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  #1   Report Post  
Posted to rec.woodworking
Don Sforza
 
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Default Potassium Dichromate

I recently scored some pattern-grade Honduras Mahogany and have a couple of
projects planned. Not being a "stain everything and slather it with poly"
guy, I wanted to try potassium dichromate. In a word... holy cow. OK that's
two words.

I mixed a very weak solution and tried it on some mahogany scraps and also
some cherry. I got the expected results with the mahogany, but the cherry
astounded me! With one application on the cherry the wood turned a deep dark
brown... not a color I'd like on a cherry piece typically, but for matching
older cherry pieces this may be just the trick.

So the question is: Have any of the wood dorkers out there had the same
experience as me? How about other woods?

Don


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Posted to rec.woodworking
 
Posts: n/a
Default Potassium Dichromate

Where did you get the potassium dichromate?? What other names might
it come under?
Pete

On Fri, 07 Apr 2006 13:46:43 GMT, "Don Sforza"
wrote:

I recently scored some pattern-grade Honduras Mahogany and have a couple of
projects planned. Not being a "stain everything and slather it with poly"
guy, I wanted to try potassium dichromate. In a word... holy cow. OK that's
two words.

I mixed a very weak solution and tried it on some mahogany scraps and also
some cherry. I got the expected results with the mahogany, but the cherry
astounded me! With one application on the cherry the wood turned a deep dark
brown... not a color I'd like on a cherry piece typically, but for matching
older cherry pieces this may be just the trick.

So the question is: Have any of the wood dorkers out there had the same
experience as me? How about other woods?

Don



  #4   Report Post  
Posted to rec.woodworking
Marilynn or Bruce Pearce
 
Posts: n/a
Default Potassium Dichromate

Through yahoo shopping

http://www.2spi.com/catalog/chem/chem2a4.shtml

wrote in message ...
Where did you get the potassium dichromate?? What other names might
it come under?
Pete



  #5   Report Post  
Posted to rec.woodworking
Joe Gorman
 
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Default Potassium Dichromate

wrote:
Don Sforza wrote:
I recently scored some pattern-grade Honduras Mahogany and have a couple of
projects planned. Not being a "stain everything and slather it with poly"
guy, I wanted to try potassium dichromate. In a word... holy cow. OK that's
two words.


A word (or a few) of caution.

Potassium dichromate is a powerful human carcinogen and a strong
oxidizer. For the former reason it has almost entirely been phased out

of industrial uses.

It is probably illegal to dispose of it by pouring it down the drain.
Though you are not likely to get prosecuted, that is really not
the point.

Probably it would be prudent to do a little reasearch and find a
way to treat it to make it safer for disposal. That _may_ be as
simple as mixing it with portland cement and then throwing
the solid chunk into the garbage.

Perhaps a real chemist can comment further.

I read, in a book on router techniques, of a similar process
using nitric acid. One wets the wood and then heats it with
a heat gun until the desired darkening is achieved, then neutralizes
with a sodium bicarbonate (baking soda) solution. That
process generates nitrogen dioxide which can be quite deadly,
but neutralizing and disposing of the unused solution is
quite trivial.

As with most of life's hazards, there is no rational reason to
be afraid to try these things, one just needs to understand the
dangers and how to mitigate them.

http://www.jtbaker.com/msds/englishhtml/p5719.htm
Joe


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Posted to rec.woodworking
bent
 
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Default Potassium Dichromate

If you get a relatively cheap wood to become black in the future would you
make a post of it for me.



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  #7   Report Post  
Posted to rec.woodworking
Jay Pique
 
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Default Potassium Dichromate


bent wrote:
If you get a relatively cheap wood to become black in the future would you
make a post of it for me.


Burn it. I use a heavy duty propane torch designed to burn brush.
Nice big round flame makes it pretty easy to scorch it evenly.

India ink.

Aniline dye and black pigmented stain.

JP

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Posted to rec.woodworking
Joe
 
Posts: n/a
Default Potassium Dichromate

On 7 Apr 2006 08:47:26 -0700, wrote:


Don Sforza wrote:
I recently scored some pattern-grade Honduras Mahogany and have a couple of
projects planned. Not being a "stain everything and slather it with poly"
guy, I wanted to try potassium dichromate. In a word... holy cow. OK that's
two words.


A word (or a few) of caution.

Potassium dichromate is a powerful human carcinogen and a strong
oxidizer. For the former reason it has almost entirely been phased out

of industrial uses.


You might be confusing this with another potassium compound.
I assume he refers to K2Cr2O7 which is useful in photographic
processing among other uses, and, as a matter of fact, is the active
ingredient in an over-the-counter headache remedy...cannot remember
the name.
Basically it is an oxidizer.


It is probably illegal to dispose of it by pouring it down the drain.
Though you are not likely to get prosecuted, that is really not
the point.

Probably it would be prudent to do a little reasearch and find a
way to treat it to make it safer for disposal. That _may_ be as
simple as mixing it with portland cement and then throwing
the solid chunk into the garbage.

Perhaps a real chemist can comment further.

I read, in a book on router techniques, of a similar process
using nitric acid. One wets the wood and then heats it with
a heat gun until the desired darkening is achieved, then neutralizes
with a sodium bicarbonate (baking soda) solution. That
process generates nitrogen dioxide which can be quite deadly,
but neutralizing and disposing of the unused solution is
quite trivial.

As with most of life's hazards, there is no rational reason to
be afraid to try these things, one just needs to understand the
dangers and how to mitigate them.


  #9   Report Post  
Posted to rec.woodworking
 
Posts: n/a
Default Potassium Dichromate


Joe wrote:
You might be confusing this with another potassium compound.
I assume he refers to K2Cr2O7 which is useful in photographic
processing among other uses, and, as a matter of fact, is the active
ingredient in an over-the-counter headache remedy...cannot remember
the name.
Basically it is an oxidizer.



Not correct at all. Read the MSDS on potassium dichromate.

Toxic as all hell, and a very well-known carcinogen.

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Posted to rec.woodworking
Baron
 
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Default Potassium Dichromate

"Joe" wrote in message
...
On 7 Apr 2006 08:47:26 -0700, wrote:


Don Sforza wrote:
I recently scored some pattern-grade Honduras Mahogany and have a

couple of
projects planned. Not being a "stain everything and slather it with

poly"
guy, I wanted to try potassium dichromate. In a word... holy cow. OK

that's
two words.


A word (or a few) of caution.

Potassium dichromate is a powerful human carcinogen and a strong
oxidizer. For the former reason it has almost entirely been phased out

of industrial uses.


You might be confusing this with another potassium compound.
I assume he refers to K2Cr2O7 which is useful in photographic
processing among other uses, and, as a matter of fact, is the active
ingredient in an over-the-counter headache remedy...cannot remember
the name.
Basically it is an oxidizer.


It is probably illegal to dispose of it by pouring it down the drain.
Though you are not likely to get prosecuted, that is really not
the point.

Probably it would be prudent to do a little reasearch and find a
way to treat it to make it safer for disposal. That _may_ be as
simple as mixing it with portland cement and then throwing
the solid chunk into the garbage.

Perhaps a real chemist can comment further.

I read, in a book on router techniques, of a similar process
using nitric acid. One wets the wood and then heats it with
a heat gun until the desired darkening is achieved, then neutralizes
with a sodium bicarbonate (baking soda) solution. That
process generates nitrogen dioxide which can be quite deadly,
but neutralizing and disposing of the unused solution is
quite trivial.

As with most of life's hazards, there is no rational reason to
be afraid to try these things, one just needs to understand the
dangers and how to mitigate them.



As a "real" chemist, I can tell you that K2Cr2O7 is potassium bichromate
(or dichromate, whichever you prefer). It is a highly corrosive poison.
I'd love to know the source of your statement that it is in a headache
remedy. Chromium in all it oxidation states has been found to be
carcinogenic. It is a matter of its physical form and how you are exposed
to it. Please keep in mind that arsenic and selenium are also necessary
trace elements. I wouldn't go around eating arsenic and chromium salts by
the handful.

As for using it to stain wood, there is no reason to do so. These type
of things were used long ago before the advent of modern light fast stains.
If the old-timers had modern stains, I am sure they would have used them in
preference to "chemical" stains.

I would be careful about using nitric acid to stain wood. A nationally
recognized expert in finishing used some once on a test block of wood.
Several years later, he cut through the piece. He was surprised by the
extent of penetration and how he could still smell the by-products of the
nitric acid. Disposal of nitric acid, while easier than chromate salts, is
not trivial. It must be carefully neutralized and the resulting nitrate
salts must be dealt with.


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Posted to rec.woodworking
George E. Cawthon
 
Posts: n/a
Default Potassium Dichromate

Baron wrote:
"Joe" wrote in message
...

On 7 Apr 2006 08:47:26 -0700, wrote:


Don Sforza wrote:

I recently scored some pattern-grade Honduras Mahogany and have a


couple of

projects planned. Not being a "stain everything and slather it with


poly"

guy, I wanted to try potassium dichromate. In a word... holy cow. OK


that's

two words.


A word (or a few) of caution.

Potassium dichromate is a powerful human carcinogen and a strong
oxidizer. For the former reason it has almost entirely been phased out

of industrial uses.


You might be confusing this with another potassium compound.
I assume he refers to K2Cr2O7 which is useful in photographic
processing among other uses, and, as a matter of fact, is the active
ingredient in an over-the-counter headache remedy...cannot remember
the name.
Basically it is an oxidizer.



It is probably illegal to dispose of it by pouring it down the drain.
Though you are not likely to get prosecuted, that is really not
the point.

Probably it would be prudent to do a little reasearch and find a
way to treat it to make it safer for disposal. That _may_ be as
simple as mixing it with portland cement and then throwing
the solid chunk into the garbage.

Perhaps a real chemist can comment further.

I read, in a book on router techniques, of a similar process
using nitric acid. One wets the wood and then heats it with
a heat gun until the desired darkening is achieved, then neutralizes
with a sodium bicarbonate (baking soda) solution. That
process generates nitrogen dioxide which can be quite deadly,
but neutralizing and disposing of the unused solution is
quite trivial.

As with most of life's hazards, there is no rational reason to
be afraid to try these things, one just needs to understand the
dangers and how to mitigate them.



As a "real" chemist, I can tell you that K2Cr2O7 is potassium bichromate
(or dichromate, whichever you prefer). It is a highly corrosive poison.
I'd love to know the source of your statement that it is in a headache
remedy. Chromium in all it oxidation states has been found to be
carcinogenic. It is a matter of its physical form and how you are exposed
to it. Please keep in mind that arsenic and selenium are also necessary
trace elements. I wouldn't go around eating arsenic and chromium salts by
the handful.

As for using it to stain wood, there is no reason to do so. These type
of things were used long ago before the advent of modern light fast stains.
If the old-timers had modern stains, I am sure they would have used them in
preference to "chemical" stains.

I would be careful about using nitric acid to stain wood. A nationally
recognized expert in finishing used some once on a test block of wood.
Several years later, he cut through the piece. He was surprised by the
extent of penetration and how he could still smell the by-products of the
nitric acid. Disposal of nitric acid, while easier than chromate salts, is
not trivial. It must be carefully neutralized and the resulting nitrate
salts must be dealt with.



Must be an old chemist to call in bichromate.
Nonetheless I certainly agree with your statements
on chromium. Don't agree with your statement on
arsenic being an essential trace element.

Nitric acid disposal may be a problem but only for
industrial use, especially if it is contaminated
with dissolved metals which it often is in
industry. Nitrates and nitrites are a problem
when they leach into groundwater but the problem
is mostly from agriculture (excess fertilizers and
stock waste). At least in small amounts the
natural nitrogen-- nitric--nitrate cycle in the
soil will take care of nitric acid. Depending on
where you live, soils will quickly neutralize
nitric acid, plants will take up the nitrates and
soil organisms will change the excess to nitrogen
gas.
  #15   Report Post  
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Doug Miller
 
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Default Potassium Dichromate

In article , "George E. Cawthon" wrote:


Must be an old chemist to call in bichromate.
Nonetheless I certainly agree with your statements
on chromium. Don't agree with your statement on
arsenic being an essential trace element.


FYI...

"... Boron, chromium, manganese, nickel, tin, vanadium, molybdenum, arsenic,
lithium, aluminium, strontium, cesium and silicon are regarded as new trace
elements in the sense that they have only recently been considered essential
in human diets...."

http://www.fao.org/docrep/U5900t/u5900t05.htm


--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.


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George E. Cawthon
 
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Default Potassium Dichromate

Doug Miller wrote:
In article , "George E. Cawthon" wrote:


Must be an old chemist to call in bichromate.
Nonetheless I certainly agree with your statements
on chromium. Don't agree with your statement on
arsenic being an essential trace element.



FYI...

"... Boron, chromium, manganese, nickel, tin, vanadium, molybdenum, arsenic,
lithium, aluminium, strontium, cesium and silicon are regarded as new trace
elements in the sense that they have only recently been considered essential
in human diets...."

http://www.fao.org/docrep/U5900t/u5900t05.htm


I think I'll reserve judgment. That statement
doesn't really make sense. An element has either
been demonstrated as essential or not. There are
several way that is possible, e.g. lack of the
element causes a disease or other problem, the
element is an integral part of an essential
molecule or needed to activate the molecule, etc.
"Considered essential" doesn't mean much. I'm
not current on the subject, but some of those
element mentioned are highly suspect.
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