I wish to make a compound curved cabinet and would like to do it by stacking cutouts. I had planned on using 3/4" (19mm) spruce plywood. Plywood because I like working with it better than mdf and it puts up with our climate better.
I would like to know what your thoughts are about using a combo of ply and mdf. I will need to stack about 11 pieces. Is there an advantage to inter-plying the two?
The cost per sheet is the same.
I would like to know what your thoughts are about using a combo of ply and mdf. I will need to stack about 11 pieces. Is there an advantage to inter-plying the two?
The cost per sheet is the same.
my experiance with plywood is it isnt as dense as MDF and chips alot easier. mostly because of the way its glued together. So to me it is not as user friendly.
Most of my experinace tho has been with furniture making so that material just makes up Expense and grain and coloring and durability.... so once again what do i know....
Most of my experinace tho has been with furniture making so that material just makes up Expense and grain and coloring and durability.... so once again what do i know....
Cal,
You probably know that the quality of MDF-priced plywood is not very high. You will have lots of voids, cracks, knots, etc. This is very hard to shape without tearing out big chunks. Soundwise, I would choose plywood, but I think at that quality level, it will be more work.
Re climate, it can't be that much wetter where you live than me?
Doug
You probably know that the quality of MDF-priced plywood is not very high. You will have lots of voids, cracks, knots, etc. This is very hard to shape without tearing out big chunks. Soundwise, I would choose plywood, but I think at that quality level, it will be more work.
Re climate, it can't be that much wetter where you live than me?
Doug
If you use plywood for enclosures, use only certified void free. Baltic Birch and marine grade are both available in a void free variety.
Most upper end speakers that use wood as an enclosure material laminate Baltic Birch (BB) on the exterior and MDF on the interior. The greater density of MDF lowers cabinet resonance frequency. The stiffness of BB yeilds a higher enclosure resonant frequency. MDF will hold on to acoustical energy longer than BB. It is a balancing act.
Why do you need to stack so many pieces? If you have a complex curve it would be more sensable to use thin material. Once it is curved, braced & secured it will be significantly stronger than a flat piece of equal thickness.
- James
Most upper end speakers that use wood as an enclosure material laminate Baltic Birch (BB) on the exterior and MDF on the interior. The greater density of MDF lowers cabinet resonance frequency. The stiffness of BB yeilds a higher enclosure resonant frequency. MDF will hold on to acoustical energy longer than BB. It is a balancing act.
Why do you need to stack so many pieces? If you have a complex curve it would be more sensable to use thin material. Once it is curved, braced & secured it will be significantly stronger than a flat piece of equal thickness.
- James
Thanks for the answers so far. I am thinking it might be best to stick with the ply throughout. I have changed from a compound curve to an "double S" shape
Doug,
I am cutting out pieces approximately 1 1/2" wide in the shape of the cabinet. All voids can be filled once assembled.
As far as shaping, I'm not, I'm stacking cutouts.
You're right. I think the climate part referred to the unheated garage I work in which happens to be where the wood is stored.
James,
I agree but I can't justify it for this set. I often use 1" multi-lam (16 lam) poplar. but again these are small so a 1 1/2" thick wall all around I think will suffice. (two layers, flat stacked 3/4") baffle and back.
That's interesting to know. These cabinets are small and will show little resonance due to their shape and thickness.
As I have changed from a compound curve (which I wouldn't be able to shape by flat stacking panels) to a double "s" curve (which I can) I now have that option but I think it would take too long adding layer after layer of 1/4" to get to 1 1/2" Also the curve might be a bit tight and cause undo stresses on the wood.
I'll need a minimum of 11 pieces to achieve the internal volume.
I am able to get all the cutouts for one cabinet from a 4X8 sheet so in all it's only 50 bucks Cdn.
Thanks again for all the answers thus far.
Taperwood said:
Doug,
I am cutting out pieces approximately 1 1/2" wide in the shape of the cabinet. All voids can be filled once assembled.
As far as shaping, I'm not, I'm stacking cutouts.
You're right. I think the climate part referred to the unheated garage I work in which happens to be where the wood is stored.
James,
AudialDelta said:
I agree but I can't justify it for this set. I often use 1" multi-lam (16 lam) poplar. but again these are small so a 1 1/2" thick wall all around I think will suffice. (two layers, flat stacked 3/4") baffle and back.
That's interesting to know. These cabinets are small and will show little resonance due to their shape and thickness.
As I have changed from a compound curve (which I wouldn't be able to shape by flat stacking panels) to a double "s" curve (which I can) I now have that option but I think it would take too long adding layer after layer of 1/4" to get to 1 1/2" Also the curve might be a bit tight and cause undo stresses on the wood.
I'll need a minimum of 11 pieces to achieve the internal volume.
I am able to get all the cutouts for one cabinet from a 4X8 sheet so in all it's only 50 bucks Cdn.
Thanks again for all the answers thus far.
Are you cutting the sections yourself with a router ang jig or similar? If so, you might want to put a couple of indexed holes in each section so you can assemble them on dowel rods. It makes it a lot easier for alignment. You could even use threaded rod, then you can use it to clamp them together as you assemble.
I'm not "seeing" your curve. Thinner material is still the way to go in order to make it curve without the potential of cracking the material. How many sides of the enclosure will have this "S-curve"? I also doubt that you will be successful in filling the voids. Maybe visually, but not under close inspection. I also still think you will be better off with something other than ply wood for the inner - unseen layers. Use a 1/8 inch BB for the outer-most layer.
Hi, to make this easy:
Picture a fish. Now lay it out on a piece of plywood. Cut out fish shape and also cut out the centre of the fish so the walls are about 1 1/2". Do this 11 times and stack all 11 fish together, add a top and bottom and you have a hollow cabinet. The outside will be coated to fill in the grain, then painted.
EDIT: On second thought, I'm not making a double S curve, I am making two S curves, sorry for the confusion.
Picture a fish. Now lay it out on a piece of plywood. Cut out fish shape and also cut out the centre of the fish so the walls are about 1 1/2". Do this 11 times and stack all 11 fish together, add a top and bottom and you have a hollow cabinet. The outside will be coated to fill in the grain, then painted.
EDIT: On second thought, I'm not making a double S curve, I am making two S curves, sorry for the confusion.
OK,
I'd rather not tell you what I used to design these as that seems to be part of the fun. I have been looking for a design for about 4 months now and discovered this while building a landscape wall on the weekend. It's a very common item that virtually everyone has used but when scaled up, has a really nice appearance to it. So as these things progress, I will post pics and the observant ones out there will recognize it. I have been building speakers forever and wanted something with a little better aesthetic appeal this time, something neat, something unique (AFAIK)
So far I have drawn and cut a paper template to do my layout. That's how I know I can get 13 of these from one sheet. I like to do my design work full sized, and it wasn't until I had two template pieces did I realize that my free-hand curves were so good that I could flip the template end for end and have the sides line up. So each cut gives me two finished edges except at the ends which are offset. Wahoo!
If it ever stops raining, I'll go get the wood and begin. It should only take about 10 hours to cut them out.
Can't even show you a pic of the template as that's down at Sonia's and I'm here.
I'd rather not tell you what I used to design these as that seems to be part of the fun. I have been looking for a design for about 4 months now and discovered this while building a landscape wall on the weekend. It's a very common item that virtually everyone has used but when scaled up, has a really nice appearance to it. So as these things progress, I will post pics and the observant ones out there will recognize it. I have been building speakers forever and wanted something with a little better aesthetic appeal this time, something neat, something unique (AFAIK)
So far I have drawn and cut a paper template to do my layout. That's how I know I can get 13 of these from one sheet. I like to do my design work full sized, and it wasn't until I had two template pieces did I realize that my free-hand curves were so good that I could flip the template end for end and have the sides line up. So each cut gives me two finished edges except at the ends which are offset. Wahoo!
If it ever stops raining, I'll go get the wood and begin. It should only take about 10 hours to cut them out.
Can't even show you a pic of the template as that's down at Sonia's and I'm here.
Okay, then you are not bending the wood. Therefore you could use any wood you desire. Except the plywood voids will still be an issue. But it does not sound like you are looking for high fi sound anyway. And I think you indicated they won't be playing low or loud.
But what I would do is slightly different. I would cut the top and bottom pieces out of thick wood, or laninate a pair of pieces to get a 1 inch thick section. Then use a rabbit bit on the outer edge of each piece, so that when stacked on top of each other you have about a 3/4 inch tall recessed area. Then you can cut a 1/8 inch sheet of plywood the height of the the internal enclosure, plus 3/4 inch. Put glue on the edge, and brad, staple or screw the plywood in place all the way around the pair of frames. You could use the threaded rod, but about six or eight 1/2 X 1/2 X distance between top and bottom slats should be able to be secured also with brads. The 1/8 inch ply would bend right around and secure to the rabbeted lip and the six to eight slats. You may need to use 3-4 smaller sections of 1/8 inch ply, as it may not bend around the tight corners. Those would be points where you have the 1/2 X 1/2 slats so that the polyurethane glue could fill any leaks. I would likely use some more of the 1/2 X 1/2 inch slats to brace it between slats. But would really depend on how loud it needs to play.
But what I would do is slightly different. I would cut the top and bottom pieces out of thick wood, or laninate a pair of pieces to get a 1 inch thick section. Then use a rabbit bit on the outer edge of each piece, so that when stacked on top of each other you have about a 3/4 inch tall recessed area. Then you can cut a 1/8 inch sheet of plywood the height of the the internal enclosure, plus 3/4 inch. Put glue on the edge, and brad, staple or screw the plywood in place all the way around the pair of frames. You could use the threaded rod, but about six or eight 1/2 X 1/2 X distance between top and bottom slats should be able to be secured also with brads. The 1/8 inch ply would bend right around and secure to the rabbeted lip and the six to eight slats. You may need to use 3-4 smaller sections of 1/8 inch ply, as it may not bend around the tight corners. Those would be points where you have the 1/2 X 1/2 slats so that the polyurethane glue could fill any leaks. I would likely use some more of the 1/2 X 1/2 inch slats to brace it between slats. But would really depend on how loud it needs to play.
Hi AD,
I don't mean that they are to be of lesser quality or low-fi, just that I have a ton of home builds already so these are as much for fun and learning than anything else. This is going to be a two way MTM with the CSS WR's and a tweeter. I will be learning about the assembly as much as anything else as I plan to do a larger version with different drivers if this goes well.
The voids I will look after while assembling and I can get the last of them after assembly is complete. If there happens to be a void with the 1 1/2 wide piece, completely encapsulated then so be it, nothing I can do short of using void free. Otherwise I will be able to get all the ones that are visible on the edges before sanding begins. At this point I have no intention of plying the outside of the curves as I am planning to use body fill and then paint.
I think I will consider your method, which sounds excellent by the way, when I decide to build the larger version. Then my options of finish will be wider.
I don't mean that they are to be of lesser quality or low-fi, just that I have a ton of home builds already so these are as much for fun and learning than anything else. This is going to be a two way MTM with the CSS WR's and a tweeter. I will be learning about the assembly as much as anything else as I plan to do a larger version with different drivers if this goes well.
The voids I will look after while assembling and I can get the last of them after assembly is complete. If there happens to be a void with the 1 1/2 wide piece, completely encapsulated then so be it, nothing I can do short of using void free. Otherwise I will be able to get all the ones that are visible on the edges before sanding begins. At this point I have no intention of plying the outside of the curves as I am planning to use body fill and then paint.
I think I will consider your method, which sounds excellent by the way, when I decide to build the larger version. Then my options of finish will be wider.
The guessing game is on!
Okay my friend:
So you are going to tease us with your little clues.
Well for one am up to the challenge my friend. The gauntlet has been thrown down! It will be a test of wits you say.
Here is my first guess based on the info you supplied.
You were building a landscape wall.
Hmmmmm more likely you were watching some else doing the work and had time to ponder your simple little thoughts.
"Picture a fish"
Hmmmmm that is a curious clue, a fish has a compound curve shape, similar to a bottle.
A very common item, once scaled up is very pleasing
Yes yes I think I have it:
You were watching someone else working on a landscaping job, while admiring their work while listening to some Jimmy Buffet music. You noticed your beer bottle was empty when you had an epiphany, a revolutionary thought so to speak! "Should we have fish for dinner tonight? or should I make a speaker that looks like a beer bottle. By gosh I have it!
My new speakers will look like a fishy beer bottle. I may even paint scales on them.
And there you have it, problem solved!
Okay my friend:
So you are going to tease us with your little clues.
Well for one am up to the challenge my friend. The gauntlet has been thrown down! It will be a test of wits you say.
Here is my first guess based on the info you supplied.
You were building a landscape wall.
Hmmmmm more likely you were watching some else doing the work and had time to ponder your simple little thoughts.
"Picture a fish"
Hmmmmm that is a curious clue, a fish has a compound curve shape, similar to a bottle.
A very common item, once scaled up is very pleasing
Yes yes I think I have it:
You were watching someone else working on a landscaping job, while admiring their work while listening to some Jimmy Buffet music. You noticed your beer bottle was empty when you had an epiphany, a revolutionary thought so to speak! "Should we have fish for dinner tonight? or should I make a speaker that looks like a beer bottle. By gosh I have it!
My new speakers will look like a fishy beer bottle. I may even paint scales on them.
And there you have it, problem solved!
MDF dulls your edged tools much quicker than ply. Then those dull tools tear out your ply... When working with MDF I include a fat percentage surcharge for sharpening and bit replacement. This generally puts you into a better grade of ply based on real costs. Not having to chew a cud of MDF dust is pure profit...
I saw this on "Modern Marvels". They were tensioning concrete bridge sections with cable inserted through holes. If Cal wanted some wiggle to that fish like object, I wonder if some light rope through slightly oversized guide holes would work. Stack, glue and feed the lines as you go, align the stack and tension the lines for final glue up. Small gauge aircraft cable instead of rope would use much smaller holes and could be easily removed as well.
Scott,
You're still one of the funniest guys I know. I was splitting a gut so bad I had to put my fishy bottle down to respond. I wish we could bottle your wit.
I got the 3/4" plywood and cut out a couple of pieces to find out that I won't have to worry about using an index dowel or rod as it appears I'll have some sanding to do. It looks like I will stack and screw and then haul out the belt sander.
ToE, thanks for your response. Again, I am learning about this stacking thing so I am just going to see if I can get these things together and decide if it's worth doing the bigger ones.
I will take my camera down to Sonia's later and snap some pics of the progress.
Fishy bottle in hand.
You're still one of the funniest guys I know. I was splitting a gut so bad I had to put my fishy bottle down to respond. I wish we could bottle your wit.
I got the 3/4" plywood and cut out a couple of pieces to find out that I won't have to worry about using an index dowel or rod as it appears I'll have some sanding to do. It looks like I will stack and screw and then haul out the belt sander.
ToE, thanks for your response. Again, I am learning about this stacking thing so I am just going to see if I can get these things together and decide if it's worth doing the bigger ones.
I will take my camera down to Sonia's later and snap some pics of the progress.
Fishy bottle in hand.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.