Copper Grease

Not really a grease but an anti seize compound. 

Copper grease as you describe it is known by many names depending on whose brand you are buying one of the most common is Copperslip. There are also similar products that are grey in colour and are Zinc or Aluminium based for specialist applications, whichever brand you choose the important thing to remember is that Copper grease is an anti seize assembly compound and not intended to be used as a lubricant to replace normal grease in a bearing. 

Most definitely it will be a useful addition to your toolbox, when used on threads of bolts and nuts that are exposed to corrosive conditions it will prevent the threads from growing together. A very important advantage if you are likely to be the person taking it apart in the future.

But don't use it anywhere near aluminium as the two metals dislike each other strongly.

Martin

The comment about not using copper based anti seize compound near aluminium prompts me to raise an issue that I nearly posted when the original post about " copper grease" was posted - that of electrolytic reaction between dissimilar metals. At the time I thought that it might just complicate matters but since it's been mentioned ............!

Take, for example steel cylinder head bolts or studs going into an aluminium cylinder block and you have a potential area for corrosion or seizure . Now add a copper based anti seize compound to the equation and you have a third element in the electrolytic spectrum.

Back in the day when we were playing about with Coventry Climax derived engines in Hillman Imps head bolt corrosion was an issue and the consensus  of opinion was not to use any anti seize compound as such but just touch of EP oil.  The other issue raised by the use of anti seize, or oil, is its effect on recommended torque values where  lubricated threads may require up to 30%  less torque than a dry thread. Hence the reason that some manuals may qualify recommended torque settings with "dry or lightly oiled " etc.

Coventry Climax, now you're talking my language.  I had a couple of ex RAF FWM 750cc engines which I was putting in an Austin 7 Special until I unfortunately lost my storage.  Of course the Hillman Imp engines were very much redesigned and most importantly die cast in the new Imp factory.  CC couldn't supply enough as sand castings.  I always wondered if the Imp castings were done in a different alloy from the old CC castings.  My Imp and Talbot 930cc parts never showed any trouble with head stud corrosion.  There was some though on my Reliant 850 engine in my Fox van, but very little and I had no trouble parting the head from its block when I rebuilt the engine (at HUGE expense for a silly little engine of which 1.3 million were made!).  Another metal that soon shows dislike on ally is stainless steel. I attached an ally guttering section to the engine bay of the Fox with a few stainless self tappers and overnight dew/condensation produced an almost immediate white powder corrosion on the ally with the stainless going a bit pink.  So, it's always something to watch for. I have used some steel nuts and bolts on the rebuild of an old greenhouse for my wife, but copiously coated them with good old Lithium grease.

Cheers,

Martin

Thanks guys for all your comments. Such a breadth and depth of knowledge and experience - from my original query about copper grease/anti-seize and lawnmowers through to Coventry Climax, Imps and Reliants.

Having just invested £3.87 in a 70g tube, I guess my question now is where shouldn't I use it? Is it just as simple as nowhere near alloy?

The mowers I have are:

Ransomes Atlas and Ransomes Anglia, both late 1930s (a quick check with a magnet indicates no alloy anywhere)

Ransomes Marquis 18inch with BSA 119cc Sloper engine, approx 1965, seems to have alloy block and head

Hayter Hobby with a 3hp Briggs and Stratton engine, bought new in 1985, again appears to have an alloy head and block.

Incidentally this B&S engine has been faultless. The only attention given has been an annual oil-change. Still on the original plug. Even the switch from leaded to unleaded fuel was painless.

I'd be torn between the BSA and the B&S engine if asked which is the best one. They're both excellent engines in my fairly short experience.

Regards

Steve