What we do · Why it matters · 05

Spray vs. weld overlay

We don’t dismiss weld overlay, and we think you should understand it. Sometimes it is the right answer — and when it is, we’ll say so.

Counterpoint plate on cool gray stock setting out where weld overlay is the right choice, with a sidebar of what it costs you. — Where overlay wins: structural build-up. If the shell has lost structural thickness, no sprayed coating will give it back.

Magnified section detailing how sprayed coating is feathered, blasted and overlapped onto existing weld overlay, with a not-like-this counterexample. — Already have overlay bands? Spray goes around them. The joint is the only part of this job that cannot be done twice.

If you require weld overlay, we will do it

We are not a spray-only shop. Where your engineering team has specified weld overlay, or where a vessel genuinely calls for it, we are certified to carry it out and we will.

What we will tell you first is the maintenance consequence: overlaid vessels need inspection and repair considerably more often than sprayed ones. A Shield is a 10+ year product. Overlay is not a decision you can make once and leave alone — budget for the inspection cycle that comes with it.

The short version

Arc spray adds no weld metal. No new heat-affected zone, no dilution, no fresh residual stress, no new cracking mechanism. 12–20 mils comes off and goes back on where needed, inside the same outage. About 3/16 in. of fused overlay is permanent.