If you can, check the comparison test of woodworking glues in Fine Woodworking. Their test was on the shear strength of glued joints of hard maple. As I recall, plain ol' PVA is as, or stronger than, most. The urethane glues, like Gorilla, weren't as strong on wood - their best use is glueing unlike materials. Surprisingly, to me at least, was that the 'vintage' glues, like hide and fish-based, were more than competitive with the PVAs and allow water cleanup (even after drying) and being protein based don't cause the same type of discoloration beneath a stain.
I keep 2 types of PVA (normal yellow and Titebond III), a fish-based (Lee Valley), cyanoacrylate ('super' glue), 2 types of epoxy ('5' minute and West Systems), and Gorilla glue in my shop. One size doesn't fit all. 😁
In North America there's poplar, as in Aspen, cottonwood, and in the US, Tulip (a rather nice, though plain, stable, and not overly dense wood) is called yellow poplar. So saying all poplar or plywood is, is rather like saying a car is a car so there's no difference between a 7 series BMW and a Kia Forte.
Regarding marine plywood: I have a lot of experience with this material, since boat building/repair is my other hobby. In the US, marine plywood is usually douglas fir for the face veneer and the core plies. Douglas fir is a good strong wood. Marine plywood is rated to be void-free on all internal plies. In my opinion, it would be a good material for speaker cabinets.
In many ways marine plywood is similar to baltic birch, but there are some differences which make BB a better material for speaker cabinets.
(1) In BB, the plies are thinner, so there are more layers for a given thickness. This makes BB more stable (less likely to warp), and have a higher screw thread strength. It is possible that more layers would make BB more damped than Marine ply, but this is speculation.
(2) Birch is a very strong stiff wood, in fact it is one of the strongest of the common "non-exotic" woods. This is apparent when using BB plywood. It is a really tough material that can take a lot of abuse. Running screws into BB has a similar feel to driving screws into a typical hardwood like oak or maple.
(3) BB plywood takes a finish really well. The face veneers are fine grade, and birch is easy to paint and takes clear finishes well. Douglas fir on the other hand is strictly a structural wood. It is harder to achieve a fine paint finish, and very challenging to stain and clear coat. However, if a veneer is going to be applied anyway, this does not matter.
If I could not get BB plywood, but marine plywood was available, I would use it. .......... j.
In many ways marine plywood is similar to baltic birch, but there are some differences which make BB a better material for speaker cabinets.
(1) In BB, the plies are thinner, so there are more layers for a given thickness. This makes BB more stable (less likely to warp), and have a higher screw thread strength. It is possible that more layers would make BB more damped than Marine ply, but this is speculation.
(2) Birch is a very strong stiff wood, in fact it is one of the strongest of the common "non-exotic" woods. This is apparent when using BB plywood. It is a really tough material that can take a lot of abuse. Running screws into BB has a similar feel to driving screws into a typical hardwood like oak or maple.
(3) BB plywood takes a finish really well. The face veneers are fine grade, and birch is easy to paint and takes clear finishes well. Douglas fir on the other hand is strictly a structural wood. It is harder to achieve a fine paint finish, and very challenging to stain and clear coat. However, if a veneer is going to be applied anyway, this does not matter.
If I could not get BB plywood, but marine plywood was available, I would use it. .......... j.
My understanding of Baltic Birch isn't so much the finish but the construction. The number of layers plus the lack of voids make for a much better final product that is stable.
I'm looking at my plywood speakers at my computer which were oak ply from HD, and then look at the same speakers I made from Baltic Birch that are in my daughter's room and there is no comparison. The really good BB comes in 5'x5' sheets, not 4x8. And here's the thing about 5' x 5', it won't fit in your minivan. I could get a 4x8' sheet of ply or drywall in without problem but there is no opening in the van that would fit 5'. And while handling a 4x8 sheet of anything is difficult, it is not impossible. You can't get you arms around 5'x5' unless you are a gorilla. I had to have the lumberyard cut it in half.
I'm looking at my plywood speakers at my computer which were oak ply from HD, and then look at the same speakers I made from Baltic Birch that are in my daughter's room and there is no comparison. The really good BB comes in 5'x5' sheets, not 4x8. And here's the thing about 5' x 5', it won't fit in your minivan. I could get a 4x8' sheet of ply or drywall in without problem but there is no opening in the van that would fit 5'. And while handling a 4x8 sheet of anything is difficult, it is not impossible. You can't get you arms around 5'x5' unless you are a gorilla. I had to have the lumberyard cut it in half.
Yes the 5'x5' sheet size is a pain. My local supplier told me the reason for this odd-size is to maximize the number of sheets in a shipping container. A few months ago I bought 4 sheets, and I rented a truck to get it home.
I recently bought some cabinet grade oak veneer plywood to make some book cases. It is 3/4 4'x8', A-A. The face veneers are cosmetically very good quality. There are some voids in the interior plies. The core plies are some low density softwood, probably popular. It is noticeably less dense than BB plywood. The BB seems to weigh almost 50% more per square foot. This cabinet grade oak plywood is very appropriate for furniture, kitchen cabinets, etc.., but I would not use it for speaker cabinets. Marine plywood would be a better choice if BB plywood could not be found.
j.
I recently bought some cabinet grade oak veneer plywood to make some book cases. It is 3/4 4'x8', A-A. The face veneers are cosmetically very good quality. There are some voids in the interior plies. The core plies are some low density softwood, probably popular. It is noticeably less dense than BB plywood. The BB seems to weigh almost 50% more per square foot. This cabinet grade oak plywood is very appropriate for furniture, kitchen cabinets, etc.., but I would not use it for speaker cabinets. Marine plywood would be a better choice if BB plywood could not be found.
j.
Thing is marine plywood is not intended for use in living spaces, at least according to EU specifications. This is because of formaldehyde emission, any waterproof type of plywood will have formaldehyde emission too high to use indoors (at least according to specification).
A few years ago I went to a local cabinet supply house to buy BB plywood for speaker cabinets. The lady thee shook her and and told me that don't sell Baltic birch any more, too hard to get. It's all Chinese now. So I bought it anyway. I was decent quality, better and cheaper than the ply available at the big box stores.
FWIW, I've found poplar nearly impossible to stain evenly. As someone else said, it's paint grade.
FWIW, I've found poplar nearly impossible to stain evenly. As someone else said, it's paint grade.
The utility BB we used did nt stain well. Every box we did got veneered or is still raw ply (althu that box is from the Murphy Ply days (anyone need a SEAstack (pick-up only) ML-TL?
dave
Read this:
https://www.somasonus.net/box-construction-methods
Brandon has done experiments on multi layered construction techniques, including plywoods (various grades and layers) single layer MDF, dual layered MDF, and damping layers sandwiched between wood (constrained layer damping)
i found it so useful I donated him a sheet of MDF
https://www.somasonus.net/box-construction-methods
Brandon has done experiments on multi layered construction techniques, including plywoods (various grades and layers) single layer MDF, dual layered MDF, and damping layers sandwiched between wood (constrained layer damping)
i found it so useful I donated him a sheet of MDF