Tobho's HT1-Inspired Cement Mixer Muller Build

More advice from non-experience.

I think I read somewhere that sea coal is charcoal. Maybe someone who knows will chime in.

 

I found that sea coal made a huge difference for me when casting iron—-sand just falls or brushes off. No exp. with bronze. I bought mine from local CANADIAN ( just cross the border from me ) OCL Foundry supply. If you absolutely can not find some locally, I could send you 5 pounds. It’s just that shipping to our good friends to the north is ( I think) usually silly expensive. But, let me know if you want to go that route.

Seems like someone has to have it in your area. Mine is simply mineral coal ground to table salt fineness. It is not nearly as fine as flour, for example

 

No, sea coal is an archaic term referring specifically to mineral coal as opposed to charcoal. The term seacoal originated when people gathered mineral coal from the English coast.

https://www.quora.com/What-is-the-difference-between-coal-and-charcoal

.interesting background: http://www.scottishheritage.net/seacoal.html

 

If you can't find sea coal somewhere, I wonder if you could substitute graphite powder?

 

Yeah, I was thinking 50 cents per pound. My local cathodic protection company sells anodes for $2 per pound. Since I get free copper I was looking for cheap brass...

 

Thanks! I knew it was something I had around.

Tobho: Coal is easy to break. How much do you put in? Coal dust in a blacksmith shop is very usable. You wet it down, drag it up to the fire, and it will coke right up into large clumps. It is also used when hot punching as a lubricant to keep a punch from sticking. You might grind it up in a sausage grinder or he may want to sell coal dust.

 

They're too hard to be zinc, and the threads hold up better than aluminum would, so I'd expect they're Zamak of some sort. Mine didn't melt while actually using the furnace. I place a 55gal drum over the furnace right after I'm finished with it. I did it after my final firing of the furnace and the next time I lifted the drum they were toast.

Pete

 

Jeff,

Let me play devils advocate concerning your toying with doing "hard labor" breaking coal into coal powder/meal. The one thing I might wonder about is whether too much coal dust or powder might reduce porosity of your green sand. Do I know that is a problem? Nope. I would just have that concern in the back of my head. That might be why the foundry sea coal I got was somewhat coarse at least compared to powder and there weren't many fines in it. So, if you do decide to try smashing up coal, (videos are required!) you might sieve out the fines, so you end up with a coal "sand" that is less likely to cause reduced porosity.

I will gladly accept any criticism of this suggestion as needless worry cuz I may be way off base.

 

This may be of interest. The first couple paragraphs of the introduction hit on some of our questions.
https://scholarsmine.mst.edu/cgi/viewcontent.cgi?article=7679&context=masters_theses

This may explain why my petrobond didn't stick like my greensand did
https://en.m.wikipedia.org/wiki/Sand_casting#Additives

Pete

 

Great find , Pete.

The conclusion paragraphs were good too suggesting particle size of sea coal had slight affect itself on permeability, but the sea coal does generally reduce permeability.

 

So can you dust the mold with powdered coal prior to closing?

 

You should get you a lump of coal and break it up just for experience. Hardness varies a lot, but basically it's about like plaster. A little pecking with a hammer breaks it right up.

 

Sorry, should have posted here really but get lost between the two threads.

Seems to be a brush on graphite (Suspended in a volatile) I know it is used with iron, maybe the same applies to bronze temps, they mention refractory nature of the coat.

My post on AA:

Here's an interesting link:

http://www.hillandgriffith.com/alcoh...g-mold-coating

I noted this particularly "Prevents burn on, burn in, metal penetration problems."