Epoxy paints should hold up well to this service. The Grainger catalog has about ten different varieties available. Talk to the manufacturers. They should be the experts. You can reach Grainger at www.grainger.com Good luck.

Just remember - everyone and their dog has a "coating" to sell you (most are from the same base stock with just slightly different additives, but that's a different story) - and the key to any successful lining is the installation/surface prep. It is all in the details, even done to the relative humidity in the air.

Fellow Guest, please could you elaborate on this;

(most are from the same base stock with just slightly different additives, but that's a different story).

Rustproofing products are a big mystery in their wide range of claims and costs but you seem to imply that the cheap ones are just as good as the dearer ones, is that right?

OK. What's in the pipe? And what's wrong with plastics? Would an alternative material such as PVDF be a better bet than many metals?

If it was a proper vacuum there would be nothing there to cause a problem. The vacuum is irrelevant! Question is what is coming out and condensing on the walls. One item could be pure water (distilled) - this is one of the most problematic substances for coatings. Epoxies can turn their toes up when submersed in it but withstand acids and alkalies of high concentration. (osmosis is the actual problem) If this is the case Plastic or stainless steel could be the answer or a very heavy Vinyl coating.

If the deposits are chemical in nature then Epoxy could work - go for amine rather than polyamide cured.

Problems can come from corrugation used to strengthen vac pipes

Do not confuse distilled and deionised water!

Be careful of any coating you use. If any peel they will get sucked into the system.

What we did here was to slide a thin wall pvc pipe into the steel pipe like a liner. We have not had any problems since then.

Careful - vacuums do not suck - this happens when you are pulling the vacuum. Outer Space is full of it and we are not being sucked there!! Vacuum cleaners are actually suction cleaners. Depends what is going on here. But you are quite correct to warn that foreign matter can be drawn into the pump. So be sure that any liner sticks good! Better to use a suitable pipe.

Loctite Extend Rust converter - you need a light coating of rust on the metal surface first - then apply the Extend followed by a coat of paint. I have seen this stuff work in a food processing plant - it held up for years in an area that was subjected to a salt brine spray. Ed

This is dangerous statement - never paint over rust! There are some so-called conversion coatings which can work in extreme circumstances but otherwise all contamination must be removed for a good job.

Loose rust should be removed before painting.

Tightly adhering rust can be converted (usually by phosphoric acid based converter) into an excellent paint base.

42-60'' pipes and vaccum 3psia????????

how are you achieving this vaccum?

which pump it is?

for which application do u need the vaccum?

interested please inform

With 1940 IR turbo-blowers moving 37,000CFM For Alittude testing.