ABOUT THAT.....i must have started making this post right before the one directly above it was being made.

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OK, let me try to answer your post in the order it was written.

I do use a RCBS Pro Melt Pot. I have tried temperatures up to 850 degrees.

I pour in the garage which is attached to my home and it is insulated and heated. Working in my tee shirt. Perspiration is not a problem.

My bench is not affected by ventilation air.

The lead I use was purchased from Hanover Metal and is the purist soft lead you can find.

I pour about 6-8 blank shots before pour with hook. Then poured about 15 with hooks without a good jig.

I have tried holding the mold with the pot spout inside the sprue hold and every position imaginable.

My plunger screw has been changed today several times. At the present time it is just at splashing.

The mold is full to the top.

I just think it might be the mold.

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Pop,It has been awhile since I have poured lead and when I did temp and smoking cured any problems that I had.Since you said a 3/0 will pour and a 4/0 will not I believe it may be that the 4/0 is having lead set up/cool on it too quickly and plugging the mold or the 4/0 is creating a venting issue by fitting too good.

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I think the venting issue might be the problem and the hook fits too well. One other thing has been going through my mind, that maybe I got a bad shipment of lead in the respect I didn't get what I ordered the last time. I am going to buy some more lead and see if that makes a difference. Thanks, Pop

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This is just an opinion.

Pure lead is more sluggish, harder to pour than lead with some tin or antimony, but, those make it harder and harder to break off the spru.

I don't think your lead is the problem.

How long have you had the RCBS pot? I have a RCBS and after a while the spout becomes plugged with "dirt",. I think it is oxidized lead. I have a larger pot and it develops dross on top. Whenever I skim it off the top, if I squeeze the lead out of it, I get "dirt".

My pot will still pour, but it just doesn't flow right. So I take a small wire and hold with a pair of pliers and run it up and down in the spout from the underneath side. I do this while the lead it hot. I wear welding gloves when I do this because the lead could splash on you while doing this.

Sometimes I have to drain the pot, remove the rod and try to clean the hole.

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Pop take a gap gauge and put the .001 blade between the plate and see if it will fill out.This would give you some venting just to see if that is the problem.Then try .002 and see if it will fill out with out flash.If you want to smoke it real good get a small piece of rag dip it in kerosene hold it with a pair of needle nose pliers light it and smoke the mold.This is how we smoke the nozzles in the die casting industry

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Any machine shop would probably give you some shim stock.Online you can get shim stock or feeler gages at MSC,J&L and Enco.Probably all unecessary as some light tinfoil should proove theory.I don't think it would hurt to use .005" thickness.If this works then you could send the mold back for modification.I am curious why this mold was made from brass instead of aluminum?

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POP,

It is trapped air venting the mold is what you need to do.

Lets see if I post a picture.

You only do it on one side.

Make the first cuts with a razor to score them in place.

Then open with a triangle file.

Or a dremel if you are good with one.

Just a hair line in to the mold cav., rest of vent channel you can make larger.

They must exit to open air.

A vent down the hook channel is always a good thing.

I you do it right only air will excape no lead.

This pictured mold pours 100 percent good heads with little flash.

P.M. for more info.

venting_718.jpg

venting_718.jpg

venting_718.jpg

venting_718.jpg

venting_718.jpg

venting_718.jpg

venting_718.jpg

venting_718.jpg

1504_thumb.attach

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Maybe the mold is cut so that the hook is positioned in a tight spot not allowing for the lead to flow past it correctly. This could be why lead is not making it into the collar area and as previously pointed out there may be a coexisting problem with the cavity not being vented properly.

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