wanted to edit my first topic but deleted it by mistake. I have a Putz VS-70, 1 year old. Over the time we had it we always noticed very small amounts of concrete on the walls of the stube, it would usually go away after a big pour. Today after waiting over an hour and 30 minutes to finish a job, there is quite a build up. I'd like help on how to remove it without dismantling the whole stube assembly. I've tried crowbar, acid, pressure washer, but how it is placed gives me very limited access in getting there. Any help? Thanks Danny

If your s-tube is big as a boom pump type you can get a small  air hammer  and get inside and chip away I just had to do mine yesterday open up the swing away in the rear if you can find a 12 inch chesiel for the air hammer the better.

Do not put your hands in there. I know people using little chipping guns and reach in there. I used to run a line pump years ago and every so often it would shift over after hours of being off. Try getting a long extension for a chipping gun. That is your safest way.

I would put a block of wood in the hopper if you are afraid of it shifting after its been sitting, a longer blade would be good if you can find one.

we have both a VS70 and VS50, both are prone to buildup, especially when doing shotcrete... You have to remove the outlet flange (4 nuts) and get in there with a flux chipper, Jet makes the best tool for this job: part # 404203, cut and paste the link below to view it http://www.marcur.com/Air%20Tools%20PDF/24-25%20Flux%20Chippers%20Marcur%20Jet%20Air%20Tools%20En.pdf you will have to build an extended chisel for the chipper in order to get into the tube far enough to chip it entirely clean, and it's still a bi&*% of a job, but much better than pulling the s-tube... We have been through this procedure many times, and it still sucks... but with the right tools, its sucks much less

thrashing the side of the s valve with a big sledgehammer in situ works for me. a tad tiring and a bit awkward with catching the remixers but does work.

A Chimeney Brush!

You are correct that build up can be an issue from slow pours.

I am intrigued about the chimney brush Idea but don’t have any experience with it. Of course staying ahead if it is the key. Clean it while it is still green. 16 Cell has the experience and has a good routine.

A couple things from the factory perspective.

Never get anything into the hopper or the s-tube with the engine running or with residual pressure on the accumulator gauge. If the gauge is faulty replace it. A block in the hopper is no substitute for no hydraulic pressure.

Be cautious of Acid, it will damage any chrome parts like your shifting cylinder’s

But the other thing is the vapors from the acid will damage the copper in the wiring and cause issues down the road. I have been told customers have had good success with a pressure washer while the concrete is green.

Building a bar that has the bend to accommodate the shape of the s-tube and a good old hammer will also work.

I am always nervous about the Bashing on the tube with a big hammer it may damage or dent causing a weakness in the s-tube wall.

No a light note I would like to see how Mythbusters would do it, We would sell lots of parts…… :)

Locate a local dealer for Thon katts their mechanics are a great source for practical mechanical help. They do it all the time.

E mail me direct and I can help you find a local guy if you need.

Traveltech.....you know as well as I do that there are a lot of joksters on here. So the block and the beating of the rock valve and S tube, I hope is a joke. I bet mythbusters would say to use dynamite to clean it out.

if you can damage an s-valve or rock valve with a big hammer maybe it's time to replace it ?

Thanks to all, especially 16 cell. Got it done half yesterday, the rest today. Bought a flux chipper like you recommended. Got a lot out, but at one point the 12" chisel was no use, the chisel wouldn't grab on anything as it was slick. We just bought a hot water pressure washer (4000psi @ 4 gpm), so this morning, hot water and a little pressure and the whole thing came out. Pump is nice and clean. Thanks for all the help guys, I know where to ask the questions from now on!