Why is mahogany different?

[AnnieAnna]

I was chatting about brass tarnishing on another thread and something I've noticed is that my brass stuff tarnishes if I keep it in wooden boxes. It stays shiny if it's kept in a plastic bag.
My brass stuff is polished so has a think layer of wax over the metal.
I've been told it won't happen if I use mahogany box.

So what chemical reaction is going on there then?

AnnieAnna

[TePe]

Never heard about the Mahogany box idea. Brass normally tarnishes because of a damp atmosphere. That's why it is OK inside a plastic bag. You can use a light lacquer spray to cover the polished surface, or try using a thin coat of Renaissance wax polish used by museums to protect their metal exhibits. You can get it from 'picreator dot co dot uk' sorry can't post proper links yet.

[shiner]

I've never heard of metals not tarnishing in mahogany boxes I've been a carpenter for over 35 years and can verify that some woods can cause metals to tarnish at a faster rate than others due to the acidity and the moisture content of the wood

[AnnieAnna]

I was told the mahogany thing. Ah ha...so it may not be true. Hmmmm....I think it was a box seller who told me it.
If I had lots of money I'd buy loads of boxes each made of a different wood and experiment. But I don't and sharn't.

Thanks for your suggestsions Tepe. I can't use lacquer as my USP is that I care about getting things right. I didn't know there was a special Renaissance wax polish.

I'm not worried about things tarnishing. Most of my stuff is sold before it does and if it doesn't a quick polish brings it up as bright as new. There is a whole lot of us reenactors who go to great lengths to make out clothes look lived in (I just live in mine :D) and turn their noses up at bling. They are happy with tarnish.

I thought the wood might be porous, or breathing, or maybe generally still drying out which would put moisture in the box. Acidity is a good idea. I hadn't thought of that.
I thought maybe the mahogany was denser or maybe more resinous...?

AnnieAnna

[TePe]

Thinking about it Mahogany was used for boxes that held ship/boat compasses made of brass. Plus it was used for good quality furniture, but I think this was more to do with the anti rot, and very good stability properties of Mahogany rather than any anti tarnish quality, it's one of the few timbers that doesn't move much during and after seasoning.

[bodrighy]

The mahogany that was used in ships was not the mahogany you are likely to get today. It is an endagered tree, Spanish or Honduras mahogany is not harvested to the best of my knowledge except by some accredited 'farms'. I have used it only when recycling old furniture. Modern mahogany isn't a patch on it and is a different wood.

Pete