Sprue not cutting cleanly

[fouronesix]

It is a shoulder screw, the shoulder sets how high the screw sits when it touches the mould. I think I would have to remove the shoulder some, and I'm not messing with that.
A washer to keep some pressure on the sprue plate sounds like a great thing.

That sounds right. Some plate screws have a major diameter and a small section of minor diameter just under the screw head. The plate should be drilled to fit the larger diameter below the shoulder with a split washer or wavy washer taking up the space of the smaller diameter just under the screw head. You should try putting a small, light duty split lock washer or a light wavy washer in between the screw head and the plate to keep the plate pivoting on the larger diameter, below the shoulder. Of course if that is the situation?

[mjwcaster]

Just got a wave washer at the local hardware store (need to stop there more often to support them, found they have better prices than the big box stores on some items).

The sprue plate fits much better now, still not perfectly flat, now it sits a little high at the front of the mold, but much better than it did before.
And I think I may be able to make it fit better if I play around with the screw tightness and then lock it in place (install a set screw I think).

While looking the mold over I noticed that the sprue plate stop has already started gouging the mold on the side, it is really rough, no where near flat. Need to take a file to it.

Not sure if I will get a chance to cast with it tonight, but I think it will work better now.

Thanks for all the help.

Matt

[fouronesix]

Sounds like progress. Any bur or irregularity on the plate will gal, mar or gouge the mold block faces. For checking bow or warp, you can lay the plate on a metal straight edge or ruler edge and look for "light".

If you have a large, flat stone or diamond stone you can lay the plate on the stone and carefully lap it flat. If it has a convex bow in it- that's a little trickier and can be carefully taken out by laying the plate on a hardwood block, concave bow down, then tapping the plate with a large plastic mallet- followed by checking with a straight edge and lapping on a stone to true up the surface.

Use a plastic (delrin works great) or wood plate whacker or a gloved hand to open the plate when casting. IF whacking, use only enough whack to cut the sprue and try to hit the plate at a right angle.

[mjwcaster]

I got a chance to try some casting today.

The wave washer kept the sprue plate much closer to the mold top.

But I still had the same issue with it not cutting the sprue hole cleanly, same protrusion left.

I tried running super hot and then cold (turned the pot off and poured until the lead started solidifying).
So hot it took over 10 seconds or more for the sprue to cool down,and all the way to so cold the sprue solidified as soon as I poured it until I wasn't even getting lead into the mold.

I tried to get cut fast enough to get smearing, but only managed it once or twice. I would cut as soon as the sprue solidified.

So I tried leaving the sprue plate open to cool it down some and even taking a break from casting for a minute and then casting with a coldish mold that didn't give good fill out but still the sprue cutting issue.

Ran the sprue plate falling off loose to so tight I it wouldn't move without pushing it.
I did manage to make a lot of other errors, and my boolits looked much worse today than the last time since I was trying different techniques and never settled into a routine.

I started with a clean mold, but did manage to get lead on the mold faces and the top of the mold. Cleaning a hot mold off is fun, used a carpenters pencil (first wooden instrument I could find this morning).
Note to self- do not over heat the mold while trying to get the sprue plate up to temperature, I had the mold so hot that after 40 seconds or more of the lead not solidifying I had the bright idea to empty the mold. Got lead all over the mold faces, at least it cooled down as I tried to get it clean.

The sprue plate fits so much better with the wave washer in place, I really expected it to work. you can still see a little light between the plate and mold interface, but very, very little.

For what I want (short range pistol plinking) these would probably still work, but you guys have inspired me to achieve perfection, I know that home cast boolits can be perfect.
And my LLA just shipped so I have a few days to play with this before I get to start loading them any way.

For now I am taking a break, maybe taking my daughter to the gun club to shoot and fish a little.

I will try to locate a straight edge and check the mold over more later.

Matt

[R.M.]

I find that if I cut the sprue too soon, it will tear a small divot. Cut it too late, and it will leave a hump. There's a fine line were it cuts properly.

[mjwcaster]

Forgot to add, even though the one or two time I got smearing I still had the hump.
I didn't even get smearing when I cut too early and the sprue was not even cooled (only did that once or twice, then had to clean the top of the mold, lead from the melted sprue fell on it).

I'm sure I am missing something, but I am trying everything I can think of at the time, running from one extreme to the other.

It does bother me that I cannot get smearing, even when I cut way to early.
The only smearing I got was just a little of the hump smeared some, but the hump was still there.

Could the reason I don't get smearing be the same reason I am getting the hump?

Matt

[fouronesix]

May be normal. Even with a perfectly fit sprue plate there may be a tiny hump where the sprue is cut. Once you're comfortable with the plate fit and tension, you might try a little (very little) Bullplate or 2 cycle oil on the plate and on the plate screw. It will migrate when hot. Theoretically the alloy shouldn't stick to either the mold blocks or bottom of the sprue plate so when opening the plate to cut the sprue the only shiny spot and small smear should be the sprue cut on the bottom of the bullet.

The behavior of each mold, alloy and temperature is a little different so will have to experiment how much cooling time works best between pour and opening/cutting the sprue. Usually at the point where the alloy has "frozen" but still pretty hot- a couple of seconds to maybe 5 seconds. The idea is to maintain a rhythm where the mold temperature is held more or less constant for best fill-out. Not allowed to cool off too much and not so fast the mold continues to get hotter.

[mjwcaster]

I just took some pics of the boolits, will try to get them posted.

The hump is enough to not let the boolits sit flat at all, they lean over badly.

On my good pours everything else looks great, good fillout, the bevel on the base is nice and crisp, everything else is much better than I ever expected on my first try. Just this sprue issue is holding me up.

And I read so often here that the base is the key to an accurate boolit that I want to get it right.

On the good side at least I can remelt all my rejects, my initial smelting is cleaner than I expected, my stove is melting my little casting pot full of lead in 10-15 minutes or less and I am having fun and as frustrating as this is I know I will be casting great boolits soon.


Matt

[mjwcaster]

Pics of the sprue hump.

[websterz]

Those don't look any worse than some of mine. I just shoot them and don't give it a thought. I'm just punching paper and shooting steel. They are plenty accurate.

[Echo]

Those look fine to me - I'd shoot 'em! The 'hump' is at the center of gravity of the boolit, so will have no effect on boolit travel - I think...

[mjwcaster]

So I may be over thinking things?

I expect there to be a mark, but it is high enough to keep the boolits from sitting any where near flat.

I will try to get these better, but if I can't I guess I will feel better about loading them up and shooting them.

I am in the process of setting my reloading bench back up today and then I will load some of my store bought coated boolits and then try loading some dummies rounds with my cast boolits so I can be ready for my recluse lube shipment.

Matt

[fouronesix]

As long as the rest of the bullet surface is filled out, I too wouldn't worry a lot about the sprue nib as shown in the photos. It looks like some form of WW mix or harder mixed alloy. Casting with those harder mixed alloys many times do show the raised nib and/or "tear out". You can try sharpening the sprue hole (cutter) by carefully honing the bevel from the top. And, experiment a little with waiting a second or two longer before opening the plate and "whacking" it open with smaller blows.

[leadman]

The boolits look very shootable to me. If they bother you take the plate off and check it with a straight edge. I have had to flatten some of them on the anvil part of my vise with a big hammer. Do check the cutting edge in the hole that you pour the lead thru. Many times I have had to use a countersink I got a Home depot to finish this as they were left blunt.
Looks like you may have lead stuck to the mold, something is causing a divot on the edge of the driving band closest to the base. The edges of the base are important as this is where the gas is sealed behind the boolit when fired.

[SteveS]

Matt, you could go ahead and shoot those bullets but they look to be be of very poor quality. The bases look terrible.

I would suggest you get a casting thermometer so that you know at what temperature you are casting. I would also suggest that you melt down that alloy, flux a few times using both sawdust and wax. I might have missed it but what alloy are you using?

Take a look at your second picture. See the lube groove on the middle bullet? The entire bullet should look like that.

And yes, the bullets should sit up straight and true. Any that don't go in the reject pile.

[dragonrider]

There is one other thing I think you should check. Examine the sprue hole on the underside of the plate, that is, the small side of the sprue hole, it should be a sharp edge from the hole to the bottom of the plate. If not this could cause your problem. There should be no surface of the hole that is 90 degrees to the bottom of the plate. If so it is like cutting with a square piece of steel.

[mjwcaster]

Just to be on the same page, the boolits pictured are from my very first 5 pours ever, one day when I was just smelting, I was surprised I got anything that even looked like a boolit. They just happened to be sitting on my desk when I went to take pictures. The base issue was the same on them as the others.

On my first time actually casting many of the boolits came out looking much better, the bevel of the bases nice and crisp, good fillout, crisp line on the lube groves.

Todays batch looked like garbage, but I spent my time playing around with different techniques. They are back in the pot waiting to be melted down again.

I do plan on getting a thermometer, but with school and sports starting back up for my daughter my gun fund is non existent right now.

Matt

[mjwcaster]

I will look at the sprue plate again. It did have sharp unfinished edges on the bottom around the sprue holes that I cleaned up (they were starting to gouge the top of the mold when I first got it on the first couple of closings) by lapping it on some fine sand paper. Maybe the holes are dull now (or were from the beginning).

I am just trying to take little steps with the mold, I have a bad habit of doing too much too fast and ruining things. Try and fix something, cast with it and then try again.

[Silverboolit]

If that is a LEE mold, the first thing I do with a new one is to remove the sprue plate and sand the bottom down. I use a piece of 400 wet or dry paper on a piece of glass. You will be surprised at how uneven the bottom is. I have found that the plate is usually raised by the pivot hole and most of the holes. This also gives me a chance to put a radius on the outer edges of the plate and prevents a lot of galling on the mold tops.

[mjwcaster]

If that is a LEE mold, the first thing I do with a new one is to remove the sprue plate and sand the bottom down. I use a piece of 400 wet or dry paper on a piece of glass. You will be surprised at how uneven the bottom is. I have found that the plate is usually raised by the pivot hole and most of the holes. This also gives me a chance to put a radius on the outer edges of the plate and prevents a lot of galling on the mold tops.

This was the first thing I did to the mold, besides cleaning it.
Not sure if I lost the wave washer at this time, or if it never had one, haven't found one by my desk yet.
It definitely had rough edges, was scrapping the mold in just a few open/close cycles.
Didn't have a piece of glass, just used the edge of my desk.