Used valves are not priced by age or by weight. They are priced by what a rebuilder or a plant can do with them next.
One: body material
Material sets the floor. A stainless or alloy body has intrinsic value even in poor condition, because the alloy can be recovered. A carbon steel body has value only if the valve is usable. This is why a worn 316 ball valve is often worth more than a clean cast iron gate valve of the same size.
Material marking is therefore the first thing to establish. If the marking is gone, the valve is priced as carbon steel until somebody proves otherwise.
Two: pressure class and size
Class and size together determine how much metal is in the valve and how demanding its service was. A twenty-inch Class 150 gate valve and a two-inch Class 1500 globe valve can carry similar value for completely different reasons: one on size, one on pressure and material.
Small valves are only worth buying in quantity. Large valves are worth buying individually, provided the flanges are intact.
Three: pattern and demand
Standard catalogue patterns sell. One-off patterns, custom bodies and obsolete designs sell only to somebody running the same equipment. That does not make them worthless, but it narrows the market and lengthens the sale.
The patterns with the widest demand are gate, globe, check, ball and butterfly valves in standard sizes and classes, plus the common control valve families and API relief valves.
Four: completeness
A valve missing its handwheel is still a valve. A valve missing its stem, bonnet or disc is a body. A control valve missing its actuator and positioner is a body with a yoke. Completeness is the single most controllable factor in the price, and it is entirely within the seller's hands.
The rule is simple: do not disassemble anything to make it easier to move. Move it whole, or move it in labelled pairs.
Five: documentation
Certificates, test records, data sheets and tag numbers all raise the price, because they remove uncertainty. On high-class, alloy, cryogenic and relief valve equipment, documentation can be a substantial share of the total value.
Documentation does not have to be perfect. A tag number and a nameplate photograph are worth more than nothing, and nothing is worth more than a guess.
Six: condition
Condition matters, but less than sellers expect and more selectively than they fear. Worn seats, tired packing and scored balls are normal and repairable. Cracked bodies, bent stems, damaged flange faces and corroded pressure seal areas are the defects that remove value.
The best way to present condition is honestly. A list that says which items are damaged is faster to price than one that claims everything is perfect, because the second list has to be verified item by item.
Questions sellers ask
Does age matter?
Only as a proxy for design obsolescence and condition. A 1985 gate valve in good condition is worth more than a 2015 valve that has been outside for a decade.
Is a used valve worth more than scrap?
For anything usable, yes, usually several times more. The exceptions are small carbon steel valves in poor condition, where scrap value is the honest answer.
Do you buy valves that need repair?
Yes. Repair candidates are a normal part of a lot, and we price them as such rather than rejecting the lot.