The muzzle energy on your builds is fantastic. What are the shot counts on those builds. Would love to see some detailed instructional posts from you.
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Anybody know of a small-scale hand-builder?
- Thread starter kahuna
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I also hope you will share rifle stock wood selection,sanding, staining and polishing tips with us. Welcome to AGN Forum.
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Grin, I would love to share, and I encourage anyone here with questions on the build designs or the wood component production to please feel welcome to ask me.
here are a some simple general/basic rules for stockwork;
Always use a hardwood for a stock, and always be certain it is dried as much as possible, by air not kiln if possible, down to at least 13% moisture content; 8-10% is better but hard to achieve with air drying in most climates. Use a digital meter to check the moisture content, to be certain. Wood that is not dry will squirm around after you shape and finish it, which for a gun stock is a bad thing. Will a warping or twisting stock be able to influence the straightness of a barrel? Oh yeah.
If you're going to use a single, solid chunk of wood for your stock, select a species that is known for stability, such as Walnut , Maple or Ash, with as straight a grain along the horizontal as possible. Solid wood stocks are slightly problematic since the areas of shaping that run counter to the grain ( such as the transition from fore-part to the grip ) will be weaker, and the stock as a whole will tend to move around with seasonal changes. Remember, there is no finish that can be applied to wood that is a 100% barrier to moisture, and changes in local humidity/temperature through the year will have an effect on stock dimensions. Slight, yes, delayed, yes, but inevitable.
That's one reason I always make laminated stock parts; multiple thin layers of hardwood with varying angles of grain, held together with the strongest adhesive possible, can be relied upon to have less movement than a solid wood stock, the mixed grain orientation means strength is enhanced in different shaping axis', and the visual effect can be appealing. ( another term for such a stock is 'engineered' wood construction. ) I normally use 1/4 inch or thinner layers for my stocks, and apply a slightly thinner outer layer of highly figured wood for visual impact. This technique also allow one to use more economical woods for the 'core' layers to save on expense, such as Sapele ( Brazillian Mahogany ) for instance, a dark, straight-grained, very dense and stable wood without a lot of figure; good for forming the 'spine' or center portion of a lamination, followed by more visually interesting layers closer to the exterior surfaces of the completed stock. I usually assemble my stock blank 'stacks' in a vacuum bag press, with urea resin glue.
Shaping;
After laminating/cutting the blank to size ( and making sure that the sides/top/bottom are all parallel and square to each other ) the first step is to either use a precise pattern, or the actual metal parts going into the stock, to layout the cut lines/mortise areas on the blank top and bottom faces, with depth markings on the sides, and plan how to remove the wood from these areas. I use my mill whenever possible to form mortises/channels, and sometimes I have to follow-up with chisels and files to get exactly the right cavity shape, but careful setup / choice of tooling on a quality drill press can yield good results too.
It's usually prudent to make the mortises just a wee bit wider than the metal parts going into them. ( wood movement, remember?) For where the barrel rests, I usually rough out the area with a mill ( or tablesaw ) and finish it by wrapping a cylinder-form of the correct diameter with sandpaper and hand-lapping it to a close fit, contour-wise, while it is held in a vise.
After the mechanism has been put in place to check for correct fit and alignment, the next step is rough exterior shaping. Again, it's best to develop an exact pattern and transfer the outline of the projected contours to the top/bottom/sides of the blank, then double-check for potential interference issues with the interior cavities before starting.
I usually make my shaping rough-out cuts with a bandsaw, a little bit outside the guide lines, inspect, then whittle away a bit more until I'm pretty close, then do the rest of the work with abrasives and/or rasps. I have an oscillating spindle sander with a pretty long reach that is a wonderful tool for complex shapes. Sometimes it's actually easier to plan the blank in more than one piece, do the rough shaping to the separate pieces and then bond them together with urea resin for finishing. Remember, once you've shaped the exterior of the blank it's usually not possible to easily clamp it up for follow-up milling, etc., because it's no longer square/parallel, so be sure that part of the process is finalized before proceeding.
Sanding and finishing;
I never use stain, it only muddies the grain; if I want a specific color I select a hardwood that has it naturally, there are over 200 species available with all the colors of the rainbow except blue and violet. Staining can also be problematic, depending on the type of wood used, when one has to sand between coats of finish, sometimes areas can become a bit lighter due to having been sanded down a little too much, causing a lot of cursing and fuming.
Sanding? Start rough ( 60 grit is good for shaping, drum sanders for contours and block or random-orbit sanders for straight sections. ) and step up by repeating with 100, 150, 220, 320 and sometimes even 400 grit, depending on the material/purpose/location on the gun. Always use a quality, closed-surface paper to avoid clogging, and reduce sanding time.
I find that, for most hardwoods, going past 400 grit before applying finish is a waste of time, but there are exceptions. The way to achieve a truly smooth, SHINY surface is to (a) use a gloss lacquer (b) spray multiple coats and sand with 400-600 wet-dry paper and a little water for lubricant between each coat, spray again, repeat, until all hint of orange-peel has vanished. A little retarder and thinner mixed with the lacquer will result in a smoother, glossier finish.
Never try to apply a finish with a brush. If you don't own a spray outfit, get a buddy to do it for you. And don't use HVLP systems, they put too much finish down.
Personally, I avoid gloss finishes because they tend to reveal / exaggerate every microscopic imperfection in the surface, and of course any handling or use always distresses high-gloss finishes, so I use satin grade, which, after sanding between coats and applying with care, still results in a nice, semi-gloss sheen, more amenable to everyday use without looking tatty, and satin finishes can usually be restored to their original look when scratched or abraded slightly, by rubbing with #0000 steel wool.
Some people prefer polyurethane or epoxy finishes, some have actually used clear-coat Imron; such coatings all have their advantages, but in my experience, a catalyst-type lacquer is the easiest and quickest of all types to do spot repairs on.
Last step? Always be sure to allow more than enough cure time before handling/trying to install the action in your newly finished stock; I've rushed things occasionally in the past, and wound up having to spot-repair thumbprints or marks!
I just belatedly realized that not everyone wants a 'hard' finish, some are committed to oil/rub-on type finishes. This addendum is for them.
First of all, the primary reason we apply finishes to wood surfaces is for protection. Protection from moisture, dirt, abrasions, acidic body oils, lubricants, chemicals....so the basic requirement is to 'fill' the exposed pores of the wood, until the finish is level across the exterior surface, and 'set' or hardened, as much as possible. With a lacquer or urethane system, this means a couple coats, (sanding between coats,) and a final layer left to harden ( cure ) before polishing or rubbing-out.
With an oil-based finish system, the key factor is the level of dissolved solids in the oil, which are deposited on application/left over after the solvent base evaporates. Getting the pores of the wood filled is a matter of repetitive application, waiting for curing, then re-applying, over, and over, and over, until the wood surface no longer takes in any of the solids.
Unfortunately, this can take many cycles of application, complicated by the need to wipe off the excess or 'bleed-out' oil before it sets up, which can result in a gummy, uneven surface if not wiped away, that requires a vigorous steel-wooling to remove the residue before continuing. ( elbow-grease!! )
The higher the solids content of an oil finish formulation, the more attention to wiping off the surface is required, sometimes repeatedly over a period of several hours before setting the stock aside to cure enough for the application of the next coat.
Oil finishes such as 'Watco' have a relatively low solids-to-solvent content, and although they penetrate well, require many, many coats to build up a satisfactory finish. ( we're talking 10-15 applications for more open-grain type hardwoods. )
Any finish containing Tung-oil derivatives has a high solids-to-solvent content, and can get the job done in 5-8 applications, but will require a lot of attention to wiping between coats, and will also take much longer to cure or 'harden' between coats.
Factors that can impact this process are temperature and relative humidity in the working environment; generally speaking a warm, dry environment is best, ( under 30% humidity, over 75 degrees temp. for best results. )
An oil finish will not yield a high resistance to wear, will be somewhat vulnerable to surface moisture damage, ( like getting rained on ) will never be as 'hard' as a lacquer or urethane, and will not present a high shine. It will also require regular maintaining over time, usually a buffing and re-application of oil at least twice a year. If damaged or dented or scratched, repair will require sanding away the defect and re-applying multiple coats of oil to the repair area. Unfortunately, oil finishes do not lend themselves well to spot repair, because over time the surface oxidizes ( darkens ) which means that a spot-repair will be lighter in color where the surface has been sanded away, and it requires the passage of time to make this darken/blend in to the surrounding surface, which can be many weeks or more, depending on how much time passed since the original application/curing.
Bottom line? An oil finish can be a thing of beauty, but it takes a lot of work to do properly, and requires regular maintaining to keep its luxurious look.
here are a some simple general/basic rules for stockwork;
Always use a hardwood for a stock, and always be certain it is dried as much as possible, by air not kiln if possible, down to at least 13% moisture content; 8-10% is better but hard to achieve with air drying in most climates. Use a digital meter to check the moisture content, to be certain. Wood that is not dry will squirm around after you shape and finish it, which for a gun stock is a bad thing. Will a warping or twisting stock be able to influence the straightness of a barrel? Oh yeah.
If you're going to use a single, solid chunk of wood for your stock, select a species that is known for stability, such as Walnut , Maple or Ash, with as straight a grain along the horizontal as possible. Solid wood stocks are slightly problematic since the areas of shaping that run counter to the grain ( such as the transition from fore-part to the grip ) will be weaker, and the stock as a whole will tend to move around with seasonal changes. Remember, there is no finish that can be applied to wood that is a 100% barrier to moisture, and changes in local humidity/temperature through the year will have an effect on stock dimensions. Slight, yes, delayed, yes, but inevitable.
That's one reason I always make laminated stock parts; multiple thin layers of hardwood with varying angles of grain, held together with the strongest adhesive possible, can be relied upon to have less movement than a solid wood stock, the mixed grain orientation means strength is enhanced in different shaping axis', and the visual effect can be appealing. ( another term for such a stock is 'engineered' wood construction. ) I normally use 1/4 inch or thinner layers for my stocks, and apply a slightly thinner outer layer of highly figured wood for visual impact. This technique also allow one to use more economical woods for the 'core' layers to save on expense, such as Sapele ( Brazillian Mahogany ) for instance, a dark, straight-grained, very dense and stable wood without a lot of figure; good for forming the 'spine' or center portion of a lamination, followed by more visually interesting layers closer to the exterior surfaces of the completed stock. I usually assemble my stock blank 'stacks' in a vacuum bag press, with urea resin glue.
Shaping;
After laminating/cutting the blank to size ( and making sure that the sides/top/bottom are all parallel and square to each other ) the first step is to either use a precise pattern, or the actual metal parts going into the stock, to layout the cut lines/mortise areas on the blank top and bottom faces, with depth markings on the sides, and plan how to remove the wood from these areas. I use my mill whenever possible to form mortises/channels, and sometimes I have to follow-up with chisels and files to get exactly the right cavity shape, but careful setup / choice of tooling on a quality drill press can yield good results too.
It's usually prudent to make the mortises just a wee bit wider than the metal parts going into them. ( wood movement, remember?) For where the barrel rests, I usually rough out the area with a mill ( or tablesaw ) and finish it by wrapping a cylinder-form of the correct diameter with sandpaper and hand-lapping it to a close fit, contour-wise, while it is held in a vise.
After the mechanism has been put in place to check for correct fit and alignment, the next step is rough exterior shaping. Again, it's best to develop an exact pattern and transfer the outline of the projected contours to the top/bottom/sides of the blank, then double-check for potential interference issues with the interior cavities before starting.
I usually make my shaping rough-out cuts with a bandsaw, a little bit outside the guide lines, inspect, then whittle away a bit more until I'm pretty close, then do the rest of the work with abrasives and/or rasps. I have an oscillating spindle sander with a pretty long reach that is a wonderful tool for complex shapes. Sometimes it's actually easier to plan the blank in more than one piece, do the rough shaping to the separate pieces and then bond them together with urea resin for finishing. Remember, once you've shaped the exterior of the blank it's usually not possible to easily clamp it up for follow-up milling, etc., because it's no longer square/parallel, so be sure that part of the process is finalized before proceeding.
Sanding and finishing;
I never use stain, it only muddies the grain; if I want a specific color I select a hardwood that has it naturally, there are over 200 species available with all the colors of the rainbow except blue and violet. Staining can also be problematic, depending on the type of wood used, when one has to sand between coats of finish, sometimes areas can become a bit lighter due to having been sanded down a little too much, causing a lot of cursing and fuming.
Sanding? Start rough ( 60 grit is good for shaping, drum sanders for contours and block or random-orbit sanders for straight sections. ) and step up by repeating with 100, 150, 220, 320 and sometimes even 400 grit, depending on the material/purpose/location on the gun. Always use a quality, closed-surface paper to avoid clogging, and reduce sanding time.
I find that, for most hardwoods, going past 400 grit before applying finish is a waste of time, but there are exceptions. The way to achieve a truly smooth, SHINY surface is to (a) use a gloss lacquer (b) spray multiple coats and sand with 400-600 wet-dry paper and a little water for lubricant between each coat, spray again, repeat, until all hint of orange-peel has vanished. A little retarder and thinner mixed with the lacquer will result in a smoother, glossier finish.
Never try to apply a finish with a brush. If you don't own a spray outfit, get a buddy to do it for you. And don't use HVLP systems, they put too much finish down.
Personally, I avoid gloss finishes because they tend to reveal / exaggerate every microscopic imperfection in the surface, and of course any handling or use always distresses high-gloss finishes, so I use satin grade, which, after sanding between coats and applying with care, still results in a nice, semi-gloss sheen, more amenable to everyday use without looking tatty, and satin finishes can usually be restored to their original look when scratched or abraded slightly, by rubbing with #0000 steel wool.
Some people prefer polyurethane or epoxy finishes, some have actually used clear-coat Imron; such coatings all have their advantages, but in my experience, a catalyst-type lacquer is the easiest and quickest of all types to do spot repairs on.
Last step? Always be sure to allow more than enough cure time before handling/trying to install the action in your newly finished stock; I've rushed things occasionally in the past, and wound up having to spot-repair thumbprints or marks!
I just belatedly realized that not everyone wants a 'hard' finish, some are committed to oil/rub-on type finishes. This addendum is for them.
First of all, the primary reason we apply finishes to wood surfaces is for protection. Protection from moisture, dirt, abrasions, acidic body oils, lubricants, chemicals....so the basic requirement is to 'fill' the exposed pores of the wood, until the finish is level across the exterior surface, and 'set' or hardened, as much as possible. With a lacquer or urethane system, this means a couple coats, (sanding between coats,) and a final layer left to harden ( cure ) before polishing or rubbing-out.
With an oil-based finish system, the key factor is the level of dissolved solids in the oil, which are deposited on application/left over after the solvent base evaporates. Getting the pores of the wood filled is a matter of repetitive application, waiting for curing, then re-applying, over, and over, and over, until the wood surface no longer takes in any of the solids.
Unfortunately, this can take many cycles of application, complicated by the need to wipe off the excess or 'bleed-out' oil before it sets up, which can result in a gummy, uneven surface if not wiped away, that requires a vigorous steel-wooling to remove the residue before continuing. ( elbow-grease!! )
The higher the solids content of an oil finish formulation, the more attention to wiping off the surface is required, sometimes repeatedly over a period of several hours before setting the stock aside to cure enough for the application of the next coat.
Oil finishes such as 'Watco' have a relatively low solids-to-solvent content, and although they penetrate well, require many, many coats to build up a satisfactory finish. ( we're talking 10-15 applications for more open-grain type hardwoods. )
Any finish containing Tung-oil derivatives has a high solids-to-solvent content, and can get the job done in 5-8 applications, but will require a lot of attention to wiping between coats, and will also take much longer to cure or 'harden' between coats.
Factors that can impact this process are temperature and relative humidity in the working environment; generally speaking a warm, dry environment is best, ( under 30% humidity, over 75 degrees temp. for best results. )
An oil finish will not yield a high resistance to wear, will be somewhat vulnerable to surface moisture damage, ( like getting rained on ) will never be as 'hard' as a lacquer or urethane, and will not present a high shine. It will also require regular maintaining over time, usually a buffing and re-application of oil at least twice a year. If damaged or dented or scratched, repair will require sanding away the defect and re-applying multiple coats of oil to the repair area. Unfortunately, oil finishes do not lend themselves well to spot repair, because over time the surface oxidizes ( darkens ) which means that a spot-repair will be lighter in color where the surface has been sanded away, and it requires the passage of time to make this darken/blend in to the surrounding surface, which can be many weeks or more, depending on how much time passed since the original application/curing.
Bottom line? An oil finish can be a thing of beauty, but it takes a lot of work to do properly, and requires regular maintaining to keep its luxurious look.
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Shot count is of course influenced by many factors, but on my builds the valve configuration/plenum size/regulated pressure and caliber ( 9mm )are usually quite similar, so the biggest variable is of course the size of the reservoir. My pistols go about 6-7 rounds before the reservoir pressure drops below the regulated point ( which is the place I always stop for a re-fill ). The latest rifle build, with the extra large reservoir, gives 20 shots before pressure falls below the regulated point.
I'm always in search of more muzzle energy; attached is photo of a hardwood block cutaway , a 112 grain slug penetration shot from 100 feet. Not good enough for me, so I'm still
fiddling!
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Brian, I got to thinking, jeez, that does seem awfully high, so this morning I got my pull-tester out and measured again; it's 5 lbs not 8, the previous figure must have been the result of 'old man eyes' I guess, didn't get my spectacles close enough to the gauge.
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Working on a pair of 14 inch carbines this afternoon; finally finished the reservoirs so I assembled them with the valves in place and started the first of 3 pressure/leakdown tests, this one is at 1500 psi. Can't wait to get them finished and shoot them!
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Welcome, fine work!
{Yes, some onerous rules at GTA but it is what it is and worth it to tough it out there. Here is a slightly different type of people but a great group too! Both have something to offer.)
GTA > 'The Darkside" > you will find rsterne a great guy who builds and is a tech guru and then there is oldpro who is also a amazing builder who invents, and tunes. Or lloyd-ss who does building and testing (Check out their Bob n Lloyds Workshop on the main page).
Plus too many other experimenters n shooters to list, you could spend weeks just reading old threads.
You should join the 'guild'
{Yes, some onerous rules at GTA but it is what it is and worth it to tough it out there. Here is a slightly different type of people but a great group too! Both have something to offer.)
GTA > 'The Darkside" > you will find rsterne a great guy who builds and is a tech guru and then there is oldpro who is also a amazing builder who invents, and tunes. Or lloyd-ss who does building and testing (Check out their Bob n Lloyds Workshop on the main page).
Plus too many other experimenters n shooters to list, you could spend weeks just reading old threads.
You should join the 'guild'
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Thanks, I am starting to plow through some of the threads; def. enough there to keep me busy for a few nights reading!
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