Building a Laminated Plywood Stock

SeamusMac

SeamusMac

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Hey Folks,

I'd like to make a laminated plywood stock for my Baikal 12g single-shot to replace the thoroughly cracked stock that's on there now. I've seen guys laminating with polyurethane glue and having good results - is there any reason I should use a 2-part expoxy over a product like gorilla glue? I'm also wondering how much pressure I should be applying to the stack and if I should laminate all the layers at once or layer by layer allowing for some curing time in between? I have access to a 10-ton press as well as a 6-ton.

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If you use too much pressure you will squeeze all the glue out... and I would use glue not epoxy. Do all the layers at the same time if you can keep them lined up when the clamping pressure occurs...
 
Yep, pressure is no substitute for poor fits.

When you say "plywood" are you talking getting your own veneers and laminating them all or are you talking about pieces of plywood that you laminate together for the thickness? I ask because common plywood is not that great what with voids and dark coloured glue in some cases.

If you are after a Boyd's style "laminated" stock then you want to start with raw unglued veneers and stack them such that they are all running fore and aft mostly with the inner layers skewed about + and - 10° or so to get some cross grain stiffness and stability gains but not so you have layers that actually run up and down like you'd have with layers of regular plywood. Then run the last two or three laminations straight fore and aft for a nice clean grain direction.

When doing this style of laminating I'd suggest you cut out the laminations a little extra long and put a hole through the laminations in those extensions. Run an alignment pin through the holes as you do the layup. It can be just a good size common nail. No need for anything fancy. Clamp or press and let it all cure. Afterwards cut off the extensions to lose the metal pins. By all means use one of the presses. But don't use the full pressure. You can actually squeeze out too much glue. You want to get to where you still have a roughly .002'ish glue line for best strength. The actual ideal amount depends on the glue you use.

I'm not really a big fan of polyurethane glue. When it foams it causes a LOT of pressure and that tends to widen the joints. I'd go with water resistant aliphatic glue or epoxy. But not common epoxy. Get some of the laminating resin which has a thinner consistency and is normally used for fiberglass or other composite layups. The longer cure time with that style of epoxy also gives you a longer working time which you want to have so you don't have to rush the coating and layup work and can better see the effects of pressure when you clamp the stack together.

For the whole layup you likely only want a couple of hundred pounds total. Basically find out what the glue maker suggests for pressure per area and go with that.
 
Thanks for the replies guys, greatly appreciated.

Guntech, any brand/type of glue you would recommend? I’m totally new at this.

BCrider, I had planned to use the thinnest plywood I could buy from the local hardware store - 3/8”??? Only because I’m assuming that veneers would require a trip to the city, which I likely won’t have the time for until February at best. The Baikal is very rough, as in $60 for the shotgun rough, so as part of a learning experience I’m ok with matching her to a less than beautiful stock at this point. Any specific product recommendations for laminating epoxy?

Infideleggwelder, due to the voids in the plywood I presume?
 
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If it was me I would use Titebond 2 or 3 (2 being water resistant and 3 being waterproof)
And for the wood I would use layers of maple and walnut or cherry or all 3...

Don’t use plywood...
 
Bigbubba said:
If it was me I would use Titebond 2 or 3 (2 being water resistant and 3 being waterproof)
And for the wood I would use layers of maple and walnut or cherry or all 3...

Don’t use plywood...
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I can definitely afford the Titebond, thanks for the recommendation. I’m going to look for hardwood veneer nearby but my googling has indicated that local sources are pricey! Where do you folks find veneer and at what price?
 
I inquired about Birch veneers at my local hardware store (I too am in a small town). I don't remember the exact price but I figured I could buy the veneer for around $100. My local store would have brought them in for me. Either 1/16" or 3/32" I believe. My plan was to stain the veneers a couple different colours and then glue and press them together. However as with many things, time didn't allow me to get this off the ground.
 
As an experiment, I made a target rifle stock out of Baltic Birch plywood from Home Depot. Glued together enough pieces to get the thickness I needed. Cut the different layers so that most of the inletting was roughed in during the glue-up. Worked well enough.
 
SeamusMac said:
Guntech, any brand/type of glue you would recommend? I’m totally new at this.
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Back in the late 60's we used plain old carpenters glue and 3 walnut boards... plain in the middle and some figure on the outside... made some decent rifle stocks... The final finish is what protects the wood and the glue...
 
Markus said:
I inquired about Birch veneers at my local hardware store (I too am in a small town). I don't remember the exact price but I figured I could buy the veneer for around $100. My local store would have brought them in for me. Either 1/16" or 3/32" I believe. My plan was to stain the veneers a couple different colours and then glue and press them together. However as with many things, time didn't allow me to get this off the ground.
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Veneer is really starting to look cost-prohibitive for this project. I’d imagine I’ll pay a similar price here, which is not what I had in mine for my $60 Russian beater shotgun haha.

tiriaq said:
As an experiment, I made a target rifle stock out of Baltic Birch plywood from Home Depot. Glued together enough pieces to get the thickness I needed. Cut the different layers so that most of the inletting was roughed in during the glue-up. Worked well enough.
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I planned to do the same thing with my stock initially. I was going to leave the bits I cut out in-place and wrapped in plastic to help maintain the inlet space size and transfer compression across the gap. Have any pictures of how your’s turned out?

guntech said:
Back in the late 60's we used plain old carpenters glue and 3 walnut boards... plain in the middle and some figure on the outside... made some decent rifle stocks... The final finish is what protects the wood and the glue...
Click to expand...

If I had walnut or another nice hardwood that was thin enough I would use those over plywood. There’s a fella down the road from me that has a lot of nice rough dawn stuff but it’s all 1”+ and I really want to see at least a couple layers on each side so his products won’t work for this particular project. What’s your go-to finish? I hadn’t thought too much about that yet.
 
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I'll take some photos of the stock.
If you can get hardwood planks at a reasonable price, and know someone with a joiner, bandsaw and thickness planer, you could mill up slices (perhaps 1/4" - 3/8") to glue together.
 
tiriaq said:
I'll take some photos of the stock.
If you can get hardwood planks at a reasonable price, and know someone with a joiner, bandsaw and thickness planer, you could mill up slices (perhaps 1/4" - 3/8") to glue together.
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Looking forward to seeing your handiwork. I have access to a bandsaw and planer at work but no joiner. I should ask around since the guy has an amazing stockpile of oak, cherry and maple at very reasonable prices. I got a 20”x48” (approximately, IIRC) piece of 1-1/2” thick Oak for $15.
 
I worked at a hardwood veneer mill that made 4'x4' underlay (the stuff with X's nail patterns you put down before you install a new floor) and hockey stick shafts.

For the underlay we used a water based glue and for the hockey stick shafts used a waterproof urea glue. The urea glue was a thin milky consistency. I wish I could be more help, I don't know if you can buy urea glue like we used.

Also both the underlay and the hockey stick shaft panels were pressed in a steam heated press to cure the glue so you should probably look for a glue that does not need heat to cure.
 
Back in the mid seventies, while on a trip to Vienna (Wein) Austria, I was invited to a small home business, where they produced custom, laminated security doors.

I was surprised to learn that the equipment he was using to press the veneers together was some of the same used during WWII to make laminated stocks for K98s as well as other firearms.

The presses were hydraulically actuated of course and surprisingly they were still using the same hydraulic pumps but the motors/hoses/pistons had been swapped out.

There were six cylinders in all, so pressure could be applied evenly.

I was surprised at how large this press was. It was originally built to hold several frames that contained the glued veneers in position while being pressed together. This process, was helped along with heat.

When I looked at the original frames, I was surprised at how small they were, until it was explained that laminated plank was just large enough to cut out two stock blanks. The press could hold 25 frames. Depending on the glues used, the process from start to finish, took appx 3 hours. Yeah, I know, slow. Just remember, this was a single press in a building about the size of a two car garage.

During the last few years of WWII, these small cottage factories were common. That way production couldn't be taken out with one big strike. They applied the same sort of system to aircraft production.

The press was perfect for making just about any size laminated doors, for which they were getting horrendous prices at the time.

They used a polymer type glue for the most part, unless the door was going to be used with one side out in the elements.

I was surprised at how little pressure they needed to exert on the glued layers of laminate. Right around 50kg. They're biggest issue was making sure the layers didn't slip in the process. That's where the frames came in, to hold the veneer layers square.

I believe most stockmakers that are gluing veneer together now use a waterproof glue. I read somewhere on CGN about the different types of glue used by both the Axis manufacturers and later the Soviet manufacturers. When we see the WWII and later stocks, they commonly have either RED or White glue.

Modern manufacturers use a clear glue that is almost invisible. Maybe something like that clear Gorilla Glue, that is supposed to be waterproof?? Gorilla Contractor's Glue is also excellent but I don't believe it really hardens. It certainly holds well.

Whatever glue method you choose, it will be an interesting project.
 
Lamented floor joists if you could find a length would be a cheep option ( 1 3/4 to2 inches thick ) you would need good saws( a band saw would be the best ) carve it out sand it down and finish it with fiber glass Resin ( I believe that you can add colour to it in the mix) I have thought about doing this my self for a SKS stock .
 
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