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Kang's Kreations - Molten Metal Madness

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It's alive!!!

But it still needs scrapers and sweeps and plows installed and adjusted.


Edit - Oh dear, my animated .gif has been removed, thanks for bringing my post into compliance and apologies for not realizing/remembering those attachments aren't permitted!  The rolling muller wheel that was in the gif can be seen toward the end of this video if anyone's interested:




Sorry about that, won't happen again.




Edited by Kang
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It is Big Bucket Mull, former cement mixer and current partially built sand muller, designed for making and rejuvenating the molding sand which I use for casting historical replicas of the Valyrian Bronze axes George R. R. Martin keeps forgetting to mention having been used by the First Men of the Dawn Age of his fictional world. And such.  It rolls and plows and squishes and squashes and smashes and bashes and mashes and scrapes and smears the sand/clay/water mixture into suitable fluffy sticky awesomeness for use, or rather it will when I'm done building it.


Having become inexplicably obsessed with backyard metal casting during an annual late September camping trip in 2013, I have been gradually building and upgrading the Northern Branch of the Forges of Qohor in my backyard over the past four and a half years or so.  Most of the pictures I have posted earlier in this thread are being held hostage by Photobucket but I have linked serveral videos from my 'Tobho Mott' youtube channel (where A Song of Ice and Fire fandom and backyard metal casting intersect) above if you're interested in seeing more about the greensand and lost foam casting processes, how I make molds and operate my homemade foundry equipment such as Balerion the Black Dread the big waste oil fired melting furnace, Lightbringer the drip injector waste oil burner, Ser Robert Tong the crucible lifter, King Robert's Rammer the sand ramming tool, and a host of other beloved characters and artifacts.  Thanks for asking; check it out, I believe you'll get a kick out of this particular internet weirdo's OTHER lunatic hobby!



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Ah, gotcha.  Thanks for watching and asking, I'm not trying to be mysterious, so I'm glad you reminded me I hadn't explained it all...  To sum up, all that mashing and smearing etc. causes each grain of sand to end up with a thin layer of clay coating it, in a much less boring and laborious way than hand- and foot-mulling.  Not to mention faster and more effective.



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Good weather at last!


Finally.  Good enough to get out into the foundry, fire up Balerion the Black Dread (the melting furnace), and cast some parts for Big Bucket Mull (the sand muller)!




8 clamps (more than I need, always pays to cast extra when using lost foam casting in case one or two don't come out right) for attaching lengths of pipe to the crossbar.  The pipe sections will hang down and have the sand scrapers (that push the sand into the wheel's path) attached to the bottom ends.


The clamps have since been cut off their sprues, cleaned up on the belt sander, had their bolt holes drilled, and a slot cut out of the ends that you can see in the pic were attached to the central pouring sprues.  A bolt will be tightened up to close up this slot so the clamps will be tight on the pipe and keep it from moving.  In theory anyhow. 


If that doesn't work, I'll simply re-melt the clamps and try something else!  :)


Follow up from some earlier posts: Tong Belwas (the pliers-tongs) worked great, and Lightbringer (the oil burner) worked better than ever now that I've scraped all the chunks of blubber out of the needle valve.  AND I even found my long lost favourite sand scoop while I was setting up the molds!  Yup, gonna be a good casting season, I can tell already.



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More pix of Big Bucket Mull's scraper assembly clamps, 2 of which are now finished up and functional...






They tighten up well, I think they'll be able to keep the sand from making the scrapers push out of alignment.


Also, a new video showing how I made the clamps, plus a close up look at the big homemade melting furnace I call Balerion the Black Dread.  AND some gratuitous fire scenes. 




If you look closely you'll see me using Tong Belwas for the first time, to add ingots to the hot crucible.  That went well, and cleaning the chunks of blubber out of Lightbringer the waste oil burner's needle valve worked wonders!  Adjusting the fuel/air mixture just got so much easier with that done.








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Well, the muller build has slowed a bit.  Easy enough to blame going on vacation and the kids both having their birthdays last weekend, but to be honest work has me a little burned out, so I've just been too tired to get out in the shed and work on stuff...  But I did get the first scraper built and tested fitted...


Click image to watch the YT video:



Since then I have also mostly finished building the other scraper and fitted it, but it needs some bending, which means I need to find my torch to heat it up so I can hammer on it and make it move.  That will be my first attempt at forging, I'm looking forward to that!  Then I want to caulk up the gap around the edge of the muller floor to keep the sand from slipping down there as mentioned in the video, and it'll be finished... aside from minor adjustments.  THEN I can try to make some new greensand!  I have the ingredients readu to go too: finely powdered bentonite clay, and fine silica sand...  The sand is a respiratory hazard, silicosis is no joke, but I will be working outside and once the mixture is mulled and tempered with water, it should stay moist enough to keep the particles from going airborne and getting inhaled.






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Oh gosh, seems like I forgot to post the video where I installed the second scraper! 


Well, too late now, you can find it on my YT channel if interested, but this one is gonna be way more fun to watch... which may not really say all that much.


Well, maybe not, the last one did have my first attempt at blacksmithing in it, which was a lot of fun...  Which you would think I would do more often, given that my youtube name is Tobho Mott...  If there were any metal casters in the (ASoIaF) series, I'd have used their name instead.  Drogo vs. Viserys doesn't count; there's no way you can melt gold medallions in a soup pot over an open fire like that, sorry George.


Anyhow... so, we had a nice weekend, rain free for a change, at least until after dinner on Sunday...  Point being, I actually got to put my Tobho Mott hat on and get some work done out in the Forges of Qohor (Northern Branch), AKA my backyard foundry!


Long story short, I finally got the muller working, and chewing up some real greensand! 


Short story long, there is video!

Ok the forum is not giving me the usual option to display that as a link instead of an embed.  If a mod could fix, I'd be very grateful. It won't even let me remove it!  


Not quite working perfectly yet, but it is working and it is mulling sand.


The one change I made to the muller before testing it with real greensand was rotating the 2nd (center) scraper a bit to improve its angle.


So far I've only used it to recondition my greensand (purchased from a foundry products supplier here in Ontario), not yet for making my own greensand from the ingredients pictured earlier. 


I wound up putting way too much water in the first batch, and maybe a little too much (not 100% sure) in the second.  



Mixing dry to see if it will break up lumps (it does this better with water added, though the big lumps take some time to make their way under the wheel either way):


Way too much water:


Squeeze test: far too wet but super sticky!


Another batch, used less water this time:


Seems to handle half a 5 gallon bucket of greensand just fine, though 3/4 of a bucket was too much for it when it had way too much water in it, it got so sticky (technical term: "stickier as frig") it just sat there in a big clump when I tried to dump it, the drum kept turning but the sand held together and let the drum just spin/slide under it and would not turn over. ::D:  


That part is at about the 12 minute mark if anyone wants a laugh at my expense.

Still getting used to just pouring the water in I guess; I always used one of those little pump-up garden spray bottles before this, to add it as more of a mist.  But with a muller, that is no longer necessary.


Youtuber Olfoundryman, one of my home-foundry heroes, left a comment saying I should ease up on the spring tension because he thinks my wheel is pushing sand to the side instead of rolling over it.  He does not use a muller but he REALLY knows his stuff; 


Youtuber Chirpy's Tinkerings (a friend and fellow metal caster) thinks I need a wider wheel, and I do not disagree; 


Youtuber Worldtraveler (another friend, who does lost wax casting) says I was right about moving the wheel over an inch so the whole width of the wheel is rolling over the area where the sand was sticking to the wheel as it stands now, rather than just half of it.


I'll agree with basically anyone who says I'm right, so that's good too...  :)


I'd like a wider wheel and IMO that would accomplish the same thing as moving the one I have over a bit as well as making it harder for sand to get pushed to the side...  I would cast one if I had a lathe to finish the job.  Or I could buy another wheel like I have and put them side by side, though they would have a gap between them. A guy on one of the casting forums suggested I could cut off the part of the hubs that stick out past the edge of the rims, to make 2 wheels able to sit flush against each other and not leave a gap between them.  It's a possibility...  


I think it is working pretty well, so any more changes would be just to make it work a little better, or perhaps work just as well only a bit faster.  


Mind you I haven't tried making new sand yet, possibly I will learn about more flaws in my build when I try that...


Hope you guys are enjoying this look at my OTHER weirdo hobby...



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Last post was Big Bucket Mull chewing up some old greensand to bring it back to life; here is the true test of his  functionality: making new greensand!




If you enjoy watching noisy machines go round and round, you might just get a kick out of it.


Here's a pic of a test mold half I rammed up after making four 15kg (dry) batches:




All in all, a great success.  Woohoo!


Next upgrades will be to attach a repurposed microwave oven timer so I can set the muller to run for so many minutes then automatically stop and beep at me to let me know, as if all that racket suddenly stopping won't be enough of a clue...  And casting a wider wheel so it will roll over twice as much sand with each revolution.



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Rammed up a few test molds over the weekend and cast one of them in Everdur silicon bronze.  My first time casting this alloy as well as the first casting poured in the new sand. 


Also made up an ingot mold with some of the new sand.


Also made a couple of styrofoam skull belt buckle patterns to cast in the same bronze alloy.




The new sand did not have as much "green strength" as the commercially made sand I'm used to, meaning that the molds were more crumbly.


The sand casting and ingots came out of the mold with the sand stuck to the castings in a thin layer that I had to remove with a wire brush.  Sand that does this is known as having poor 'peel'.  Carbonaceous sand additives like powdered sea coal are known to improve peel, but is normally reserved for ferrous (iron/steel) casting.  I need to level up a few times before taking a run at cast iron, cripes I almost burst into flames manupilating a crucible containing 30# of molten silicon bronze!  That's closer to 1000 than 500F cooler than cast iron.


Organic additives are said to improve peel, and corn flour supposed improves green strength... So I'm thinking of adding some so that it makes up maybe 1% or so of the sand's dry weight.


The ingots has scabby looking marks on their undersides which I have identified as being caused by metal penetrating into the sand. Maybe I could have done a better job ramming up the I got molds, no big deal.  I'm far more bothered by the peel.




The sand casting did not fill, but I had not added any venting to the mold, and the same casting in aluminum had failed to fill in similar fashion when I molded it without venting in the old sand too. 






The bronze also has pinholes in some areas which could come from all sorts of things, but I suspect my having left the mold to sit overnight and dry out slightly was a likely culprit.  I was surprised how brown the casting came out of the mold, like it had been given a patina.  My aluminum bronze axes always came out looking like shiny metal, but then, non-molten aluminum bronze is resistant to oxidization and will not take a patina easily...


The belt buckles... One was a great success.






The other, a dismal failure.  The Dreaded Sand Float strikes again!  I knew it was a failure when I saw the sand on the surface of the mold get pushed upwards from below during the pour. 






Sand Float defects are so weird!  The top part of the casting in the mold gets pushed upwards on a raft of molten metal, separating it from the bottom part. - See how one side of the belt loop stayed right against the back of the slice of skull, while the other side got floated?  So bizarre...






Back to the lab to see what I can do to get my sand working right...  I thought building a muller would make it easy to make my own greensand.  Turns out it also makes me have to do a whole bunch more research on what actually goes into good greensand.  Lucky for me I enjoy this sort of thing...


Here's about a 15# ingot preheating next to my dross skimmer by the exhaust vent in my furnace lid:




One more craziness that happened during that session:  See the turnbuckles used to support the weight of my furnace lid?  I found out their tighteners are NOT made of steel when BOTH of them melted and fell apart halfway through melting the bronze!






PS. All pix were taken after I brushed the stuck on sand off the castings.


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Was pouring more castings just to test my sand, big dummy that I am sometimes, I chose to fill my crucible right to the top with bronze because I did not want to have to take the time to melt a second pot of bronze.  A #12 crucible brim-full of anything hot is too dangeous, but full of bronze it's also heavy enough to be hard to control.  Splash!  Hello 3rd degree burns on my right foot.  Luckily I had my leather steel toes on or I'd be an even bigger dummy with it 1 foot.


Shoes took no damage, the worst 2 of the 3 burns happened right through the leather in the amount of time it took for 2 small molten BB's to bounce off my shoe.


Video shows my crispy feet, don't click if you're squeamish about feet or seeing fresh burns.  Talespinner, please take note and learn this painful lesson the easy way!




I did pour all 3 molds in bronze then melted a pot of aluminum for the last test casting of the day before I went in for bandaids and beer.  


All the sand castings were failures, but I got some good data about the new sand.  Namely, it does stick to castings more than my old sand does, and it does not have the same green strength (ie. stickiness).  Now researching sand additives I can use to correct these...  Such as sea coal (bought a bag of bituminous coal dust - a rough equivalent - from a local blacksmith whose existence I just discovered) and dextrin (baked cornstarch, made some but stank the house up because our oven is hotter than it says it is) and a different type of bentonite clay (calcium bentonite) than what I had used as a binder in the sand I made (sodium bentonite).  The clay is for the strength and the others are to stop the sand burning onto castings.


This was 2 weeks ago.  Foot is healing well but slow.  I'm back in socks and shoes now, no more wearing my slippers to the office like last week!  :)




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Damn dude!  Ouch. Just don't let that get infected.  Infected burns are the worst.  I'm REALLY good at learning from the mistakes of others.  Of course, my largest crucible only holds about 3/4 of a cup of liquid, so I don't have the control issues you ran into.


How do you like the Everdur?  My bronze is similar, Herculoy (substituted when I tried to order Everdur but they were out).  Apparently, the two have very similar properties, the Herculoy having 1% zinc in addition to the silicon.


I have found the silicon bronze to be a bit too hard for my purposes.  The stuff takes an edge nicely though.  You should consider making an axe head out of it.

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I'm more angry at myself for pulling a dumb move out of nothing more than just laziness (not wanting to have to melt more bronze after pouring) than I am in pain.  No signs of infection so far thank goodness, I'm keeping a close eye on it.  I was taking to my friend Martin from Australia (aka Olfoundryman on YT) and he told me he'd gotten a teaspoon of cast aluminum down his shoe once which took 6 weeks to heal.  Mine happened about a month ago now and the wounds are smaller than they started out, but still very much holes in my foot.  The short video of the spill I linked above is unlisted, I just uploaded it to show friends who are into this stuff in the hopes it might keep them from making the same mistake.  I've since edited a longer video about the accident with a lot more fire and molten metal.  Same message, but maybe more entertainment...




How do I like the Everdur?  I love it.  Even though every sand casting I've tried to use it for has been a failure, it's amazing stuff.  I went to skim the dross of the first pot I melted before pouring, and there just wasn't any... The surface of the melt looked like an orange-yellow hot mirror already! 


One of those molds actually was an attempt to cast a silicon bronze axe... I know a guy who really wants one shaped like mine who asked me if I could make one for him in everdur.  He wants some kind of bronze cap to go on the other end of the handle too, something with skulls on it.  Pretty sure it's just going to be a wall hanger, so holding an edge well would be nice, but not really necessary in this case.  I haven't designed that cap yet, so I've got some work to do there...  So while those were all test castings, if that one had worked it would have been really nice...


Since then I've made some adjustments to my molding sand. The new recipe is 2% calcium bentonite clay, 2% sodium bentonite clay, 1% dextrin, 1/2% "sea coal" (actually finely ground bituminous coal dust, should be similar), balance fine dry screened silica sand.


The addition of the dextrin made a huge improvement in my sand's green strength.  I haven't had a chance to try casting anymore of the bronze to see if the seal coal works to stop the sand from sticking to it. Even the dextrin may help with that.  My old sand from the foundry supplier doesn't do that, so I know it can be fixed...


Here are a couple of test castings in aluminum from the sand after I tweaked the recipe:




(Other side says "drink beer" if you hadn't guessed, lol.) They look a bit rough but some of that is from the rough patterns I used to make the molds (cheap imported cast iron from the hardware store once again, like a lot of my test patterns. They work, but cast aluminum might not be the best choice for bottle opener metal).  However the silica sand I used to make the new greensand is a bit more coarse than my old sand, so that may also be a factor.  I'm planning to cast one of my really smooth patterns next to see how smooth of a casting the new sand is capable of.


I also learned I had been mulling my sand in the wrong order (mixed all dry ingredients, them mulled in the water).  Should have been mixing the sand and water THEN mulling in the binders and other additives.


Anyhow, just need one or two more tests to check how the sand works for bronze now, and for smoothness.

Edited by Kang
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Well, the testing and tweaking of the new molding sand is complete.  I have gone from crumbly sand producing bronze pieces encrusted with sand like this:




To nice and sticky sand producing nice clean smooth castings like this:




The mold ran out one side when the hydrostatic pressure of the molten bronze caused the top half of the mold to float.  I thought the casting was lost for sure, but a moment later just before pouring ingots I remembered the whole part was molded in the bottom half...  Figuring the metal that ran out would have frozen by then and blocked the gap, I resumed pouring and somehow the casting was saved!  Not one bit of burned on sand.  Not one little bit of flashing either.  Umm, unless you count that runout.  :)


Video of part 1 of the sand testing follows.  Have not yet edited the next part.





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