Prepping for a dive trip - checking my gear and realise by two big float arms are water logged.

As you should, you pull out the artillery and get them apart. Using my bearing puller and aluminium jaws in the vice, I've managed to pull one end off the float. The carbon tube is actually very solid.

Now the difficult part. I can clean up the open end and re-epoxy that. However, the end that's still left in the carbon tube - I can't think of a delicate way of getting that one out without making up some elaborate jig to hold the carbon tube as I try to pull the remaining end.

I could:

1. hope that the glue joint that was leaking was the one I was able remove and the other end is fine.

2. lay out a new layer of epoxy internally at that end and hope it's going to withstand the pressure if there is any leak here.

3. cut ~10mm off the tube as neatly as I can and then re-glue it to the end cap after i'v ecleaned it up. Will have slightly less buoyancy.

4. Heat it up maybe and try and soften the existing glue?

5. Just buy two new floats and worry about this some other time.

6. ... any other ideas?

Lateral thinkers, let me know your thoughts.

I would think that any repair on the other end would best be done from the outside. Any time you are doing waterproofing any sort of barrier is generally laid from the wet side, that way the water pressure pushes it on rather than the pressure acting to lift the layer of water proofing away from the surface. Cleaning up and getting a good key down inside the float would also be a potential issue. You could glue on some waterproofing tape over the seam perhaps? something like this:

https://www.bunnings.com.au/t-rex-50mm-x-1-5m-strong-waterproofing-tape_p0088307

might look ugly? but could be vaiable solution though it may not be permanent.

Having said all that given you are spending $$$ on a dive trip the cost of some new arms would be good insurance I think. Dive centre Bondi would likely have the INON float arms in stock if the buoyancy they provide suits. I use the 390GR lift arms and have been happy with them.

Buy some 2-part epoxy resin and paint it on the seam after gluing the removed cap back on. Use two or three coats, 24 hours drying time between each.

Edited September 16, 2025Sep 16 by Dave_Hicks

Put the end in boiling water for perhaps 15-20 minutes then tap it out once the epoxy is soft.

5 hours ago, foetusmachine said:

Prepping for a dive trip - checking my gear and realise by two big float arms are water logged.

As you should, you pull out the artillery and get them apart. Using my bearing puller and aluminium jaws in the vice, I’ve managed to pull one end off the float. The carbon tube is actually very solid.

Now the difficult part. I can clean up the open end and re-epoxy that. However, the end that’sw still left in the carbon tube - I can't think of a delicate way of getting that one out without making up some elaborate jig to hold the carbon tube as I try to pull the remaining end.

I could:

1. hope that the glue joint that was leaking was the one I was able remove and the other end is fine.

2. lay out a new layer of epoxy internally at that end and hope it's going to withstand the pressure if there is any leak here.

3. cut ~10mm off the tube as neatly as I can and then re-glue it to the end cap after i'v ecleaned it up. Will have slightly less buoyancy.

4. Heat it up maybe and try and soften the existing glue?

5. Just buy two new floats and worry about this some other time.

6. ... any other ideas?

Lateral thinkers, let me know your thoughts.

Aww man, that’s no fun. I’ve come to appreciate Stix floats because of their flexibility. they’re also durable, though they look like cheap pool floats in photographs. The large floats (which are tiny) displace 82g and the jumbos displace 181g each. You can mix or match to suit your needs, even on the fly. I’m curious how Marelux' Flexibuoy is catching on? https://www.marelux.co/collections/flexibuoy

The Flexibuoy is interesting but I don't know if I want to be actively managing the buoyancy of my camera as well as myself on a technical ascent. Unless it has some sort of OPV and I can simply inflate it to maximum at depth?

The price is appealing and it looks like it would travel easily.

I dumped these types of float arms once I had one separate underwater and almost lost a strobe.

ULCS and Stix and never worry about it anymore.

Since 10 years I have my own floating arms... never break one and lost something.

one time an arm imploded ok it was at 50 m deep... and it was an arm buil with PLA not the best best.

Yeah, like Craig @humu9679 and Lewis @Lewis88 .... just get ULCS arms and Stix. I bought mine in 2000 and they are still good as new.

The heating method worked. I used a heat gun. I imagine the glue would weaken over time with heating in the sun too, so maybe there's a lesson here not to leave them exposed.

I did make my own, much smaller arms many years ago with 25mm carbon tubes. For those, I ran an aluminium thread up the core to connect both ball ends. I think I'll risk it here though.

Perhaps another safety option would be to run a thin dynema cord from the housing ball mount, through the eye of the mid ball clamp and onto the strobe

But for now, onto selecting the most durable epoxy to have these last another 10 years.

Edited September 16, 2025Sep 16 by foetusmachine

Meditating on this for the last hour, I think one of the structural weaknesses is with the key into the carbon tube.

The aluminium end cap actually has a groove for the adhesive to key into. But the carbon is just the smooth bore, perhaps roughed up a little.

The carbon tube is 2mm thick, so what im going to do is create a number of very small keyways in the inner bore of the carbon at the cap/glue interface. Maybe even a complete ring groove that aligns with the groove in the cap.

Even if the bond eventually fails and it leaks again, I hopefully won't be dealing with a lost strobe.

Update on this. Did 9 dives on the repaired floats. I ended up cleaning up all the old adhesive off both the aluminium ends and the inside of the carbon tube. I used a small dremel to create a shallow notch all the way around the inside of the carbon tube. This created a good key for the new epoxy. The aluminium already had key grooves.

I used this epoxy to put them back together. Available in Australia, but possibly elsewhere: