Hi. New to this particular forum and pretty impressed with the wealth of information available. Hope you all have some good answers for me to read!
I am in my first year of the Fine Furniture program at Rio Grande Community College and am currently finishing a walnut highboy (FWW 117) and need to decide on finish. An instructor of mine suggested that I try nitric acid and seedlac as he believes it will give me the warm organish/cinnamony color that I am looking for. I am, however, loathe to use nitric acid and believe some of the other issues involved in its use make it an unworthy candidate. I am sure that I can achieve a similar color with some combination of aniline dyes and shellac but am not sure what the proper combination is. If anyone has any advice or secrets!!! they want to share I am all ears. If push comes to shove and I have to use the nitric acid then any do’s/dont’s would be handy. Nad if you have any pics to go along that would be even better! And as I am sure that it makes a difference, I am using air dried walnut…
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Most people use Walnut because of the color. The color will change over time. The finish will most likely yellow some over time.
Most woods like Walnut are best finished with an oil finish. Oil finishes tend to bring out the darker colors in the wood and the finish will also amber some. Colorless or clear finishes look best on light colored woods like Maple, etc.
The best thing to do is to completely prepare a small scrap of the same wood and finish it to see what the finish would look like.
Edited 3/22/2006 9:20 pm by gb93433
I haven't used nitric acid but have seen a very interesting sample of walnut dyed with that material. I'd be curious what you see as the issues involved in using the nitric acid.
I'm not entirely sure you can achieve the same effect from commercial dyes, particularly if the look involves the lightening effect of ageing, as you description suggests. You might have to use a two part bleach to remove the natural color, and then replace it with dyes, and stains.
First of all - From what I understand, its a one shot deal. Drips and such show and there isnt a whole lot you can do about it.Second - In order to create required reaction, it is necessary to use a heat gun. unfortunately heat guns throw of small pieces of charred metal from the coil that show up as rather noticeable black spots.
Thanks. I can't say I've observed metal specks coming off of heat guns, but I haven't made a study of it. I understand the drips and runs, though even with aniline dye applications will want to avoid these too. If the look of the nitric were really right on, I suspect I would work on technique to minimize the drip and run problem.
Before I scrapped your instructors program, I would experiment on scraps from the project to see exactly what you would be aiming at in terms of coloration., using the nitric acid process as a base line. You need to test on scrap in any event, and a mistake can usually be remedied by a pass or two through the planer. Remember that with dyes or chemical processes you won't be able to judge the final effect until a top coat has been applied, or at least simulated with a mineral spirits wipe.
Wouldn't do it... it's very nasty stuff (more corrosive than hydrochloric or sulfuric)- denatures proteins very easily (your hands are made of proteins, as is your trachea...)
I'd use oil instead- either tung or BSO.
Glaucon
If you don't think too good, then don't think too much...
Also, if nitric acid gets on bare skin, the reaction turns the skin black and since it's a chemical reaction, it doesn't go away until the skin wears off.
"I cut this piece four times and it's still too short."
As a chemist I would be concerned about the use of nitric acid under these conditions. You might use the "Ask the Experts" heading above. Perhaps there is someone there who has more experience with that approach. Good luck.
I didn't think he had specified the conditions underwhich the nitro would be used. I guess I assumed that in an academic context there would be sufficient protective gear, ventilation, and known proceedures for diluting acids, etc. This clearly requires care and attention to detail, but dilute nitric acid isn't going to jump out and bite people--if they are focused on safety.
It appears that the ask the expert section requires a subscription. If any one could pass on my initial question I would greatly appreciate it.
You are attending a real little gem of a school, hdgis1. Have previous students used this method? What does Eric have to say about the process?
Beat it to fit / Paint it to match
Eric's biggest complaint(s) had to do with the method of heating and the 'one shot; nature of the application. In fact, aside from the hazardous nature of the acid, his complaints are mine.Should I assume that you have had experience with the school? Would love to hear some antecdotes if you have. Did you find that the job market was wide open upon completion of program?
Forgot the previous student part - As far as I know, Mark (the current assistant) is the only one to have tried the method. The pics were amazing! Ill try and see if I can get a copy of them.
Is Eric Matson still teaching there? I think he would be the one to know about such finishing methods. The only thing I've ever seen about nitric acid was in reference to marquetry dyes. They apparently used it as a mordant, mixed with copper for a green color.Beat it to fit / Paint it to match
Yes Eric is still there. He did offer some suggestions, yet I find I have the bad habit of looking other places for more information. Combine Erics knowledge with everyone here and you cant lose!Were you a student at Rio yourself or have you worked with Eric in the past?
I wish I had attended Rio but programs like that were just a dream in my day. I was a woodworking instructor and did some research about what was going on around the country in various schools. Your school stood out for offering a unique educational opportunity. If I remember correctly, someone I met at the VICA Nationals told me about Rio. I hope you take full advantage of the program.I have a PDF with some information on coloring wood in the 18th century. It talks about Roubo's "L'art du Menuisier" and Diderot's Encyclopedia. It doesn't answer your question but I think you will find it interesting.Beat it to fit / Paint it to match
You might also contact Old Mill Cabinet Shoppe. They carry a full line of chemical dyes and colorants, including 10% Nitric Acid. They are on the web at http://www.oldmill.com
I'd avoid it. Safety is a real concern. Unless you're working in lab-like conditions with a vacuum booth, and have it properly diluted, it's not for amateurs.
There are more than enough varieties of commercial stains to get the color/tone you'd want.
If you elect to use nitric acid, make sure you soak any rags you may use in a lye solution, let dry and then dispose of them. Nitric acid, sulphuric acid and cotton make nitrocellulose, also known as guncotton.
I don't know if dilute (10% was mentioned) nitric acid by itself will convert rags to guncotton or not, I'd suggest not finding out, myself.
Good luck,
Leon
Edited 4/1/2006 11:02 pm ET by lwj2
What the heck is guncotton?
It is an explosive material used (at least at one point) in making smokeless powder and other blasting materials. It also is a component of lacquer. The nitrocellulose and other resins including alkyd are dissolved in solvent. When you see some one saying he uses NC lacquer, the NC means nitrocellulose.
As Steve noted, it's (nitrocellulose) an explosive material that's widely used for a variety of things.Guncotton refers to the duffel-bag quantities of it that are used to propel, amongst other things, sixteen-inch shells from naval rifles.It was also used as film base until a more stable base was developed.Leon
An instructor of mine suggested that I try nitric acid !!!!
Well, Good luck.. I worked a 'bit' in plating metal long ago..
Nitric acid IS NOT SOMETHING TO PLAY WITH!..
I hope you LOVE your Eyes.. PROTECT THEM WITH A FULL FACE SHIELD AND GLASSES UNDERNEATH IT!
I had a co-worker I knew that is blind now..
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