You won't have to upgrade the motor, it works fine for the size of the drum. If you spend 200 to convert, you're not a very good scrounger.
True. I'm not a very good scrounger, largely due to being (socially) stupid and chronically ill. I can spend thrice the time and energy that most do trying to scrounge things - or I can spend what energy I have trying to make things. I've usually had better luck with the latter, even if I'm broke.
Well that's a good thing because there aren't going to be very many bicycle portable options for mulling 800lbs of sand. When I was considering same for myself it was going to be traditional wheel muller, 3-5hp in a 24-30" drum with a dedicated gear reducer. I have the gear reducer, motor and various other parts but didn't do the fab. It would easily weigh 400-500lbs and I was estimating ~100lb batches. Granted, they're not what I describe above, but I think the HF mixer conversions have proven to be very good bang for the buck. Is this green sand? Because if it is (or maybe even if not) I wouldn't underestimate the benefit if aeriation versus full mulling. Ol'froundryman seems to get a lot out of it. In a similar train of thought, unless you're looking to provide a public service to your source of sand, conditioning a smaller amount of facing and near pattern sand might be sufficient. There was a fella either here or on AA that had a paddle mixer and would do 10-15lbs at a time with it mounted in a 1/2" drill, in a 5 gal bucket held between his feet.....for 5 minutes or so. I can easily believe it because I have mixed refractory and sodium silicate bound sand that way with great success.........and that actually would be bicycle portable The simple bent rod type paddles are actually better and produce a relatively high amount of sheer. Best, Kelly
I get what you're saying. I was a little nervous at the point of no return when first taking a cutoff wheel to the drum of my Proncess Auto on-sale 1/3hp cement mixer to remove the top and open it up to make room for the muller guts. I can't seem to cut a straight line or drill a square hole, and I can only just barely weld (I hesitate to even call it that). All I can say is, it was worth the risk for me. If I can fabricate and install a crossbar with wheel and plows for an effective cement mixer muller conversion, I really believe anyone who can get their hands on an angle grinder, drill, and 2 wrenches can pull it off. You do need a small piece of steel plate to cut out and tack in a flat round floor that can take some wear, but the crossbar could simply be made from some bits of angle iron bolted or welded together. You can make the plows out of the left over corner pieces of the floor plate. Use an inflatable tire like HT1 if you go this route -if you have to buy a wheel. That is cheaper and seems to work as well as if not better than the two side by side 8" iron caster wheels I used. Ever since I loctited the grub screw that keeps the pulley from vibrating off the end of the motor shaft, the only trouble mine has even given me has resulted from overloading it. That is a sand too deep bogging down the wheel issue, not a too wimpy motor problem. When fed no more than 1/2 a 5 gallon bucket of petrobond at a time, or maybe as much as 3/5 a bucket of greensand, mine is reliable. If a bit noisy. It would also be fun to watch your muller come together from scratch! I am not sure I could pull that off, but if I did I think I would make sure it is wide enough to shake molds out directly into, like Ironsides' muller. Jeff
Currently, yes. Fine-mesh (100? 110?) Olivine, mixed flavors of Bentonite, and a few surreptitious additions of wood flour. Thus far, I've though to duplicate - sort of - the layout of the commercial units. I've found a source of wheels, these being the rear wheels of pallet jacks - 8 inches/20 cm in diameter, 2 inches/5 cm wide. Plan is to use two, just like a commercial unit. They are to be carried on swingarms, either cast or welded.
I'll just throw in an idea about direct shakeout into a muller. This seems, on the surface, like a good idea and it may work well for some folks. For me, I have found that dumping all of my used sand onto a concrete floor (could also be a mud mixing pan) and doing some shoveling the sand to mix it all together and walk on it and smack big chunks of hard sand to pre-condition it prior to dumping into the muller is a time saver. I shovel the 400 or 500 pound batch from one pile to another a couple times. You will find the big chunks just naturally roll down the pile to the edges of the heap. Then I walk around the pile crunching crispy lumps of sand. after shoveling the pile a couple times it is pretty uniform in moisture, all of the fist-sized lumps are squashed, and it is ready for the muller. By breaking down large hard lumps by hand, the muller does not have to do that job and that saves time. Mixing relatively dry cooked sand from the cope with moister less heated sand from the drag gets the whole mess of relatively uniform moisture content so that batch-to-batch water addition becomes pretty uniform. That makes the process more routine. Otherwise one batch starts out quite dry and I have to titrate the water until the batch seems right. The next batrch takes less water---oops overshot water. Now add dry sand. Back and forth. With more uniform sand you can fall into a rhythm more or less. That feels better to me but might not be everybody's best method. Just sayin, I started out expecting my muller to just take anything I threw at it and figured it should be able to get the job done. Now my muller and I cooperate. I give it pre-conditioned sand and it seems happier. ;-) I'm sure if you watched ten of us mull sand you'd see ten somewhat different approaches. Jeff mentioned cutting down the tub on a mixer. I did that too. One easy way to get a uniform height cut was to start the motor and get the tub rotating, brace the angle grinder on some stationary part or support and let the grinder start cutting a groove through the tub after it makes quite a few turns. Seemed easier than trying to follow a sharpie line. BTW, the off-cut made a nice lid for my furnace after I attached a sheet of steel over the narrow part of the off-cut cone. Denis
When the direct flask-to-muller-dump works, it works well - with smaller flasks. Heavy molds notsomuch. The intermediate transfer is a lot less hard on the body and back. Petrobond doesn't really create the large hard lumps like greensand, but having just done a couple of pours with iron in greensand Melterskelters experience rings true. On another note it's important to not give your backing sand shortshrift when it comes to mulling. A couple of dropouts will convince you of that. Ask me how I know. Pete
Hence run the whole of each flask through the muller each time? I'm willing to, but the two furnace locations are about twenty miles apart. (Hence an alternate grinder, one readily portable, might be wise, as well.) I have considered a dump-out pan, and will be donating a number of ten gallon/38 liter plastic tubs to each place, once I have wheeled cabinets built in numbers.
I mull all my sand that I plan to use on a molding session. Otherwise the sand would vary widely in moisture content and green strength besides being mighty lumpy. as Petee pointed out, after only a couple dropouts, most people are looking for any way they can avoid that unfortunate event. Nothing like having an hour or more into making a mold only to have it drop out as you flip it in preparation for joining cope to drag. I try to do everything I can to make the sand work perfectly and even then you still have the occassional cussed failure. Denis Denis
