ammonia

[Pete]

Will ammonia turn new pine gray.

[Bill Rogers]

Did you fall asleep on the ENTER key? 350 lines??

Concentrated ammonia? Dunno about the gray part, but do know you should handle it like it's opposite, a strong acid like sulfuric, or hydrochloric. Wear rubber gloves and goggles, and keep a lot of water readily available. I know of a person who dropped a large glass bottle of conc ammonia. He didn't make it to the door, but was rescued by someone who knew what had happened and what to do. The fumes are corrosive and deadly.

Bill.

[Alan W]

A baking sode paste applied to purpleheart turned it dark brown, try that on a scrap of pine.

ALan

[xrongor]

what happens when you put some on a scrap?

randy

[Andy Dingley]

No.

If you want a grey on pine, try an iron acetate mix. This is very easy to make, and less unpleasant to work with than ammonia.

Take a jar of strong vinegar. You can just use an empty pickle jar and contents, but clean pickling vinegar is cheap. IMPORTANT - Knock a couple of holes in the metal lid as a gas vent - this mixture outgasses a little, and you don't want a glass shrapnel bomb in the workshop.

Throw in a little clean iron. Steel wool is good, and reacts quickly. You can use old woodscrews too. Then place a big heavy nut or something on top to weight it down. Make sure that there's no wire wool poking above the surface of the liquid.

Leave it for a week and ignore it. You should then have a dingy grey/black solution. Any red or brown colour is bad, as this will give a rusty brown stain on the timber (you probably had the wire wool exposed to the air). The mixture keeps for a few weeks, but throw it away after 3 months, or if it discolours. Taking the iron out improves keeping.

To use this, just wipe it over your timber. Leave it for 20 minutes or so, then wash off. Sometimes a mere spot of detergent helps to wet the surface.

It works best on tannin-rich timbers like oak. I've no idea what the chemistry is - clearly the old "iron gall ink" recipe is involved, a reaction that produces iron tannates. However this recipe also works on some timbers that are practically tannin-free, including softwoods. It tends to grey rather than black, but there's definitely a colouring action (and not just a pigment effect) I can't promise this will work on your timber, but it's certainly worth the experiment.

I'd also be interested to find out what the chemistry is here.