I have used the acetone soak method for many years to de-oil stocks that were to be refinished. While it works for that purpose beautifully, there is an after effect I have noticed that is troubling. When the old wood dries it is almost always smaller than it was originally. Maybe it's because all the moisture has been driven from the wood along with the oils. The metal then stands proud of the wood, which looks really bad on an otherwise nice looking gun.

Is there a way to successfully reintroduce moisture and/or natural oils to the wood that will return it to it's dimensions before the soak, and also before the stain and stock finish is applied? I don't recall having ever seen this issue addressed, but can't believe I'm the only one to whom it has occurred.

Thanks SRH

Stan, I'm the unhandiest hand in the bunkhouse here, but I've had guns where that had happened and I liberally applied walnut oil out of my wife's spice cabinet to the wood. It soaked in pretty well and may have helped. It certainly smelled better...Geo

Might work, Geo. Since my only issue is with the head of the stock I'm wondering if steaming it would bring it back near original dims, then using a natural wood oil following that.

SRH

Stan, I had a forend machine copied for me in the Pacific Northwest. It is quite humid there. It was a good job and I lived in Anchorage which is quite dry, especially in winter. When I started to tend to the machined forend afer having it a few months, I found it ha shrunk and sort of twisted a bit .

I wrapped the forend in a damp cloth and let it sit for a couple of days. After that I found the forend had absorbed some moisture and had returned to the proper shape. I applied an oil finish over the entire forend and it never reverted to its twisted , shrunken shape. Why not with a buttstock, too ?

Excellent, Daryl. Thank you so much for that reply.

SRH

This may cause a smile. After the soaking in Acetone let the Acetone dry out of the wood. Next soak the wood in Vodka overnight of course do not use good quality Vodka though. As you would expect the Vodka soaks into the wood, then you allow the Vodka to dry off but only the Alcohol escapes the wood quickly leaving a small amount of water in the wood. You could use a low percentage industrial Alcohol but on this side of the pond they put all sorts in the stuff to make it smell and taste not so good to stop people drinking it, hence the Vodka.

I seem to remember maybe David Travallion (sp?) mentioning swelling the wood in a humidity cabinet then painting the inletting with water thin super glue to lock it in place. I've never tried it but it sounds like it may work.

I've only used built up finishes to correct slightly proud metal. I don't really like built up finishes but didn't know what else to do.

You know something, the original recipe for de-oiling a gunstock with acetone called for a subsequent soak in isopropyl alcohol. I got into the habit of skipping the alcohol soak, as I couldn't see where it was doing any good after the acetone. Perhaps I was all wet, pardon me, in thinking that the purpose of the alcohol soak was to further remove oil. Maybe the reason for it was to re-introduce moisture to the wood that the acetone had removed. Vodka, being about 60% water, would certainly do that. Isopropyl alcohol that was down around 50% water would, too.

Interesting stuff, damascus. Thanks.

SRH

You have figured it out. Acetone over dries the wood and pulls not only the extra oil out of the wood but also the natural oil of the wood and too much water as well. In a humid area like where you are the moisture will gradually re-enter the wood if it has time. Problem is that we refinish the wood too soon and seal most of the ways back into the wood.

I set the wood aside for a couple of weeks if I can. Worst place is near a heat source which will just keep it over dry. If in a hurry I wrap it in a towel and wrap that in another slightly damp towel and then in a plastic bag but not sealed. Change it several days and then let it rest. The damp towel just puts moisture near the stock, the dry towel keeps from raising the grain too much. You could do the same thing with a cabinet that had a slightly raised humidity like your humidor.

Thanks Jon. I think I'm on the way to resolving this issue now.

Thanks all! SRH

Interesting thread!

Three days in acetone and then three days in denatured alcohol which appeared to come out clean. A week was necessary for the wood to shrink back to normal size so the water was absorbed. I never used alcohol again. I never noticed weakening of the wood after the acetone and I am still shooting some of those guns ten years later and they still look great.

I'm confused by your post, builder. Are you saying the alcohol was necessary to re-introduce moisture into the wood, or that you tried it using the alcohol bath once but never again?

My issue is that the wood has always shrunk too much, when using acetone alone, and the metal is proud of the wood. This is a big issue. For it to look right the action would have to be annealed so that it could be filed down to the level of the shrunken wood. Much work that needs to be avoided at all costs. Some way to reintroduce moisture into the wood, other than letting it sit for a year in high humidity is necessary.

SRH

Sorry for the confusion Stan. I was making two points.

First, the alcohol did not really remove anything that the acetone had not already done.

Second, I believe the denatured alcohol introduced a lot of water into the stock and it took a week to shrink back to normal.

I have not experienced shrinking of the wood due to the acetone. Maybe I was just lucky but I have done a couple of dozen with no shrinkage.

We had a similar discussion several months ago in the main forum. From everything I have learned about the effects of organic solvents like acetone on the structure of wood, I am still of the opinion that long soaks of heavily oiled stocks in these solvents should be minimized.

The conundrum is that doing nothing about oil soaked wood also continues to degrade the structure, so something must be done. But much of the oil and crud can be removed by heat, absorbent materials such as whiting, tissue paper, or kitty litter. I then proceed to things like washing with Murphy's Oil Soap, or a solution of household ammonia which saponifies mineral and skin oils. The saponified oils become water soluble. Of course, these must be thoroughly rinsed off of the wood and dried. Dawn dish detergent is another great oil remover. This assumes that the old finish has already been stripped for anything beyond surface cleaning. I then proceed to using isopropyl or methyl-ethyl alcohol soaks if more oil removal is needed, and only use acetone or lacquer thinner soaking as a last resort for the most heavily oiled wood. But doing it this way takes time and doesn't give instant gratification. And if you think your acetone soak is removing every last bit of oil that has soaked into the wood for the last 75 years or so, just put your clean stock aside for a few months before refinishing to see how more oil discoloration migrates back to the surface.

Wood is mostly composed of cellulose, hemicellulose, and lignin. Google "lignin soluble in acetone" to see if you think prolonged soaks in acetone are healthy for your gun stocks. Of course, even alcohols can dissolve lignin with prolonged soaks. Water and alkalies can dissolve cellulose, as is done in paper making processes. Does this mean that a few days soaking in acetone will dissolve your stock? No, of course not. But more cellular damage will be done to the very thin sections of L.C. Smith inletting, for example, than to a 1 1/2" thick butt section. Short soaks in solvents are probably better than leaving old gun oil in your wood, but prolonged soaks in harsh organic solvents are best minimized or avoided whenever possible.

Stan's wood shrinkage was probably due to the acetone carrying out much of the higher moisture content that would be found in a humid climate such as Georgia. Restoring that moisture will swell the wood near normal dimensions. But long soaks in organic solvents are likely removing other things besides water and old gun oil. The fact that your stock doesn't break after cleaning and refinishing does not mean it is as strong as it was initially. The guys who are flooding their wood with thinned epoxy or crazy glue after solvent soaking have probably learned that they need to do something to strengthen wood that has been weakened by oil rot and solvent soaking. Every stock needs to be evaluated on an individual basis and treated according to condition and stability of the wood.

One of the rare times mixing alcohol with shotguns is recommended. Gil

I'm gonna give it a try, and buy a bottle of the cheap stuff this afternoon, just to see the face of the clerk when I tell him what I want it for. I can hear him muttering to himself as I walk out, "I've heard some lame excuses for buying liquor, but that's got to be the worst".

SRH

Be prepared Sunday morning Stan. Word travels fast in Church circles. They'll be lying in wait for your 'intervention'...Geo

SRH

I do hope my suggestion of Vodka has not started some sort of wayward behaviour from our American cousins!!!!
Just a food for thought post. I am sure that I have mentioned this before sometime in the past but I am still of the mind it is the finest method for removing oil from a gun stock, but not the cheapest initially but does have a lot going for it after its initial set up. With the only ongoing cost is a roll of Toilet tissue per stock.
Before I retired I was doing some work in a factory making ultra high voltage transformers, the final operation for each transformer was to impregnate all the windings with an Epoxy insulator and moisture barrier this was initially a liquid but set solid after an hour. This was achieved by putting the transformer and liquid epoxy in a small vacuum chamber then applying a vacuum, this caused the air trapped in the windings to be removed and could be seen producing bubbles on the surface of the surrounding liquid Epoxy. After 10 minutes the vacuum was slowly reduced and in doing so the liquid was drawn into the transformer windings.
My next visit home I put a gunstock with an oil saturated head in my suitcase for vacuum chamber experimentation, here I must say it was only a one time experiment. I left the stock on a hot radiator over night, next morning I wrapped the stock in a complete roll of toilet tissue to soak up the oil. Placed the stock in the vacuum tank and lowered the pressure slowly to minus 3 Bar keeping it there for 12 hours, then slowly bring it up to atmosphere. The results where surprising the toilet tissue was saturated with oil from the head and chequering, and just to make sure I did it all over again only this time very little oil came out in fact I would say minimal. I have always had in mind for an entrepreneurial person could do something with this on your side of the pond, we don't have the numbers of guns with oil soaked stocks here to make the expense of having this equipment worth wile.

I believe it's pretty common for folks who want to stabilize wood with some sort of curing liquid to draw a vacuum on the piece to remove moisture and natural oils, so there's little voids for the polymer to enter. It's pretty easy to rig pipe with threaded caps and a fitting to draw a vacuum inside. A brake bleeder could do it, but that would be painfully slow for a container large enough for a stock.

Interesting about the pressure tank. Five gallon units are sold on eBay for 150$, not sure if they would work or not.

Only thoughts, but the tank could probably be sourced from the scrap yard. Stuff like flanged pipe, cut open an old O2 cylinder, etc. With a perfect vacuum, which may not happen, the maximum force pushing in on the vessel would only be one atmosphere. It could collapse, but wouldn't burst outward as if it were pressurized. I'm familiar with things like this. You only really need to tap one little hole for a vacuum hook up. A ball valve will shut it off so the pump doesn't have to run constantly, and a tee off of it for a vacuum gauge is a good idea. With a little familiarizing, it could be a good time saver with likely little worry for the wood. Only thoughts.

I think I should mention the reason I never continued any further with this system when I returned home. The main problem was the expense of purchasing a quality vacuum pump and control gear capable of producing vacuums of 3 bar and over and keeping it stable for an extended period of time. The pressure vessel was not a problem to assemble from a length 6 inch diameter 3/8 inch wall steel pipe welded shut at one end having the vacuum pipe inlet fitted also a vacuum release valve and at the other end a bolt flange fitted with a steel closing plate and rubber gasket for access.

How about using a vacuum pump like those used to purge an A/C system on an automobile. They're pretty slow, but it is my understanding that they really are powerful. Like this:

https://www.harborfreight.com/25-cfm-vacuum-pump-61245.html

It is rated to 10 Pascals. That is .0001 BAR. Anybody understand all that enough to know if it would work, or if that is enough vacuum?

SRH

They've got a higher priced one that goes to 3 Pascals. I don't know if that is better or worse ................more or less.

SRH

Those things are a head scratcher Stan. There're probably a dozen different brands that label that basic machine. I'd consider seeing if the amp ratings are available. Chances are the truly stronger motor will get to where they can, a bit quicker. If a person had some confidence in assessing used machines, they seem to be available for pennies on the dollar.

I feel that I should give you folks the results of my enquiries about what type of vacuum pump is required to produce a good workable vacuum.
The pump needs be a "Rotary Vane Double Stage Oil Bath Vacuum Pump". I also found that gauges and control gear for compressors and pressure vessels are a very reasonable cost, but as soon as you enter the world of vacuum generation all price logic seemed to go out of the window and be replaced by high costs indeed. This is all the knowledge I have about duplicating the vacuum kit I used in the factory. I hope the prices are much lower for the bits and pieces needed to build it on your side of the pond, though here in the UK it is far to expensive.

The $149.99 one pulls to 22.5 microns. Can anyone help translate that into gunsmithing-ese? Specifically, is that enough vacuum to do the job? On a conversion table that translates to 0 bars. Am I correct that 0 bars is a greater vacuum than the 3 bars damascus mentioned? Or, am I bassackwards?

This apparatus could be a huge improvement over soaks if it will work and could be assembled for under $300. I believe I can make the pressure vessel from salvaged pipe, etc. It would be so easy to repeat the toilet tissue wrap, and let sit overnight in the container, as many times as needed to remove most of the oil. The possibility of picking up a used one cheap is a good idea too, craig, thus lowering the initial costs even more.

SRH

I feel that I may have made things a little difficult by using the word Bar. So to make it clear the gauge on the factory unit was in Bar the unit was put together by the factory them selves the gauge could have been sourced from anywhere. Now the Germanic logic!! Atmosphere is 14.27 psi so according to the gauge on the unit 1 bar is 14.5038 psi with this being the case the internal atmosphere inside the vessel was lowered by approximately 3 atmospheres.
I had to dig out my Diary and look up the notes I made at the time so I could make a unit when I returned home.
I hope this makes things clear for you all. I will now take my aching head for a sleep and to help things along a glass of Bison Grass Vodka should work just fine.

I was commenting from the perspective that relatively common, inexpensive things can create enough vacuum to draw natural oils and water out of wood. I'm pretty sure damascus is using equipment that can do a better job.

My understanding is that almost all vacuum pumps can get to a certain point, and then to get the last little bit, the cost starts to go way up or go very slowly. I think it's pretty well known that oil can be drawn out of a stock basically by chemically diluting it and or wicking it out with an absorbent. I wouldn't be surprised if a little warmth to lower the viscosity and some vacuum could work well.

I think a home setup vacuum tank may slowly leak, so if someone wanted a long vacuum hold, they might want to check it and refresh it if needed. I wouldn't buy it from a purpose built supplier, but if you look at wood working bag clamps, you can get an idea of how a vacuum pump and shut off valve could be hooked up to a tank. Those bag systems have an advantage though that the atmosphere collapses the bag around the work piece so it's easier for the pump to do its job.

I haven't looked in a number of years, but I've seen Gast brand double vane pumps come up for very inexpensive prices. But, maybe a tad bit more vacuum wouldn't make much difference that could be made up with a bit more time. It's interesting to me that damascus had success, but as he reminds, there's caution not to mix apples with oranges.

Back a few years ago I was casting acrylic and rotted wood for a pen making project on a wood lathe. Part of the process was to place wood into a container of heat cured acrylic which filled in most voids in rotted wood. First you pull a vacuum to about 99.7%, let it soak then reverse to 60-80 psi to drive the liquid acrylic into the cellular structure. Then remove and cure at 190 degrees f.. Then you placed the wood into a mold and fill the mold with another kind of acrylic which was pressure cured at 80 psi.

I used the Harbor freight vacuum pumps but could not pull enough vacuum. Had to buy a used Gast pump off EBay. My chamber was a paint pot. First was a 2 1/2 gallon then upgraded to a Binks five gallon pot. Much better made pot and could go up to 110 psi if needed. Never tried to pull oil out of a stock but no reason it would not work if you could get the stock into your chamber or use a vacuum bag like they use to clamp veneer for glueing.

As you approach true vacuum the boiling point for a liquid is falling. Guess at absolute zero pressure the oil should all come to the surface. If you have it wrapped in an adsorbent material most of the oil should be caught but if you don't there is nothing to prevent the surface oil from being pulled slightly back into the wood.