Letter 36075

BF4 - fluoroborate paint additive  

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I am trying to reproduce a high temperature enamel used in Russia on their battle rifles, such as the AKM, for historical accuracy. I do not know the type of enamel other than it is an enamel, not a two part epoxy. It is a high temperature coating but not necessarily oven cured. I have been informed that they used a "BF4" additive and understand that could mean many types of Flouroborates. Any clues as to what type it could be ? Or what kind of BF4 would be useful in a semi-gloss black heat resistant enamel ? Furthermore, is this possibly a compound used as a reactive compound ? Or is it likely a heat-shedding additive.

A simplification : What uses are there as paint additives for Flouroborates (BF4) and what do they accomplish, which types are used in paints?
Thank you,

Dan Collins
Researcher / designer - Orlando, FL, USA

Dan,

Borates are frequently used as a fluxing agent in ceramics. This means, they melt at slightly lower temperatures than the primary component.

This pre-melting aids in the melting and mixing of the other components offering savings in time and heating costs.

An additional and unintended benefit to this process is that the lower temp melting makes vitreous materials not unlike your enamel coating some what more "flexible" and less ridged especially when exposed to thermal shock. Which I would expect in a gun barrel and receiver.

The same effect is seen in glassware. And is put to the same use by Pyrex and Kimex for their high temp boron cooking glass ware. The borate material greatly reduces the probability the glass will shatter when going from a hotplate to an ice bath.

I believe the BF4 compound is relatively inert in an aqueous or liquid solution and probably does not react appreciably with the pigments or solvent of the enamel. It is probably their to prevent chipping and cracking of the enamel coating.

John Underwood
- Boron, CA, USA

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