Need Help

[boatswainsmate]

Hello All,
I need advice on how to make my MP 45 Ruger Only 2 cavity mold work correctly. I've tried different temp's, ladle pouring and sustained cooling in-between pours with the same results. I'm getting nice fill out everywhere except the section where it's frosted. The first bullet shows how nice one side comes out and the next 4 show my issue. Thanks in advance. Boats
https://i.ibb.co/smz8tfk/DSCN5086.jpg (https://ibb.co/mDgfSj1)

[country gent]

Look at the vent lines closely make sure they are clean and deep enough to vent properly. I would also contact MP and see what they suggest.

Did it cast good bullets and stop or has it always been a problem? Sometimes a new mould needs a few break in sessions to do really well. Tine to develop the patina to really cast well. The only thing I will add to the above is to use a bamboo skewer stick gently to clean the vent lines

[boatswainsmate]

Look at the vent lines closely make sure they are clean and deep enough to vent properly. I would also contact MP and see what they suggest.

Did it cast good bullets and stop or has it always been a problem? Sometimes a new mould needs a few break in sessions to do really well. Tine to develop the patina to really cast well. The only thing I will add to the above is to use a bamboo skewer stick gently to clean the vent lines

Thanks for the advice. I've tried everything I know how to with this mold. IE: De-greased with dawn and hot water, heated to casting temp in my toaster oven/let cool 3 times and checked for lead on the cavities.

[Winger Ed.]

Really, really clean the vent lines.
If they even have a speck in them, they'll clog up like a plug in a water hose.

I use a solvent and scrub them with a old toothbrush, then blow 'em off with a air hose.
Be quick, an aggressive solvent also melts the toothbrush.

I've had fits with them here & there, but that seems to work for me.

[boatswainsmate]

Really, really clean the vent lines.
If they even have a speck in them, they'll clog up like a plug in a water hose.

I use a solvent and scrub them with a old toothbrush, then blow 'em off with a air hose.
Be quick, an aggressive solvent also melts the toothbrush.

I've had fits with them here & there, but that seems to work for me.
Thanks for the advice.

[6622729]

It looks like you are plenty hot. It looks like trapped air to me. I'd be surprised if MP missed something on the vent but it's always possible. I'd try to slow the pour speed.

[boatswainsmate]

It looks like you are plenty hot. It looks like trapped air to me. I'd be surprised if MP missed something on the vent but it's always possible. I'd try to slow the pour speed.

Thanks for the advice.

[Dave W.]

I am no expert, but it looks to me like either the mold is too cold or the mix needs more tin in it.

[boatswainsmate]

I am no expert, but it looks to me like either the mold is too cold or the mix needs more tin in it.

Thanks for the advice.

[Bazoo]

I had that. What solved it for me was pouring excess alloy over the sprue puddle. I never determined the exact cause of it. Similar can be caused by a too hot mould coupled with a too cool sprue plate (something you find with aluminum moulds most often) according to a snippet in The Art of Bullet Casting book. Though I personally think for me it was trapped air as I was getting it right at the web between bullet cavities. I've noticed that an alloy with minimal tin does that more than an alloy with more tin, say coww vs 95/2.5/2.5.

[bosterr]

Slow down your rate of pour.

[Dragonheart]

First give the mold a good cleaning. I would scrub it several time under hot running water using Dawn and a nylon brush. Then a bath in Acetone to remove any possible hint of oil.

After it is clean & dry, polish out the cavities with a #2 pencil lead, use a very sharp point inside the bands. Also a very sharp point run into the vent lines. While you are at it color the top of the mold and under the sprue plate with graphite. If it is frosting I would think you are hot enough. You didn't mention what type of filling method you are using? I would say you need a faster fill starting 1-2-3-4 in either direction, but making sure a cavity is completely filled before going to the next and end up with a heavy sprue. I think this process will solve the problem.

[boatswainsmate]

I had that. What solved it for me was pouring excess alloy over the sprue puddle. I never determined the exact cause of it. Similar can be caused by a too hot mould coupled with a too cool sprue plate (something you find with aluminum moulds most often) according to a snippet in The Art of Bullet Casting book. Though I personally think for me it was trapped air as I was getting it right at the web between bullet cavities. I've noticed that an alloy with minimal tin does that more than an alloy with more tin, say coww vs 95/2.5/2.5.

Thanks for the advice.

[boatswainsmate]

Slow down your rate of pour.

Thanks for the advice.

[boatswainsmate]

First give the mold a good cleaning. I would scrub it several time under hot running water using Dawn and a nylon brush. Then a bath in Acetone to remove any possible hint of oil.

After it is clean & dry, polish out the cavities with a #2 pencil lead, use a very sharp point inside the bands. Also a very sharp point run into the vent lines. While you are at it color the top of the mold and under the sprue plate with graphite. If it is frosting I would think you are hot enough. You didn't mention what type of filling method you are using? I would say you need a faster fill starting 1-2-3-4 in either direction, but making sure a cavity is completely filled before going to the next and end up with a heavy sprue. I think this process will solve the problem.
Thanks for the advice.

[JonB_in_Glencoe]

I had that. What solved it for me was pouring excess alloy over the sprue puddle. I never determined the exact cause of it. Similar can be caused by a too hot mould coupled with a too cool sprue plate (something you find with aluminum moulds most often) according to a snippet in The Art of Bullet Casting book. Though I personally think for me it was trapped air as I was getting it right at the web between bullet cavities. I've noticed that an alloy with minimal tin does that more than an alloy with more tin, say coww vs 95/2.5/2.5.

Ditto for me (highlighted in red)

I call it shrinkage. (I haven't seen many others call it that, so if I am misusing a term, forgive me.)
What is happening is, as the boolit freezes, the alloy shrinks. As the alloy is shrinking, it needs to pull more alloy into the cavity from the molten sprue puddle. If the sprue puddle is small, it will freeze before the boolit inside the mold freezes and shrinks. If there is no molten alloy to pull into the mold, the boolit will just stay shrunken...typically in the center, just like the boolits in the photo shown.

[boatswainsmate]

Ditto for me (highlighted in red)

I call it shrinkage. (I haven't seen many others call it that, so if I am misusing a term, forgive me.)
What is happening is, as the boolit freezes, the alloy shrinks. As the alloy is shrinking, it needs to pull more alloy into the cavity from the molten sprue puddle. If the sprue puddle is small, it will freeze before the boolit inside the mold freezes and shrinks. If there is no molten alloy to pull into the mold, the boolit will just stay shrunken...typically in the center, just like the boolits in the photo shown.

Thanks for the advice

[cupajoe]

Maybe tilt the mold a smidge, pour off center just a tad causing the alloy to swirl. Loosen the sprue plate so it swings freely. Does the mold has a slight bevel on top of the blocks to help venting?

[Rich/WIS]

Have had this problem at times and found that leaving a larger puddle on top of the sprue plate and lightly dropping the mold onto a hardwood block while the puddle was still liquid would cause the problem cavity to fill.

[boatswainsmate]

Maybe tilt the mold a smidge, pour off center just a tad causing the alloy to swirl. Loosen the sprue plate so it swings freely. Does the mold has a slight bevel on top of the blocks to help venting?

Not that I'm aware of. Thanks for the advice.

[boatswainsmate]

Have had this problem at times and found that leaving a larger puddle on top of the sprue plate and lightly dropping the mold onto a hardwood block while the puddle was still liquid would cause the problem cavity to fill.

Thanks for the advice.

[Wayne Smith]

So, have you solved the problem??

[boatswainsmate]

So, have you solved the problem??
I haven't a chance to cast with the mold again yet. Thanks

[Bazoo]

One thing I've noticed that helps with fillout problems is having more of a freefall. I ladle pour, so my description is based on that. If I rest the ladle on top of the mould (not spout to sprue plate) while pouring I get maybe 1/4" freefall. But if I hold the ladle over the mould a bit to get 1/2-3/4 freefall I get better fillout. Especially using wheel weights and little to no tin.

[boatswainsmate]

One thing I've noticed that helps with fillout problems is having more of a freefall. I ladle pour, so my description is based on that. If I rest the ladle on top of the mould (not spout to sprue plate) while pouring I get maybe 1/4" freefall. But if I hold the ladle over the mould a bit to get 1/2-3/4 freefall I get better fillout. Especially using wheel weights and little to no tin.

Thanks for the advice.

[Dragonheart]

One thing I've noticed that helps with fillout problems is having more of a freefall. I ladle pour, so my description is based on that. If I rest the ladle on top of the mould (not spout to sprue plate) while pouring I get maybe 1/4" freefall. But if I hold the ladle over the mould a bit to get 1/2-3/4 freefall I get better fillout. Especially using wheel weights and little to no tin.

Good advice, and a big advantage with a bottom pour pot and a mold rest because you have reasonable consistency in the pour. I noticed this when I purchased my RCBS Pro-Melt a number of years ago.

[boatswainsmate]

I changed to my homemade version of hardball alloy and got great fill out. The mold makes HP's also so I'll need to figure out a good lead to tin combo for this mold also. Thanks for all the advice.

[Bazoo]

If I pressure cast like I describe and run the mould just below frost temperature I get good fillout with wheel weight alloy and no or very minimal tin.

[Mitch]

I did not see if this is a brass mold.i had the same problems.mostly with brass molds.adding more heat will not help.cleaning the molds seems to make it wors.in fact nothing in general seemed to help me.this was with MP 4 cav hp 38 molds.
OK my alloy is 2.5%sb 2.5%sn 95%pb.Heat the mold realy well on the hot side on a hot plated.I have a Pid a themometer will work just as well.heat alloy in the casting pot to 740 deg f.Now start casting i found that your timeing has everything to do with the problem.i cast very fast npt time to look at your bullets.no dallying.when i cast with these molds it is cast dump cast dump.it seems to me the temp where the mold likes to be cast is kinda narrow.so the time witch in my case is realy fast is the key to keeping the mold at happy temp.this was with the large HP pins in the mold.Each mold will be different so you may have to play with the temp a bit.And as you cast more time with the new mold it will get better.good luck with the new mold when you put the hp pins in happy to see you have it casting solids.

[boatswainsmate]

If I pressure cast like I describe and run the mould just below frost temperature I get good fillout with wheel weight alloy and no or very minimal tin.

Thanks

[boatswainsmate]

I did not see if this is a brass mold.i had the same problems.mostly with brass molds.adding more heat will not help.cleaning the molds seems to make it wors.in fact nothing in general seemed to help me.this was with MP 4 cav hp 38 molds.
OK my alloy is 2.5%sb 2.5%sn 95%pb.Heat the mold realy well on the hot side on a hot plated.I have a Pid a themometer will work just as well.heat alloy in the casting pot to 740 deg f.Now start casting i found that your timeing has everything to do with the problem.i cast very fast npt time to look at your bullets.no dallying.when i cast with these molds it is cast dump cast dump.it seems to me the temp where the mold likes to be cast is kinda narrow.so the time witch in my case is realy fast is the key to keeping the mold at happy temp.this was with the large HP pins in the mold.Each mold will be different so you may have to play with the temp a bit.And as you cast more time with the new mold it will get better.good luck with the new mold when you put the hp pins in happy to see you have it casting solids.

Thanks

[Phlier]

I changed to my homemade version of hardball alloy and got great fill out. The mold makes HP's also so I'll need to figure out a good lead to tin combo for this mold also. Thanks for all the advice.

Good to hear.

When you say that you changed to a home made version of hardball, does that mean that you used more tin than you did previously?

Whenever I've had a mold that just refused to fill out properly, even if I did all the things mentioned in this thread, adding additional tin always solved it for me. I have an old (circa 1955) Lyman mold that just won't fill out unless I use at least 5% tin. When my Dad gave me the mold, he had even put a note in it "use 5% tin minimum with this mold." I tried pretty much all of the advice given in this thread on that old mold, and it turns out Dad was right... that mold insists on eating large quantities of tin in order to produce a fully filled out boolit.

[boatswainsmate]

Good to hear.

When you say that you changed to a home made version of hardball, does that mean that you used more tin than you did previously?

Whenever I've had a mold that just refused to fill out properly, even if I did all the things mentioned in this thread, adding additional tin always solved it for me. I have an old (circa 1955) Lyman mold that just won't fill out unless I use at least 5% tin. When my Dad gave me the mold, he had even put a note in it "use 5% tin minimum with this mold." I tried pretty much all of the advice given in this thread on that old mold, and it turns out Dad was right... that mold insists on eating large quantities of tin in order to produce a fully filled out boolit.

Yes. The alloy I used had more tin and antimony in the mix. This is the first MP mold I have needed to do this. Thanks

[samari46]

I use a rowlladle. You see the adds rifle and handloader magazines.Think the company that sells them if I remember right is advanced car movers. Think mine about 2.5" in diameter and hold more lead than your standard ladles. Bought a couple as I plan to start casting 45/70 500 grain bullets for a Pedersoli Sharpe. Alloy is nothing fancy just wheelweights with 2%tin. Frank

[boatswainsmate]

I use a rowlladle. You see the adds rifle and handloader magazines.Think the company that sells them if I remember right is advanced car movers. Think mine about 2.5" in diameter and hold more lead than your standard ladles. Bought a couple as I plan to start casting 45/70 500 grain bullets for a Pedersoli Sharpe. Alloy is nothing fancy just wheelweights with 2%tin. Frank

Thanks.