New Guy needing some help or direction

[nathanrhoades]

Just joined the team and I've been trying to find some troubleshooting threads. However, after searching for a couple of days, I was hoping someone could point me to the right one. I just started casting 9mm's with a Lee 124 gr two cavity micro grove mold. One of the cavities throws perfect boolits almost every time starting with about the third fill. The other cavity (closest to the handle) will not produce a good boolit. I have degreased, cleaned, smoked, cleaned again, heated, cooled, etc. and can't figure out what is going on. I will try to post some pictures, but the second cavity will not fill all the way up and when it does, the micro bands are rounded and not properly filled out. I thought there was beeswax getting in from the sprew plate pivot screw, but I no longer think that is it. I got a few good boolits to drop after switching and filling the problem cavity first, but it is still hit or miss. Could this be a situation where the sprew plate and mold are too tight and air is not able to escape the cavity????? If so, How is that addressed?

Here are some pictures. The boolit from the good cavity is on the left and the boolit form the problem cavity is on the right from four different castings side by side:


Any help would be appreciated!

Nate Rhoades

[Bent Ramrod]

Once the front cavity starts making keepers, start filling the rear cavity first. Aluminum moulds shed heat pretty quickly and the extra metal on the handles and hinge at the rear take it away as well. Also, raise the temperature of the pot. And don't stint on the size of the sprue that you pour on the plate.

[runfiverun]

heat is most likely the culprit...you can adjust the venting of the sprue plate by tightening or loosening the screw.
if you tighten it a tick it opens the venting to the cavity away from the screw.
if you loosen it it opens the venting to the cavity closest to the screw.
another way to improve the venting is to take a sharpening stone and run it down the corners of the mold right across the cavity's at a 45* angle.
about 2-3 swipes is all you should need.
I'd still get the mold hotter before I done anything else and maintain a pace that keeps the mold hot.

[Dusty Bannister]

I agree that you need more heat. The cavity closest to the plate hinge and handle hinge is the one with incomplete filling? Be sure mold heat is adequate and try pressure filling that cavity not filling properly. It may be that you still have some contamination in that cavity. Are you Bottom Pour or Ladle casting? If Ladle, perhaps you should dip and fill one cavity, then dip and fill the second cavity. It is probably going to take a few casting sessions to get a new mold broken in, and that also means getting it up to temp, and sometimes over heating and then backing off the heat or slowing the tempo. Ambient air temp can also be a factor to consider. Keep at it.

[MtGun44]

Standard advice for new casters is: "Because your mold is dirty and too cold."

Scrub with toothbrush and Comet for cleaning and cast fast and do not inspect
real time for heat. Think of each pour adding a "chunk" of heat to the mold and
each second it is not being poured into as "losing a chunk" of heat. Gotta get the
heat up. Also, a couple percent of tin is very helpful to get good fill out in the
mold.

Welcome - hope you enjoy the hobby.

Bill

[aspangler]

Check the sprue hole on that cavity. I had to open mine up to get it to cast that same cavity. Same mold btw. Don't need much but a little goes a long way.

[JonB_in_Glencoe]

heat is most likely the culprit...you can adjust the venting of the sprue plate by tightening or loosening the screw.
if you tighten it a tick it opens the venting to the cavity away from the screw.
if you loosen it it opens the venting to the cavity closest to the screw.
another way to improve the venting is to take a sharpening stone and run it down the corners of the mold right across the cavity's at a 45* angle.
about 2-3 swipes is all you should need.
I'd still get the mold hotter before I done anything else and maintain a pace that keeps the mold hot.

Standard advice for new casters is: "Because your mold is dirty and too cold."

Scrub with toothbrush and Comet for cleaning and cast fast and do not inspect
real time for heat. Think of each pour adding a "chunk" of heat to the mold and
each second it is not being poured into as "losing a chunk" of heat. Gotta get the
heat up. Also, a couple percent of tin is very helpful to get good fill out in the
mold.

Welcome - hope you enjoy the hobby.

Bill

YES YES YES YES to the above !!!

[nathanrhoades]

Thanks all. I've tried all the normal temperature stuff including raising the mix and the mold to the point of heavy frosting in both cavities and the problem cavity still does not fill all the way. I am going to try to open the sprue hole a little and maybe hit the edges of the cavity with a stone and see what happens.

[JeffG]

I had a similare issue on my Lee 452-255-RF and came to the conclusion it just wasn't venting well enough. I could pressure fill it but that became a pain, and loosening the sprue plate wasn't quite solving it for me. I ended up removing the sprue plate and sticking a piece of 220 grit paper down to a flat steel work surface. I turned the mold upside down, pressing it flat to the sand paper and making a single stroke over the sand paper. This in effect added some venting on top of the mold. This solved the venting and that cavity now fills normally. Don't get aggressive, just a single stroke and stop, that should be enough.

[MtGun44]

Ok, if you are up to frosty, then you are hot enough.

More tin, loosen the sprue plate so it swings loosely, vents the corners.

And scrub the mold with Comet and a toothbrush.

Bill

[bangerjim]

I would recommend trying pressure casting. That ALWAYS solves any fill problems I have even on totally COLD and tricky fill molds!

Just put the pot spigot into the sprue taper and pour away. Using a FULL pot (important) you will get rapid pressured filling of every nook and cranny. If done right, you will feel a little "tick" in the handle when the lead fills the cavity and you know it it full. There will be no puddle on the top.

Works every time for me!

banger

[nathanrhoades]

I don't have a bottom discharge pot so I'm using a ladle. I did notice that when I filled the ladle completely and held the spout to the sprue taper longer than necessary it did fill the cavity better, that's one of the things that makes me think it is a venting issue. Thanks for the recommendation, I think working on the venting tomorrow will get this mold in shape.

[Dusty Bannister]

I don't have a bottom discharge pot so I'm using a ladle. I did notice that when I filled the ladle completely and held the spout to the sprue taper longer than necessary it did fill the cavity better, that's one of the things that makes me think it is a venting issue. Thanks for the recommendation, I think working on the venting tomorrow will get this mold in shape.

Well Nathan, if you have any obstruction in the nozzle, that will also slow down the flow. So be sure the pot is clear of dross and the ladle is filled with clean alloy. Keep the ladle in the melt to keep it hot so it will flow freely. Are you using clean and well fluxed alloy?

[Wayne Smith]

Turn your mold sideways, place the nipple of the ladle directly in the sprue, and turn upright. Do a slow count to three, turn back sideways, remove ladle. This is pressure casting with a ladle. My 457122 mold loves to be pressure cast. Pre-heat the mold and I get perfect boolits from the first cast.

[Dan Cash]

Nathan,
I am the heretic here. I think your sprue plate is cold. Try, after pre heating your mould on the edge of your pot while the pot comes up to temperature, pouring a full ladle of melt over the top of the sprue plate for the first 8 to 10 casts. To clarify, pour the first cavity full, then the second cavity full letting the excess melt continue to flow over the first cavity. Work fairly quickly and keep a large puddle of melt on top of the sprue plate until the bullets are properly filled. I had similar problems with an aluminum 4 cavity mould; using a large 1/2 cup ladle and generous application of melt solved the problem.

[nathanrhoades]

Thanks Mr. Cash.. I was at that conclusion after my first couple of hundred pours and dumped several ladles over the sprue plate and even tried warming it up with a torch (gently...). Nothing seemed to help besides pouring that cavity first and pressure filling but still could not get consistent results. I just did a little work on the top of the mold and will update my results in a few hours when I get back to casting later today.

Thanks all!

[nathanrhoades]

Success! Took JeffG's advise and ran the top of the mold across some 220. Helped a lot but did not quite do the trick. Using a fine scribe, I created a very fine score from the top of the cavity to the edge of the mold and now it is throwing perfect boolits every pour.

Thanks again for all the help,

Nate