bendable plywood any good for cabs?

[JBLnsince1959]

Hi Merlin,

They are using thin layers of MDF to build up the curved back and side profile.

The MDF layers are glue laminated together. A result of stressed panels(bent) is that they don't resonate. That's some science used by old aeroplane builders...curved wing surfaces makes a more rigid airfoil.

how thin for the layers and how thick once glued together? ( how many layers)

[Hoerninger]

... , do you know how sharp a radius you can make with this material? The plywood can make an 80 mm radius minimum, it's really very flexible. I was wondering if the MDF would not break along the kerf if bent too tight?

Scorpio,

sorry for the delay.
I have not found any information regarding the smallest radius. But I know it can be quite small without breaking.
The attached picture shows how the new Everest is made, consisting of 9 mm and 16 mm MDF glued together (White Paper).

(http://www.soundstage2.com/lasvegas2007/showstop03.html)
____________
Peter

[richluvsound]

What you can see is both halves of the Jig. I needed something that would last for more than one pair of speakers. I used 25mm MDF and Tulip wood. Glued and screwed as I did'nt want movement in the frame . It's strong enough to be used with a nuematic press should I get more orders for this design. The first panel is curing as I write this . I'll post a photo of the outcome tommorow.

Rich

[grumpy]

Nice Jig! Forthcoming pics of end product?

I have not found any information regarding the smallest radius.

see post #6. -grumpy

[Andyoz]

Wow, even your jigs look good Rich. What are you up to there? Making more than one hey...hmmm

[richluvsound]

cheers Grumpy,

I wish seen that post before I started. My supplier said he could only get 9mm

so I had to double it up ££££££. I filled the gaps to with resin and . I did'nt think I should leave any voids. Ah well , it'll be bloody bomb proof atleast !

Rich

[macaroonie]

Nice jig pretty much as we discussed. Did you go a few % beyond your ideal curve to allow for relaxation ? Are you putting a layer of glass mat in between ?:dont-know

[macaroonie]

That these guys were just at the end of my street.
http://www.aitwood.com/default.asp

Check it out under Millwork curved PLY sheets all kinds of radiussessss

[Andyoz]

I reckon that jig would make a nice bed for one of the "visitors", imagine the lumbar support when that thing's laying on its side.

[grumpy]

I wish That these guys were just at the end of my street.

http://www.aitwood.com/default.asp

That's where I found the neatflex/neatform stuff... they almost
-are- at the end of my street. <30min away. I don't recall what
pointed me there... probably someone here

I have yet to make it over there in person, but rest assured, I will. -grumpy

[richluvsound]

Hey fanny paws !

it aint pesch ! . No relaxation either. I'll measure these 2 or 3 times before I cut this small fortune. I did'nt use any glass layer. I did'nt see a reference to it in any off widget's posts- If its good enough for the master its good enough for me . I just wish we could get the magic goop tho !

Rich

[macaroonie]

Hey you are the guy on the spot so what do I know.I would still be tempted to try 4 x 4mm baltic birch with glass interleaves. You have the jig now so a tryout would not be a big deal esp if you halved the sheets.
Just a suggestion -- why dont you get some steel angles and fix them along the length of both parts of your jig that way you could use bolts to crank it all together.
Magic goop -- at one time I worked for Ariston and we were messing about with QLN speakers from Sweden. They had a board system that derived from the bus and truck industry. in essence the sheets were laminated with a layer of visco elastic with a very lossy nature. About 1mm as I recall. Very similar to Stycobond flooring adhesive. Anyway the end result was as dead as dead can be.
There were endless tech sheets in Swedish and German to substantiate the effectiveness of the treatment.
Betcha a web rummage would turn something up.

[macaroonie]

Oh now that I remember , at Ariston we turned out a couple of solid plinth turntables using 15mm mdf/ goo / 15mm mdf or it may have been 12/goo/12/goo/12. . At the development stage we had 'controls' in place ie non treated decks for comparison and the improvement was substantial and at low cost too ( per plinth ).
Made a rega sound pretty stupid but then that aint hard.

[richluvsound]

Mac ,

good idea on the use of steel . The jig can evolve, but I have to watch the pennies at the moment . Plus, I want to get the panels done before Ian arrives. I takes up a fair bit of room and I don't want the poor Aussie bugger snorting resin fumes in his sleep.... Shame you can't make it down Mate.

Rich

[Andyoz]

Sorry I haven't been more involved with this but I'm flat out at work and my key "dealer" is off on holidays, back tomorrow apparently.

Rich, don't worry about Ian + fumes, where I came from the lads used to sniff all sorts of things.