Copper slip, where to use it and torque values?

Can someone give me some sort of definitive answer about how much to torque bolts, relative to the recommended value, where copper slip has been used?

Are there any bolts where it definately should not be used?

Can I spread copper slip thickly on every part of my motorbicycles with a spatula like Nutella on a banana?

I'm starting a new regime of preventative maintenance when I'm working on the bikes.

[yorkie_chris]

Nothing inside the engine.
Many bolts require loctite instead. Ironically loctite also helps prevent stuff seizing up, the plastic-like layer of it prevents corrosion

Do bolts on feel, -10% of torque is reckoned, use that if you want. No substitute for feel though.

I think electro has tried spraying his bike in it

Cheers. Does it make sense to only put copper slip on the head end of a bolt or all the way? I know it's a but of a petty question but please humour me.

bit on the end of the threads is normally plenty.

I use general grease instead of copper slip, as shown by Rictus. I dont recall him saying general grease is better/worse, but I didnt have any copper grease at the time so maybe thats why it never entered the equation.

I just dab a bit on the end and screw it in. Probably not any tangible difference??

[yorkie_chris]

Originally Posted by monkey

Cheers. Does it make sense to only put copper slip on the head end of a bolt or all the way? I know it's a but of a petty question but please humour me.

If you're going to use it then it doesn't hurt to slart it.

The bit on the threads will reduce the risk of head snapping off, the bit under head will reduce risk of rounding it.

[embee]

Quoted torque figures usually refer to a dry condition as used in production environments (oiling is frowned upon for H&S reasons, emissions reasons, and also significantly it tends to attract dirt and contamination). Fasteners are sometimes supplied lightly waxed.

Sometimes workshop manuals do specify an oiled condition since it is recognised this is what most mechanics will do.

I remember doing some definitive tests for certain fasteners on an engine many years ago, and as YC indicated oiling/grease tends to reduce the torque required to reach a given clamp load by around 10-20% depending on head type, but interestingly we found that liquid threadlocks tended to increase the torque required slightly (not really what you'd expect, when liquid you'd think it would act as a lube). Production usually uses dry patchlock type fasteners where necessary.

I'm usually pretty cautious about torquing sensitive bolts into light alloys when reassembling, I always work up in steps from say 50% of the quoted value and see what it feels like. Quite often I've stopped well short of the quoted number because it didn't feel sound.

Anti-sieze stuff like copperslip or alum paste is only really needed in harsh environments, high temps/corrosive etc, or where the metals are prone to pick-up or galling, like stainless bolts. For general use any mineral type lube will usually do, but copperslip is often convenient anyway.

There are recommendations that copper based products should not be used with alloy brake parts (calipers), not sure if that is purely precautionary or whether real life problems have been seen (dissimilar metals, electrolytic corrosion especially with salt). For light alloys there are aluminium based pastes, they do the same job. I tend to keep copperslip for nuts on exhaust studs etc., or at least steel/steel situations.

Originally Posted by yorkie_chris

I think electro has tried spraying his bike in it

You are gonna look so good in rubber grease when I come up next

Originally Posted by Electro

You are gonna look so good in rubber grease when I come up next

sounds very wrong!

[mister c]

If our diesel fitter is anything to go by, then you slap copious amounts on anything with a screw thread on it.
Tried to tell him that too much of a good thing doesn't make it a better one, but, he knows best.............................................. ...Or does he? lol