fittig reffing gear /screws &electrolitic action

[shantymanuk]

I am about to fit new plastimo roller reefing jib ,and they say to use silicon to stop electrolitic action between the ss screws and the alumimium ,and wondered if a good winding of ptfe on the screws may give better insulating properties as it is more fluid and will adhear to the threds better , whats the thoughts on that idea please

 

[Skyva_2]

Duralac jointing compound is usually recommended for ss screws in aluminium.

Available from chandlers.

Also used on aircraft.

 

[VicS]

They meant silicone not silicon no doubt and I imagine the object of the silicone would be to keep water out of the joint but did they mean a silicone grease or a silicone sealant. If they meant the sealant Sikaflex 291 (polyurethane rather than silicone) might make a better seal as it is adhesive as well but I do not think it has the water repellant properties that silicones have. Silicone grease might make it easier to remove the screws again at a later date if necessary.

Otherwise I agree with Skyva_2 Duralac, which is a barium chromate paste, is the usual compound to use betwen aluminium and stainless steel

 

[DavidGrieves]

Hi

Try here for Duralac
http://secure.silmid.com/action_catalogu...2~%5E0~%5ES~%5D

about £5 a tube or you could try a chandler at about £10 for the same stuff.

 

[Guest]

No to PTFE.

Half the world uses Duralac. The other half, where it is a banned substance, uses Lanolin based gunk.

I've never found a rigger who uses Silicone either side of the Atlantic. All sealing compounds work on the principle of a layer thick enough to take up any thermal or mechanical movement. Duralac protects at the contact points and does not require large amounts.

However, if they are writing instructions for world use, they can not mention products not available in the countries they target.

One more vote for Skyva_2