To Epoxy Or Not?

Should one expoxy button rail screws or not?

I use a drop or 2 of CA on the screw threads. Easier to remove should the need occur.

Depends on what airframe you are using.

Thicker fibreglass?, not strictly necessary (if you drill and tap threads into it nicely). BlueTube or Phenolic? - I'd epoxy them in maybe. Wood inserts behind paperboard tubes? - no need if you are using wood screws (not machine bolts).

There ARE downsides to gluing them in - the main being that you won't be able to remove them. And buttons do wear out, so being able to unscrew whatever fastener you use is definitely desireable.

I've been using 8-32 PEM nuts in glass and BlueTube airframes for a while now on most of my HPR rockets. THEY are epoxied in. It's a bit more work to do but definitely the way to go - bomber holding power, easy to mount and/or replace buttons, nice and clean, etc.

For MPR rockets I generally drill/tap glass & BT airframes and screw directly into that (with no epoxy), and I use wood screws for paperboard airframes (with wood blocks inside to screw into.

s6

I want them to be removable. either wood screws into.... wood. or machine screws into thick tapped fiberglass, or weld nuts through thin tubes, but always removable. I know lots of people epoxy them in, but what happens if it wears out or gets messed up?

Screws that have been epoxied in can be removed by heating a screwdriver with a propane torch and then applying the screwdriver to the screw, may take a couple times to get the screw hot enough but once it is, the screw will back out very easy. Surprisingly the screw doesn't really need to get that hot for this to work.

Greg

I did use epoxy on one where I dipped the 8-32 screw in candle wax, then ran a nut up and down to clean out the threads. after the epoxy cured you could remove the screw.

RKeller said:

I did use epoxy on one where I dipped the 8-32 screw in candle wax, then ran a nut up and down to clean out the threads. after the epoxy cured you could remove the screw.

Click to expand...

Poor man's mold release! Great idea! I'm assuming it was dipped in melted wax.

+2!

I use to just drill an tap them in FG tubing but, CA helps prevent them from coming loose.
No need for epoxy...... It makes it easier if your rocket crashes.
First thing usually recovered are the rail buttons.

JD

timbucktoo said:

I use a drop or 2 of CA on the screw threads. Easier to remove should the need occur.

Click to expand...

Teddy (OneBadHawk) gave me a great idea:

1. Use a PEM nut.
2. Drill so that it seats flush.
3. Slather the screw in Vaseline.
4. Screw the railbutton on until the nut is very tight.
5. Mix some carbon fiber with epoxy, and form a mound over the back of the PEM nut.
6. After it is cured, you can remove the railbutton, and the PEM nut stays epoxied in.