1. How does one know if ply wood is void free
2. the only solid wood i have found here is teak (various grades of teak with Burma Teak being the most expensive)
3. I have had expansion problems with Solid wood too. I have seen my doors and window frames jam and they were made out of Burma teak in 1961 so they are atleast that old.
4. funny thing. in India ply wood is cheaper than MDF. I guess it is becuase ply is most prefered and MDF is hardly used. I can get marine grade plywood (still dont know if it is void free - the retailers here dont know either) cheaper than MDF.
5. Some of you know I am trying to work on a cabinet that resembles the Sonus Faber Amati / Wilson Benesch Act 2 in shape. If ply wood easier to bend? If that is so maybe I should try ply.
cheers
2. the only solid wood i have found here is teak (various grades of teak with Burma Teak being the most expensive)
3. I have had expansion problems with Solid wood too. I have seen my doors and window frames jam and they were made out of Burma teak in 1961 so they are atleast that old.
4. funny thing. in India ply wood is cheaper than MDF. I guess it is becuase ply is most prefered and MDF is hardly used. I can get marine grade plywood (still dont know if it is void free - the retailers here dont know either) cheaper than MDF.
5. Some of you know I am trying to work on a cabinet that resembles the Sonus Faber Amati / Wilson Benesch Act 2 in shape. If ply wood easier to bend? If that is so maybe I should try ply.
cheers
Marine grade ply should be void free. It is a safety thing in the case of boats. If it has voids you will eventually cut into them.
Plys/unit width is a general measure of quality, but i'm sure the material the plys are be made of makes a difference -- Baltic Birch is good. What trees do they use to make plywood in India? Marine Ply?
Many thin, laminated together with some sort of epoxy. Super-ply.
dave
Plys/unit width is a general measure of quality, but i'm sure the material the plys are be made of makes a difference -- Baltic Birch is good. What trees do they use to make plywood in India? Marine Ply?
Many thin, laminated together with some sort of epoxy. Super-ply.
dave
Navin,
To make plywood easier to bend you can get a circular saw and set it to cut at a depth about 1/2 to 2/3 the thickness of the ply wood. Then on the side of what will eventually be the inner concave surface, cut a series of straight parallel lines with the circular saw. In places where you want a tighter curve radius, simply space the lines closer together. The plywood will now bend a whole lot easier while retaining a smooth continuous good-looking exterior. Once it has been set in place you can then use a filler to fill in the cuts (It's just occured to me that using a putty type filler may even help to dampen panel resonance).
(Gosh, all this has only just occurred to me. I might even have give it a go myself now!).
Joseph
To make plywood easier to bend you can get a circular saw and set it to cut at a depth about 1/2 to 2/3 the thickness of the ply wood. Then on the side of what will eventually be the inner concave surface, cut a series of straight parallel lines with the circular saw. In places where you want a tighter curve radius, simply space the lines closer together. The plywood will now bend a whole lot easier while retaining a smooth continuous good-looking exterior. Once it has been set in place you can then use a filler to fill in the cuts (It's just occured to me that using a putty type filler may even help to dampen panel resonance).
(Gosh, all this has only just occurred to me. I might even have give it a go myself now!).
Joseph
First, a word on using generic terms for plywoods. Recommending everyone use Baltic Birch plywood can be dangerous. Usually, this is void free when bought from a good supplier, but all bets are off when you go down to the local home improvement store. (Home Depot and Lowes for U.S. people are notorious for selling lower grade plywoods with terms like baltic birch) When looking for grade of plywood, the two key things are "void free", meaning there are no holes or gaps inside each layer (the wood split or had a knot at that point that fell out, etc) and the number of layers used. (Count the number of layers visible, the higher the number the better)
As to marine grade plywood, it was my understanding that all this actually specified was that the glue used to hold the layers together was water resistant. I don't believe it requires that it be void free. (But I could be wrong, I've not really looked into it)
For those with questions about wood shrinkage, I found a nice little web page that will show you how much wood will move given relative humidity swings and the particular species. It can be found at http://www.woodbin.com/calcs/shrinkulator.htm
As to the technique that Joseph recommends for bending the plywood, it'll work and make the bending much easier, but I'd be afraid that it would destroy the stiffness of the cabinet walls. I would still go with layers of thinner plywood or solid wood instead. (Sorry Joseph, good idea, but I think it'll present more problems later on)
As for sources for veneers, take a look at http://www.wdfinder.com/ I don't know how good it is outside the U.S. but its worth a look.
Enough ramblings for now... enjoy!!
As to marine grade plywood, it was my understanding that all this actually specified was that the glue used to hold the layers together was water resistant. I don't believe it requires that it be void free. (But I could be wrong, I've not really looked into it)
For those with questions about wood shrinkage, I found a nice little web page that will show you how much wood will move given relative humidity swings and the particular species. It can be found at http://www.woodbin.com/calcs/shrinkulator.htm
As to the technique that Joseph recommends for bending the plywood, it'll work and make the bending much easier, but I'd be afraid that it would destroy the stiffness of the cabinet walls. I would still go with layers of thinner plywood or solid wood instead. (Sorry Joseph, good idea, but I think it'll present more problems later on)
As for sources for veneers, take a look at http://www.wdfinder.com/ I don't know how good it is outside the U.S. but its worth a look.
Enough ramblings for now... enjoy!!
wow. you guys are real wood specailists.
1. I dont have a table saw I will use a regualr carpenters saw
2. i think schaef is right in saying that marine grade only determines th glue used. however my contention is that if they are going to use a better grade glue they might as well use a better wood and make a really good marine grade ply
3. i fear the suggestion provided by bm_mode (Joesph) might weaken the ply bonds.
and .... 4.
to complicate matters for all you wood gurus out there what if I use 3 layers of MDF and 3 layers of ply. I found that 3mm MDF bends as easily as 4 mm of ply and hence using 3 layers of each I get 12mm of ply and 9mm of MDF that is 21mm.
Baffle will be 2 layers of 18mm MDF and bracing will be 6 horizontal braces (plus one internal division to seperate cabient into 2 and isolate 6" from 8") made of 18mm MDF with 4" dia holes cut into to it.
Damping...oh that is another thread....
cheers
1. I dont have a table saw I will use a regualr carpenters saw
2. i think schaef is right in saying that marine grade only determines th glue used. however my contention is that if they are going to use a better grade glue they might as well use a better wood and make a really good marine grade ply
3. i fear the suggestion provided by bm_mode (Joesph) might weaken the ply bonds.
and .... 4.
to complicate matters for all you wood gurus out there what if I use 3 layers of MDF and 3 layers of ply. I found that 3mm MDF bends as easily as 4 mm of ply and hence using 3 layers of each I get 12mm of ply and 9mm of MDF that is 21mm.
Baffle will be 2 layers of 18mm MDF and bracing will be 6 horizontal braces (plus one internal division to seperate cabient into 2 and isolate 6" from 8") made of 18mm MDF with 4" dia holes cut into to it.
Damping...oh that is another thread....
cheers
navin said:
There's not much wrong with using the carpenter's saw. You can still get very good cuts with it, provided you take your time and use a straight edge when cutting. (Trust me on the straight edge, its a lot easier)
You would think that, but I wouldn't rely on it. Manufacturers can be notoriously cheap. But, again, I haven't worked with it or looked into it, so it may well be void-free.
I didn't even think about that part! It will be even worse if the ply is not void free! However, in other applications Joseph's suggestion is used on a regular basis with a great deal of success.
Why does the layering complicate things? It might actually help make the cabinet stiffer! I'm definately interested in seeing pictures of progress! When are you planning on starting?
as soon as the 3mm MDF arrives. I have a day job (http://www.emagindia.com) so please be patient. in case I get busy between my day job, night job (http://www.pbase.com/advani) and the speaker to post please drop me a email (navin@vsnl.com) to wake me.
I have never heard of "Panzerholz". We get OSB (oriented strand board) here, it consists of thin (.5 to 1 mm) chips that can be 1 - 7 cm in length and about 1 cm wide, pressed together and held by some sort of resin. The stuff has better bending strength than particle boards, but is lighter than MDF (probably lighter than particle, too) and according to measurements by HobbyHifi, it well allow more sound through.
Then we have a stuff that might be what Jonathan is describing, but it's not called Panzerholz (I will have to look at the name though). It is much heavier than MDF, but the wood particles look like they are somewhat larger than those in V100 particle board. The laminate is waterproof, and there is a brown plastic coating on both sides that is very hard and has regular 1 mm squares to make the surface rougher. One application they advertise is using it as the floor for open car trailers.
Regards,
Eric
The stuff for open car trailers capslock describes is called "Siebdruckplatte" and its a plywood with phenol.
I use a plywood called "Multiplex" its used for steps stairs for example. Its a high quality plywood.
you could see it on the pic at the last post of the first site of this thread:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=7032
The smell isnt awfull like this OSB and partivle stuff and the dust you have when cut it isn´t that bull* like if you cut MDF. I hate MDF.
I use a plywood called "Multiplex" its used for steps stairs for example. Its a high quality plywood.
you could see it on the pic at the last post of the first site of this thread:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=7032
The smell isnt awfull like this OSB and partivle stuff and the dust you have when cut it isn´t that bull* like if you cut MDF. I hate MDF.
I have never heard of "panzer-wood" but from what I can gather of jcarr`s link above apparently what we call "Multiplex" here in Germany is the same thing.
My prefered material as well!
till,
what I can see from the picture - this does not look like Multiplex to me.
This is multiplex:
Attachments
the picture shows part from the box below from a few cm distance
An externally hosted image should be here but it was not working when we last tested it.
I'll add that the Japanese reinforced wood may look like wood but sure doesn't smell like it, not at all. Smells like some kind of petroleum-based substance - undoubtedly whatever resin was used to impregnate that particular type of reinforced wood.
You do get a subtle sense of a wood-like grain when you touch the stuff with eyes closed, but the total feel is smooth and glossy (albeit not oily/waxy) and very much finer-grained than any kind of natural wood that I know of (except petrified wood
)
jonathan carr
You do get a subtle sense of a wood-like grain when you touch the stuff with eyes closed, but the total feel is smooth and glossy (albeit not oily/waxy) and very much finer-grained than any kind of natural wood that I know of (except petrified wood
)jonathan carr
Check this link to see a cool way to make real wood baffles. Click on the first picture and then keep hitting the next button. Be warned - you'll start dreaming up ways to buy more woodworking tools!!
http://www.meadowlarkaudio.com/planttour1.htm
I'll say I have to agree with Bill F. on the cabinet adding sound issue. The less it adds the better. Nelson is used to listening to large horn speakers if I recall, so any noise the box might add is probably an improvement on the "horn sound"
Russ
http://www.meadowlarkaudio.com/planttour1.htm
I'll say I have to agree with Bill F. on the cabinet adding sound issue. The less it adds the better. Nelson is used to listening to large horn speakers if I recall, so any noise the box might add is probably an improvement on the "horn sound"
Russ
Schaef said:
I have it, second hand, from several organ builders that marine grade plywood is void free. I think even Fisk used it for his chests, at least for a while. Seems of late however that true baltic birch has come into favor.
I think MDF is a good choice if one has not much woodworking experience. And keep in mind that combining real wood and either MDF or plywood introduces the tricky issue of wood dynamics.
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