Time to wait before opening mould...

[Etienne Brule]

Hi,

I cast since a few time: I use to open the mould when the sprue is solid: so, it was 10 to 15 seconds and that was it.

I just heard to wait for 1 minute 15 seconds... so long: I trid it and... bingo...every detail was so great; a very nice bullet and a new girl !!!

so I am now waiting those 95 seconds before opening the mold...

It is just great; So I am still learning... paradigm...

Etienne Brule

[RP]

never heard that before do you have any problem with your mold coolind down to much??

[Etienne Brule]

Hi Ricky P,

I use a Lyman Postel 45-70.

Everything was goeing very smoothly... It was quite long waiting : 1 min 15 seconds... Time to smoke all those cigars I already quit...

But, ... ... t hat was it: a great bulllet with a lovely base and grooves that make me crazy...

And, 0.1 to 0.2 grains differences between each bullet, no more...

Etienne Brule

[mooman76]

As soon as I see the lead on top of the sprue change color to a dull gray so that I know it hardened I open it about 3 or 4 seconds after that. The whole process only takes usually about 6-8 seconds. Any longer and I turn the heat down so it isn't so hot. Smaller bullets cool quicker and I take into consideration that a heavy bullet mould will take a little longer to cool.
If you like the wait it is good to have two moulds going at once.

[DLCTEX]

I think you are getting things way too hot. Is it hard to cut the sprue after you wait that long? When the melt and the mold are hot enough I push the sprue plate open with a gloved hand. Are you using an electric pot? Bottom pour or ladle? Are you preheating the mold? We need to know more if we are to give good advice. DALE

[warf73]

Sounds like your alloy is way to hot if you are waiting 95 sec to open the spur.

Once everything is right: alloy temp, mold temp, I get into a rythem of 2 pours a min and can run that speed until the pot needs refilled. By that time I start getting heat issues with the mold. I can pour faster but the mold heats up way to fast.

This is with a iron 4 cavity mold, but can almost run the rythem with alum if I get the pot temp right.


Warf

[Etienne Brule]

I think you are getting things way too hot. Is it hard to cut the sprue after you wait that long? When the melt and the mold are hot enough I push the sprue plate open with a gloved hand. Are you using an electric pot? Bottom pour or ladle? Are you preheating the mold? We need to know more if we are to give good advice. DALE

Hi,

- I use a Lyman mold.

- It is a single hole

- For a 45 cal 535 grains bullet ( for a 45-70 BP cartridge ): the bullets have to be as perfect as possible: it is for competition at 600 yards; I need (and hope to get) a mean weight +- 0.1 grain

- I have an electric pot

- I use a Rowland ladle

- The mold is preheated for at least half an hour.

- Ratio: tin: pure lead 1 : 20

- The first 20 bullets are discarded whatever their appearance.

- Fluxing every 20 bullets.

- I push the sprue plate open with a gloved hand

BEFORE:

I used to wait about 10 seconds before opening the mold.

I was told and I read that I should open the mold as soon as the sprue was solid: about ten seconds and that was it .

Everybody seems to do it that way: so this is the way to go ( is that a paradigm ?)

NOW:

I wait 95 seconds and I find that I am getting bullets with a better standard deviation of their mean weights.

Why ?

I read that somebody was using the 95 seconds method with great success...

I got the book from Paul A. Matthews:

"Loading for Black Powder Rifle Cartridge" ( p.60)


"Like many other bullet casters, I am short on patience while waiting for the sprue to harden, During one casting session with my Lyman 457132 mould, I laid my watch on the bench and timed each bullet form the time I removed the dipper from the mould until I swung the cutoff plate. One minute and 15 seconds ! Not a second sooner or else I had minute cavities in the base !"

And I tried it:

I just find their best appearance: nice bases. Moreover, the variation in the weight from one bullet to the other was greatly diminished ( my primary goal with a perfect base ).

I did not have any difficulties to open the sprue plate, with a gloved hand.


So I am wondering if I will keep it that way: and maybe use two molds to give some kind of acceleration on those working hours....

Thank you for your kind attention; this is a GREAT forum

Etienne Brule