Casting problem. What problem is this a symptom of?

[prickett]

I've been casting for a while, but am seeing flow around the base of my boolits for the first time. I suspected my sprue plate needed tightening down, but it was tight. So, what is the problem that results in "base flow".

[slim1836]

Could be you're cutting the sprue too soon, not letting it cool down enough.

[John Allen]

It looks like you have a bow in your sprue plate. Put a straight edge on it and make sure it is not bowed.

[selmerfan]

Yep, looks like a warped sprue plate.

[swheeler]

It looks like you have a bow in your sprue plate. Put a straight edge on it and make sure it is not bowed.

That's what it looks like a warped sprue plate.

[Bullshop]

Sprue plate screw too tight is one possibility. Pressure pouring is another and a warped sprue plate is a third.
To get the correct tension on the sprue plate screw so the plate will lye flat on the top of the blocks try this,
First loosen the screw so there is not tension to the plate. Now hold the mold up to a light and watch the point where the plate lays on the blocks. Now while watching slowly tighten the plate screw. As the screw gets tight you will see the plate lift up off the top of the blocks and you will see light between the plate and blocks.
Adjust the screw to the point where it just lays flat on the blocks.
If you have a set screw that holds the plate screw from turning continue to watch as you tighten that. Often times tightning the set screw will also lift the plate off the blocks. If that happens back the plate screw out about 1/8th turn and try again until you get just the right adjustment so the plate will lye flat on the blocks.
That might do it.

[williamwaco]

If that is happening only on the front cavity, the sprue cutter is too tight and "cocked-up".
If it is happening on both cavities, it could be too loose and "floating" the sprue plate up.

Could also be warped.

Try placing it on a flat surface and see if it "rocks".

.

[Bullshop]

I just went back and read your post and from what you said about the plate screw being tight has me fairly well convinced that it is too tight and is causing the problem I described in my first post.
The plate screw should not be too tight or in some cases not tight at all. Each mold will be different and will require this adjustment .
Try the process I described and I think you will solve your problem.

[brstevns]

My frist thought would be the spur plate, however there may be one other thing. Know it sounds strange but here it is. Years ago when I frist stated casing I had some problems with a Lyman mould just like you are having. I found it to be two things. One running my lead to hot and two not enough WW to lead ratio. If the alloy was to soft I had the fins on the base like you are having. Hope this was of help.

[prickett]

If that is happening only on the front cavity, the sprue cutter is too tight and "cocked-up".
If it is happening on both cavities, it could be too loose and "floating" the sprue plate up.

Could also be warped.

Try placing it on a flat surface and see if it "rocks".

.

I should have mentioned this is a 6 cavity Lee mold and it is only the cavity closest to the sprue plate bolt. Sounds like too tight just might be the cause.

[prickett]

My frist thought would be the spur plate, however there may be one other thing. Know it sounds strange but here it is. Years ago when I frist stated casing I had some problems with a Lyman mould just like you are having. I found it to be two things. One running my lead to hot and two not enough WW to lead ratio. If the alloy was to soft I had the fins on the base like you are having. Hope this was of help.

Interesting theory. It did seem to calm down towards the end of my session when the temp decreased from over 700 to just a bit under 700.

[MT Gianni]

Make sure that the base of the sprue plate does not have a lead booger under it. Use a good sprue plate lube like Bullplate.

[prickett]

Thanks for all the suggestions everyone! Lots of good information and things to try.

[Balta]

i did have same problem when i to tighten the sprue plate ..

[Jamezius Maximus]

After you get the warped plate fixed, Try some carnuba red lube, put it on the block after its heated up and this may help.

[Rattlesnake Charlie]

I had something similar, but not as drastic. And, it was happening on all four cavities of a Lyman mold. Turned out I was casting too fast and the sprue plate was really hot. Some intermittent cooling with a damp cloth solved the problem.

[captaint]

I like to keep my sprue plates loose enough to swing under their own weight, or very nearly so. While I haven't had the OP's particular problem, I have had my share of the usual issues. If I had to vote, I would say it's too tight, actually pulling the open end up. Just my .02. enjoy Mike

[zomby woof]

Is that a LEE 9mm 120? I had the same problem. The sprue plate was concave on the underside. I should have sent it back but sanded the underside flat. It was real bad.