Undoing fused nipples

[paddlingpool]

Hi all,

I wanted to true up an old wheel at the weekend but couldn't as when I came to do so I found that
the majority of the nipples had fused on to the spoke threads.
I have been putting plus gas on them for the past 3-4 nights but they are still fused.
Any suggestions on how to free them up? I don't really want to cut all the spokes out.

Cheers.

 

[marc two tone]

I've had a similar senario where, a nipple head sheered off and left a spoke waggling about.
As a precaution after i had replaced said mangled spoke and nipple, i inspected them all to realise the spokes twisted as i attempted to undo them, basically all seized, like yours.

You see, i was in a position to just cut the spokes as i had ideas for the rim and hub elsewhere.

If plusgas hasn't helped, i expect freezing them may break the seal as it is steel vs alloy, should work, freezing does for seized alloy posts in steel frames. If you don't have access to a chest freezer, to leave the wheel in for a couple of days, I would suggest some freezing aerosol like this.....


http://www.ebay.co.uk/itm/PH-Crack-It-S ... 48429368c7

This may prove labourious esp X 32/36 but just might work, maybe do 3 spokes at a time. You blast it on til a frost appears then, leave 2 mins (or whatever the instructions say).

good luck.

p.s swap nipples and/or lightly lube each one at the same time as you reinstate them.

 

[Elysarian]

If freezing doesn't work heating might - remember that aluminium's coefficient of thermal expansion is higher than that of steel.

While freezing works well for when the Alu part is inside a steel part (seat pin), heating may be a better option when the steel is inside the Alu.

One issue though: if your spokes are stainless steel then heating/cooling might not be very effective as the relatively small volumes of metal coupled with the similar coefficients (23.1 linear for alu vs 17.3 for SS, plain steel is 11 to 13 - numbers are microns per degree kelvin) means there might not be enough expansion/contraction to break the oxide layer up.

Heating/cooling cyclically might work too (esp with application of penetrating lube between cycles).

Your only way out might be to replace the spokes (make sure to grease everything up this time!)

 

[poweredbypies]

Thats assuming he has ally nipples.

 

[KermitGKona88]

I know that this may sound completely daft but it helped me the other night when rebuilding a wheel, I had 1 stubborn spoke like yours and I did two things that helped 1) I held the spoke to stop it from twisting and 2) I first turned the nipple in the opposite direction first (tightening). You could give this a try

 

[Elysarian]

:facepalm: I assumed ally because I've never had a brass nipple seize to the extent where a little lube didn't shift it

 

[jonthefish]

I had similar problem - 5 days of WD40 and still they wouldn't move. Ended up working all nipples with spoke key, holding spoke to prevent twisting. If nipple moved then I moved it back to start point. If it didn't then I tried harder and ripped off the treaded part of the nipple with the spoke key. :facepalm: Yes - I know.

Anyway, the nipples were alloy and spokes steel and spoke threads were fine. Once the long, threaded bit of the nipple had been thus pulverised and removed the nipple heads screwed off ok from outside (again holding spoke to prevent twisting). New nipples applied to lubed spokes as required. Trued up wheel. Drastic but worked. Should you try this at home i accept no responsibility.

 

[paddy311]

be careful unscrewing your nipples.

I tried it with my belly button and my bum fell off :shock:

I'm here all week..... etc etc....

 

[integerspin]

I squidged the nipples with a mole wrench, it split them and I was able to easily remove them and fit nice new brass ones.

 

[rc200]

I've freed seized alloy nipples easily using the flame from one of those 'turbo' type lighters. Bit of heat directly o.n the nipple and they come undone