copper anti seize on spark plugs

[Joel]

I'll be fitting Bellanger headers soon and at the same time fitting new plugs(RC12LYC?). I noticed in a recent post that Jerry Scott said "Next time use a good non-copper anti-sieze compound on all plugs, like the one that Griot's Garage sells".
Why non copper? I've always used copper grease on plug threads and never had a problem. What have I been doing wrong if anything? I need to learn.

 

[Fred(DrivingSchool)Kinder]

I suspect Cu and Al form an unwanted intermetallic compound, rate of reaction increases with heat. Remember the 96 side sills that blistered around the fastener. Dissimilar metals reacted forming intermetallic with different densities, result blisters under the paint. Copper reacts very easy.

 

[Joel]

Thanks Fred. Thats a good point and may be a good enough reason not to use copper but in order for corrosion to take place there must be an electrolyte ie moisture as in the sidesills. the main purpose of using antiseize on plug threads is to prevent galling, I think. . I'm a little unsure of my chemistry here so correct me if I'm wrong. Anyway is there a good generic antiseize which doesn@t contain copper?(and which is available in the UK.)