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Finishing Gun Stocks With Acraglas

by Marc Stokeld

I feel that acraglas is the best stock finish for gun stocks that will be used in the field. The finish is tough, impervious to just about any type of chemical attack, it reduces dents and abrasion in finished wood, and it makes questionable wood take finer checkering. This finish can be made to look like oil, epoxy, or any other type of finish by properly manipulating the top coats of finish. That being said, I do not recommend it for every gun. I would never use this finish on a Holland and Holland. It just does not seem right, even though the finish would be superior to the traditional English oil finish. I am a very pragmatic person, but I am just too much of a traditionalist to use this on a gun like an H&H.

I make no claims that this is the best way to use acraglas as a stock finish. It is the best method that I have found to date, but the process is always evolving. Please contact me if you find other methods of application that you feel are superior.

Sand and whisker the stock as usual. Always use a sanding block when sanding. For long, straight sections, I use a 5" piece of micarta with a piece of 10 oz. Leather glued to one face. The micarta block will keep straight sections straight, not pretty straight. For smaller areas, I use an artgum eraser. If I need to get into a tight area, I cut and grind a piece of hard felt to fit my needs. This may sound like a lot of trouble, but it makes a difference in the way a finished stock looks. I dry sand with the following grits: 100, 150, 220, 320, 400, 600. I use only the eraser as a sanding block for the 400 and 600 grit papers.

I whisker the stock with either denatured alcohol or hot water. For a heat source, I use a hairdryer or a propane torch. Be careful when using the torch with alcohol. If there is alcohol standing on the surface of the wood, the torch will cause a flame-up when it gets too close. This is very exciting. I start whiskering after the 320 grit step in good wood, and after the 220 grit step in not so good wood. I whisker and resand with the same grit two times. I switch to the next finer grit after the third whiskering. This is done until no scratches show up in the 600 grit finish. Do not sand after the last whiskering on the 600 grit. We want the pores to be as open as possible.

The acraglas used is the original kind (not the gel). Mix it according to the instructions, but do not add the flock. All we want is four parts resin and one part hardener. I use the "itty-bitty cups" sold in the Brownell's catalog for mixing. I fill the resin up to the one dram line, and then I add dram of hardener. This last measurement is not very accurate. I just eyeball it, and it turns out ok. This amount of glass will be more than enough for a regular rifle stock. It might be enough for a Mannilicher, but it will be too close for comfort, My philosophy is that acraglas is cheap compared to the time I have in a stock, so I mix more than I should need. A 2-gun kit of acraglas, as sold by Brownell's, should do one regular size rifle stock. I buy it in bulk-28 oz. of resin, and 7 oz. of hardener. This stuff is great to have around the shop. I used it for attaching my knife handles when I made custom knives, and I still use it for attaching tool handles or any other task that calls for epoxy. It is stronger than the Devcon epoxy that comes in the dual syringes. Keep in mind that the resin and hardener does not have an infinite shelf life. It will go bad in time. I would not use acraglas that was over two years old. I have had trouble with it when it went beyond that age.

After the glass is thoroughly mixed, pour a dab on the stock. I pour a line about 4 inches long on the side of the butt. I then work the acraglas into the wood with a piece of T-shirt. I cut a square about 9"x9" and fold it into a ball. The smoothest side of the ball is used to spread the glass. I add more acraglas to the surface of the stock until it is completely wet. Be careful here. You want full coverage, but you do not want runs. Runs are a nightmare to sand off after they harden. When the entire stock is wet with glass to the point where it wants to start to run, I apply a good deal of heat. The heat will make the glass as thin as water. This allows the glass to get maximum penetration in the wood. Only apply heat until the glass gets runny. Keeping the stock hot too long at this stage of the finish will cause the glass to set up before it has gotten full penetration Let the stock stand for a few minutes, then wipe all excess acraglas from the surface. Set the stock aside to dry. I put the stock in a cabinet to keep it from getting dinged up and to keep the dust off of it. The dust really does not hurt anything at this point, because it will all be sanded off later. Wait 12 to 24 hours, and repeat the process. These two sealer coats should be sufficient, but I am a worrier by nature, so I usually use three penetrating sealer coats.

At this point, you have several options. If you want the traditional oil finish, wet sand the stock with your oil of choice and 400 grit paper for the first coat. After it is dry, wet sand with oil and 600 grit paper. This will get any dust and built up acraglas off of the surface. If desired, stain the stock at this time. This is another advantage of acraglas. Solvent-based stains will not lift the finish out of the pores. This is a problem with most other stock finishes. Proceed with the oil finish as normal from this point on. The acraglas sealer coats will make the oil finished wood more stable and the wood will be less prone to dent after an impact.

There is another way to get the look of oil with far more impact resistance, greater stability, and greater resistance to abrasion. If the pores are filled level to the surface of the wood with glass, the finish will be much more durable. The pores will stay filled even under hard use and abuse. The acraglas will make the wood take fine checkering better. This is especially true of wood with large pores. The glass is hard and cuts well with checkering tools. The increased amount of glass is also what helps to seal the wood against moisture migration. Acraglas will not make wood act like a fiberglass stock, but it will move much less than a stock finished with more traditional methods. This is something I have proven in the controlled environment of a humidity cabinet.

To fill the pores with acraglas, apply it in the same manner as you would a sealer coat. However, do not add the heat to thin the glass. After a few minutes, wipe all excess glass from the surface of the wood. All you want to do is wet the wood and get the glass in the pores. Any glass that dries on top of the wood is going to come back to haunt you. Hang the stock to dry for at least 12 hours. Repeat this step at least four times. Dry sand the stock with 400 grit paper. (NOTE: I find the acraglas sands better after a full 24 hour cure. Due to the chemical process involved in the hardening, either cure time will be hard enough for a good finish. I just find that the 24 hour cure cuts a little smoother with the sandpaper.) You should sand down to the top of the wood, but no deeper. If you sand too deep, more pores open up and you get into an endless loop. Repeat the process until all pores are full. I suggest adding one or two more coats than you need. Just don't build it up too high before sanding. When all pores are level with the top of the wood, lightly dry sand with 600 grit paper. If staining is desired, do so at his time. Mix up another batch of acraglas and apply a thin coat to the surface of the stock. The key word here is thin. All you want to do is get it wet. Do not let dust get on the finish from this point on. Apply at least four of these thin surface coats. At this time, the finish will look like a dull factory on a Winchester or Ruger. If this is the look that you desire, lightly dry sand with 600 girt (just to even out the surface) and you are through. If you want a high gloss finish like Remmington's RKW finish, sand with 1200 and 1500 grit paper between the next few coats. Use a rubbing compound to get that final bit of shine.

I personally do not like the finishes mentioned above. They have a dead plastic look to my eyes. I prefer to use oil as a topcoat. I use the slacum oil in Purdey's Warthog kit. It isn't magic, I just happened to have it handy and I've gotten used to using it. More importantly, I really like the way it smells. The first step is to wet sand the stock with the oil and 600 grit paper. Tread lightly. All you want to do is sand the thin coat of acraglas on top of the stock. If you break through to the wood, it will show up and look terrible. If this happens, you will have to build up the glass before you can go on to the oil. After the stock has been wet sanded, wipe off all oil and sludge. Hang the stock in a place where it will not be exposed to dust. After 2-3 hours, wipe down the stock with a clean, soft cotton rag. Hang until the next day. Repeat the process above at least one more time. After the day of drying, inspect the stock for irregularities in the finish. If the finish looks even, put a few drops of oil on the stock and rub it in with your hand. Do not build up a thick layer of oil. All you want to do is get it wet. Set it aside to dry for 2-3 hours. Rub down with a soft cotton cloth. Hang the stock and let it dry for at least two more hours. Repeat this process until you get the desired look. After the last coat of oil, continue to rub down the stock with a soft cotton cloth several times a day. Be very careful to only use a clean cloth for all rubbing operations. A little grit on a piece of cotton can destroy days of hard work. If the coats of oil start to look uneven, lightly wet sand with 600 grit paper.

The oil can be applied without the buildup of acraglas on the stock. This finish will look 100% like an oil finish. It will be more weather resistant than straight oil (due to the glass sealing and filling), but it is far inferior to oil on top of built up glass. The thin layer of glass goes a long way in slowing down the migration of water into and out of a stock. The only thing you would do differently with this method is to not build up the 4+ thin top coats of acraglas. After all pores are full, dry sand to the top of the wood, being careful not to get too deep and open up the pores. Lightly wet sand the first two coats of oil in the wood. If desired, stain at this time. Proceed as you would with a normal oil finish from this point forward.

It is possible to fill the pores in one coat. After the first two sealer coats, Apply a thick coat of acraglas to the entire stock. If the pores are small enough, all pores can be filled in one step. However, the acraglas must be left above the surface of the wood in a very thick coat. It will have to be sanded down to the bare wood before the finish can be built up again. This is incredibly hard work. When I made custom knives, I sanded hardened steel on a regular basis. I would rather do that every day than sand one more stock that had a thick coat of acraglas on it. It took me over five hours to sand the last stock I treated in this manner. Never again! You spend fewer days in the finishing process, but you spend more hands-on hours doing it this way.

Acraglas can be wet sanded in an attempt to more quickly fill the pores. One way to do this is to thin the glass with heat. The problem with this approach is that the heat causes the glass to set up before much sanding can be done. If you try this, only do a small piece of the stock at a time. Another method of wet sanding is to sand the stock when it gets tacky, This should be about two hours after the glass has been applied (will only work if no heat has been added). Try these if you like, but I get much more even finishes with less time and effort by using the build-up method.

Use caution when coating the inletting with acraglas. It is imperative that you do not let any glass harden above the surface of the wood. The best way to apply the glass to the inletting is to heat the cup of mixed acraglas until it gets thin. Do not heat any longer than necessary. Doing so will cause the glass to set up before it soaks into the wood. Wet the inletting, being sure to wipe the excess from all inletting surfaces before the glass hardens. If any acraglas gets built up in the inletting, you will have to remove it with scrapers before the metal can be put back in place. Inletting protected with acraglas will be very hard and impervious to all gun oils. One coat of glass should be enough for the inletting. I often just use Laurel Mountain Forge Permalyn stock sealer on the inletting. It depends on the gun and the application. It is not as strong and chemical resistant as the glass, but it easier to apply and it is not as prone to excessive build up. However, if you need maximum strength and protection, use the glass.

The easiest way to clean acraglas from the hands is to wash with straight white vinegar. After the glass has been removed, wipe your hands off with a cloth towel. Do not use water yet. Next, use Go-Jo on your hands. Now wash your hands with soap and water.


WARNING - the dust generated by sanding acraglas is not good for you. It will make you very sick. Respiratory protection should be worn during all dry sanding operations. This is especially true if you fill the pores in one step. Doing this will generate a lot of sanding dust. This is another reason not to fill the pores with one coat of acraglas. If you breathe enough of the dust, you will feel like you have pneumonia.

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