Stainless machine screws stuck in aluminium

[dgadee]

I am thinking about removing and replacing the genoa tracks before leaks develop. But some bits which I have removed from the boat already have had the odd bolt stuck in the aluminium (turning blocks, traveller). I would not want the hassle of bolts which don't want to come out. Did I see here some time ago someone using acid to free bolts? Or was that my imagination?

 

[DownWest]

I just picked up one of those little gas torches that chiefs use to 'burn' the top of Crème Brulée It has a very sharp flame and it did occure that it might be good for heating small areas?

 

[fredrussell]

As above. Freed off a very stubborn furler assembly for a friend recently. Only heat would do it. Trouble is, the bit you are heating up is right next to fibreglass if I understand correctly, so heat may not be an option. That said, once nuts all removed below deck, you should be able to lift track with stuck bolts in place and remove with heat then / or a tap with a hammer at that point.

 

[dgadee]

As above. Freed off a very stubborn furler assembly for a friend recently. Only heat would do it. Trouble is, the bit you are heating up is right next to fibreglass if I understand correctly, so heat may not be an option. That said, once nuts all removed below deck, you should be able to lift track with stuck bolts in place and remove with heat then / or a tap with a hammer at that point.

No, the track will be off - usually nuts are easy to remove, it's the machine screw gets bonded to whatever it passes through. I had access to a press which got most out, but not all.

But was I wrong about acid being usable?

 

[greeny]

I removed the mainsheet traveller to fix leaks and found it was Fixed in place with a sikoflex type product. I couldn't get a cheese wire in to cut it and it finished up pulling areas of gelcoat non slip off with it. PIA to repair. Be careful.

 

[rogerthebodger]

When I fitted my genoa tracks to my current boat it came with countersunk plastic washers to fit into the top of the track to insulate the stainless steel from the aluminum track.

No issue with corrosion

The only I found to remove stainless fittings in aluminum is heat, force or drill the bolt out

 

[dgadee]

I removed the mainsheet traveller to fix leaks and found it was Fixed in place with a sikoflex type product. I couldn't get a cheese wire in to cut it and it finished up pulling areas of gelcoat non slip off with it. PIA to repair. Be careful.

Nothing has been glued in place so far, so I hope the tracks are similar. I plan to use butyl rubber wrap around the bolts.

 

[vyv_cox]

Yes, hydrochloric acid reacts with the typical marine carbonate deposits, will not touch the stainless steel and slow to attack the aluminium. Wash off fully after removal. Photo and article at the bottom of this page Corrosion

 

[dgadee]

Yes, hydrochloric acid reacts with the typical marine carbonate deposits, will not touch the stainless steel and slow to attack the aluminium. Wash off fully after removal. Photo and article at the bottom of this page Corrosion

Thanks. Memory not completely shot yet.

 

[Boathook]

When you put it back together use some sealant / Tefgel / durulac around the bolt head to try and reduce corrosion. I have also used nylon washers.

 

[ashtead]

Another thought is boiling water if you can make a reservoir around offending parts -it might be simpler than acid?. When I had to remove some mainsheet traveler end blocks it worked to free stainless screws in track.

 

[ducked]

Could try resistive heating with an arc welder or car battery. Explosion of the latter a possibility so contain.
Refitting use PTFE tape and/or polythene on threads