Uneven Tenon

[andrew l]

Title edited. Please see rule 9.

I have a pipe where the tenon is loose when fully inserted yet enters the shank with appropriate tightness. I need to slightly increase the diameter of the tenon's stem half (without altering shank half's size).

Anyone with experience here? I was thinking maybe a light epoxy coating fine tuned by sanding but am unsure of the advisability of using epoxy on the tenon.

 

[Chasing Embers]

If the tenon is vulcanite, you can heat it carefully and it will expand.

 

[chopper]

Nail polish on the tenon has worked well for me.
One needs to rough up the surface a little with sandpaper before applying the nail polish.
Then let it dry hard before inserting it back into the mortise.

 

[OzPiper]

I've used clear nail polish.
Advantage is ease of application and removal
May need to be re-applied

Beeswax also works reasonably well.

 

[chopper]

I've used clear nail polish.
Advantage is ease of application and removal
May need to be re-applied

Beeswax also works reasonably well.

Beeswax works well for a loose stem but judging by Andrews description he needs to build up a gap with something more substantial.

 

[sasquatch]

Thing with nail polish is that you can apply it in micro-thin doses, and it's sandable if you get too much. Epoxy is going to make that pipe never fit together again, is my guess. We're talking about 1/1000th of an inch.

 

[sablebrush52]

Or, you can return the tenon to its original dimensions by simply heating it:

instead of screwing around with it.

 

[kcghost]

The simple solution in this case is best.

 

[andrew l]

Heating would be problematic as I only want to expand part of the tenon, toward the stem.

 

[Ryan]

Heating would be problematic as I only want to expand part of the tenon, toward the stem.

In that case, it may take both heating and sanding. Heat to expand the tenon, and then sand the portion that needs it.

 

[andrew l]

Some light flame heating appears to have done the trick. I'm always cautious here as warpage is a risk.

Thanks to all.

 

[sablebrush52]

Sounds like your tenon is slightly thicker at the head end, where it first inserts into the mortise. It got that way because someone heated the tenon and then pressed the end of it against a solid surface, which compresses and spreads the vulcanite at one end. It's a popular and bad way to tighten a tenon. Heating as is shown in the video by Walt Cannoy restores the original shape. Vulcanite has shape memory and will return to it's original shape when carefully heated.
I used to do the dumb repairs until I learned about how to do it properly. Works like a charm, provided the vulcanite hasn't been otherwise messed with.

 

[andrew l]

Confession: the stem, not vulcanite, came way too tight & I over sanded it. If the current fix doesn't hold I'll fall back on the nail polish option, though with a brush I think epoxy could be applied just as thinly. Epoxy seemed a good first choice as epoxys are high temp resistant.

If vulcanite stems were more easily found I would have replaced and not messed around with repair.

 

[jpberg]

Is that Lawren Harris in your avatar?