Blasting of Flanged Valves

You need a machines surface for the flange seal to be tight. If you use a walnut or other non-aggressive medium you should not have any trouble. If you only have aggressive medium you should cover the mating surfaces with something that will protect it from the blast.

Also, make sure the gears or stem seals are not damaged or retain any medium after you are finished. If the valve is completely dissassembled and removed from the pipe, seal off the flange, and stem / gears and blast away. If it is blasted on the pipe, make sure to seal off the stem and flange.

Drew K

It might erode the gaskets until they leak, and it might damage some valve trim, but probably not the valve body unless the blasting is prolonged and/or severe. It would be wise to consult the valve manufacturer.

we are doing complete blasting of Valve. Though we are covering some stem portion.I am afraid it may affect the trim portion as you said.

If sand is going inside the Valve trim , is there any possible way to remove the sand inside the Valve.

Don't let it get in in the first place.

Keep it out.

If the valve is that badly corroded that it needs sand blasting, then it is not fit for service. Scrap it, and install a new one.

What if they're just removing 50 layers of paint?

Polystrippa would do that, and the valve would survive, except if it were made of plastic.

Unfortunately for the forum, the original poster says nothing as to why the valve needs sandblasting in her view, nor the materials of construction. Nothing is said about the size of the valve either; as a new 15mm stainless steel ball valve can be had for the same price as two takeaway meals it may not be worth the effort sandblasting.

What a cr@p original post.

They've waited 48 layers too long.

Is that really untypical?

If it moves, salute it.

If it doesn't move, paint it.

There are variations, such as if it moves, grease it.

Or, if it doesn't move, eat it; if it does move, f it.

I heard of a fishing boat incident where some guy was told to paint all the valve bodies, but not the stems; and then did just the opposite.

In military fuels, we just painted stuff till it stopped moving!

Drew K

We would plug the ends to insure there was no damage to the mating surface. And to keep damaging sand from inside the valve.

Depending on the type of valve. Closed the valve to limit the amount of stem exposed below the handwheel. Tape up what stem that was exposed.

These were used to plug the valves and blow out preventer in the oil feild before they were sand blasted to get the layers of paint and crud off.

reposted broken image

Is this not applicable? : Vibrating Tumblers

This is quite safer than sand blasting.

In the refined fuels industry we have sandblasted valves in the past many times. The bodies are usually heavy cast and will not be damaged by normal sand blast cleaning of paint or minor corrosion. Tape and card stock or plastic is often used to seal areas you don't want blasted, then the greenest guy or whomever got in trouble last is suited up to blast away...I took my turn a time or two.

We don't sandblast with the valves in place because of the risk of static spark.

Drew K

Before attempting to sand blast, take a pressure washer with a capacity of around 3,000psi or greater and see how much of the surface materials can be removed by that method. If numerous coats of the material to be removed are present this will remove some or all of them so less sand blasting has to be done later. Plug the ends of the valve with the "expansion test plugs" that plumbers place in openings or branches of residential fixture drain piping, McMaster 2613K25 or something similar.

If you are worried about sand blasting, use sodium bicarbonate, Baking Soda, as the blasting agent. This will do an excellent job of cleaning with very little abuse to the valve. It will abrade almost nothing but do an excellent job of cleaning and removing "junk".

As always, caution must be used when preparing the valve for cleaning. Proper masking, covering, plugging, etc. must be used to protect sensitive parts of the valve.

In the chemical industry we used this method to clean and not harm numerous different items. Valves were probably the item most frequently cleaned with the sodium bicarbonate blasting.

If necessary other methods mentioned of nutshell flour, wood flour, abrasives and sand can then be used if necessary.

Good Luck, Old Salt

The valve will need to be pressure tested before presenting back to the line anyway so based on that I would take the opportunity to strip the valve down and change all packings, Gaskets etc and sand blast it as just the body casting / forging.

I would imagine sand grains blasted at speed would be pretty searching.

Good luck

A very big gamble if you try it. Sand will get into everywhere it can and is harder to remove than you think.

I had the unfortunate experience of ruining a $4000 rebuild on a motor for racing, when I though it would be good to get an aluminum color on the much massaged cast iron heads. I blasted the dis-assembled heads and tried very carefully to keep sand away from the valve guides, and thought I thoroughly cleaned the heads before re-assembly. Well...apparently it was almost thoroughly. At about the 1000' mark of the drag strip I took out a very expensive piston with a jammed valve. The culprit - you can guess that - a grain of sand.

If you must blast anything with mechanical moving parts, be prepared for problems.