Mold tuning

6K Views
Last Post 31 January 2014

CBA President

John Alexander posted this 27 January 2014

I bought a new 225415 a few years back. I was surprised to see that it was quite different from one I bought 45 years ago - quite a bit longer and with a 10% claimed increase in weight but same number.

Finally got around to casting with it this past week. The sprue plate had been punched out and there was a lip around the edge. If the sprue ran over the edge I had to stop and pry it off because it would be stuck tight to the edge. Ground a smooth bevel around the edge and cured that problem.

Then I found that the hardened sprues still wouldn't come out of the conical depressions over the holes even if it was just a neat round puddle over each one because of the rough machining marks. I grabbed up the nearest thing that I thought would work - three different sizes of round headed screws and some 220 grit valve grinding compound and ground away until shiny. That mostly civilized the mold but the solidified puddles still don't come out as gracefully as they should. Will polish more.

Are others finding these problems with current molds or was I just unlucky? What is a better way to smooth the rough conical depressions over the holes?

That mold could better be described as a mold kit instead of a mold since it wouldn't work as received. I should have sent it back.

John

Attached Files

11 Comments

Order By: Standard | Newest | Votes

Standard Member

onondaga posted this 28 January 2014

http://www.castbulletassoc.org/view_user.php?id=6375>John Alexander

You did the hard stuff already. If you can get the sloped wall of the sprue gate hole smoother, go for it. Re-blueing with cold gun blue is good too. Still, a regular pencil will help too. Write on the area with the pencil lead heavily. The graphite in pencil lead is a very good anti-flux and will not allow lead to stick.

I have repaired rough tool marks on a sprue gate hole slope with an abrasive rubber point and a Dremel tool. I re-blued and used the pencil trick too. works well.

Gary

Attached Files

CBA Member

delmarskid1 posted this 28 January 2014

Lyman? Yes, sometimes. Lee? Yes, often.

Attached Files

Standard Member

j35nut posted this 28 January 2014

Why not just make a new sprue plate with more appropriate sized sprue holes for 22 cal.

It always bugged me that the base on most 22 cast bullets is practically all sprue cut.

My sprue plate for my 225415 has .007 diameter sprue hole's and works real nice.

Jay C Dye wrote up a article in one of the Fouling shots i believe it was # 175 , you need a center reamer or a counter sink to recut and smooth and sharpen your sprue holes.

I know there are at least three different as to weight and shape 225415 molds out there.

---J

Attached Files

CBA Member

mrbill2 posted this 28 January 2014

"My sprue plate for my 225415 has .007 diameter sprue hole's and works real nice."

Dats a widdle hole.:taz:

mrbill2

Attached Files

Standard Member

j35nut posted this 28 January 2014

mrbill2 wrote: "My sprue plate for my 225415 has .007 diameter sprue hole's and works real nice."

Dats a widdle hole.:taz: Yes it is, and I was skeptical as heck when a more experienced caster than myself recommended it about six years ago .

-----J

Attached Files

CBA Member

fa38 posted this 28 January 2014

Maybe the sticking sprue is not just the rough machining.

I have found that taking a cloth with some WD40 on it and wiping it all over the top of the sprue plate helped getting the sprue to come off easily. When they start to stick again just repeat with the cloth.

Attached Files

CBA Member

Duane Mellenbruch posted this 28 January 2014

As long as you are discussing the diameter of the sprue holes, you might keep in mind that the very small holes may not be compatible with bottom pour free flow casting.

I had a learning experience with a Saeco #221 that helped me learn a lot about this issue. The original mold came with the standard large holes, but the mold was cut with a very short gas check shank. I sent it back and after a new mold was made, received it and found that I could not get good base fill out when using my normal casting method with the bottom pour pot. I found that I had to pressure cast and that was slowing me down. The replacement mold had smaller sprue plate holes.

I discussed this with the folks at Redding and a used sprue plate with the larger holes was provided. This allowed me to have faster production but rough bullet bases. After some consideration, I opened up the plate with the small sprue holes to the next size with a very sharp drill. This happened to be a 1/8” bit (.125). Basically, this just cleaned up the hole a little bit, but now I can free flow from the BP pot and have nice bullet bases again.

So if you are normally a ladle caster with the pour spout in the sprue hole, or a BP caster that pressure feeds, the smaller hole will be very good. If not, then you might have some frustration thinking your mold went south on you.

Larger is not always better, and sometimes smaller is not such a good idea either. Duane

Attached Files

Standard Member

JeffinNZ posted this 28 January 2014

I made 5mm thick 7XXX series aluminium sprue plates for my 225415 and 225462 each with 2mm holes. Work GREAT. I ladel pour with contact against the sprue - semi pressure pour I guess you would call it.

http://smg.photobucket.com/user/JeffinNZ/media/Shooting%20stuff/225462.jpg.html>http://smg.photobucket.com/user/JeffinNZ/media/Shooting%20stuff/22base2.jpg.html>

Cheers from New Zealand

Attached Files

CBA President

John Alexander posted this 29 January 2014

Thanks to all who replied with suggestions. I will try some of the tricks offered.

As to why I don't make a new sprue plate it is just laziness and irritation that the one on the mold SHOULD work if you sell a mold.

As far as the smaller sprue hole I too believe they could be a bit smaller for the short 22s although as Duane mentioned that could be overdone. I use my hand to cut sprues and if it becomes difficult I just offset the sprue plate to reduce the size of the hole. No one has said that it has to be round and in the center and when you cut it smooth with hand down pressure they shoot just fine.

Jeff, when you go into production and start selling those sprue plates let me know. John

Attached Files

CBA Member

porthos posted this 29 January 2014

JOHN:

you might try making a lap out of a piece of wooden dowel rod. one half inch would work. the distance that i measure across the spru holes is appx. .450. turn it is the drill prress or lathe to the appx. angle of the spru hole and run in drill press with grinding compound the pressure of the drill press and speed will form the exact angle of the spru plate bevel

good luck

porthos