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21" Maelstrom Curved Box Build - Page 4

post #91 of 729
4/2/10 at 7:18am
I think this looks really cool. I can't wait to see it once you start smoothing it out. Great idea and nice job.

I do have one question, does your plywood have any voids in the layers at all. In my experince, there always seems to be some spots that aren't perfect in any piece of plywood. If so, how are you handling that - wood putty?

I think you mentioned that you did this by hand which is amazing - I wonder what it would cost to have someone CNC the pieces - then they would perfectly line up?
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post #92 of 729
4/2/10 at 9:28am
corock I love this. And I'm impressed with the chisel work on the first page, for real. I want to see the development of this project.

I do have to warn you, though. I have done 4 translams, all mdf. You do have to be careful of the stack being 90 degrees and even, of course. Smoothing is a pile of work, yes. But you'll love the product.

One thing I haven't seen in the comments in a quick read, you need to waste no time to seal the box. During soothing, if you stop work for a while, I would even seal it good without building up any above the surface, both in and out.

I have a crack over an 1/8" in my center channel. I can fix it, but I wish I had sealed as soon as the smoothing was done. It wintered in my house and shrinkage across the total stack of plys opened a slot in the weak part, the middle of the mdf, to relieve the stress created. Clamping once it does crack won't work-it'll deform the top or bottom first. I'll have to fill it with bondo. this is the same with plywood. the plys are soft wood and are just sponges. as long as the humidity stays the same--no problem. But once is has the form you want, stabilize it with something that is a good sealer for your chosen top coat.
I'm going to veneer, so I can surface with bondo just fine. you need to preserve the wood if you're going to finish showing the grain.

This is a cool idea, keep up the good work!

Dave
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post #93 of 729
4/2/10 at 11:05am
Thread Starter 
Quote:
Originally Posted by Video View Post

I think this looks really cool. I can't wait to see it once you start smoothing it out. Great idea and nice job.

I do have one question, does your plywood have any voids in the layers at all. In my experince, there always seems to be some spots that aren't perfect in any piece of plywood. If so, how are you handling that - wood putty?

I think you mentioned that you did this by hand which is amazing - I wonder what it would cost to have someone CNC the pieces - then they would perfectly line up?

Because its sanded plywood the gaps are minimal, but yes plywood is never perfect. There are a handful of little gaps in the ply. I'm undecided if I want to leave the gaps to have that natural look or fill with wood filler for a perfectly smooth surface. I'm planning on sanding this ridiculously smooth and put a gloss finish, so I'm leaning towards filling the gaps.

CNC would sure cut down on the time, cutting and sanding. I almost approached a local manufacturer about doing it, but decided I wanted to do everything myself on this project. If i did another one I might look at the CNC route.
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post #94 of 729
4/2/10 at 11:11am
Thread Starter 
Quote:
Originally Posted by orbifold View Post

corock I love this. And I'm impressed with the chisel work on the first page, for real. I want to see the development of this project.

I do have to warn you, though. I have done 4 translams, all mdf. You do have to be careful of the stack being 90 degrees and even, of course. Smoothing is a pile of work, yes. But you'll love the product.

One thing I haven't seen in the comments in a quick read, you need to waste no time to seal the box. During soothing, if you stop work for a while, I would even seal it good without building up any above the surface, both in and out.

I have a crack over an 1/8" in my center channel. I can fix it, but I wish I had sealed as soon as the smoothing was done. It wintered in my house and shrinkage across the total stack of plys opened a slot in the weak part, the middle of the mdf, to relieve the stress created. Clamping once it does crack won't work-it'll deform the top or bottom first. I'll have to fill it with bondo. this is the same with plywood. the plys are soft wood and are just sponges. as long as the humidity stays the same--no problem. But once is has the form you want, stabilize it with something that is a good sealer for your chosen top coat.
I'm going to veneer, so I can surface with bondo just fine. you need to preserve the wood if you're going to finish showing the grain.

This is a cool idea, keep up the good work!

Dave

Well I live in Saskatchewan, +40c in the summer -40c in the winter, so yeah there are some humidity changes. What do you think of the earlier suggestion of sealing the interior with an epoxy?
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post #95 of 729
4/2/10 at 11:31am
I too say job well done, by no means am I putting your work down. I am rather just giving some input on what more than likely will happen as far as cracking.

Even these arrays which were the main pieces cut from the pieces of wood which became those monster sub cabinet, were all cut on the CNC over 2 weeks of cutting and assembley of the small stacked pieces all lined up with wood dowels then filled with SAND.

Every piece of these cracked and all these pieces sat in the shop as a filler job, over 2yrs of settling they still cracked.

So I ended up sealing filling them one last time, sanding the pieces sealing them then veneering all the pieces book matched all pieces and mirror the right and left speakers.



My main advice is to complete them to the finish state you are happy with.
Then put them in your home for a week do not touch them.They will acclimatize and then if they are OK then do your finishing.

All the best.
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post #96 of 729
4/2/10 at 11:32am
Thread Starter 
Quote:
Originally Posted by orbifold View Post

I have done 4 translams, all mdf. You do have to be careful of the stack being 90 degrees and even, of course. Smoothing is a pile of work, yes. But you'll love the product.


Dave

I checked out your home page. You are THE MAN! Your speakers make mine look like child's play. Those are absolutely beautiful, first class job all the way. I can see where you would have trouble with the layers not staying 90 degrees with that height, I did have to battle that a little with mine.
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post #97 of 729
4/2/10 at 11:38am
Thread Starter 
Quote:
Originally Posted by RAWAC View Post


My main advice is to complete them to the finish state you are happy with.
Then put them in your home for a week do not touch them.They will acclimatize and then if they are OK then do your finishing.

All the best.

I appreciate the input RAWAC. This is new to me so I'll take all the input I can get. The praise is nice, but I need people to point out problems and share their ideas as well. I agree with letting them acclimate in the house. Will one week be enough?
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post #98 of 729
4/2/10 at 11:59am
You are welcome

A week should be enough all depends on the amount of moisture in the wood.

These array towers were in the shop and I was applying bondo into the cracks over and over till they got finished.You can see some cracks all over the MDF unfinished had cracks all over plus many spots you can see were filled with bondo.

Just let them rest as I said even assemble them and let they be for awhile to let them settle.

As I said I have done this method of clamping on several pieces


All of these pieces just for this array I did I learned allot. Take your time and you will be fine.


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post #99 of 729
4/2/10 at 1:57pm
Quote:
Originally Posted by RAWAC View Post

Every piece of these cracked and all these pieces sat in the shop as a filler job, over 2yrs of settling they still cracked.

So I ended up sealing filling them one last time, sanding the pieces sealing them then veneering all the pieces book matched all pieces and mirror the right and left speakers.

Sounds painful.

How about sealing with polyester resin inside and out?
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post #100 of 729
4/2/10 at 8:40pm
Thread Starter 
Quote:
Originally Posted by noah katz View Post

How about sealing with polyester resin inside and out?

I did some research on this and it seems polyester resin doesn't bond as well to the material its applied to as well as epoxy resin, its more brittle and can self ignite during the curing if not mixed properly. That would be a story, build this thing then have it go up in flames from the sealer.
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post #101 of 729
4/2/10 at 8:51pm
Thread Starter 
Here is a mock up of the baffle I was working on. The test baffle is the actual size of the enclosure face so it gives you and idea of what the Maelstrom 21" will look like mounted. I'm not going to do this because I've decided to have a black face on the box instead of wood, but I still kinda like it.
The first picture is of the baffle with a landing area routered around the driver's basket. That was for a wood donut I was going to use to cover the mounting area. The gaps around the donut are me experimenting with different router edges.



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post #102 of 729
4/2/10 at 8:51pm
Quote:
Originally Posted by corock View Post

and can self ignite during the curing if not mixed properly. That would be a story, build this thing then have it go up in flames from the sealer.

Then you can tell everyone your sub was so hot it caught on fire.

I asked before but didn't see an answer or find in the HTS thread, but what's the internal volume of the box please? Just a rough # would sate the curiosity.
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post #103 of 729
4/2/10 at 9:01pm
Thread Starter 
Quote:
Originally Posted by A9X-308 View Post

what's the internal volume of the box please? Just a rough # would sate the curiosity.

I've calculated and recalculated several times using several different parameters and it will be between 6.5 & 7 cu ft. 7 was my goal, but I removed two layers purely for aesthetics, I thought the square sections above the curve were too big.
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post #104 of 729
4/2/10 at 9:04pm
Quote:
Originally Posted by corock View Post

I've calculated and recalculated several times using several different parameters and it will be between 6.5 & 7 cu ft. 7 was my goal, but I removed two layers purely for aesthetics, I thought the square sections above the curve were too big.

Thanks for that.
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post #105 of 729
4/3/10 at 9:48am
Thread Starter 
Quote:
Originally Posted by Kanaris View Post

Looking good..... put a few coats of epoxy to the inside.... that will harden it up and close up anything that wants to come apart..you would be good to go...no matter what..

I've checked into this idea and found some great products they use to seal boats. If it works for boats I don't see why it wouldn't work on my enclosure. I came across West System epoxies and they have a clear coat version. I may consider even doing the outside if it looks good on a test piece.
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post #106 of 729
4/3/10 at 2:37pm
surely lots of lurkers on your build corock...just thought i'd chime in to say that i am enjoying following your (enormous work) build.
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post #107 of 729
4/5/10 at 10:27pm
Thread Starter 
I have the sub all glued together except the caps and the main body are still seperate. I've left them off for now so I have easier access to epoxy the inside of the enclosure. Once I'm done epoxying the interior the end caps can be attached. When the hole is cut in the baffle I'll be able to epoxy the two seams where the end caps are glued on.



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post #108 of 729
4/6/10 at 3:42am
Comming together nicely!
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post #109 of 729
4/6/10 at 5:40am
Very Cool build corok.... thanks for sharing...
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post #110 of 729
4/6/10 at 6:31am
excellent! good to see something different around here.

Subscribed!
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post #111 of 729
4/6/10 at 8:37am
Cant wait to see this unique Sub come together

Sorry if I missed it, What was the Model showing for Low frequency Tune from 21" mealstrom in 7cf box..

Cheers..
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post #112 of 729
4/6/10 at 9:16am
Thread Starter 
Here is Exodus Audio's model from the Maelstrom application notes. Note this model is with 500W only

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post #113 of 729
4/6/10 at 9:24am
Thanks Corock for going to the trouble of posting the model, Looks like one of Kevins models..
Looks very good for 500w excellent output..

What sort of W RMS are you going to be powering your 21" with, Behringer EP 2500 bridged ?

Cheers...
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post #114 of 729
4/6/10 at 9:33am
Thread Starter 
Yes, I have a Behringer EP4000 that I will use in bridged mode.
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post #115 of 729
4/6/10 at 3:41pm
If you want to really make sure there are no seams, paint on a very thin layer of epoxy, then lay on a fairly thin sheet of fiberglass, apply just a bit more epoxy and pull a squeegee over it until it's fairly smooth. Sand and finish however you want.

you can buy some nice fiberglass cloth that will become 100% transparent with good epoxy.
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post #116 of 729
4/7/10 at 9:26pm
Thread Starter 
Even without any sanding and clumps of glue all over the place, a couple coats of clear epoxy sure makes the plys look good. Thanks to Kanaris for the suggestion of using epoxy on the inside. And I think I'm going to go with Noah Katz suggestion of using black epoxy for my black baffle.

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post #117 of 729
4/8/10 at 12:22am
Quote:
Originally Posted by ltd02 View Post

surely lots of lurkers on your build corock...just thought i'd chime in to say that i am enjoying following your (enormous work) build.

+1
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post #118 of 729
4/8/10 at 8:56am
good to see your purchased the West system,, used it for years on boats and is really nice to work with,,

it does offer a nice change in color to the ply surfaces,,

Derry
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post #119 of 729
4/8/10 at 9:38am
I think the results on the inside give you validation to leave the plywood grain showing on the outside.

What about having your front baffle made from Aluminum or steel that is anodized or painted black? It could be pretty cool looking with a mix of the wood and metal.

I don't have Klipsch speakers, but the front of this sub has an aluminum baffle that looks great.

http://www.klipsch.com/na-en/product...-thx-overview/
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post #120 of 729
4/8/10 at 10:50am
Quote:
Originally Posted by corock View Post

And I think I'm going to go with Noah Katz suggestion of using black epoxy for my black baffle.

Actually I'm partial to my other suggestion of black glass, and a perfect finish w/o work.

I think its thickness, w/radiused or beveled edges,

I think it's pretty affordable too.
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