Does aqua-fortis work ok on walnut?

[Martin_G]

A buddy of mine is getting ready to refinish a stock but unlike curly maple that a member said the use of aqua-fortis helps to enhance the curl, will it work on other types of wood that have figuring?

I've not seen his stock, so I'm not sure which type of walnut he has or the amount of figuring. Is there any wood AF won't help with the grain?


Thanks,

Martin

[Dphariss]

A buddy of mine is getting ready to refinish a stock but unlike curly maple that a member said the use of aqua-fortis helps to enhance the curl, will it work on other types of wood that have figuring?

I've not seen his stock, so I'm not sure which type of walnut he has or the amount of figuring. Is there any wood AF won't help with the grain?


Thanks,

Martin

Unless its really pale I would use a dark linseed oil based finish on it. I suspect Chambers oil will work.
Staining walnut is only needed if it has no color of its own.
Dan

[KentSmith]

If you like a black stain it works fine.  It will turn walnut black.  I haven't found it enhances the grain on walnut. 

[KentSmith]

Might add - AF will give walnut and cherry a nice aged look by simulating the oxidation occuring over the years.   See some of the dark walnut House rifles.  You will have to rub it back with steel wool and a lot of elbow grease but it highlights the carving nicely and if you want a dark walnut look this is one way to go.  For highlighting nicely figured grain on walnut, no, I would fill the pores and use a good oil.

[g.pennell]

We've tried it on very light colored (sapwood, basically) English walnut...gives a beautiful red-brown color, much like it does with maple.  Haven't tried it on anything darker hued.

Greg

[keweenaw]

The dark from the aqua fortis comes from the iron interacting with the tannins in the wood.  Maple has relatively little tannin but where it stain penetrates the end grain it darkens appreciably.  Walnut has considerably more tannins and most of the stuff we use doesn't have end grains coming up like it does in curl so it just gets dark.  AF used on oak, with loads of tannins, will turn black - just put a nail on a wet piece of oak and watch the black stain appear almost instantly.  Bottom line is there are lots better ways to bring out the grain in walnut, the AF will cover up most of what's there. 

Tom

[Dphariss]

To elaborate further.
You must use dark oil, thinned with a little real turpentine, as a sealer before putting anything else on. If you use plastic like Permalyn, varathane,  any other clear or light colored modern finish or a "filler" you will not get the same color reaction in the wood. Which make take 2-3 days or a week to really develop.
I have not used Chambers oil but it should work for this.
It is also best to age the turpentine in a shallow pan 2-3 days before mixing.
There are various posts on real oil finishes and even how to make your own in the archives.

Dan

PS
 I have used AF on oak with wonderful results.

[T*O*F]

Use chromium trioxide....DGW and others sell it.  Mix solution per bottle instructions, but disregard the rest.  Have your stock sanded to 200 grit.  Before going to bed, swab the stock with the solution.  Hang it overnite.  The next morning get out your rubber gloves and a small bowl of cider vinegar.  The stock will be black and charred.  Back some 400 wet sandpaper with a small rubber sanding pad.  Wet sand the stock using the vinegar as your wetting agent.  As you sand, what you see under the wet sludge is what your stock will look like when the finish is applied.  Stop when you reach your desired shade.

DO NOT remove the sludge as you sand.  Leave it on the stock.  When finished, hang the stock overnite again.  The next day, split a  piece of maroon Scotchbrite.  Use the inner part of the pad and dip it in the vinegar. This time, immediately wipe off the sludge as you go, doing a section at a time.  Allow the stock to fully dry again and then apply your oil.  Formby's Satin Tung Oil works well and is easy to apply.

CRO3 will make plain walnut POP.  It brings out all kinds of little details that would otherwise be hidden under normal circumstances like little whorls and chains of cells.  It will bring out any oranges, reds, or yellows that are present in the wood.  Any natural figure will be enhanced.

Disregard any negative comments others may make about CRO3.  They apply to maple, not walnut.

[Martin_G]

He had been talking about using some sort of stain to bringout whatever grain or figure is present.

At that point I had mentioned using AF to bring the grain out, but I needed to find more info on useage.

Do you think he should use stain then finish with oil, or just use something like tung oil or BLO?

If it was mine I'd be a little leery using stain. I think some of them are too strong and would cover up grain instead of "helping" it!

I'll let him know this evening what ya'all suggest.


Thanks,

Martin

[Dr. Tim-Boone]

I like TOF's results in the pictures above.

In anycase I would suggest he try a couple of approaches on some small spots on the stock to see how this particular stick will look best.  It can always be sanded off!!
Otherwise just seal and finish with Chamber's Oil varnish. It makes walnut nice!

[keweenaw]

Martin,

There is little unanimity of opinion about this on this board.  The AF will greatly darken the wood which may cover up subtle effects in the grain.  The effect of just using an oil on the wood will also vary with the piece of wood and the finishing oil used.  Some people like the darkening of the wood with the oil, others don't.  Stains are another issue entirely.  AF really isn't a stain per se, it's a chemical reaction between iron compounds and the wood.  Most stains are pigmented, that is the color comes from small particles of stuff suspended in the carrier.  Almost any stain can cloud the surface of the wood if not used properly.  Ideally you get the colored particles down in the pores and not built up on the surface.  Depending on the stain that may require thinning and any stain will require considerable wiping before it is dry to get it off the surface.  Most people who have had bad problems with stains let them on too long and can't get it off the surface.  Stains can also be used to change the color of the wood - make it redder, browner, yellower or whatever.  If the object is to change the color aniline dyes are much more effective than stains and do not cloud the surface.

TOF likes CrO3 but not many of us use that as if not used appropriately it can turn green through time, an effect that is terrible against a light background like maple.  I have no experience with it on walnut but TOF's stock look good.  As he points out it is a bit of work to use it.

If I wanted a simple way to finish a walnut stock without any danger of doing something bad and that was simple to do, I would fill it with the black Constantine's filler that Jim Chambers sells and then finish it with his Oil finish.  Walnut wants some filling to look good and the filler will pick out the differential pores in the grain pattern.  Jim's oil finish has a bit of a reddish tint to it that works great on walnut and it while it darkens the wood a bit it doesn't make it too dark.

Most of us have many cans of stain, many bottles of dyes, fillers of various types, and many different bottles of finish around that we've experimented with over the years.  I might use very different finishing techniques and compounds on different jobs depending on the wood and what I want the final finish to look like.  No easy answers.

Tom

[satwel]

Several people mentioned Chromium Trioxide (CRO3) as a stain. I used it on my first rifle (maple) and I achieved the dark color I was looking for. That was almost 25 years ago and it has not turned green. I tried it again on a replacement CW rifle musket stock that I think is birch and it didn't work.

Everyone, please be aware that Chromium Trioxide is a powerful carcinogen. When I happened to mention to a chemist at work that I had used CRO3 to stain a gunstock, he was shocked that I could even buy it OTC. He said it's nasty stuff and to make sure I never got any on my skin. He urged me to find an alternate means of staining wood. I got rid of my remaining crystals when my town had a hazardous waste removal day.

If you decide to experiment with CRO3, please be very careful!

[Martin_G]

Looks like my buddy has to decide which is the best route for him to take. I'm going to get ahold of him later this evening and let him know whats been said here.

I believe he's going to be in for a bunch of experimenting. While I was out today I was thinking about this and the idea I came up with is far from new.

IMHO, he should definitely find out which walnut he has (Claro, Bastogne, Black, etc), then find a place he might be able to get a couple wood samples such as a sawmill or one of the places that builds furniture.


Thanks for all of the suggestions!


TDF, that walnut stock in your pic is very nice

[T*O*F]

TOF likes CrO3 but not many of us use that as if not used appropriately it can turn green through time, an effect that is terrible against a light background like maple.  I have no experience with it on walnut but TOF's stock look good.  As he points out it is a bit of work to use it.

Tom,
It is the only stain I have ever used on walnut and always had excellent results.  My way eliminates the need for whiskering and grain filling, so time is saved there.  I tried to add a disclaimer that it applied to walnut and not maple so we didn't have to go into the whole green discussion again.  I've used it on over 20 stocks as well as numerous knife scales and ramrods too.

On the bottom gun, I didn't remove the sludge.  Instead, i wet sanded it with thin oil.  That gun has about 20 coats of oil on it, applied like a custom paint job on a car....put it on, let it dry, take it off.  However, there is very little film thickness to the final job.