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Posted: 6/4/2003 10:26:04 AM EDT
[Last Edit: 6/4/2003 10:27:10 AM EDT by zhukov]
Due to the number of people on this board mucking around with their SAR-1 furniture,
I thought I'd write up an article to talk about various finishing options. I originally
poseted this on AK-47.net.

I assume that we're starting with the "as-is" wood that was on the rifle. If you're really
interested in wood finishing, I suggest the book "Understanding Wood Finishing" by
Bob Flexner. It is an excellent reference. Lots of books will tell you to finish
a certain wood always in a certain way, because "it's just done that way". But wood
finishing is a very personal thing, and not everyone likes the same result. With that
in mind, I do have several hard opinions which you may choose to disagree with:

1) Oil, or Oil/Varnish blends (most Watco, Formby's, "rubbing" finishes, etc.) are
NOT the best way to finish wood on rifles. Yes, they're easy to apply and they do
look good, but they are not a very protective finish for a rifle. If it's on display,
OK, but if you're going to shoot it a lot, then oil is not your best choice. Oil
penetrates, but don't be mislead to think that that equals protection from moisture.

"Boiled" linseed oil isn't really an oil, but linseed oil to which driers
have been added. It cures in about 1 day. I'll quote Flexner's
book here: "Of all finishes except wax, linseed oil is the least
protective. It's a soft, thin finish, so it provides no significant
barrier against scratching. It's also easily penetrated by water
and water vapor. Liquid water will penetrate through a linseed oil
finish and cause a smudge within 5 to 10 seconds."

Tung oil is marginally better, but still not ideal. Oil and oil/varnish
blends can't be built up on the surface of the wood because they
cure too soft.

I believe the Bichwood-Casey Tru-oil is a polymerized Tung oil, which is
very tough and durable. Polymerized finishes are difficult to use
on larger projects because they tend to dry too fast and are
expensive. Otherwise, polymerized finishes are very tough.

Read the label on the bottle carefully. Most of the time, the
manufacturer will call something an "oil" because of the feelings
of familiarity it causes. It may actually be something completely
different (such as a thin varnish suitable for wiping). The same
concept spills over to film finishes. Varnish and/or lacquer with
water cleanup ? Then they're not true vernishes/lacquers, but
a different animal altogether call water-base finishes.

If you have a wiping finish and you're not sure, pour some on
a piece of glass and let it cure. If it dries soft and wrinkly, it's
indeed an "oil" or oil/varnish blend. If it dries hard and (at least somewhat)
clear, it's something else, most likely a varnish. Most of the oil-
varnish blend and wiping varnish products have a name like
"Tung Oil Finish", or "Tung Oil Varnish". There's very few finishes
available which are pure boiled linseed or Tung oil. If you're going
to use a wiping varnish, you might as well use straight varnish,
because it will build up film thickness faster and yhou can save yourself
a lot of time.

2) A FILM finish is best, in particular tough finishes like Polyurethane. Film finishes
also include lacquer, and water-based finishes, but these are not as durable as
varnish or catalyzed film finishes (the latter is best, but you need access to spray
equipment. I like Sherwin Williams Water White Conversion Varnish). In particular,
I would recommend spray polyurethane to most people due to its ready availability and
easy of application.

As far as brushing polyurethane - actually, that is the preferred
methodon larger projects. The slow curing time of varnish
makes a really sticky mess of the overspray. One thing you
have to do when brushing a varnish is to level it and rub it
out. The steps are no different than the ones I listed, but take
more work since the sirface you start with is not as flat as when
you spray it.

In regards to varnish - varnish is created by heating a resin with
an oil to create a chmically new substance. Varnishes are
usually named based on the type of resin used: Polyurethane
and Alkyd are the most common. Spar varnish is used for
outside projects. It has a higher ratio of oil before being heated,
and makes for a more flexible film. This is a desired quality
for outdoor projects, as wood kept outside will still absorb
moisture to a greater degree and expand/contract more. If
the film weren't more flexible, it would crack. So spar varnish,
while you may believe it to be more protective, actually isn't.
Weird, huh ?

....continued in next post....
Link Posted: 6/4/2003 10:26:45 AM EDT
....continued from last post....

The first thing you'll have to decide on is if you want to retain the original finish
or strip the wood and start from scratch.

If you choose the latter, you'll want a good stripper to make the job faster. I can't
recommend any particular stripper, but those containing Methylene Chloride work fastest.
It's nasty stuff and will burn the crapola out of your skin, so be sure to follow the
directions and protect your skin.

Now that you have the bare wood, you'll want to sand prior to staining. The question
is - how fine to sand ? Actually, you don't need to go better than 120-150 grit. The
most important thing is to sand with the grain. Look at the wood under a bright light
at every conceivable angle to make sure you don't have any cross-grain scratches.
Any imperfectionswill be highlighted once you stain the wood.

The choice of stain is up to you. There's three major categories of stains: Dye, pigment,
and dye/pigment combinations. Think of pigment stains as thin paint. The color is
provided by tiny colored pigment particles which lodge in the pores of the wood. Pigment
stains are usually oil based and provide lots of time to work with. The drawback is
that they don't add a lot of color to dense woods like maple. Think of dyes as a colored
liquid - the stain is completely dissolved within the carrier. The color goes where the
solvent goes. The solvent evaporates and the color stays. Dyes usually come in powder form
and the most popular kind are water soluble so you mix your own. There is an incredible
amount of colors available so you have a lot of artistic freedom. I personally like dyes
for most woods other than oak or ash, but they're not that easy to work with. I like
spraying on the stain in several thin applications to obtain the color depth I want.
Dye/pigment combos are just what you think, and usually oil based. Minwax stains
(the oil based variety) fall into this category and will work well for most applications.
Some stains are pure pigment stains and muddy up the grain of the wood too much
in my opinion. There's obviously many choices, so I'll leave the decision up to you.
You can also bleach the wood with oxalic acid if you prefer. If you're interested in
dye stains and have more questions, drop me an e-mail.

The next step, after the stain has completely dried, is to apply a finish. The reason
for not sanding the wood finer than 120-150 grit is that the finish builds up on top
of the wood and you wouldn't feel it anyway. Again - I recommend spray varnish out of
a can. Practice on another piece of wood so that you can put down a thin, even film
without runs or drips. You want to "wet" the surface so that the film can flow together,
but you don't want it so thick that it will sag. The first coat will probably not look
very impressive, but don't worry about it. The biggest mistake is to start sanding too
soon - don't do it. Let the finish dry according to the manufacturer's directions, and
then wait a little longer. When you sand the finish, you want to flatten the surface.
A good product to use is stearated sandpaper in very fine grits, 320-600. Stearated
paper looks like wet/dry sandpaper with white dust over it. The dust is actually a
lubricant to help the sanding process. Sanding a finish, especially varnish, is somewhat
difficult as it tends to gum up the paper. The varnish stuck on the paper can then scratch
the finish deeply so be careful:
1) Use a soft backing block. I found that a whiteboard eraser works really good. It's
cork with a felt bottom which makes it easier to sand contours on gun stocks. Use
just the paper on highly contoured surfaces, but make sure the paper is pliable.
2) Sand very lightly until you get a feel for it. The coarser the paper, the lighter
the pressure.
3) Be very careful not to sand through the finish. If you sand through
the finish and mess up the stain, you'll have to start over.
4) Sand only enough to knock down any high spots. It shouldn't take you very long.
Wipe off sanding dust with a damp cloth and dry. When there's no shiny spots left
and you can tell that everything looks evenly dull, you're done.

The next coat will bring the shine back to the surface by flowing into the scratches.
Make sure there's no sanding dust left on the surface. Another tip for polyurethane
is to work in an environment that's as dust-free as possible. It takes a little while
to dry, and will attract dust.

Repeat this process for subsequent coats. You'll probably find that subsequent coats
take much less effort. You might have to start with 320 grit paper after the
first coat, but find yourself quickly moving up to 400 and 600 on subsequent coats
as the finish becomes smoother.

You obviously do not sand after your final coat. 3-4 sprayed on coats should do it.
If everything went well, you'll have a near glass-smooth surface after the final
coat with not touch-up needed.


If you're starting with the original finish, you go through the same process of sanding
and finishing. The factory varnish is poorly applied and the surface is nowhere near flat.
I started sanding with 320 grit paper, and it took a long time to knock down all the
high spots. Your progress will be easy to follow - the low spots will be really shiny, while
the high spots will be dull from sanding. Be careful not to cut through the finish.
You won't have to apply more than 1-2 coats, since you still have the original varnish as a base.


An important choice is the SHEEN of final finish you want - gloss, semi, matte. Most
finishes are available in a variety of sheens. You can always knock down a glossy
finish to something less shiny, but you can't go the other way.

I personally like the look less shiny. You can still start with gloss (which has slightly
more protection; semi-gloss has flattening agents added which slightly undermine film
strength) and then gently buff the final coat with 0000 steel wool. That will get you a
semi-gloss look. If you want a super glossy finish, rub out the final coat with rottenstone.
It's very important to let the finish cure extensively after the final coat before you rub it out.
You can also hit it with 600 grit stearated paper for a flat finish.

My choice of finishing the SAR-1 was to sand down the stock with 320/400 grit paper and
then buffing it with 000 synthetic steel wool (it's all I had left in the garage). It's
a nice finish, somewhat less than semi-gloss. It somewhat resembles an oil-type finish,
but I have the original protection of the varnish. I've posted a picture so you can compare
before-and-after shots on the thread "Post pictures of you Romanian AK's" above.

-END-
Link Posted: 6/4/2003 11:54:49 AM EDT
THanks for some good info, zhukov

I'm trying to lighten some Rommie laminate to match Ironwood's and ain't doing real good.

The oxalic acid, is there a trade name?

Thanks,
Winn
Link Posted: 6/4/2003 1:24:11 PM EDT
[Last Edit: 6/4/2003 1:24:36 PM EDT by zhukov]

Originally Posted By WinnR:
I'm trying to lighten some Rommie laminate to match Ironwood's and ain't doing real good.

The oxalic acid, is there a trade name?



There's actually three types of bleach:
1) 2-part bleach (sodium hydroxide and hydrogen peroxide) removes the natural color of the wood.
2) Chlorine bleach removes dye from stained wood, and
3) Oxalic acid removes rust and water stains.

2-part bleach is sold by Woodcraft, www.woodcraft.com. Search for "bleach".
Link Posted: 6/5/2003 6:06:39 AM EDT
Not to be arguementative, but if Linseed oil is such a poor protectant, why did the Europeans use it for so long. Both the Russians and Germans used it very heavily in the time period from 1914 - 1945.

I have not heard of anything added to the linseed oil but am not an expert. Could you shed some light on this?
Link Posted: 6/5/2003 8:41:54 AM EDT

Originally Posted By obershutze916:
Not to be arguementative, but if Linseed oil is such a poor protectant, why did the Europeans use it for so long. Both the Russians and Germans used it very heavily in the time period from 1914 - 1945.

I have not heard of anything added to the linseed oil but am not an expert. Could you shed some light on this?



The answer is pretty simple - because there was nothing else available !

Shellac and wax is all there was. Lacquer has been around in some form for a while, but neither are good film finishes. Lacquer has only moderate water and water vapor resistance, while shellac has excellent water vapor resistance, but poor water resistance.

Modern finishes are a very recent invention, being an offshoot of the plastics industry. I think that happened sometime in the 50's.

About linseed oil - pure linseed oil will take days to dry, if ever. Drying agents are added to make what's called "boiled" linseed oil to speed up the drying time.
Link Posted: 6/5/2003 9:50:28 AM EDT
On another link you show a photo of your SAR1 that you "flattened the finish" on using 320 grit sandpaper, if I recall correctly. It sounded like this was all that you did. Did you apply a top cout of polyutethane? Again, it came out really nice.
Link Posted: 6/5/2003 10:18:38 AM EDT

Originally Posted By BillSP1:
On another link you show a photo of your SAR1 that you "flattened the finish" on using 320 grit sandpaper, if I recall correctly. It sounded like this was all that you did. Did you apply a top cout of polyutethane? Again, it came out really nice.



Sandpaper was used to make the surface flat, which is to say smooth. It was a little dull, so using 0000 steel wool brought up the sheen slightly.
Link Posted: 6/5/2003 10:33:02 AM EDT
Here is an artical I wrote a few years ago. I can only recommend oil finishes for wallhangers. Modern finishes are so much better and look great, too.

PART I (to avoid posting limits):

Stimpy asked a question about refinishing wooden stocks, and I thought there may be others that have the same question. Since I have built a number of sporters and stocked them with blanks and pre-inletted stocks, I thought that I might relate my experiences, for what they are worth. These principles apply to FAL stocks, even though I have never refinished a wooden FAL stock.

1. First thing you want to do is strip the old stock as much as possible. If the wood has been oiled, like many from tropical countries, I would take all the hardware off and boil the wood for about 15 minutes (I have done this on Garand stocks and it works well). After the boil is done, wash the stock down with a degreaser - dish detergent works great - rinse, and let dry. Drying time will vary according to a variety of factors. It could take from a week to a month. Err on the side of caution and let it dry longer. You may have a little warpage after boiling, but if the wood was properly cut and correctly dried before it was made into a stock, the warpage should go away as the stock dries out.

2. If there is a protective finish over the wood, you will need to use some kind of solvent to remove it. I have had pretty good results with commercial finish removers, most notably, a product called Strip-eez. It will remove lacquers, waxes, varnishes, paints, and urethanes. It may or may not remove stains - it just depends on what kind of stain was used. Chances are it will remove at least some of the stain. Using a chemical stripper is messy and dangerous. Use in a well ventilated area, and use eye and skin protection. For my hands, I use heavy-duty rubber kitchen gloves. Do not attempt this with thin plastic or latex gloves, unless you just like to lose skin. After using a chemical stripper, scrub in a degreasing solution, rinse, and let dry.

3. There are different categories of wood damage to be addressed once the finish is removed. I will call these "dings", "chips", and "gouges". Dings are easy. These are the normal wear and tear that military rifles accumulate with use. The less serious ones may be steamed out. To steam a ding out, wet a heavy cotton or wool cloth, place it over the ding, and then place a hot clothes iron over the cloth where the ding is. You may have to do this several times, but if the surface has not raised by the sixth or seventh time, you may as well quit. Chances are the compressed fibers will expand somewhat, and you may be able to feather out the ding with judicious sanding later.

4. Chips and gouges are a little more serious. Depending on the damage there are a couple of ways to approach them. If you will be using an opaque finish, I recommend that you fill them with a high-quality commercial wood filler. If you plan to use a transparent finish and you know what the species of tree the wood came from is, you may be able to find a commercial wood filler to match. I have used homemade wood filler made of sawdust and waterproof white wood glue (the glue is mostly clear when dry, but does not accept stains). If you go the homemade filler route, you want to add just enough glue to give the sawdust the consitency of putty. Regardless, use several thin applications, drying in between, to raise the level of the damaged area.

Once, I saw an old cabinet maker cut out a portion of a stock that was damaged, and match the cut out with another piece of wood of the same species, glue it on, and refinish the stock. It was probably the best piece of that style of repair work I have ever seen - grain going the same way, no break in the lines. But you could still see the repair; in fact it was obvious to even the untrained eye. It was functional, however. If you are going to attempt this type of repair, keep two things in mind: first, the stock takes a lot of stress during firing, so use a good epoxy-style glue; second, consider an opaque finish, since the repair will not be so obvious.

5. Preparation prior to finishing is the key to a good-looking product. If you have to scrimp time and effort, do it at any other stage than this one. I start out by going over the entire stock with 80-grit garnet paper. I use this paper to feather out imperfections and slightly alter lines, if needed. I use progressivly smaller grits, ending up with 320. When I am satisfied with the surface, I rub it with a tack cloth to pull all the sanding residue off. Then I take an atomizing water bottle and lightly spray the entire surface of the stock. This light spray has the effect of raising the grain in the wood. I put the stock aside for about 5 minutes, then I go over it with 240-280 grit sandpaper until I can no longer feel the raised grain. Then I wipe down with a tack cloth again. Repeat this process until you can wet the wood and do not feel any grain. NOTE: I like to sand by hand, but I have used a random-orbit electric sander on occasion. When I do, I always do the last sanding by hand, to make sure the "feel" is right. The last sanding is done with 320-grit.

Link Posted: 6/5/2003 10:33:53 AM EDT
PART II:

6. At this point, you are ready to begin applying the finish. You may or may not choose to stain the wood. If you do choose to stain DO NOT USE A WATER-BASED STAIN. I can promise you that if you want a stock you can be proud of, you will not have one if you use water-based stains. Some high-quality sporting arms will use lacquer-based or pastewax stains. In my opinion, these are much too delicate, and look out-of -place on an MBR. Therefore, I recommend that you use an oil-based stain from a company known for quality, such as Minwax. Choose your color carefully; we have all seen those cheesy, red, SKS stocks from Communist China. With a high-quality, fine-bristle brush (1 - 1.5 inch wide will do fine) put a coat of stain over the entire wood surface. Let it dry completely. Then put another stain on. If you did step 5 correctly, you should not have any raised grain in this step. After the second coat, consider whether you want the color any darker. More than three coats of stain gets you into the diminishing returns area, but personal preference is what it is. Make sure the stain dries completely between coats.

If you are going to apply an opaque finish, I highly recommend acrylic paints over enamel for durability. Acrylics are more expensive, but will stand up better to heavy use. With acrylics, you will need to apply a primer. Because acrylics go on so thin, I recommend two coats of primer. This will help to fill in the pores in the wood and give the topcoats a more pleasant look.

Once your stain or primer is dry, it is time to apply the final finish. For stained or natural wood, I recommend a topcoat of polyurethane varnish. Again, DO NOT USE A WATER-BASED VARNISH. Did I say that water-based finishes look like crap? I use Captain Z-Spar Marine Spar Varnish on the vast majority of my stocks. It comes in glossy (yuk!) and satin (yum!). Z-Spar is an attractive, extremely durable finish. It will be applied in several thin coats. Usually, with the first coat, I use a mixture of thinner and varnish in a 1:5 ratio. This allows the polyurethane to soak deep into the wood, contributing to stability. Do not shake this mixture, or you will get bubbles in your first coat. Use a high-quality natural bristle brush.

After you have applied the first coat to all the possible wood you can reach with your brush, hold the dried surface at an oblique angle to a light source. If you are a geezer, you will need your reading glasses. As you examine the surface, you will find that you can see pores in the wood where the varnish. Your goal is to put enough coats of polyurethane on until you cannot see any pores (this goes for acrylic paint as well). Between each coat, let the coat dry completely and lightly sand it with 400 grit wet/dry paper. Then rub down with your tack cloth. You should not sand between coats if you are using acrylic, but do use the tack cloth, as dust in an acrylic coat can look pretty shoddy. Cover the entire surface of the stock (including channels and holes) for maximum wood stability. When you get a coat on that reveals no pores, you want to rub that coat down vigorously with 0000 steel wool, wipe it down with the tack cloth, and put the final coat on. NOTE: While good results can be obtained with a brush when finishing in acrylic, it is easier to obtain good results with a spray applicator.

When the final coat is dry, you are finished. Allow the stock to "cure" for 24-48 hours before assembling the rifle.

Link Posted: 6/5/2003 12:36:16 PM EDT
Zhukov, thanks, I figured that was what you were going to say. I have used Linseed oil for years with good results, but I use the origional military methods.

I am also one of the few die-hards that still uses bees wax on my Mausers!
Link Posted: 6/5/2003 4:24:07 PM EDT
[Last Edit: 6/5/2003 4:24:35 PM EDT by zhukov]

Again, DO NOT USE A WATER-BASED VARNISH. Did I say that water-based finishes look like crap? I use Captain Z-Spar Marine Spar Varnish on the vast majority of my stocks. It comes in glossy (yuk!) and satin (yum!). Z-Spar is an attractive, extremely durable finish. It will be applied in several thin coats. Usually, with the first coat, I use a mixture of thinner and varnish in a 1:5 ratio. This allows the polyurethane to soak deep into the wood, contributing to stability.


It's a myth that shaking a varnish will contribute to bubbles. Bubbles can always occur when brushing, and the trick is getting them to pop before the film cures.

Thinning varnish does not in any way contribute to it penetrating the wood and providing stability. All film finishes build up on the surface of the wood, not in the wood itself.

Thinning the varnish will make it spread more evenly, flow out more smoothly and help in reducing or eliminating bubbles when brushing. You may choose to thin all your coats to make application easier, but you'll have to apply more coats to build up a film with an adequate thickness.
Link Posted: 6/5/2003 8:44:53 PM EDT
Zhukov,

Thanks for the description of your SAR-1 furniture refinishing process.

I used 320 grit sandpaper and "00" synthetic steel wool pads to knock down the existing glossy finish on my SAR-1, and I'm very happy with the results.

Still doesn't look as good as your SAR, though
Link Posted: 6/6/2003 10:38:19 AM EDT

Originally Posted By zhukov:
Thinning varnish does not in any way contribute to it penetrating the wood and providing stability. All film finishes build up on the surface of the wood, not in the wood itself.



I beg to differ. Cutting into wood that has been coated with unthinned spar varnish and thinned spar varnish reveals distinct differences in penetration. Try it on a piece of scrap - you'll see.
Link Posted: 6/7/2003 7:40:29 AM EDT

Originally Posted By FALPhil:
I beg to differ. Cutting into wood that has been coated with unthinned spar varnish and thinned spar varnish reveals distinct differences in penetration. Try it on a piece of scrap - you'll see.



Phil:

Let me rephrase what I was thinking about. First of all, thinning the finish may slightly increase penetration into the wood. Even unthinned, it *may* penetrate into the wood. If you've previously used an oil-based stain, I doubt this will happen because the binder in the stain will seal the wood to a large degree.

The second point is - does the finish, which has penetrated below the surface of the wood, provide any additional protection ? I would not rely on this, as you don't know how deep the finish has penetrated, if at all. If the film, which is built up on top of the surface is damaged, then I would not want to rely on the finish below the surface. As a matter of fact, if the finish below the surface provided any protection, you would never be able to re-stain wood from which you sanded off the finish, as the cured finish below the surface would prevent further stain penetration.
Link Posted: 6/8/2003 3:47:32 AM EDT

Originally Posted By zhukov:
As a matter of fact, if the finish below the surface provided any protection, you would never be able to re-stain wood from which you sanded off the finish, as the cured finish below the surface would prevent further stain penetration.



Exactly. And that has been my experience with oil-based polyurethanes that I have thinned out on the first coat. In order to restain, I have had to take a *lot* of wood off. OTOH, they don't absorb water at all.
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