Rail Button Backing Block Tips?

[ActingLikeAKid]

(insert joke about "yeah, I saw the Rail Button Backing Blocks back in '87 before they hit it big")

I've seen people fabricate backing blocks for rail buttons so there's something for the screw to "bite" into. Probably overkill but I was thinking about using 1/2" plywood or pine. (with wood CRs, I'd just screw into the CRs, but this has glass CRs, so I can't. I suppose I could also use the Apogee-style tee nut backers, but ... I mostly just felt like trying something new with this build).
Any tips/suggestions for backing block material?

 

[cvanc]

These do not work on paper or phenolic frames but if it's a FWFG tube these are excellent. They're called rivet nuts or well nuts:

https://www.mcmaster.com/=1fnjnez

You need to compress them for the install and a variety of tools are available to do it, but honestly on the smaller sizes you could probably cobble up an installation tool with some spacers and wrenches to get the job done. Here's a list of all the tools

https://www.mcmaster.com/rivet-nut-installation-tools

...And here's the specific tool I bought - it works great. It makes the nut permanent but it still 'floats' a bit due to the rubber sleeve. These are excellent, at least for larger diameter airframes.

https://www.mcmaster.com/96349A305

Good luck with your project.

 

[ActingLikeAKid]

Thanks, Carl. Sorry, I shoulda specified - this is a LOC 3" cardboard tube.

 

[smugglervt]

I would go with epoxying the 1/2" wood blocks to the fiberglass CR and screw into them with wood screws. The bond between the blocks, CR and inner tube should be plenty strong to hold the buttons.

 

[Nytrunner]

Also check out weld-nuts. They're like toothless t-nuts and work great for me because I can pick them up in #6, #8, #10 or 1/4" at Lowes

(no idea why that lousy quality image is so huge)

 

[David Schwantz]

I would not use pine, it can split very easy. Use the ply.

 

[Handeman]

I cut a circular piece of 3/4" oak the ID of my cardboard tubes. I trim off a piece about an inch long and glue that in. That gives me about 1/4" of wood for the screw to bite into and the wood block matches the ID conture of the tube so it glues in really well. Also, when you've trimmed all the pieces off a 4" circle, you can cut it down to 3" and do the same thing.