Wednesday, December 31, 2014

More Muffins with a Side of Greensand

There hasn't been much post-worthy lately but I have made a little bit of progress on my casting projects. The holidays have been fairly busy and it seems like the days where I don't have anywhere I'm supposed to be, it's been cold and spitting rain so I still couldn't work on any of it.

I managed to melt the rest of the bike pieces and a few other items and now I'm just shy of a dozen aluminum muffins.
I also got the greensand ready to go. I ended up using a mix of 10% bentonite clay (by weight) and play sand with a little water based on recipes I saw on several websites and in videos. 

Initially it was having trouble finding the bentonite in either the amount I wanted (I didn't need a truck load) or in the granularity I needed (one of the big uses of it is for kitty litter which is way too coarse). 

Eventually, I learned that it is the same stuff they use in mud masks at day spas. I found a nice 2 lb container of it on Amazon that ended up being the perfect amount for what I needed.  When mixed with about 18 lbs of play sand, it was just enough to fit in a 5 gallon bucket (without compressing).

For the play sand, it was nothing special. I just used the stuff from the big box hardware store that is sold for kids sandboxes.  I did, however, screen it first using a screen I made out of some window screen I had from another project.  There was a surprising amount of small pebbles in the sand I used and I'm glad I took the time to get them out before mixing everything together.

One of the bigger tips I can pass along for anyone else trying this is to use a spray bottle to add the water. It is very easy to put in too much water and, of course, very hard to get it back out.  Okay, not hard, but it takes time waiting for it to evaporate. I can't take credit for this tip, I saw it on a couple of the websites/videos, but highly recommend doing it this way.

As far as just how wet to get it, I followed the general rule: dry enough to not stick to your hands but wet enough to stay together when squeezed. 
It also should break cleanly and not crumble. 
The resulting sand packed great. I can't wait for the weather to clear up so I can finally get around to making the mold and casting.

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