Solid Wood Baffles with MDF/Ply boxes?

[DaveFred]

Hello,

What have been peoples experiences/thoughts on combining solid wood baffles with sheet good (MDF or Ply) boxes?

My 30+ years of woodworking experience tells me that such a large cross grain joint is a bad idea that can only end with the baffle splitting. Yet, I have seen countless examples of such construction posted on the Interwebs.

I know one thing that would help for sure, and that is "ripping and flipping" the wood, so you end up with a quartersawn baffle (of all the lumber cuts quartersawn has the least amount of movement).

Are people getting lucky?

Is it that we live in climate controlled houses where the humidity is fairly constant?

Is it that the modern PVA glues that we use have some "give" to them?

Are there any guidelines people have used for how wide a solid wood baffle they would on an MDF/ply box?

Does the thickness of the baffle matter?

Any failure examples where the baffle did crack?

What about where the baffles were a glue up of layers of plywood? With this type of baffle, you would think there would still be movement as the layers are not constrained in their "thickness", just in their width and length.

What are your thoughts?

Thank you,

David.

[herr_der_ringe]

hello, dave,
my experiences are different.

- i have built a small speaker in solid wood (http://www.hifi-forum.de/index.php?action=browseT&forum_id=137&thread=831&postID=5#5), which shows no ruptures even after years.
- exactly the same speaker was built in the original (https://www.lautsprechershop.de/hifi/bonbon.htm) from glued MPX, which showed ruptures after a few months.

the cracking is independent of the glue. also the thickness of the wood is only of secondary importance. much more important is that the wood is adapted to its later environment with regard to dryness to reduce further work of the wood to a minimum.

my tips:
- small speakers or surfaces
- "dry" wood
- optimized arrangement of the growth rings (annual rings "standing")
- construct the housing in a way that it's possible for the wood to continue its work (example (http://www.hifi-forum.de/bild/ls-gehause-holz_194073.html))
- small "climate" changes in the room for the speaker
:prost:



hallo dave,
meine erfahrungen sind unterschiedlich.

- ich habe einen kleinen lautsprecher aus massivholz (http://www.hifi-forum.de/index.php?action=browseT&forum_id=137&thread=831&postID=5#5) gebaut, welcher auch nach jahren keine risse zeigt.
- genau derselbe lautsprecher wurde im original (https://www.lautsprechershop.de/hifi/bonbon.htm) aus verleimtem MPX gebaut, welche nach einigen monaten risse zeigten.

die rissbildung ist unabhängig vom leim. ebenso ist die stärke des holzes nur von zweitrangiger bedeutung. viel wichtiger ist, daß dieses hinsichtlich trockenheit seiner späteren umgebung angepast ist, um ein weiteres arbeiten des holzes auf ein minimum zu reduzieren.

meine tips:
- kleine lautsprecher bzw. flächen
- "trockenes" holz
- optimierte anordnung der jahresringe ("stehend")
- die gehäuse konstruktiv so aufbauen, daß das holz weiterhin arbeiten kann (beispiel (http://www.hifi-forum.de/bild/ls-gehause-holz_194073.html))
- geringe "klima"änderungen in der späteren umgebung des lautsprecher
:prost:

[capslock]

kleinen lautsprecher aus massivholz (http://www.hifi-forum.de/index.php?action=browseT&forum_id=137&thread=831&postID=5#5) gebaut, welcher auch nach jahren keine risse zeigt.


rod glued rubberwood / stabverleimter Gummibaum?

[herr_der_ringe]

rod glued rubberwood / stabverleimter Gummibaum?

ikea "aptitlig"
:built:

[Kalle]

Hallo Dave,
I was not succesful let alone lucky:D with jaw,spruce, ash.
Now i will test 3 layers of glued bamboo sticks without ply or MDF Sandwich.
I hope .......:rolleyes:
Greets Kalle

[newmir]

ikea "aptitlig"
:built:
Bamboo is not Rubberwood ..... or do I miss the joke here?

[herr_der_ringe]

maybe you can't see the forest because of the bamboo (https://www.ikea.com/at/de/p/aptitlig-schneidebrett-bambus-80233430/) // eventuell sieht man den wald vor lauter bambus (https://www.ikea.com/at/de/p/aptitlig-schneidebrett-bambus-80233430/) nicht :D

[Kleinhorn]

Hi...
My experiences are only good ones...The trick, made with a cnc are slots inside the glued wood and a sandwich cabinet. 18mm glued wood outside and inside 16mm chipboard. It still works until 5 years without any crack. The chipboard plates doesent touch the other. At least 1,5 mm distance to each other because wood is always working.
The slots and the sandwich built prevent any cracking until yet.
55635

The Amps are in the feet...:)

Pedda