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Forum topic by FarmerintheWoods posted 07-21-2017 03:21 PM 687 views 0 times favorited 15 replies Add to Favorites Watch
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FarmerintheWoods

36 posts in 282 days


07-21-2017 03:21 PM

Topic tags/keywords: question ash cherry walnut bandsaw router

I am interested in making my own laminated plywood, which will be finished using a router. I have a good supply of hardwood, some of it highly figured, most of it is regular grain. If anyone has any experience in DIY laminating, or running plywood past a router, I’d be glad to learn what you know.

I have several questions, and probably not all the questions I should ask.

1. I’ll be making the layers of the laminate in the shop, using a bandsaw, with layers at ~1/8” thickness. What should I do to prepare the layers for lamination, and what adhesive should I use?

2. Is it essential that I alternate the grain 90 degrees at every plywood layer to get maximum strength? I can see advantages to having all the grain running parallel when it comes to running the plywood past the router bit.

3. I have access to black walnut, black cherry, and ash. Mixing these species among layers could be very attractive. Does mixing these species have any effect on your recommendation for wood preparation, grain orientation, or adhesive?

P.S. The result, if successful, will be used for making gunstocks, etc. I might simply go into making hardwood plywood.


15 replies so far

View Loren's profile

Loren

9604 posts in 3481 days


#1 posted 07-21-2017 03:44 PM

1. thickness sand or use hand planes to remove
machine marks. Plastic resin glue is probably
ideal. Commercial plywood layers are made
by peeling layers off a turning log with a
long knife, sort of like a giant pencil sharpener.
Carbide tipped band saw blades leave the
best surface finish for laminating due to the
lack of set in the teeth.

2. Grain should alternate direction for maximum
strength but if it’s the same direction it will
be pretty strong anyway, as strong as solid
wood of the same thickness, more or less.

3. Shouldn’t matter much as long as those woods
are at similar moisture content. Those are
common domestic hardwoods and move at
similar rates.

View MrRon's profile

MrRon

4491 posts in 3077 days


#2 posted 07-21-2017 04:47 PM

I’m not too crazy about using good hardwood for interior layers of plywood. Commercial plywood is made up of layers of a cheaper species of wood and the hardwood is used only for the faces.

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AlaskaGuy

3628 posts in 2142 days


#3 posted 07-21-2017 05:04 PM

Remember all commercial plywood has an odd number of layers ((3, 5, 7).

https://www.google.com/search?q=why+does+plywood+have+an+odd+number+of+layers&ie=utf-8&oe=utf-8

-- Alaskan's for Global warming!

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nkawtg

263 posts in 1084 days


#4 posted 07-21-2017 05:08 PM

John Heisz did a video very recently on this subject.

https://www.youtube.com/watch?v=60NMei0TAic

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bondogaposis

4475 posts in 2184 days


#5 posted 07-21-2017 06:02 PM

If you don’t alternate the layers 90°, you may as well use solid wood. The biggest advantage of plywood is it’s stability. You won’t get that if you don’t alternate the layers 90°.

-- Bondo Gaposis

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Rich

1972 posts in 423 days


#6 posted 07-21-2017 07:14 PM

The April, 2017 issue (#231) of Popular Woodworking had an article on making your own plywood. I’d be happy to share it with you.

-- No matter how much you push the envelope, it'll still be stationery.

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ArtMann

677 posts in 649 days


#7 posted 07-21-2017 08:35 PM

I laminated two exterior layers of 1/4 inch cherry plywood with an interior layer of birch plywood because I needed 3/4 inch cherry plywood and already owned both cherry and birch plywood. It is difficult to clamp large pieces together with enough force to form a strong and consistent thickness sheet. My first efforts yielded interior glue gaps due to inadequate and inconsistent clamping. I would suggest several 50 pound bags of sand or something similar to press a 2 X 4 foot piece together. I finally constructed an array of 2X4 blocks that were connected and provided uniform pressure across the surface. The force (~500 pounds) was generated by a hydraulic car jack and a 4X4 from the ceiling down to the clamp table. (By the way, that is also a good way to laminate two sheets of 3/4 MDF to make a router table top). I used Titebond Original and it worked well.

All this is different from what you are wanting to do but it gives you an idea of what is required to get a reliable lamination. The job is absolutely not trivial.

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TungOil

740 posts in 328 days


#8 posted 07-21-2017 09:47 PM

Vacuum bag! Research vacuum veneering.

-- The optimist says "the glass is half full". The pessimist says "the glass is half empty". The engineer says "the glass is twice as big as it needs to be"

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runswithscissors

2557 posts in 1858 days


#9 posted 07-23-2017 05:05 AM

At one time there was a (construction grade, I think) plywood with 4 layers, and the 2 inner layers were at a 45 deg. angle, not at right angles. I don’t know how well this worked out. I never used any. There is (or was) also solid core plywood. A single inner core, made up of more or less random widths, with veneer on both faces.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

View Loren's profile

Loren

9604 posts in 3481 days


#10 posted 07-23-2017 05:20 AM



At one time there was a (construction grade, I think) plywood with 4 layers, and the 2 inner layers were at a 45 deg. angle, not at right angles. I don t know how well this worked out. I never used any. There is (or was) also solid core plywood. A single inner core, made up of more or less random widths, with veneer on both faces.

- runswithscissors

I’ve encountered “lumbercore plywood” a few
times in old plywood pieces I was demolishing
or working on for some reason. I suppose
it’s still available but I’ve never seen it for
sale.

View cabmaker's profile

cabmaker

1621 posts in 2642 days


#11 posted 07-23-2017 11:40 AM


At one time there was a (construction grade, I think) plywood with 4 layers, and the 2 inner layers were at a 45 deg. angle, not at right angles. I don t know how well this worked out. I never used any. There is (or was) also solid core plywood. A single inner core, made up of more or less random widths, with veneer on both faces.

- runswithscissors

I ve encountered “lumbercore plywood” a few
times in old plywood pieces I was demolishing
or working on for some reason. I suppose
it s still available but I ve never seen it for
sale.

- Loren


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cabmaker

1621 posts in 2642 days


#12 posted 07-23-2017 11:41 AM

lumber core ply is alive and well !

View WAPY's profile

WAPY

53 posts in 160 days


#13 posted 07-24-2017 02:54 PM

FarmerintheWoods,
bondogaposis’ suggestion is very correct: if you want stability you must cross the grains of layers. I can imagine you are thinking of having all layers parallel to avoid grain visibility, but it could work only if the finished piece is to be small. If this will be your choice i’d recommend inverting the fiber direction at least so that each layer goes in opposite direction of the adiacent. I do the same whenever I have to make a through body bass neck with different woods glued together, to avoid it bends up or down. Keep posting on the results buddy

-- the good woodworker feels what the tree wanted to become

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FarmerintheWoods

36 posts in 282 days


#14 posted 07-24-2017 08:25 PM

Just to clarify a couple things: The reason I’m interested in making my own plywood is that I can put the highly figured wood on the outside, and the more regular stuff on the inside. Switching species between layers would just be a way to add coolness.

My concern about grain orientation has more to do with how the resulting plywood works with a router. I have read that lots of people have problems with ‘tearouts’ when working with plywood and a router. I’m thinking that having the grain all running (mostly) in the same direction will minimize this issue. Perhaps I’m worrying about this too much?

If plastic resin glue is most highly recommended for making plywood, are there any brands/products you recommend?

View Loren's profile

Loren

9604 posts in 3481 days


#15 posted 07-24-2017 08:31 PM

Tearout can be reduced by making template
cuts in small depth increments. To do this
you’d either have to use a template guide
collar or a pin router. Regular bearing guided
bits demand the whole depth of the cut
be taken all at once and this can cause a
lot of tearout if you’re unfortunate with
the grain, especially on curvy parts.

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