How to repair the galled stem?

Measures to repair the galled stem:

a.Use a file to remove the burrs on the galled part of the valve stem. For the part with shallow galling, use a flat shovel to process it to a depth of about 1mm, and then use emery cloth or angle grinder to polish and roughen it. Then, a new metal surface will appear.

b.Clean the surface with metal cleaner to make the repaired surface free of oil, dust, dirt, etc.

c.Apply wear-resistant repair agent.

d.Detail finishing.

Preparation and applying process of wear-resistant repair agent:

a.Prepare it according to the volume radio of 3.8:1.

b.Scrape the adhesive on the galled surface. The first coat shall be applied as little as possible, and shall be from top to bottom as well as without bubbles.

c.One hour after first coat has been applied (i.e. after initial curing of adhesive), remix the repair agent as required, and apply it for the second time, which shall be 1~2mm higher than the original size.

d.After natural curing for 1 hour, heat with iodine-tungsten lamp between 80~100℃for 3 hours.

Detail finishing process requirements:

a.Remove the adhesive higher than the original size with files, scrapers, emery cloth and other tools, measuring at any time during operation. Do not make the adhesive layer lower than the original size, and reserve 0.5mm as the amount of finishing.

b.When the size reaches the finishing amount, use the pre-processed grinding mould to trim (pad with 80 mesh emery cloth).

c.When the size is 0.2mm higher than the original size, replace the emery and grind it to the actual size accuracy.

Note:

Since it is on-site repair, in order to ensure repair quality, dust and greasy dirt around the repair parts, especially the upper part, must be cleaned up. And if there is any defect (such as small air hole) after repair, the glue shall be replenished and the operation process is the same as above.