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Epoxying together 2 Stainless Steel surfaces

I have an application where I need to epoxy two stainless steel surfaces together. The problem is there is not a lot of common surface area for adhesion and one of the surfaces is not flat.

Here are the details. I have a 3/8" (O.D.) 316L Stainless Steel tube. The wall thickness is only 0.035". In the tube is a 0.165" dia. (nominal) hole drilled perpendicular through the wall. I am inserting a hose barb into this hole. The barrel diameter of the barb that passes into the hole is 0.166" nominal, so there is a slight interference fit. The hose barb has a shoulder on it which is .265" in diameter which contacts the OD surface of the tube and only allows the barrel to insert into the wall a depth slightly less than the wall thickness. The barrel cannot be allowed to go into the ID, neither can any of the epoxy.

Because of the geometry of a flat surface against a curved surface, there are some areas where there is as little as .015" contact between the two surfaces, and at most 0.035". The bond needs to be air tight but will not be under pressure or high temperature effects. Because there is so little surface area, I need the strongest epoxy possible. Any suggestions?

Thank You,

Jeff Summers
Newnat, Georgia
1999

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I would TIG weld it in or at least TIG tack it on two sides or at a real minimum use a dot welder to tack it.

For adhesion, grit blast the areas that the epoxy will touch for an improved mechanical adhesion.

I would contact Master Bond for an epoxy recommendation. They have more formulations on the shelf than most.

For dirt cheap, use JB Weld ⇦ this on eBay or Amazon [affil links] and put a ring all the way around the tube.

Possibly a hot melt glue gun with an appropriate stick would do the job.

James Watts
- Navarre, Florida
1999