Fins

[Wrbjr]

Lee 6 cavity 175 (.40) TC. All of a sudden I have fins leaking between cavities at the base. I see no light anywhere.... it looks sealed but FINS. I have a couple of hundred through the mold that were good.. then FINS. Anybody have a solution or suggestion? :killingpc

[country gent]

Several things can cause this. Look the block faces over under good light for a speck of dirt or lead on the face. Also check the pin alighnment and for burrs raised around them. To much Pin depth or a burr can cause this also. I would give the blocks a good cleaning with a toothbrush and dish soap. then under a strong light examine them very closely, Looking for burrs and debris.

[gray wolf]

As said above,
also a bit of lead on an Aluminum mold face can be easily overlooked.

[R.M.]

Are you pressure casting? Every time I try it, I get the same thing.

[Wrbjr]

Are you pressure casting? Every time I try it, I get the same thing.

Not sure what you mean?

[Wrbjr]

I cleaned the block faces this morning with acetone to try and clean them up.... they are quite shiny now and I didn't see any lead... but I will take them apart and magnify the surfaces with a fresnel lens. I'll report back shortly with any findings. Also the sprue plate doesn't seem to tighten enough. This mold has a bevel base and it is no longer clean but has a bit of lead on top of the boolit when dropped from the mold... just enough to leave a skin and the weight is too high.... Will take it off and see what's going on while I do it.

[Larry Gibson]

If you hold the sprue handle with the mould handles when casting this can slightly pivot the block apart and cause the fins.

Larry Gibson

[Wrbjr]

Did find some light slivers and splatters... Cleaned off now.. also found lead under the pivot/swing point of the sprue plate. All clean now. Will hit it again tomorrow after lunch and report on any progress. Hope I am back in business now.....

http://i1275.photobucket.com/albums/y441/bryan578/LeadSplatter_zpsb1557edb.jpg (http://s1275.photobucket.com/user/bryan578/media/LeadSplatter_zpsb1557edb.jpg.html)

[Wrbjr]

I probably have been doing that without thinking about it. Will concentrate on it tomorrow.

[gray wolf]

Also you shouldn't have to smoke up the mold.

[Wrbjr]

Also you shouldn't have to smoke up the mold.

Only did that the first time I used the mold.

[detox]

Your alloy may be getting too hot during casting.

[Wrbjr]

Your alloy may be getting too hot during casting.

Wish I knew where that temp is... I cast when they get shiny... have been told frosty is good too.... I use a thermometer and try and keep it around 750.

[madsenshooter]

Your fins had a different source, but I've found that I get fins when I ladle cast at 750 using NOE molds. Their really good venting system allows the alloy to flow into the vents. Must've been cut with the drip caster in mind.

[JonB_in_Glencoe]

Did find some light slivers and splatters... Cleaned off now.. also found lead under the pivot/swing point of the sprue plate. All clean now. Will hit it again tomorrow after lunch and report on any progress. Hope I am back in business now.....

http://i1275.photobucket.com/albums/y441/bryan578/LeadSplatter_zpsb1557edb.jpg (http://s1275.photobucket.com/user/bryan578/media/LeadSplatter_zpsb1557edb.jpg.html)
I see in your photo, that one of the sprue plate screws appears to be loose.
A loose sprue plate can give the boolit base some flashing...if that is what you mean by 'fins'
Good Luck,
Jon

[blaser.306]

Also something to consider is your alloy itself! Too much tin will make the lead flow like water!! That and a combination of high pot temp and lead pressure will help it find all manner of way's out of the cavities. Have you tried letting the molten lead hit the side of the sprue plate as it enters the cavity? I have a couple of different blocks that want high heat but wisker and fin like mad , unless I let the lead "swirl" it's way into the mould. Just my thoughts and of course YMMV!

[Wrbjr]

Your fins had a different source, but I've found that I get fins when I ladle cast at 750 using NOE molds. Their really good venting system allows the alloy to flow into the vents. Must've been cut with the drip caster in mind.

Well, I might try it at 700 and see how it goes. Can't hurt. Experimenting is part of the game I guess....

[Wrbjr]

Also something to consider is your alloy itself! Too much tin will make the lead flow like water!! That and a combination of high pot temp and lead pressure will help it find all manner of way's out of the cavities. Have you tried letting the molten lead hit the side of the sprue plate as it enters the cavity? I have a couple of different blocks that want high heat but wisker and fin like mad , unless I let the lead "swirl" it's way into the mould. Just my thoughts and of course YMMV!
I have not tried that but will give it a go tomorrow. Thanks for the tip....

[Wrbjr]

I see in your photo, that one of the sprue plate screws appears to be loose.
A loose sprue plate can give the boolit base some flashing...if that is what you mean by 'fins'
Good Luck,
Jon

Yes it was a tad loose... I did that when disassembling the mold. All tight now. It was coming loose during casting and that's when the lead got under the plate.

[Blanco]

I had similar issues and after thinking on it I was applying too much pressure to the mold handles. This will cause some of the Lee molds to cam open just a bit, which will give you the flash (wings) on the boolits. Putting pressure on the sprue handle will do the same thing. I actually put my sprue plates on backwards so I don't touch it when i'm casting.
If you are ladle casting try using the little round one with a spout from Lyman. With a little practice it is much less messy.
I use the same mold and ladle cast at 600~625 deg. and get really pretty boolits.

[williamwaco]

Every time I have had that problem it is always caused by a warped sprue plate.

[Wrbjr]

I had similar issues and after thinking on it I was applying too much pressure to the mold handles. This will cause some of the Lee molds to cam open just a bit, which will give you the flash (wings) on the boolits. Putting pressure on the sprue handle will do the same thing. I actually put my sprue plates on backwards so I don't touch it when i'm casting.
If you are ladle casting try using the little round one with a spout from Lyman. With a little practice it is much less messy.
I use the same mold and ladle cast at 600~625 deg. and get really pretty boolits.

I am using that ladle. But... at 600-625 my alloy is barely liquid. I will try and see how low I can get the temperature tomorrow and still cast.

[Cloudwraith]

If you hold the sprue handle with the mould handles when casting this can slightly pivot the block apart and cause the fins.

+1

I had the same problem using a 6-cavity mould for the first time. I didn't know what was causing them until I realized I was holding the sprue handle with the mould handles it was causing the mold to separate slightly.

[Wrbjr]

+1

I had the same problem using a 6-cavity mould for the first time. I didn't know what was causing them until I realized I was holding the sprue handle with the mould handles it was causing the mold to separate slightly.
I found myself doing this without even being aware of it. Now I concentrate on not doing it... but still on the odd cast will catch my thumb on that sprue plate handle. Getting better though....

[captaint]

wrbjr - you don't want to try to cast with alloy at 625 deg. I know I couldn't do it. Go on up to 700 anyway. Even 725 won't kill ya. Much over that and you will be oxidizing the good stuff out of your alloy. More important than alloy temp, however, is mold temp. Just keep casting until the boolits frost a little when they sit a minute. Just trying to help. Mike

[Wrbjr]

wrbjr - you don't want to try to cast with alloy at 625 deg. I know I couldn't do it. Go on up to 700 anyway. Even 725 won't kill ya. Much over that and you will be oxidizing the good stuff out of your alloy. More important than alloy temp, however, is mold temp. Just keep casting until the boolits frost a little when they sit a minute. Just trying to help. Mike

Timely post captaint... I cast a hundred or so today. Much better quality results I am happy to report. No fins... and they were quite shiny. As to temps... I find that at around 650 or so the ladle opening gets clogged with solid lead so much I can't abide it. So today I was able to cast just below 700... and all is well. No more 750 and up. I am also guilty of pressure casting as I caught myself several times and really had to concentrate on leaving that sprue handle alone. I feel much better about the process now. Many thanks to all who have contributed to my boolit bank.:bigsmyl2:

I also noticed that that they were just on the edge of frosting... a tiny touch of frost in the lube groove beginning to form when I dumped them so I must be in that sweet spot.