Found Dreaming

Those do look really good Mike, very professional.

Nice job Mate!!

Thank you Jerry & Latza

That's more like it, Mike!! Those are BEAUTIFUL!! FYI... You can reduce the volume of stickle-back vents by broadening risers out the opposite end of your cast, or add risers on the three sides of your cast opposite of your in-gating. You can also reduce potential of steam build-up and face defects by reducing your sand moisture content to within 3 to 5%. I'd venture to say you're closer to 10% (or more) at least from the surface defects you've been experiencing. Add a bit more (1%) of bentonite to your sand and mull that in real well. It'll aide in bonding, give you smoother cast finishes and bring your moisture content back to being more manageable. A dusting of the mold face with powdered charcoal will also add to the cast finish quality. I, personally, would do the coal dusting to the pattern during making the mold right after powdering with talc. But with flat surface plaques you still have to vent real well either with stickle-back vents (that's my term, not necessarily a foundry term), or through added risers. Once you get your sand right you'll soon see occasional casts that will have a silver dollar size scaley patch that will give you hint your sand needs better mulling to distribute the moisture content more evenly. Increased venting will only aide in preventing dramatic scaling effects and blow outs. Minor scaling over all is a combination of too wet sand and, at times, too hot of a pour.

Not sure what kind of metal you're using. With every alloy there are inherent characteristics in how they react in green sand mixes. You can dial in your sand to accommodate pretty much any alloy you use but it will not work as well with another alloy of the same generic type. Keep a journal of everything you do with every type of scrap or alloy you use. Those notes will aide in giving you greater success over the many casts you do in the future.

I was looking at an old foundry book from the 1800's, it had a different greensand mixture for each kind alloy. It was online, I'll have to go back and see if I can post it on here somewhere.

Jammer wrote:I was looking at an old foundry book from the 1800's, it had a different greensand mixture for each kind alloy. It was online, I'll have to go back and see if I can post it on here somewhere.

That would be a very interesting book to read Jerry, there is a library section just for this type of thing

F.C. wrote:That's more like it, Mike!! Those are BEAUTIFUL!! FYI... You can reduce the volume of stickle-back vents by broadening risers out the opposite end of your cast, or add risers on the three sides of your cast opposite of your in-gating. You can also reduce potential of steam build-up and face defects by reducing your sand moisture content to within 3 to 5%. I'd venture to say you're closer to 10% (or more) at least from the surface defects you've been experiencing. Add a bit more (1%) of bentonite to your sand and mull that in real well. It'll aide in bonding, give you smoother cast finishes and bring your moisture content back to being more manageable. A dusting of the mold face with powdered charcoal will also add to the cast finish quality. I, personally, would do the coal dusting to the pattern during making the mold right after powdering with talc. But with flat surface plaques you still have to vent real well either with stickle-back vents (that's my term, not necessarily a foundry term), or through added risers. Once you get your sand right you'll soon see occasional casts that will have a silver dollar size scaley patch that will give you hint your sand needs better mulling to distribute the moisture content more evenly. Increased venting will only aide in preventing dramatic scaling effects and blow outs. Minor scaling over all is a combination of too wet sand and, at times, too hot of a pour.

Not sure what kind of metal you're using. With every alloy there are inherent characteristics in how they react in green sand mixes. You can dial in your sand to accommodate pretty much any alloy you use but it will not work as well with another alloy of the same generic type. Keep a journal of everything you do with every type of scrap or alloy you use. Those notes will aide in giving you greater success over the many casts you do in the future.

Thanks Frank....On these patterns ( see photo ) I was doing about four 3/8 risers at the back of the pattern only and no stickle-back vents at all, with the last run of castings I still did the four risers but I sure put a heap of vents using a brassing rod.....Next time I'll try the charcoal dusting, I also dont use talc I've been coating the pattern with graphite, then if I'm doing repeat molds I use plumbago, I do have a few buckets of calcium carbonate here with I also use from time to time
With regards to my sand If it feels right and grains don't stick to my hands I'll use it,but I have no doubt it is probably a tad damp I will add a 1% extra bentonite and see how i get on
At the moment nothing is happening here as my lower back has turned to shit again, Doc suggest that I should start thinking about give up working for a living..... I had a MRI done yesterday and a doc's appointment for later today so we'll see how that goes

Frank, I'm using Alloy wheels and any another cast aluminum that I can find. A lot of what I use is from broken gearbox casing that end up in the scrap metal bin at work

Mike do you have muller for you sand or are you mulling it by hand I can't remember if you built a muller or not.

If you don't have one I would seriously consider building one as it will make a world of difference in how you sand behaves.

be sure you hang that Brazing rod/Vent wire up within arms reach of the molding bench.

Plumbago is a fancy name for graphite.

What did the Doc say about the spinal column?? he tell you to start drinking water or some other distasteful liquid like lemonade

dallen wrote:Mike do you have muller for you sand or are you mulling it by hand I can't remember if you built a muller or not.

If you don't have one I would seriously consider building one as it will make a world of difference in how you sand behaves.

be sure you hang that Brazing rod/Vent wire up within arms reach of the molding bench.

Plumbago is a fancy name for graphite.

What did the Doc say about the spinal column?? he tell you to start drinking water or some other distasteful liquid like lemonade

No muller Dave so its all done by hand.....I know plumbago is graphite Dave, but I find there is a difference between the graphite from the auto store and the plumbago that I have, the graphite is much slicker or smears on the pattern better
Doc says I have arthritis on the lower spine and has given me some pain killers to try. I really don't want to be doing regular work with the pain that I'm in at the moment