Sprue Plate question

[MSalyards]

How loose or tight do you like to run your sprue plate? I have a new mold from one of the popular mold makers and I'm getting some finning on the butt end of the bullet. I never had it there before. It seems pretty sloppy before it goes away.

Mike

[Woody]

If you are bottom pouring, you can have that finning with a loose plate. Ladle pouring, usually is not plate tension sensitive. If you are ladle pouring, then your plate or blocks may not be flat. A lot of production moulds don't have flat sprue plates. Easy to check and fix. Lap the plate on a piece of glass with oil. You can use wet/dry 400 grit oiled on the glass and will know if the plate is flat immediately.

Woody

[Woody]

If you are bottom pouring, you can have that finning with a loose plate. Ladle pouring, usually is not plate tension sensitive. If you are ladle pouring, then your plate or blocks may not be flat. A lot of production moulds don't have flat sprue plates. Easy to check and fix. Lap the plate on a piece of glass with oil. You can use wet/dry 400 grit oiled on the glass and will know if the plate is flat immediately.

Woody

[MSalyards]

Thanks Woody. This is a custom mold by one of our more popular mold makers but it gives me a place to start. I'm ladle pouring and the finning is very light but it is there and I never had it there before . I'm able to remove it with my thumb nail and the bullets bases are still flat and nice , and the bullets are dropping at .5 gr +-.


Mike

[bpcr shooter]

X2 on what woody said.....

you can try and put a larger washer on your hold down screw as well.

[Clarence]

As Woody suggested, lap the sprue plate. When you re-install it, set it so that it rotates easily but is not sloppy.

Also, I find that each mould has its own "personality", requiring slightly different techniques. Some require longer times for the dipper to be held tightly, some like a loose dipper with lead oozing around the tip, and some fin if the dipper is held too long or too tight. You might experiment with different techniques.

Hope this helps.

Clarence

[MSalyards]

Kinda what I been doing . I'll lap it and report back.

[Kurt]

I use 800 grid wet dry paper on a glass plate and figure 8 it. I also use a tight plate I have to push open when the mould is cold and empty. I use a pouring routine that settles the alloy by vibration and the edges are sharp. pouring with a free swing plate on a empty mould gives me a lot of variances in weight when I pick the ladle up off the plate and ley it empty over the hole. This tends to lift the plate when it's free moving and I get flash over and more weight the way I cast.

[bruce m]

I have had moulds that were dished on top as well.
the same lapping process as with the sprue plates will flatten them
problem is if they have a pin rather than a screw in the top it can be an issue.
moderately tight sprue plates can get quite loose when things heat up, and need to be adjusted in hot condition for best results.
if adjustment just won't do it, get out the glass and sand paper.
bruce.