Replies

1. 
   SteveSchoene | May 25, 2011 12:02pm | #1

   If there is still an old fashioned drafting reproduction place that still makes actual blueprints, they may be willing to sell you 28% ammonia.  And, for that I would definately want a repirator with cartridges made specifically for ammonia.  They exist.  You didn't mention what brand of mask you have, so I don't know if it has the ammonia filter canisters available for it. 

   It's much more practical to find something like the Ace Hardware Janitorial strength ammonia, which is 10%. It will basically just take longer. 

   Since mahogany does contain tannin it will be darkened by fuming, but that process is seldom used for mahogany so it is likely that the results may not be wonderful.  TEST first using the same wood.  Also it realy helps if the piece you are fuming has it's show faces all from the same tree.  Effects may vary.  There are other ways to color mahogany.  A solution of slaked lime and water works.  So too does potassium dichloride (but this is poisonous..)

   But aniline dyes can achieve virtually the same visual resutls with much less hassle, and with much more control.  Mahogany accepts both dye and stains well. 

2. 
   PSeverin | May 25, 2011 02:05pm | #2

   Familiarity & Ignorance.

   One of the first jobs in an architect's office was running blue prints in the back room and changing bottles of ammonia.   I would hold my breath, grit my teeth and change the bottles.  Ammonia will force you from the room I think,  long before it does real damage.   I've even poured gallon after gallon of ammonia down the utility sink.  Whew.  So I tend to believe that it is not as dangerous as many would have you believe and mine was not an uncommon experience.  

   I've found a good painters mask with filters works with ammonia and your exposure pouring a little into a pie pan and sliding it into a tent is not that great.   

   Go find a place that sells blueprint equipment and get a gallon.   They still make the stuff although blueprints have disappeared from common use.   I wonder if agricultural distributors might also carry it in the industrial strength you'll need.  

   Finally there was an article on embonizing wood in Popular Woodworking where he used a bark tea rich in tannins to turn the color of any wood.  It was suggested that the tea also would work with fuming.  But my experience with fuming is that it is a lot of work for less than spectacular results.  

   Peter