because of this post I started to compile info about mixer safety through the database. It is a huge job. This is what I have come up with so far. Please, if you have the time, add info to this subject for our PC Manuel. Ev
Mixer Safety
Posted Fri May 4, 2007 by "slurryguy"
Wear heavy boots.
Why?
Did you hear someone shout a shocked, angry, chagrined, outburst last night? It was probably me! "%$%!@% WHAT THE HECK????"
I was using the bucket method to work with some slurry last night. I
had my drill spinning a blade in the bottom of a 5 gal bucket. The
drill got going a little fast. I probably wasn't paying attention as
carefully as I should have been. The blade sliced right through the
side of the bucket, through the side of my heavy leather work boot,
through my sock, and just nicked the skin of my foot. Nothing a
little anteseptic and a bandaid wouldn't solve.
There have been a few times I've performed that same procedure while wearing old running shoes. If I had been wearing those shoes, I'd
likely be on crutches right now. I'll never wear anything but boots
when working with papercrete from now on.
I'm also going to dull the corners of my mixing blade a little to
help keep it from slicing through a bucket like that again.
I've inspected my buckets closely, 2 of them are very worn where the
blade tends to scrape the side of the bucket. I grabbed a can of
spray paint and put a big X on the side. No more mixing slurry in
worn buckets for me.
Think boots make you look goofy? Not having too healthy feet when
you could have easily kept them healthy would look far far goofier.
Please learn from my near miss.
From: Pat B Parham <texasweldinginspector@...>
Subject: Blade safety
To: papercreters@...
Date: Monday, July 7, 2008, 11:41 PM
There has been several notes about blades coming through side of buckets and this is the way I protected myself from this hazard, took very little time and less than $5. Remember safety does NOT cost money or time, but unsafe cost you and your loved ones. Instead of a big drill I found a 1'' impact wrench on E-BAY and as this did not have a chuck to hold my blade. I bought a 1/2'' floor flange and a 4"X1/2'' NIPPLE at the hardware store, and then bolted flg. to center of bucket. Then welded blade 2'' up the mixer shaft, inserted 2'' of shaft into nipple and now no matter what my mixer blade STAYS in the center of my bucket. Worked on the 30 gal. drum I built also. Just make sure you turn your shaft clockwise looking down and the nipple will never come out. Also makes a handy holder, just release the switch and everything stays put. I did put a 1/4'' wafer wood false bottom on to hold the bolts.
http://ph.groups.yahoo.com/group/papercreters/spshow/bd68
From: slurryguy <slurryguy@...>
Date: Saturday, July 12, 2008, 8:59 PM
I think it is appropriate to point out that the welds holding those
saw blades to the central mixing paddles are the only thing keeping
the blades from flying off. Wouldn't that be a frightening
experience?
Since someone using a userid, "texasweldinginspector" is the one that
built and posted the one pictured, I have confidence that the welds
holding those particular saw blades in place very strong welds indeed.
Contrast this with a typical lawn mower blade design, where the blade
itself is one piece and does not have any welds holding the blade
itself together. An amateur with minimal mechanical experience can
easily assemble that and achieve similar strength and quality as if a
professional mechanic assembled a straight blade design.
I'm NOT saying that a lawn mower blade cannot fail. Of course it
can. A metal fatigue failure could happen with either design though.
I urge caution and care if someone wants to duplicate this saw blade
design. Welding is a skill that takes time to perfect. Weak welds
in such a design could be extremely dangerous. The faster the blade
spins, the higher the stresses on the welds.
If there is the slightest doubt in the quality of your welding, I
suggest finding someone that can make the welds perfect.
From: Pat B Parham
“Please take note of what slurryguy says but the main thing here is the use of the floor flange and nipple to keep my mixer shaft in the center of my barrel. This is what I wish to demonstrate for everyone.â€
Mon Jul 14, 2008 8:51 am
Greg House ghunicycle@...
From: slurryguy <slurryguy@...>
>I think it is appropriate to point out that the welds holding those
>saw blades to the central mixing paddles are the only thing keeping
>the blades from flying off. Wouldn't that be a frightening
>experience?<
It wouldn't be too hard to do something like this without welds. You could use
two circular saw blades bolted into a piece of all-thread with eccentric
bushings to hold them at an angle. Maybe take a 2" piece of pipe and cut it at
20 degrees or so with a chop saw, use half on each side of the blade. That way
the circular saw blades don't need to be cut to be used. Maybe add a paddle type
blade at the bottom to help circulate the material (create a vortex).
Greg
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