Found Dreaming

Well I don't know whats happening here, but I had another explosion yesterday, sand was fine so I'm thinking some crawling little bugger got in . I do keep the pouring cup covered to try and keep things out but one little sneaky bugger must have slipped by me. We do have a ground dwelling spider that could of got in as they move rather quickly http://australianmuseum.net.au/huntsman-spidersThis time I was not so lucky a bit of metal landed on my scull, my back and down my glove so three smallish burns, so no real damage, wife did inform me tho that I have one more chance then she''ll be wanting me to shut it all down ..I have modified a new steel crucible with a cover to try ad deflect and metal in the future, I have no idea what I'll do when I'm pouring brass or bronze. I'm also thinking I'll heat the molds before closing but with in being winter here they may think that's nice and toastie

Be Careful Mike. I don't know, I've never had anything like that happen. Bugs or some other critter, or just not enough venting so steam has nowhere to go.

put a piece of window screen over the pouring basin so them little critters can't get in. also you may want to riddle all the sand that's close to the pattern.

As Jerry said Be CAREFUL

I use a 1/4 knitting needle to vent, but I only have been putting 2 at the back of each coaster, guess I'll do a few more now, I guess you can't have to many....This issue has only just started, I've never had venting issues this serious before, or problems with bugs

I generally use a piece of MDF to cover the pouring basin, but will give window screen ago

One way to make sure nothing is in the mold don't close it until your ready to pour, but I would try the window screen, use the fiberglas type.

if your pouring the plaques face down use a sharpened needle and put a bunch of vents all across the back or cope side. I use 3/32 brazing rod.

The way I was venting was working but for some reason it just don't wanna anymore, I'll do it Dave's way

What I was doing was putting a number of small risers at the back of the pattern, and for the most part it was working, but I'm guessing the way the metal was flowing every now and then the steam was getting trapped which resulted in the explosion, I'll now vent as Dave said, which is the way I was doing it but changed to the small risers. sometimes it does not pay to move away from recognized practices, it can hurt

use a small rod and sharpen it to a blunt needle point so that it won't stick into the pattern and leave the smallest hole if any at the pattern face. Books say to stop 1/8" short of the pattern,

And your right sometimes change hurts like hell specially when its 2000 degrees!!!

Melt some metal have some fun and BE SAFE

I poured some cast iron into an ingot mold one time that I forgot to preheat, or didn't heat enough, blowed the stuff 15 feet up in the air with no place to run to lucky non of it hit me, bad thing was I had a guy over here watching me pour and it was his first iron pour, not sure of the impression I left him with but he was awful quite when he left.

I have had that happen Dave, I poured Lead into a cast iron mold and it spit and sputtered for about a minute. I don't know where that moisture comes from, just from the air, I guess.

Here is a photo of the casting


The casting cut in half