Two question for you

[unique]

Invariably when doing a marathon casting session I get a build up of lead on the mold surface usually on top associated with the spruce cutter.

First question, how do you remove that. I tried local heating with torch but fear warping my mold or use knife edge and scrape off but don't like doing that because mold does get scratched in the process.

Second is there a way to prevent this. I tried some light lube on surface where 'leading' occurs but that always seems to volatizes and end up in mold somehow with results of poorly filled out boolits that requires time to clear up.

Thoughts/Suggestions?

[LenH]

I use the palm of the welding glove I use for casting. I have used the edge of a paint stick to scrape the top of the mold or the bottom of the sprue plate.

I get that smear of lead when I try to cast too fast and usually when I am using an aluminum mold with a steel sprue plate. I us a dab of synthetic 2 stroke oil an
a q-tip to coat the top of the mold and the hinge bolt of the sprue plate.

I hope this helps.

[pworley1]

I cast with 2 molds at the same time. I will pour one and then the other. I open the first and repour it, then open the other and repour it, This gives the sprue time to cool enough to cut clean. This has been working for years without any build up or smear of lead.

[mdi]

Similar to LenH, but I scrub with a rough cloth, a kitchen towel, between casts when the mold is still hot. I use 2 cycle motor oil to lightly coat the mold top, underside of the sprue plate, hinges and locating pins...

[Recycled bullet]

Invariably when doing a marathon casting session I get a build up of lead on the mold surface usually on top associated with the spruce cutter.

First question, how do you remove that. I tried local heating with torch but fear warping my mold or use knife edge and scrape off but don't like doing that because mold does get scratched in the process.

Second is there a way to prevent this. I tried some light lube on surface where 'leading' occurs but that always seems to volatizes and end up in mold somehow with results of poorly filled out boolits that requires time to clear up.

Thoughts/Suggestions?Read the thread I made called " so I'll be raining bullets"

The two cycle oil cleans it right up if you have got temperature management under control.

The torch will help you get there and if you are careful and even in the application of heat your mold will be clean and usable as it will ever be inside of ten minutes.

The synthetic two cycle oil dabbed on a 100% cotton rag is your thermometer and cleaning tool simultaneously.

[Recycled bullet]

Can you post picture of the problem?

[Winger Ed.]

I don't use a thermometer or one of those fancy PIDs,
When I see shrink holes starting to form, I back off the heat or slow down a bit.
I've found that staying right below the edge of the alloy or mold being 'to hot' greatly minimizes the effect
of both shrink holes and that 'smear'.

[MT Gianni]

Synthetic 2 cycle oil is your friend as is an old style wooden, graphite pencil. I think many sprue plates are over tightened and that one of the best things Veral Smith ever did is the hold down screw for a sprue plate.

[hoodat]

For the sprue plate, I keep a brass brush handy as I cast. The aluminum blocks -- I wonder if you're cutting your sprue too soon.?
jd

[stubshaft]

I use a q-tip saturated with synthetic two-stroke oil on it and periodically swab the top of the mold and the bottom of the sprue plate with it.

+1 - On LBT's hold down finger!

[unique]

I cleaned these up by heating with torch already so do not have any real useful pictures to share. I don't like using a torch hence the reason for my post.

I forgot about using a pencil...I did that a few times in the past and seemed to work. For those using 2cycle oil, any problem getting that on the inside of the mold? What I mean is I have put a very light dab of oil on top of mold in the trouble area and seems like I immediately get fill out problems until it gets 'burned' out and I contribute this to the oil vaporizing and finding its way into the mold.

[Minerat]

Don't use a lot, 1 or 2 drops on a q-tip is enough to do the mold and sprue plate until the q-tip is shot. Only apply when there are boolits in the mold that way you won't contaminant the cavities. If you think you have too much 2 cycle oil on the mold wipe it off before dumping the boolits.

[bosterr]

I apply synthetic 2 stroke oil with a q tip then use the dry end to take off any excess.

[405grain]

Usually, when you're getting lead smearing on the underside of the sprue plate it means that you aren't waiting long enough for the alloy to solidify before cutting the sprue. If you closely examine the sprue after casting a bullet you can watch the liquid metal solidify. Don't cut the sprue just yet, instead keep watching. After the alloy has solidified you might see it change from a bright silvery color to a more grey and flat toned color. If you cut the sprue while it is solid, but still silvery, not all the metals in the alloy may have fully solidified. Once the sprue goes through the change and the color turns a duller grey, then all the constituents of the alloy have fully solidified. Change your casting cadence so that the metal completely solidifies before cutting the sprue.

To remove metal from the underside of the sprue plate, what I've found to work best is an ink eraser. This is similar to a pencil eraser, but is usually a light grey color instead of pink. I wasn't able to find these at office supply stores because apparently no one writes with pen & ink anymore. I was able to locate ink erasures on Amazon. An ink erasure has micro-fine particles of sand embedded in it. Use an ink erasure to scrub off the lead smears from the bottom of the sprue plate and the top of the mold blocks. (mold needs to be cold to do this) Make sure to blow out any crumbs from the erasure after scrubbing the mold.

To help prevent lead build up on the sprue plate, take the cold mold blocks and draw all over the bottom of the sprue plate with an ordinary pencil. This will leave a thin layer of graphite that lead doesn't like to stick to. I use a tiny amount of 2 stroke oil to lubricate the sprue plate pivot, but I haven't tried it as a leading preventative on the mold parts, so I have no firsthand knowledge to share in that regard.

[Shuz]

To remove the lead from the underside of the sprue plate, I take a sheet of 400 grit sand paper and lay it across a piece of plate glass and sand away the bottom of the sprue plate until the lead is gone.
This method insures that the underside of the sprue plate stays flat. It also tends to sharpen the sprue hole edges.

[floydboy]

while mold is hot rub with a cool lead ingot. Smear will come off.

[Wheelguns 1961]

When your alloy and your mold are up to temp, fill the cavities, cut the sprue, and with the cavities full, wipe the top of the mold and the bottom of the sprue plate. I use a scrap piece of rag with a small amount of 2 stroke oil. I keep this rag near me when casting. Sometimes I will also wipe the bottom of the mold, and the guide, if it feels like it is dragging across. I only use enough oil to moisten the rag. This will stop the oil from entering the cavities.

[GregLaROCHE]

Make sure your sprue plate is perfectly smooth on the bottom. Straight with no burs. Tighten it as tight as you can work with it. Be sure the top of the mold is smooth and even too. Something made of wood can be used to scrap off lead residue, but you shouldn’t really need to. Lots of people like to use something to lube with. I don’t because I’m always afraid of it contaminating the mold.

[charlie b]

I also make sure the sprue screw is adjusted, almost flatten the Bellville washer. Also make sure it is flat and smooth. I do 'lubricate' it with a lead pencil on the top of the mold and the bottom surface of the sprue plate.

[farmerjim]

I cast with 2 molds at the same time. I will pour one and then the other. I open the first and repour it, then open the other and repour it, This gives the sprue time to cool enough to cut clean. This has been working for years without any build up or smear of lead.

+ 1

[waksupi]

Don't use a lot, 1 or 2 drops on a q-tip is enough to do the mold and sprue plate until the q-tip is shot. Only apply when there are boolits in the mold that way you won't contaminant the cavities. If you think you have too much 2 cycle oil on the mold wipe it off before dumping the boolits.

This has what others have left out. Lube the mold top with bullets in the mold, then wipe.

[Willie T]

I also apply two stroke oil on the sprue plate and top of the mold with the cavities full. One or two drops is enough for a six cavity mold. It does not take much. Then before opening the mold I wipe the lubed areas with a dry cotton cloth. Letting the alloy fully set and not over heating the mold will eliminate the lead smears from happening. As mentioned already a cotton rag will usually wipe them off if there is a very light coat of lube. For stubborn lead smears, scrub with a lead ingot.
Oxidized tin on the mold face is the PIA. Bees wax, heat, and either a popsicle stick or lead ingot and a lot of elbow grease and cussing is the way I remove oxidized tin. Getting the alloy and mold too hot is usually when I have seen tin from my alloy oxidize on the mold face.
I think I have done everything I could do wrong at least once. Unfortunately it seems I have to pee on the electric fence to learn not to do it. Sounds like lead smears from cutting your sprue too soon is what you were dealing with. Slow your tempo down a smidge and it will stop happening.
Willie

[georgerkahn]

I, for the most part, do not have aluminum moulds -- my casting of late had been ~ 80% brass and 20% iron moulds. Regardless, when I get lead smears the solution which has worked well for me is the use of "chore girls". I honestly do not recall if they're the brass or copper ones -- I did try and find copper "way back when" -- years plus memory is not a good combo, and stuff is downstairs ;) -- but either/both metals will do the job. Purchased at local supermarket.
geo

[unique]

Lots of great suggestions here. Yes sometimes I do cut the spruce too soon and that means slow down. That happens on my lyman 429383 which takes longer for the spruce to solidify. I understand that one.

The one that has me perplexed is a Saeco #307 3 cylinder which is 180gr 30 cal. There I was sure I waited long enough and then a little more. The problem grew from nothing for the first 300 of so pours to a slow build up like it was galling slowly but surely with each pour on the top of the mold. A little on the spruce cutter but mostly on the top edge of the mold.

I am going to try 2 cycle oil with bullets in the mold. I never thought about having the bullets poured before applying dab of oil. I also like the eraser idea as well as the rub with ingot if I do get build up.

...and I thought I knew everything...nope.

[WRideout]

When I start to see frosted boolits, I touch the mold to a cloth pad wet with water. This cools the mold down, and coincidentally helps the boolits let go and fall out of the mold. I do this every 5-10 pours. Also, I use the silicon bulb grease; the kind that comes in a little packet from the auto parts store. A dab in the sprue plate holes and a bit under the plate is all I need. If you can see it it's too much. I lose one or two boolits that way, but it keeps things lubed up for a session.

Wayne

[PhilC]

If you closely examine the sprue after casting a bullet you can watch the liquid metal solidify. Don't cut the sprue just yet, instead keep watching. After the alloy has solidified you might see it change from a bright silvery color to a more grey and flat toned color. If you cut the sprue while it is solid, but still silvery, not all the metals in the alloy may have fully solidified. Once the sprue goes through the change and the color turns a duller grey, then all the constituents of the alloy have fully solidified. Change your casting cadence so that the metal completely solidifies before cutting the sprue.
Precisely what I do before cutting the sprue. 8-)

[jdgabbard]

Another vote for Synthetic 2-Cycle Oil. I apply it with just a half a drop on a Q-Tip, and rub a little on the top of the mold and the sprue plate. Lead usually flakes off with just the q-tip. But you can also scrap a little with a graphite pencil. And occasionally a wooden toothpick can help remove stubborn bits.

Just buy any cheap synthetic 2-cycle oil. It really is that good.


Sent from my iPhone using Tapatalk

[Walks]

I apply synthetic 2 stroke oil with a q tip then use the dry end to take off any excess.


YUP,

Opening mold too soon, wait 3-5 seconds more.

[35 Whelen]

I open the sprue with a gloved (leather) hand and when I get lead smears I just rub the palm over the top of the mold.

However, a better solution is to tue and polish the bottom of the sprue plates and if possible the top of the mold. I use a piece of plate glass with wet/dry sandpaper on it beginning with 320 or so grit, depending on how badly the sprues are scored, and work my way down to 1500 grit. Some before/after shots-

https://i.imgur.com/5B97VnJl.jpg https://i.imgur.com/VB1nP5ol.jpg

https://i.imgur.com/IaxLuvHm.jpg https://i.imgur.com/uwqjEe4m.jpg

https://i.imgur.com/G7W0ezem.jpg https://i.imgur.com/ilRK4Jwm.jpg

https://i.imgur.com/wIew80wm.jpg https://i.imgur.com/ThVCP60m.jpg

35W

[mehavey]

Bad smears... copper brush (steel moulds)
Periodically rub both surfaces (bullets still in place) w/ a piece of cotton dishcloth barely* impregnated w/ synth engine oil.

*Baaaaaarelry.... been using the same dishcloth piece/no new oil for years.
Just leaves a "shine" in the surfaces.

[kevin c]

I usually go for sparing use of two stroke oil. Not much at all, as I get wrinkles for a few pours afterwards.

More recently I’ve been scrubbing the underside of the sprue plate with a pad wrapped with sisal or hemp twine; it seems to remove lead spots and lead haze pretty well. Really stubborn spots I use a carpenter’s pencil.

But better yet, I’m learning, is prevention. I’m finally learning the “feel” of a sufficiently hardened sprue as I cut it, one that won’t crumble or smear, and learning the various little things to adjust to stay in the sweet spot. Just some of the things I’m fiddling with: time that the mold is filled versus empty, length of the complete pour cycle, time the mold is open versus closed after dropping the casts, ditto whether the plate is swung open or closed over the blocks, size of the sprue, alloy temp, ambient temp and wind.

If I hit the right combo, the casts look great, the mold barely and rarely needs lead removal or application of oil (except on the bottom of the blocks and on the mold guide as lubricant).

[Bazoo]

I never could get the hang of using a dab of 2 cycle oil. I over oiled, then I liked to never got it all off. So, I started using graphite. Bob's your uncle, that did the trick. Not only does it do the trick, but a carpenters pencil is good for picking any lead off the mould top during the casting session.

I haven't ever done it, but I seen in the weet method for mould lapping thread, that you apply powdered graphite with a bristle brush after cleaning. That might just be the ticket.

I tell you one thing, don't make the mistake of using a nylon bristle toothbrush on a hot mould. You cannot get melted nylon off of a mould no matter how much you plead with it. The way I finally got it off was to pick it out with skewers the best I could and then use a bronze bore brush in a drill, half the mould at a time, and scrub it out. It was a real nightmare.

Now, keeping a bronze brush handy is a good habit to get into. Especially if you use iron moulds. Though, I have used one sparingly on an aluminum mould.

[unique]

Wow, I asked two questions and got years worth of experience in return. Thanks everyone.

[fredj338]

I also use a super thin coat of 2 stroke. I never get lead on my mold halves but but spru plate if i cut too soon.