If you want to apply a maker’s mark or other repeated pyrogram to wooden goods, but can’t justify the expense of a custom branding iron, a practically identical effect can be achieved by applying a strong solution of ammonium chloride, for instance using a foam rubber stamp, followed by relatively mild heat.

On heating, ammonium chloride decomposes into ammonia gas and strong hydrochloric acid. Ammonia diffuses away into the atmosphere, leaving the strong acid behind, which burns the wood. The resulting chemical burn is indistinguishable from a heat burn for all practical purposes.

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