Replies

1. 
   Rufus | Oct 13, 2006 05:03am | #1

   Speaking as a chemist...

   dichromate (Cr2O7)2- contains Cr(VI), which was the subject of the movie Erin Brochovitch

   Basically is isn't good for you (carcinogin), but neither are a bunch of other things we use on a daily basis. It will depend on concentration, but try not to spill any on yourself. Immediate worries would be dermatitis, and if it is a senseitizer, once you have been exposed, you are more likely to suffer worse responses every time you work with it. Long time exposure would lead to higher risk of cancer.

   You may hear a bunch of old timers tell you that they used to bathe in the stuff. But, they also used to tell pregnant women not to stop smoking because they were already irritable. Be careful and you'll probably be ok.

   Boris  

1. 
   Jackson21 | Oct 14, 2006 07:20pm | #7

   Good info. Thank You.

2. 
   dtraversi | Oct 13, 2006 05:47am | #2

   respirator and gloves- but that's no different than I'd advise if you were shooting laquer from your spray rig :-).

   have fun
   dave

3. 
   agomega | Oct 13, 2006 07:14am | #3

   Well, you got the safety advice, not sure if you wanted some application advice as well.

   I would recommend starting out with a pretty dilute solution. Maybe try 1/4 teaspoon to 8 ounces of water or less. If the color is too light then add another quarter teaspoon or just put on another coat. It is easiest to get it to dissolve completely when the water is warm, however it is best to apply it at a uniform temperature as warmer water will get deeper penetration into the wood. This means that the color may lighten as the mixture cools. Best to dissolve it in 4 ounces of hot water and then add 4 ounces of cold water to get it down to room temperature.

   When you apply it avoid drips and overlaps. Once you have applied the solution wipe it down with a clean rag and don't leave any puddles. To prevent that fuzzy raised grain feeling raise the grain with water, then let it dry and sand with 400 before applying.

   Hope this helps.

   Phil

1. 
   Jackson21 | Oct 14, 2006 07:23pm | #8

   Thank you, good info.

4. 
   tms | Oct 13, 2006 08:52pm | #4

   Hey Jackson,

   Personally, I would look for an alternative to dichromate. As rufus pointed out, it's a class IV carcinogen (gasoline is class III). I work in a lab that use to use dichromate routinely, and we've switched to alternative methods both for health and safety reasons, and because it's an environmental nightmare to dispose of.

   You don't say what you're trying to darken, but on reactive woods like cherry, you can use a dilute solution of household lye. It will do the same thing safer, and you won't have to worry about rinsing it down the drain.

   Tom

1. 
   highfigh | Oct 13, 2006 11:45pm | #5

   " It will do the same thing safer, and you won't have to worry about rinsing it down the drain."Plus, the drain will be cleaner that before. Still, be careful with lye, too. It's very caustic and can burn skin and cause blindness. Good neoprene or nitrile gloves and a full face shield is better than just safety glasses or goggles.
   "I cut this piece four times and it's still too short."

5. 
   Pondfish | Oct 13, 2006 11:53pm | #6

   I use dichromate for staining maple -- makes it look like lignum vitae with a nice green-grey tone.

   There are other ways to color wood, but if you are careful dichromate can be a useful tool.  Yes, it's a carcinogen.  So is wood dust.  When I took histology, we used to wash the excess glue off our hands with benzene.  I haven't died yet (though I might, someday).

   BS chemist, PhD Biochemist, so I know what I'm doing.  If you don't know how to respect toxic chemicals, then stay away from dichromate (and nitrocellulose lacquer, and...). 

    

   Recommending the use of "Hide Signatures" option under "My Preferences" since 2005
6. 
   Telemike | Oct 15, 2006 08:33am | #9

   Another angle: This stuff is a pretty strong oxidizing agent and can cause a fire hazard when soaked into rags and paper towels and dried.

   In organic chemistry lab, there was a big bowl of glassware cleaning solution in a fume hood that would remove just about any tarry mess we could make. When it was fresh and hot, a paper towel would catch fire if a corner was put into it. It was a saturated solution of potassium dichromate in concentrated sulfuric acid.

   On top of that, this stuff is "hazardous waste" anywhere where humans care about drinking water and pollution from landfills - virtually the entire world, civilized or not. If you use it, just chucking the residue down the drain and the towels etc in the trash would demonstrate a pretty poor attitude towards our only planet and those that will be here when we've gone.

   Other posters have it right: find another way to get your color.