Sprue not cutting cleanly

[mjwcaster]

I am a new caster (first real casting session today after finishing up smelting the last of 250lbs of range lead, cast 10 boolits the other day just for kicks while smelting).

I have tried searching and found some info but want more input as I can't seem to get the boolit cool enough to get a clean sprue cut.

The sprue is not cutting cleanly on the base of my boolits.

The base of the boolits looks great except for the sprue issue, this is a beveled base boolit and the bevel looks great (well most of the time, not all my pours were good ones).

It is not smearing, just leaving a tit the size of the sprue hole.
Have not had any smearing at all.
Actually very few issues, except for the sprue.

I have played with temperature, if I let the mould cool enough after pouring that I have to hit the sprue plate (with my hand, no sticks or clubs for me) it was cleaner once, still not perfect, but every other time even when I tried to let it cool for at least 10 to 15 seconds it still left a tit, and was hard to open the sprue plate.
Tried letting the mould cool down, still had the sprue issue, plus fillout issues.

Lead- range scrap, fluxed and cleaned surprisingly well ( I thought).
Mould- New Lee 452-230 TC, scrubbed with tooth brush, dish soap and boiled.
Casting on coleman 2 burner gas stove and 2 quart pot.
Temperature- unknown, no thermometer yet and the stove varies depending on how much the tank is pumped up. Noticed things seemed to be getting cooler, flame smaller, throttle wide open and had to pump up the tank again.
Preheat- no hot plate, just dipping mold in lead until it stops sticking to the sprue plate, then pouring and dumping fast until I get good fill out and then trying to cast boolits.

Right now my sprue seems to be cooling in 3-4 seconds and I wait a few more seconds, maybe 6-10 total. A few times I have really waited, 15 seconds or so, but the sprue plate is hard to open, have to hit it a time or two with my hand.

All I have done to this mold is clean it, tried to lap the sprue plate a little with fine sandpaper and applied a little anti seize to the sprue plate.
I had the sprue cutting issue on my first 5 casts the other day and then applied the anti seize for todays session.

Other than the sprue issue I am very happy so far.
The rear cavity sitcks a little, need to help the boolit out by hand, but that can be fixed.

All other issues have been operator related-
Some issues with fillout and pouring huge sprues or not enough.
Got some lead on the face of the mould twice, so got finning on the boolits. Need to keep a wooden stick out by the casting station (have a popsicle before casting).
need to get a better ladle (going to modify my spoon).
set up a better work area, too low, not enough room, horrible workflow, dropping sprues and boolits in same bin, dropping boolits on each other, etc,
Stop dropping boolits on other boolits, I have a lot of dented boolits (but I was just farting around today, trying to get as many cast before the rain and get a routine down)
get more experience casting, I still don't have a routine.

Next on my list is an electric pot, having to stop casting because the rain started sucked.
And I couldn't cast/smelt the last few days because of the rain (and then work)

This is fun I am hooked, really cool having a couple of hundred boolits sitting here on my desk that I made, even if I will be remelting them.

I can't stop playing with them.

And the boolits seem to be averaging 234-235 grains.

Thanks,

Matt

[DrCaveman]

Pics? A tit? And you cant stop playing with them? That sounds a bit racy :)

Usually i get more of a tear, with a bit of the boolit base getting torn out as i cut the sprue (when things arent going so well). Im still unclear about this issue too, since a lot of my 'best' boolits have some tearing, despite excellent fillout and perfectly round bases

Hopefully the masters will chime in

[John Boy]

Adjust the sprue screw so the plate swings open from the top of the mold when you flip the mold with your wrist. Then when you have waited your seconds for the sprue puddle to frost, cut the puddle with a downward motion of the sprue plate

[Beagle333]

Cut the sprue sooner. Cut it somewhere between slow enough to leave a tit and fast enough to smear. Find your happy zone in there.
Good luck!

[mjwcaster]

Yes I couldn't figure out how to phrase it better, and I tried.
Pictures would be nice, need to figure out the macro setting on my camera and then how to post a pic here (working on that now).

And most of the issues I found were tearing related, not what I have.

I want to get this figured out, all the other issues I have had I think I know how to fix.
And I want to pour more boolits tomorrow, LsStuff was supposed to be pouring my order of recluse lube today.

I want to be shooting my own cast boolits next week.

Matt

[country gent]

With a good light behind it look at the sprue blocks junction and see if light shows thru, if so is it a even line? Spure may be a little on the loose side. Make sure there are no burrs around the screw hole cocking or holding it up out of alighnment. Also check around the hole in the sprue plate. A straight edge held along the bottom of the sprue plate with light behind it will show if plate is warped or bent. If it isnt to excessive try some and it may not affect accuracy all that much. Im assuming your ladle casting from your post above. Another trick to try is to hold mold at 90* insert ladle and roll upright together to fill mold pressure pouring the metal into the mold and letting the wieght of the ladle rest on the sprue plate.

[mjwcaster]

Adjust the sprue screw so the plate swings open from the top of the mold when you flip the mold with your wrist


Forgot to mention that the sprue plate swings open freely, it actually falls open on its own when the mold is empty if you turn the mold sideways.
The sprue plate screw is tightened down as far as possible, checked it again during my casting session, thinking that the plate was too loose.

[mjwcaster]

Cut the sprue sooner. Cut it somewhere between slow enough to leave a tit and fast enough to smear. Find your happy zone in there.
Good luck!

Never did have it smear, I will have to try it even faster.
Now I want to run out and set up some lights so I can try it right now.
If I hadn't had a Captain and coke (large captain) I might just do it.

No, I'm not hooked, I can quit any time I want, I just don't want to yet.

This site should come with a warning label, most addictive thing I've found.

[Frank46]

I've found that some sprue plates do not have a good cutting edge. I usually take a center drill as used on a lathe and set up the plate in a vise with the bit in a drill press then recut the hole so's it has a sharp edge. If any nurrs on the mold side just put a piece of 320 silicon carbide paper on an old surface plate i have and sand until all the burrs are gone. Frank

[mjwcaster]

Just go the mold out of the garage.

The sprue plate does NOT sit even on the top of the mould.

It touches the front of the mould (furthest from the screw) and thats it.
Major light under the sprue plate.
The lip on the screw seems to be holding it up, if I push the plate down it sits better, but then when I open and close it, again it is cockeyed, not touching the mould at all except for the very front of the mould.

I do not have a good straight edge, but with the sprue plate screw removed the sprue plate sits fairly flat on the top of the mould (hits in the center of the sprue plate with a little light visible both front and back, but no where near the gap that is has with the sprue plate screw in).

The plot thickens.

[websterz]

Is there a wavy washer UNDER the sprue plate by any chance?

[mjwcaster]

Is there a wavy washer UNDER the sprue plate by any chance?

No washer, just a shouldered screw and the plate.

[websterz]

Just checking the obvious. Does the screw seem perpendicular to the mold block? It could be that it is tapped crooked. Stranger things have happened. Do you have another mold of the same design you could swap sprue plates with?

[mjwcaster]

Just checking the obvious. Does the screw seem perpendicular to the mold block? It could be that it is tapped crooked. Stranger things have happened. Do you have another mold of the same design you could swap sprue plates with?

Screw seems perpendicular (as far as I can tell with the old MKII eyeball).
No other moulds, this is my very first one.
Almost ordered one for 380 the other day, put it on my wish list for now.

[fouronesix]

Had the same thought. There should be either a split lock washer or wavy washer between the screw head and the top of the sprue plate. They're not to lock the plate screw in place- those washers are there to maintain a small amount of down tension on the sprue plate. If that screw shoulder is under the plate then that is not right. That would keep the plate from sitting flat on top of the mold blocks.

Also, make sure to loosen the sprue plate screw set screw (if present) before adjusting, then re-tighten after adjusting. The sprue plate should sit flat on the top of both mold blocks and should be neither tight nor loose- experience and trial and error will determine amount. Too loose and it may cause uneven bases. Too tight and it may damage the mold.

There should be no teat where the sprue hole is cut. There should only be a shiny smear.

[country gent]

Try cutting a washer from a tablet back ( card board ) and intall it under sprue plate screw head and see it the added compresion helps to get the plate down. If so the local hardware should have wave washers or belleville washers in a size to fit under the head and provide tension to the plate. You will have to set tension and try. Adding the thickness of the washer under the shoulder bolt may keep it from fully tightening up. If this happens a set screw to lock sprie plate screw will need to be installed

[mjwcaster]

Had the same thought. There should be either a split lock washer or wavy washer between the top of the sprue plate and the screw head. That's not to lock the the plate screw in place- those washers are there to maintain a small amount of down tension on the sprue plate.

Also, make sure to loosen the sprue plate screw set screw (if present) before adjusting, then re-tighten after adjusting. The sprue plate should sit flat on the top of both mold blocks and should be neither tight nor loose- experience and trial and error will determine amount. Too loose and it may cause uneven bases. Too tight and it may damage the mold.

There should be no teat where the sprue hole is cut. There should only be a shiny smear.

After seeing the sprue plate sit funny I thought that a washer on the top of the sprue plate might do the trick, and a wavy washer sounds just right.

Is there supposed to be one on the new Lee 2 cavity (the sprue plate screw is the newer LH threaded).

There is no set screw on the sprue plate screw.

[.22-10-45]

I wonder if that sprue plate screw is too long & bottoming out in hole? Might try removing & file or grind small amount off end?

[Le Loup Solitaire]

Sometimes the sprue plate/cutter needs to be touched up so that the edge around the pouring hole is a little sharper; this can be done by lapping the underside on a piece of plate glass with some fine valve grinding compound in between. The edge does not have to be razor sharp. When the cutter is back on top of the blocks it should not be tightened down-tight....when the mold is tilted the cutter should swing freely on its own weight. No slop up and down. This will also allow air to escape when the alloy is poured. A generous sprue puddle is necessary to allow for shrinkage as the bullet sets up, otherwise you risk the possibility of a void (sometimes not visible) under the base of the bullet. If the blocks and the cutter are dead flat there should not be light visible between them...molten lead can go where there is light/space and you can have uneven bases, teats or smears. 1%-2% tin helps make sharper and better filled out bullets. A good mold lube also will help. This all may sound like a lot of hoop-lah to juggle, but with a little practice it becomes second nature and you will get better bullets. LLS

[mjwcaster]

I wonder if that sprue plate screw is too long & bottoming out in hole? Might try removing & file or grind small amount off end?


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.

[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]

113623113624

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.

[Yodogsandman]

Your range scrap might also be too hard. I recently read comments from another member stating that most range scrap was high in antimony and low in tin. He responded to the PO to mix the clean range scrap with pure lead to dilute the antimony. Then add 1 to 2% tin to aide in mold fill out. Check the threads in the lead alloy section on range scrap for more detail.

http://castboolits.gunloads.com/showthread.php?250164-Mixing-range-lead-and-COWW-to-get-best-alloy-how-much-of-each

[mjwcaster]

I got smearing, finally.

I sharpened the inside of the sprue holes up the other day with a round file.

I finally got a chance to do some test casts today and the bases are looking better.

I managed to get smearing and tear out at the sprue hole, never could get that before.

Funny that I am happy that I managed to get another fault.

On almost all the boolits the bases look much better, I even got some fairly smooth ones, that I never could before.

I ran the heat wide open, fluxed and started casting as soon as it melted and then kept casting with the heat on, turned the heat off when it was taking 10-15 seconds for the sprue to cool and kept casting until the pot got too cold (sprue cooling as soon as poured).

Besides working on the sprue cutting I figure this is a good way to learn how heat affects the pour, and I sure saw a huge change.

I even got the mold hot enough that boolits were actually jumping out on their own as soon as opened the mold, so I know my mold can do it, most I have to gently help out. I may still clean up the cavities, but I want to do as little modification to this as I can right now and just learn as much as possible.

I plan on cleaning up the sprue plate holes a little more, the front one cuts smoother than the back one.
And cleaning off the mold face again, I cleaned it up this morning, but I can still see a little light and get the slightest finning, visible, but you cannot feel it.

I have a lot to learn, but I am making progress.

I know I could make shootable boolits right now (good enough for close pistol work), but I will play around some more in the chase of perfection.


Thanks,

Matt