Wood movement
Poobah said:
This is in general true. Wood, if it is constrained from expanding when moist, will crush some of its cells internally and thereafter expand less. But that wouldn't apply to, e.g., railway sleepers.
There is a lot of uninformed discussion about wood (not just on this forum). For anyone seriously interested in the topic, I recommend Bruce Hoadley's Understanding Wood (Taunton Press: http://www.taunton.com/finewoodworking/store/pages/070490.asp). It's readable by the non-technical.
Hmmm, this sounds like I'm setting myself up as an expert on the topic. Not really the case, but I wanted to recommend the book.
Poobah said:
This is in general true. Wood, if it is constrained from expanding when moist, will crush some of its cells internally and thereafter expand less. But that wouldn't apply to, e.g., railway sleepers.
There is a lot of uninformed discussion about wood (not just on this forum). For anyone seriously interested in the topic, I recommend Bruce Hoadley's Understanding Wood (Taunton Press: http://www.taunton.com/finewoodworking/store/pages/070490.asp). It's readable by the non-technical.
Hmmm, this sounds like I'm setting myself up as an expert on the topic. Not really the case, but I wanted to recommend the book.
Here in the U.S. there is a whole new industry growing... Companies are actually harvesting 100-200 year old trees from river bottoms. I guess this is happening mostly around the locations of old sawmills etc... where the most logs fell/sank.
They are turning the stuff into veneer and getting great prices for it. And the fact that is has soaking for 200 years doesn't appear to have caused any damage. Keep in mind, these are cold locations... but still.
They are turning the stuff into veneer and getting great prices for it. And the fact that is has soaking for 200 years doesn't appear to have caused any damage. Keep in mind, these are cold locations... but still.
Hey Aengus,
Does this book get into any discourse on steam bending? I have only found a bit of information on that topic.
Does this book get into any discourse on steam bending? I have only found a bit of information on that topic.
Cloth Ears said:
It won't change the rate of movement.
What you will get is wood that has acclimated to its surroundings and will not warp or twist or bow or check... unless you start working it, or move it to a different location (eg; barn to house, bridge to garage, etc).
Then you could be worse off than useing something that's been recently dried and stored in a climate similar to your intended final location.
Wood never stops responding to climatic changes.
Steam bending
Hi Poobah
Right after I posted, I went looking for my copy of "Understanding Wood" and - of course - couldn't find it. But as I recall, it's more about how wood responds and why it does what it does.
Lee Valley Tools have a good booklet on the topic. It's available on-line at http://www.leevalley.com/wood/page.aspx?c=1&p=31161&cat=1,45866,45867. The reason the booklet exists is that they'd like to sell you their steam-bending tools, but I think most of them are overkill unless you're planning to set up shop.
I don't have a lot of practical experience with it, but typically one uses stovepipe for the steamer or builds a plywood box. Prop up one end a bit so condensation will drain, stuff the ends with rags, and run some tubing in the bottom end to feed it steam. Steam source can be a kettle; I'm told that tool rental places have wallpaper steamers that work well.
The idea is to get the wood hot; the wetness is incidental (guitar guys use dry heat when forming guitar sides).
Other sources of information: try the boatbuilding section in the library. If you want to search the Wooden Boat magazine index (I think they have one on-line), and find any articles you're interested in, let me know - I have back issues and could likely scan some reasonable amount for you. Also, they sell most back issues except for the early ones.
What are you thinking of bending? I'm currently thinking about some nicely curved OB speakers - front blending into wings with about a 4" radius - but will likely cold-mold them.
Regards.
Hi Poobah
Right after I posted, I went looking for my copy of "Understanding Wood" and - of course - couldn't find it. But as I recall, it's more about how wood responds and why it does what it does.
Lee Valley Tools have a good booklet on the topic. It's available on-line at http://www.leevalley.com/wood/page.aspx?c=1&p=31161&cat=1,45866,45867. The reason the booklet exists is that they'd like to sell you their steam-bending tools, but I think most of them are overkill unless you're planning to set up shop.
I don't have a lot of practical experience with it, but typically one uses stovepipe for the steamer or builds a plywood box. Prop up one end a bit so condensation will drain, stuff the ends with rags, and run some tubing in the bottom end to feed it steam. Steam source can be a kettle; I'm told that tool rental places have wallpaper steamers that work well.
The idea is to get the wood hot; the wetness is incidental (guitar guys use dry heat when forming guitar sides).
Other sources of information: try the boatbuilding section in the library. If you want to search the Wooden Boat magazine index (I think they have one on-line), and find any articles you're interested in, let me know - I have back issues and could likely scan some reasonable amount for you. Also, they sell most back issues except for the early ones.
What are you thinking of bending? I'm currently thinking about some nicely curved OB speakers - front blending into wings with about a 4" radius - but will likely cold-mold them.
Regards.
Wow,
The web just bets better every day. A year and half ago all I could hit was one article that had been posted and copied all over the place. This guy guy knew how to bend... but he didn't know the why's.
Reason I ask is because I am working on a boat... all my bending is done. But when this boat comes off the sled my neighbor wants to build a canoe. I never bothered to build a real decent rig... my pieces were 16 feet long. So I used a turkey fryer, building foam, and Red Green's best friend to build a box.
The canoe however requires that oak be brought to a noodle-esque state.
Thanks for the link!
🙂
The web just bets better every day. A year and half ago all I could hit was one article that had been posted and copied all over the place. This guy guy knew how to bend... but he didn't know the why's.
Reason I ask is because I am working on a boat... all my bending is done. But when this boat comes off the sled my neighbor wants to build a canoe. I never bothered to build a real decent rig... my pieces were 16 feet long. So I used a turkey fryer, building foam, and Red Green's best friend to build a box.
The canoe however requires that oak be brought to a noodle-esque state.
Thanks for the link!
🙂
OT warning - but brief
A boat - cool. What is it?
I've built a Steve Redmond Whisp, and am currently fantasizing about a sliding-seat sculling boat. The Whisp had only gentle curves and no steam-bending was required.
End OT.
A boat - cool. What is it?
I've built a Steve Redmond Whisp, and am currently fantasizing about a sliding-seat sculling boat. The Whisp had only gentle curves and no steam-bending was required.
End OT.
poobah said:
Not just cold locations, hot ones too. People are now combing the rivers here for the same thing. A few years back a friend of mine bought a some acreage with a fair sized pond just off the river. He found some old lumber jack tools near the pond burried in the mud. After some investigation, he discovered that the pond was a staging hole for floating the logs down the river. He found enough lumber to build a nice house, the found wood inside and fresh cut for the frame. Some of the beams are huge and all of them knot free.
Solid Woods Bad Rap Here!
I think it's true that there is an incredible amount of real-world experience and knowledge here about Speaker Enclosure Construction practices....here's a few of my observations...you must be very clear about what the application of your sound making venture is:
1. Are you building cabinets for sound reproduction like Home Hi-FI, Studio Reference Monitors, or PA System?
2. Or for sound creation like Acoustic/Electric Guitar/Bass/Keyboards speaker enclosures.
Sound reproduction is supposed to be reproducing sound with the least coloration to the original mix and mastering done by the creators(Artists,Engineers Producers). This requires massive engineering and Anechoic testing of the speakers response to the designed cabinet. Bowers & Wilkins has done a tremendous amount of study over many years in the arena of the truest sound reproduction for both Home Audiophiles and Studio Reference Monitors. That's why some of their Speaker Systems can cost in excess of $40k EACH! Their Matrix bracing structure is through the roof!
On the other hand, sound creation like and acoustic guitar, electric guitars and basses, Pianos, Violins harps, ect is an utterly and completely different ball game, sorry you MDF lovers, acoustic guitars and acoustic pianos, violins ect... are never, repeat never--- made out of MDF for obvious sonic reasons. I realize that electric instrument speaker cabinets like Electric Guitar, Electric Bass, Synth and keyboard speaker enclosure cabinets are in a different subdivision than acoustic instruments. Solid wood speaker cabinets sound freaking amazing if they are made correctly. Personally I use multilayered solid wood cabinets. I mean I engineer each panel with 3/4" or more thick pieces of whatever...and don't believe oak is not a great tonewood.....because it most certainly is...most guitar and violin makers never use it because it's extremely difficult to bend and probably because it's so hard, or because of the cell structure. I don't use it that much because of the sheer weight of it. I want my cabinets to be very light so because some hard woods are so heavy I end up using , Pine, Ash, Aspen glued up in layers
of 3/4" nominal or a full 1" rough, dried furniture grade lumber.For the baffle, top, sides bottom, back and I also brace the internal cabinet as well where the glued up panels need it. The whole purpose of engineering the solid wood this way in multiple pieces is for "ZERO SPLITTINGor CHECKING" and strength to stop the flexing which adds a type of blurring distortion to the sound. So no I don't use single pieces of solid 1" wood because of the remote possibility of the wood checking over years of vibration, the best made acoustic instruments do not split....because the luthier hand selected the wood, in solid wood/veneered construction I still inspect the wood stock I use to make sure it is not only showing no signs of improper drying but also for straightness which is primary to the construction of extremely sound built and fitly framed panels. Of which are sealed with acoustic caulking, on the inside.The cabinets are glued and screwed with solid-wood rounded edged cleats on the inside for bracing and then covered with Tolex or Vinyl, Finger jointing and dovetailing is not necessary since the cabinet is covered and so fitly ;glued ,screwed and braced. The finished cabinet is just as light as a regular plywood cabinet, and even lighter sometimes, especially using neodymium speaker magnets.The sound is astounding using quality speakers where the internal volumes, ports have been modeled correctly for a particular speaker.😎
I think it's true that there is an incredible amount of real-world experience and knowledge here about Speaker Enclosure Construction practices....here's a few of my observations...you must be very clear about what the application of your sound making venture is:
1. Are you building cabinets for sound reproduction like Home Hi-FI, Studio Reference Monitors, or PA System?
2. Or for sound creation like Acoustic/Electric Guitar/Bass/Keyboards speaker enclosures.
Sound reproduction is supposed to be reproducing sound with the least coloration to the original mix and mastering done by the creators(Artists,Engineers Producers). This requires massive engineering and Anechoic testing of the speakers response to the designed cabinet. Bowers & Wilkins has done a tremendous amount of study over many years in the arena of the truest sound reproduction for both Home Audiophiles and Studio Reference Monitors. That's why some of their Speaker Systems can cost in excess of $40k EACH! Their Matrix bracing structure is through the roof!
On the other hand, sound creation like and acoustic guitar, electric guitars and basses, Pianos, Violins harps, ect is an utterly and completely different ball game, sorry you MDF lovers, acoustic guitars and acoustic pianos, violins ect... are never, repeat never--- made out of MDF for obvious sonic reasons. I realize that electric instrument speaker cabinets like Electric Guitar, Electric Bass, Synth and keyboard speaker enclosure cabinets are in a different subdivision than acoustic instruments. Solid wood speaker cabinets sound freaking amazing if they are made correctly. Personally I use multilayered solid wood cabinets. I mean I engineer each panel with 3/4" or more thick pieces of whatever...and don't believe oak is not a great tonewood.....because it most certainly is...most guitar and violin makers never use it because it's extremely difficult to bend and probably because it's so hard, or because of the cell structure. I don't use it that much because of the sheer weight of it. I want my cabinets to be very light so because some hard woods are so heavy I end up using , Pine, Ash, Aspen glued up in layers
of 3/4" nominal or a full 1" rough, dried furniture grade lumber.For the baffle, top, sides bottom, back and I also brace the internal cabinet as well where the glued up panels need it. The whole purpose of engineering the solid wood this way in multiple pieces is for "ZERO SPLITTINGor CHECKING" and strength to stop the flexing which adds a type of blurring distortion to the sound. So no I don't use single pieces of solid 1" wood because of the remote possibility of the wood checking over years of vibration, the best made acoustic instruments do not split....because the luthier hand selected the wood, in solid wood/veneered construction I still inspect the wood stock I use to make sure it is not only showing no signs of improper drying but also for straightness which is primary to the construction of extremely sound built and fitly framed panels. Of which are sealed with acoustic caulking, on the inside.The cabinets are glued and screwed with solid-wood rounded edged cleats on the inside for bracing and then covered with Tolex or Vinyl, Finger jointing and dovetailing is not necessary since the cabinet is covered and so fitly ;glued ,screwed and braced. The finished cabinet is just as light as a regular plywood cabinet, and even lighter sometimes, especially using neodymium speaker magnets.The sound is astounding using quality speakers where the internal volumes, ports have been modeled correctly for a particular speaker.😎
Oh, and the Sealed or Ported cabinet would have Ultrastouch damped insides of course if its ported, the port area needs to be open enough to let the Woofer breath, good Damping is very critical to the ultimate sound and standing waves which lead to modal pile-ups...lol
Acoustic guitars and violins almost always use spruce for the top or sound board because it has good resonant properties. Oak isn't used because it does not. Violins have carved soundboards not bent. The bent pieces are mostly the sides which are often made from maple or other fine grained hardwood.
One option would be to affix the solid wood panels with midly flexible adhesive (or fasteners and gasketing) as cosmetic panels. You then can float them independently of each other, using the spacing as a cosmetic feature, and not worry about expansion.
Polvo.... I love real wood. I think it's far too precious to use on the inside of a speaker cabinet. Now, on the outside, or the baffle... there's lots of opportunities. But like a good old-time chest of drawers, save the nice stuff for the outside. No one cares what the drawer runners are made of. 🙂
Of course, the sound and variability and machinabilty are all issues as well.
Best,
Erik
Of course, the sound and variability and machinabilty are all issues as well.
Best,
Erik
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