Disgusting casting results

I have a mold that I have never been able to get work well.

1. Made by Steve Brooks
2. Casts .462 bullets using COWW and 20 to 1.
3. Style is 512 grain Government RN.
4. Forward bands are .454 getting larger to last bands.
5. I have 2 ladles. Lyman cast iron and RCBS aluminum.
6. I have also poured a few bullets with my 3 lb ingot casting ladle.

My results
1. About 95% of bullets cast have a smiley face wrinkle on the nose at 45 degrees corresponding to the beginning tilt angle when I start pouring metal. It seems impossible to get rid of this wrinkle.
2. I have varied the pouring technique from pressure pouring with the ladle in contact to air pouring. Fast and slow. Hot and cold. Big spru little sprue. Alloy flooding the sprue plate.
3. Worst problem is the bullet nearly always sticks in the left mold block which is the side on top as I pressure cast. I roll the mold and dipper vertical to pour.
4.The stuck bullet is very difficult to knock out of the left block.
5. If I run the metal hotter the sticking switches from left to right without any pattern. The bullet may stick in either side and is difficult to knock loose.
6. I have also tried a bottom pour furnace with even worse results.

7.It seems to be impossible to cast a bullet that does not have the smiley face and releases at the same time.

This has gone on for about 3 casting sessions and maybe 200 casting attempts. I think I have gotten 20 useable bullets.
Those few I have been willing to shoot are very accurate. Groups vary from 2"down to about 1" at 100 meters.

My 20 to one came from roof flashing mixed with 60-40 solder.
At this point I don't have a clue of how to make this mold work.

You might try a very sharp scribe and clean / slightly deepen the vent lines. My Brooks mould is a adjustable cup base PP mould and likes to run 20-1 around 725*-750*. I use a cast iron rcbs ladle to cast the spout has been opened up from the standard .187 hole to .205 size for better flow. I found this modification to the ladle helps a lot on the big bullets. Last is to pre heat the mould good. I like to have it hot enough to have to wait a little longer than normal for sprue to cool / set up. This way it is to temp all the way thru.
One other thing to try is use a clean new pencil eraser and lightly rub the cavities down all surfaces, this will lightly remove any hard deposits, pull any burrs and give a light polish to the surface.
My mould also has the vented sprue plate so I pour a full ladle into the sprue hole letting the excess run back into the pot. This keeps the bullet molten longer giving air and gasses more chance to escape.
Last is to color the cavity with graphite rubbed on from a #2 lead pencil. this provides a smoother surface for release and air flow. Be careful here a light coat is al that's needed and a heavy coat can change bullet dia.

Perhaps the info/suggestions in this archived topic might help?
http://castboolits.gunloads.com/show...ot-filling-out

Post #5 in that topic might give you something to try if the vent cleaning mentioned doesn't help.

G'Luck! & if ya figure it out, please share your info here to help others who might run across a similar issue.
:)

P.S. - Maybe try pouring just half to 2/3 a boolit in that cavity and see if the smiley wrinkle is still there. That might help ID a venting issue since the open sprue would be allowing more venting than just the little vent lines & perhaps help ID the issue.

It doesn't always work, but I've had some success by using a bullet from the mold to spin polish the interior of the mold. Pour one, drill and tap the base to install a post, lightly coat the bullet with Flitz and then reintroduce it to the cavity. Spin it in the cavity as you slowly close the mold together. The idea is to polish the interior of the mold. Go lightly as too much will enlarge the mold cavity and ruin it. If you have a variable speed drill, I've used that first in one direction and then in the other. Has helped with sticking issues. GO SLOW.

Good luck. Nothing seems as frustrating as a mold slightly out of whack.

I had a similar problem. turned out to be the driving bands. I broke the edges with a die sinkers file and used a commercial mold release made by "Spray-on". It solved the bullet release problem for that mold for the most part. it has gotten better with use. Good luck, they can be a real pain in the neck sometimes.

I have had occasional occurrences of wrinkled castings with a Brooks mould, but since the sample boolits he included in the box had no such defects, I figured it was something I was doing (or not doing) in the casting process. Never had a problem with sticking, though, as all my Brooks moulds are paper patch.

I clean my new moulds with that spray electronics or brake cleaner that has chlorinated solvents in it, to remove any oil. I would try the Q-Tip trick along the cavity edges to check for burrs, and a mild lapping with Clover 320 on a good casting if they are present. (A new break-in session would probably be needed after this.) Country gent’s suggestion of judicious scribing along the vent lines is a good one, too.

I have found that some balky moulds respond well to side pouring (mould held vertically, metal poured from the side like would be done from an open ladle rather than locked together and turned vertical as with the spout type). I do all my round ball castings like this, using Lyman and RCBS spout ladles, and haven’t seen a wrinkle in several years. The mould and metal needs to be hotter for this to work, and I have no idea why it does, since moulds that work well with the normal 90 degree turn produce nothing but culls doing it this way.

In extreme cases (and my level of patience during a casting session goes to “extreme” pretty quickly), I’ll smoke or spray the mould with Mould Prep. If this reduces the diameter, my micrometer doesn’t show it.

I find that a lot of these custom moulds, made by any of the small manufacturers, tend to be prima donnas, especially starting out. They’ll need a break-in session, or just a few sessions in general to obtain familiarity; they’ll need the sprue plates tightened or loosened just so, the blocks opened by the Paul Jones technique, intolerance to certain alloys and temperatures, general PMSing N.O.S., etc., etc. Once this introductory phase is passed, the boolits they turn out are all that is advertised.

In the extreme case, I would call Brooks about the problem. He stands behind his products, and will fix any problems. Actually, this should be done before any of the home remediations are tried, but I’m an incurable tinkerer.

A few things a person could do with a mold giving them fits:
1. Check the centering of the mold. Take your calipers and measure from the inside of cavity to the outside of the mold on each half. If one is less than the other, the mold blocks were not centered when they were cut.
2. Take a cue tip and drag it around every edge of the mold cavity slowly. The idea is that a bur will catch the cue tip and you will feel it or see cotton stick to it. You can then use a razor blade to carefully remove the bur.
3. For the smiley/wrinkle, disassemble the mold and boil it in dish soap and water. This will remove any stubborn grease or oil in the mold.

Ok guys I appreciate the input.
My mold has been scrubbed and degreased multiple times and still appears like new.
I have never tried the graphite pencil trick.
I have not tried smoking this mold either.
This is my one and only high dollar custom mold so I expected easier fill out and release. I sure don't like tapping on the mold handles all day to get a bullet to release.
I guess I need to examine the mold grooves for burrs in the lube groove areas using a loupe.
Then look at the vent lines. I have messed with the vent lines before but I never noticed any difference.
Whose mold prep do I use?

Is it brass ?
I have 2 moulds that absolutely drove me ....... They were a PITA .
1 is an NOE .....all on me by the way , I'm smarter now . I must have cast it 20 times could not get over 3/5 good bullets per pour . Just know it was me not the mould or maker or metal ...... A hot plate , this particular piece , likes to be hotter than is the routine for the other 11 NOEs and it absolutely wants hotter than typical metal . No idea why but that's what it needs to be happy .

Hollow base brass M-P mould . I followed the letter of the instructions . I tried all of the suggestions . Did all of the usual stuff . Patina ...... I don't know how that works for a brass mould but I had white barrels ML that took 10 yr to get to gun metal grey and the brass to dull . I had to really work at patina on the brass mould it took over a dozen sessions to get what I needed to get to make it cast decent .

In my limited experience if it wrinkles , drips or has a line the mould is not hot enough .
Pulled back or rounded square edges tend towards dirt , oil , solvent , cutting fluid , and/or migrating sprue lube , some times it's the mould too hot .
Venting usually it's a bug that comes and goes .

The switch hitter cavity hang up has happened to me several times . It seems to be uneven temp of the mould . 90% of the time my trouble maker is a 4c and will hang on the sprue plate hinge corner cavity and/or the off side at the other end .
I ladle pour everything and except the brass HB I rest the mould on the pot between pours on the sticky corner .
Pour about twice as much sprue as you think you need and slop it around . I'd bet it helps .

My Steve Brooks molds are a little rough on the sides of the grease grooves. When new they did not let the bullets drop easily. They got better with use. I run my molds hot. My 45 mold did not vent well and I stoned a tiny vent on the top edge of both blocks and now I get better base fill out. I mean tiny probably .005". If you continue to have problems contact Steve Brooks and he will help you.

I got some Midway mould prep but it doesn’t work any better than the soot from a candle. I always have one around the pot for fluxing with the drips and lighting the smoke that comes off while stirring. The soot can be deposited on hot or cold moulds, whereas spraying is more consistent before the mould is heated up.

Do make sure the vent lines stay open.

Preheat the mold more.

Micro fine ground graphite from Brownells is about the best since Ray Rapine retired and is not longer supplying product.
Paint it in the cavities with a cotton que-tip.

I am sorry you are having trouble with the Brooks mold. He is a very good mold maker and it is not normal for his molds to get out with problems as he pre-casts them and I am sure you received your mold with an unopened perfect bullet in it. Sorry, that is little help when you are clearly have an issue but hang in there. The advice about is good and the best advice is to call him before doing ANYTHING to "his" mold; or he may take a less than happy view of replacing it were that needed. FWTW- I just saw Steve at a match last week and he is not making many knifes and is full time making molds. They should be great.

One of my experiments was to cast bullets with the sprue plate about .03 to .04 off of the stop pin. That way I could tap it toward the stop pin then away from the stop pin to shear the sprue. When doing that the bullets released a little better and often stuck more on the other side of the mold.
BTW my mold exhibits the best workmanship of any I have used.
It is very round and perfectly centered. The surface finish is basically flawless and free of tool marks.
It is a steel mold.
Guess I need warmer weather so I can try out smoking, graphite and deburring.
I know the one time I tried COWW metal it seemed to cast better than 20 to 1 lead and tin as if the shrink rate had some effect. Though not really a lot better. Maybe a whopping 10% yield instead of 5% yield.
I felt kind of foolish but I did call Steve Brooks several months ago and we had a short discussion.
He really could not suggest anything new so I decided to try with you guys.
It almost seems these molds need to be ran several thousand cycles in a Magma automated set up just to break them in.

You could try running the lead /and mold hotter and swirl the lead into the sprue plate ,I've a mold that wrinkles unless I swirl the lead into the mold.

I also would try pre-heating the mold more. I use a lab ceramic top hot plate to get my many molds up to proper temp and do not have any of the problems that the original poster complained about. The nose having wrinkles is a big clue that the mold is not hot enough.

Quote:

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Originally Posted by Deadeye Bly

My Steve Brooks molds are a little rough on the sides of the grease grooves. When new they did not let the bullets drop easily. They got better with use. I run my molds hot. My 45 mold did not vent well and I stoned a tiny vent on the top edge of both blocks and now I get better base fill out. I mean tiny probably .005". If you continue to have problems contact Steve Brooks and he will help you.

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I was going to suggest this, when I have this issue with a mold I always do this after checking the vent lines. It never hurts and usually helps.

EDG,

What are the sprue plate feed hole diameters?

Best regards,

CJR