I recently installed a fence where the posts are 4" x4" pressure-treated wood with an aluminum pipe rail, similar to this: fence

fence image without wood top rail

and this, but without the wood rail: fence with wood rail

fence with wood top rail

I use a member's suggestion and used PVC end caps. The pvc end caps are snug, but they can come off. The same thing with the aluminum pipe inserted in the pvc end cap.

Essentially, the aluminum pipe isn't doing anything to add strength to the fence, and I would like to change that.

Is there any adhesive that I can use to secure each end of the aluminum pipe to the pvc end cap, and the pvc cap to the wood post? Thanks

Or if anyone has any other suggestions, they would be greatly appreciated.

  • do not expect much strength if you do not have a top rail
    – jsotola
    Jul 1, 2018 at 4:05

2 Answers 2


Epoxy would be your best all-round bet for this type of application. It bonds reasonably well to clean PVC as well as to aluminum. It bonds extremely well to wood.

I'd have recommendations for a specific type of epoxy, but just about anything will work in your project.

The strength comes from clean surfaces. Use a light sandpaper on the aluminum, perhaps clean the PVC with acetone, even a bit of sandpaper on the wood is a good idea, blowing out the sawdust. The sanding of the aluminum provides a bit of a grip area along with getting a clean bond.

Epoxy does not require clamping for good results. Excessive clamping forces out the epoxy reducing the bond, but you would not have an easy job clamping your project as described.

  • Thanks for your reply. Do you think that using epoxy will give it as much strength as putting a top rail?
    – rbhat
    Jul 1, 2018 at 14:36
  • It's unlikely that you'd get the equivalent strength of a top rail using any adhesive method. If you are planning a single piece of tubing between the posts, there's a limit on the work you can perform for this objective. If it's one piece of tubing, consider to drill a hole through all three components and drive a pin (steel round bar) into the hole, engaging everything and increasing the surface area taking the load. The pin should fit the hole snugly to get best results, but nothing comes close to the top rail method.
    – fred_dot_u
    Jul 1, 2018 at 21:13

With temperature and humidity changes, I'd expect the epoxy connection to fail after a while, especially joining to the wood. I'd recommend a mechanical fastener like the pin suggested by @fred_dot_u. I'd probably use exterior grade screws instead of a pin for future maintenance.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.