Cubic Boron Nitride – Any Use to Framebuilders?

Cubic Boron Nitride – Any Use to Framebuilders?

I have had some problems in releasing my home made seat tube heat sink from the seat tube after brazing, in as much as the heat tends to seize up the threads and cone mating surfaces making it difficult to loosen. Otherwise my simple design works very well. More sophisticated heat sinks may not suffer with the same problems.
I therefore decided to try a Cubic Boron Nitride lubricant, which is available conveniently as a spray quite widely at prices of £20-£30 a tin. Whilst expensive, a little goes along way. It is normally used as a releasing agent for stainless steel moulds for firing glass in a kiln and apparently can be used on mig welding tips to prevent spatter sticking. It is often used as lubricant for bullets in a powder form (thankfully sold only in the USA), and is the “ceramic” in ceramic lubricants.
It is supposed to be stable up to about 600 degrees centigrade or thereabouts, and still remains active for repeated use. I sprayed the components of my heat sink before use and am pleased to say it worked really well, the whole item unscrewed and removed easily and the product itself was not consumed.
It is true that I was silver soldering, so the temperature would probably be well within the specification, but I doubt the internal temperature of the sink would reach brass brazing temperatures so I am optimistic it will still work. I’ve also used it to lubricate the threads on my Jig where they are exposed to heat.

1 Comment

Charlie Merivale

about 2 years ago

Hi Stephen, I was thinking of you recently, aware that you hadn’t posted for a while. I hope that everything was alright. A very Merry Christmas to you and yours, and a very Happy New Year. With best wishes, Charlie.


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