Sprue Plate Temp?

[Nora]

Was out casting today and stated thinking about the temp on the sprue plate. Has any one noticed any direct relation to the temp vs. the base fill out? I'm thinking along the lines of it being able to draw in the final bit of lead or not as it cools and the sprue hardens. I don't have any problem with good fill out myself but was just curios as to how much effect it has beyond does the lead smear or not, or is it easy or hard to cut?

Nora

[mooman76]

I don't know how much it affects base fill out but I am sure it is a factor. The sprue plate does need to be warmed up just like the mould. If the spure plate is not heated up it cools the lead down before it gets in the mould and you get poor fill out. I believe that is a big(er) issue than some people especially new casters realize when they are casting and banging their head against the wall trying to get good bullets. As big as the sprue cutter is on the Lee 6x moulds I have a harder time getting it up to a good temp when first starting out.

[Le Loup Solitaire]

Hi, There is a relationship between sprue plate temps and fillout, but no one has nailed it down. The question/idea/concern fist surfaced on an article by Col. E.H. Harrison in his article in the NRA loading handbook titled, "Aluminum Sprue Plate Rated High". The Alu sprueplates apparently produced better filled out bullets as they did not retain as much heat....allowing the sprue to convey more of it to the bullet quicker and/or for a longer period of time. There is also the factors of sprue plate thickness both for the aluminum and the steel/iron ones. Its definitely a subject area that merits further investigation. I've made and fooled around with a few aluminum sprue plates and they do make better cast bullets...there has to be a reason and an equation to it. Maybe someone else knows more. LLS

[MakeMineA10mm]

I think you're absolutely right. I noted that today while casting as well. I also agree it's not 100% nailed down info. either.

I noticed today that when I used the iron moulds with thin steel sprue plates (2-cav. Lyman 358156) that I was getting regular rounded edges on the base of the bullet in one cavity while the other was filling out perfectly. I had been casting in just the cavity that was working well for awhile (that cavity is HPed and I was primarily trying to cast up HPs), and it kept working well, but the second (solid-nose) cavity didn't fill-out about every-other cast.

When I switched to the Lee alum. mould with thick steel sprue-cutter plate, I tried several different tactics.

I tried filling each cavity individually. (After getting a feel for how much lead filled a cavity, I tried to "meter" out that much lead, leaving a small sprue puddle over each cavity.)
I tried filling each cavity individually, but running all the sprues together by letting them bump into each other.
Finally, I held down the valve handle and let the lead stream continuously while moving the mould from cavity to cavity as each one filled up and once the sixth cavity was full, I ran the stream down the top of the sprues again to build-up the lead/retain more heat on the sprue plate.


I felt this last technique produced the best fill-out/least number of rejects.

[10mmShooter]

MakeMine10

With my lee 6cav, through trail and error I found the last technique the best as well, I set my flow from Mag20 to a managable level. then open spout and in one continuious movement fill from front to back cavity never stopping the flow of lead.

[runfiverun]

i do the same thing with my lyman 4 cavs and the magma pot with 2 fill holes.
it keeps nice square bases by allowing the mold to fill over the small amount of time given to the lead in the mold.

[Echo]

I like to have a nice pool of alloy on the sprue plate, and generally use the continuous-flow method, no matter whether 2-, 4-, 6-, or 10-gang mold. I have even Dremeled out the space between pour holes to connect the sprue pieces, and increase the heat on the plate.

[mrbill2]

I made larger sprue plates (3/8") for both my single and double cavity molds. They both have a generous sprue with plenty of metal for the bullet when cooling.
Nice flat bases.

[MakeMineA10mm]

That is cool, Mr.Bill. Also, I note the extension for tapping the sprue plate open looks longer on your custom ones, making opening easier. Nice design and execution.

Does it take longer for the sprue plate to heat up to casting temperature? (I imagine so, as that's the point - it will also loose heat slower, thereby giving you better filled-out bases...)

[45r]

I put my sprue hole right up to the nozzle on my rcbs tilted to the right and just loose enough to tell when the pour is full and drop down to make a sprue puddle.As soon as the puddle hardens I put it in front of a fan and cool it for a few seconds and turn the mold back and forth so it doesn't get too hot.I don't have to run two molds at a time this way.If the mold gets too hot it is usually on the right side from excess pour dribbling over that side if I don't lean back left soon enough.The sprue plate holds heat on the left side so this way kinda balances out and I open the mold and put the hot spot toward the fan for a while and that stops any shruken boolit syndrome if that starts.Keeping the mold and sprue at just the right temp can be done with a fan once you find what the mold likes.Putting the sprue hole up kinda tight to the nozzle always gets better base fill-out for me and fan cooling helps getting better fill-out everywhere else for me also and I can concentrate on one mold.I like saeco and rcbs molds for fan cooling.I don't need it that much for my aluminum Mtn Molds.

[mrbill2]

That is cool, Mr.Bill. Also, I note the extension for tapping the sprue plate open looks longer on your custom ones, making opening easier. Nice design and execution.

Does it take longer for the sprue plate to heat up to casting temperature? (I imagine so, as that's the point - it will also loose heat slower, thereby giving you better filled-out bases...)

I preheat the molds on a hot plate and use a open ladel when casting. Takes a second or to longer for the sprue to cool but I'm in no hurry. I just move the plate to what ever mold I want to cast with.

Mr. Bill2

[wallenba]

I made larger sprue plates (3/8") for both my single and double cavity molds. They both have a generous sprue with plenty of metal for the bullet when cooling.
Nice flat bases.

Seems like a nice business to get into Mr Bill, I'd like to be the first to place an order for some!:D

[TAWILDCATT]

I think its not the temp as that should be what the mold is.most of my plates have been modified.I used a ball end mill to go between the holes A LA H&G.
its the quantity of lead over the hole allowing the shrinkage to be filled.I have not done it to Lees because I no longer have access to a mill.It would be nice to do it and then anadise the plate.I have to find a machine shop only one in this county.
up north there all over the place.
no I am Not moving back.