Venting

[Echo]

Yo;

Picked up a couple of double-gang Ideal molds on eBay. One is the 3118 (that I will keep), and the other a 358432, of which I already have a 4-banger. They are in great shape. Neither have any venting grooves. Makes me wonder. I intend to gently stone the top edges to provide SOME venting, but welcome any comments.

[HeavyMetal]

I'm gonna go out on a limb here!

First I've cast with both the old Ideal molds that had no vent lines and the newer Lymans that did. Sadly I have never had the oppertunity to cast with the same boolit in the two different designs.

So what I have learned is each mold has it's own preference as to how and what makes it work right: the mythical "sweet spot"!

The non vented Ideal's seem to prefer hotter mold and alloy temps to work right but some Lymans with venting also have this need.

I think it has more to do with design and size of the boolit than how much it's been vented.

Getting the boolit base to fillout sharply has been a big question I've seen posted on this site for the last year or so.

I to had the problem from time to time and did, and still do, take a small sharp file and angle the top of the block directly under the sprue plate for an additional vent line each time I aqquire a "new" mold no matter who makes it!

I am not convinced this works, in and of itself! Lately I have taken to dipping the sprue plate, when possible, into the alloy and heating it just as I would dip the blocks themselves in the alloy to get them up to temp.

Between the new vent line and the plate dipping my rejection rate for rounded boolit base's has pretty much dropped to nothing!

Now this works real well for one bangers and I actually developed this technique while wrestling with my first HP molds. For bigger molds like the Lyman 4 bangers or the Lee six's I needed a different approach because it is not possible to dip the sprue plate's on these designs.

What I did was weld a pair of 1/2 inch thick square steel bars about 5 inchs long on top of a square flat plate about 7 x7inch's square.

this sits on top of an electric hot plate and I set the mold on it so the handle that holds the block fits into it and allows the mold to sit flat "ON IT'S SIDE" thus allowing the sprue plate to always be in contact with the heated plate.

I do have to heat the sprue plates by pre heating the mold while the alloy comes up to temp. Since I try to cast with two molds One will go on it's side on the hot plate then I start my lead pot and set the other mold, sprue plate down, on top of the pot to pre heat.

This has worked very well and only requires a quick dip of the blocks into the alloy to get them up and running very quickly when the alloy is ready.

So if you use these non vented molds and have an issue with base fill out try a couple of the tricks I've outlined and see if they work.

By the way sorry to be so long winded.

[Echo]

Thanks, HM. I will try some boolits this week with WW+2%, and post results.

[yondering]

You might try beagling the mold, this causes a slight air gap between the blocks and will "vent" the mold.