Anyone fumed alder with ammonia?

[tor]

I am looking to build a large knot free table that will be dark. Are there enough tannins in alder to darken it?

Thanks.

tor

[wood_newbie]

I've never worked with Alder so can't say yes or no. However, you can always mix-up a solution of tannic acid to brush on the boards first.

Tannic acid is available as a powder which you mix with water yourself. It's fairly benign stuff, so not too much to worry about. Got mine from Post Apple Scientific off the web.

One caveat: Tannic acid will usually add enough tannin to react with the ammonia. However, the resulting look isn't always pretty. On ash and maple, two woods notably week in natural tannins, the wood comes out a mousy brown...not particularly attractive at all.

On some wood, particularly cherry, I find the tannic acid helps control the uniformity of the fuming. If you're not working with boards from the same tree, it can often be a good idea to help out mother nature with it.

Good luck, and let us know how it comes out!