Mini Inclined Tumbler (aka cement mixer)

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snoman701

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Joined
Oct 8, 2016
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2,108
Location
SE MI
It has been said that a poly tub cement mixer can be one of the most useful tools for a small refinery.

My problem is simply the scale.

As of right now, I have no reliable way to exhaust the fumes from a polytub cement mixer. They aren't small when you are just working out of a small garage, and already seeing all of your tools rust due to poor ventilation.

This is my answer to that. A more modular system with 2 gallon buckets. It's small enough to fit right in my hood, and light enough that I can throw it up on the top shelf

It amounts to not much more than a welded frame hoisting a 1/4 Hp 90v DC motor with speed controller, 10:1 right angle drive, then a faceplate with an aluminum disc on it. If I didn't have the parts on hand, I would have used a 1/4 Hp 208v AC 3 phase 56C motor, a similar gearbox, and a 110 V in AC VFD. The faceplate should be available from any motion control house, but even a large cast iron pulley with a piece of plywood would work. This was literally done with parts I had laying around, the only machining I had to do was to make a key between the motor and gearbox, and drill the holes to mount the disc to the faceplate.

I just bolted an empty 2 gallon bucket to the disc, but the disc is large enough to bolt a 5 gallon bucket. This bucket amounts to nothing more than a clamping method for the bucket in use.

So the beauty of this is that I can just pull the bucket out and drag it off to whereever to prep, clean the bucket, whatever.

It's first project will be converting a 2 L beaker of silver chloride to elemental with sulfuric and iron, then I've got lots and lots of other stuff. Silver contacts, 50% silver braze, grinding ash, even stone removal in karat scrap (with a glass beaker or teflon bucket).
 

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When i was experimenting with recovering copper from spent solution i built a tumbler out of a old electric walking tread mill. The bucket laid on the belt and was turned by friction while it was guided by 4 casters i got from Harbor Freight. It held 5 gallon buckets as well as 10 gallon poly drums.
 
I like the ingenuity involved. Here is what I have to work with yet. I still haven't done much with it other than I did find a cast iron pot that will fit pretty snug in it.

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=61&t=25496
 
Shark said:
I like the ingenuity involved. Here is what I have to work with yet. I still haven't done much with it other than I did find a cast iron pot that will fit pretty snug in it.

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=61&t=25496

I looked for one on the used market but those little guys are $400+ new and don't seem to hit the used market.

I've had mine running my silver chloride with scraps of steel off the bandsaw. There isn't any white left and it seems to be forming a nicer mixture of cement. I'll filter it with borax/nitre later this week and get it melted.




Sent from my iPhone using Tapatalk
 
I had no idea they were that high. Being able to switch out the containers seems like a handy feature, maybe I will get to try it pretty soon. I like Palladium's idea of using a tread mill too, if you have a large enough source of materials.
 
goldsilverpro said:
A 5 gal plastic bucket would fit like a glove into a steel cement mixer I used to have. I ran many different things in those buckets.

Good to know! I'll be shopping for one and hadn't even considered that option. I'll need to upgrade to a bigger drum as soon as I get an enclosed mini room (probably a shower pan, complete with the nice sliding glass door). I like buckets because of the tight fitting lid. I need to figure out a swivel for an exhaust, so that I can tumble parts closed in the bucket, and have it a closed system. Doesn't need to be perfect, I just want to have the fumes captured. Right now I've just got a hole drilled in the center, even centering a funnel over the hole would probably get 99% of them.
 
Shark said:
I had no idea they were that high. Being able to switch out the containers seems like a handy feature, maybe I will get to try it pretty soon. I like Palladium's idea of using a tread mill too, if you have a large enough source of materials.

Neither did I! I thought I had found them previously for like $150. But yes, being able to switch out the containers was one of my primary goals.

I'm short on space, so a treadmill would be hard for me to fit in the shop...plus it would always be eye'n me trying to get me to exercise.

anachronism said:
Looks great.

One thing- make sure you paint every single piece of exposed steel.

I need a sacrificial anode like on a ship!

The fumes are killer...can't believe how quickly everything has rusted. I'm going to have to spend a week with a wire brush and oil just bringing my hand tools back to life.
 
Try concentrating them in a fume cabinet- - it makes you realise just how caustic they are. 8)
 
anachronism said:
Try concentrating them in a fume cabinet- - it makes you realise just how caustic they are. 8)

Oh, I've seen some things...

The melt shop I work at on occasion does a lot of stone removal. His exhaust is minimal, enough to make it so he can use a respirator for the tiny amount of handling....but that leaves the fumes to just condense in the room. I'm surprised the nails holding the 2x4's together haven't rusted away completely. Or, maybe they have...but it's ugly! You know it's bad when the fumes eat through polished chrome on tool handles.
 
You need to capture the fumes. A respirators only a failsafe. Metal salts absorb through the skin n theyre nasty, trust me on this you probably wont know until its way way to late. The neurotoxins what are noticable and kill you are the least if your worries, its the carcinogens and mutagens.
You need a valve or pipe fitting called something like a pipe or tube rotary union fitting/joint what can turn 360degrees repetitively fitted to your exhaust system and vent outside.
Theyre expensive.
But i have been looking at a garden water sprinkler system you know the spinny thing? It might just be able to be adapted and do the job? Worth a look for under a tenner!
 
There's no need for expensive rotary joints. Just put a lid onto the bucket with a hole in the center. Then put a tube into the hole and some suction to collect fumes. The lower pressure in the bucket makes it impossible for fumes to move against the airflow between the lid and the tube.

Göran
 
No you need to change the air from your whole working space regularly. Anything else simply isnt good enough. Some would say every 30 minutes. My place is geared to changing the air every 10 minutes.

Ask Nickvc or Patnor they've been there- its fresh air all the time. No fumes hanging around or building up in weird places.

Edit: spelling and terribad punctuation. :lol:
 
Yeah, my work space is a bit different, I'm just describing what the fumes can do. I just now got the fume hood so it sucks good enough that smoke a foot out gets sucked right in with the window all the way up. My heat bill doubles on processing days! Before it just didn't have the power. I had to keep the glass shut.

You bring about a good point Jon...I've never seen anyone on this board mention room changes, whereas my veterinary medicine books describe minimum ventilation in terms of room changes per hour.
 
The old standard rule is: 100 cfm exhaust per square foot of hood opening. A 4' X 3' hood opening would require a 1200 cfm blower. From my experience, that number is right on. Of course, you need at least that much make-up air entering the room. I would think the number of air changes in the room would be totally dependent on the blower size.
 
It is Chris. Blowers size is air turn over. Blower’s pressure drop, pipe run and the sash opening control face velocity.
 
I personally really like the 100 cfm number, it keeps it simple, as long as your ducting is open and short, which I assume most is.

One thing I would caution people against, if doing something similar to this project.

If your gut says use lock nuts and fender washers on the plastic, do it. I just had a heavy bucket fall off the plate and sling material everywhere. Thankfully I was just washing the material at the time, so it's just water...but I should have known better.
 
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