Darryl Keil Last Activity 2025-09-09 11:09 AM
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Christof

Posts: 3

Joined: 2008-04-12
Location: Windy City

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Subject : Tricky little corners.....
Posted : 2008-04-12 12:29 PM
Post #34492

I'm building a complex geometric shaped form (Rhombicuboctahedron) with 26 sides. The will eventually have a hole cut in it to house a speaker driver. The cabinet has six large sides 14" x 14", then all of the edges and corners are truncated which yeild 8 more panels 3.5" x 14" and 8 small 3.5" triangles.

Using my Vacupress hiflo and bag, I've tried to veneer first and then break down my panels into the sizes I mentioned. I then try to assemble the thing and no matter how dialed in I get my saw and no matter how accurate I try to be, for the life of me I cannot get all 26 sides properly aligned such that all the joints are acceptable. I now build the enclosure with just the big sides pre-veneered in the bag and I need to somehow get the veneer attached to the little sides without using the vacuum press?

I hope I have made this explanation clear enough. Here is a picture of a the 26 sided enclosure I built using PVA and iron on method...I'm just not sure about the longevity of iron-on veneer using PVA???
http://www.audiocircle.com/circles/galleryimage.php/albuu91/Zach_back_side.sized.jpg

I appreciate any feedback.
Chris


 
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Anton Gerner

Posts: 45

Joined: 2003-09-04
Location: Melbourne, Australia

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Subject : RE: Tricky little corners.....
Posted : 2008-04-12 5:28 PM
Post #34493 - In reply to #34492

You have to get your saw set up right.
It doesn't look that hard to cut using an accurate saw set up.
Too hard and too slow to veneer once assembled.
I'd try again with the saw


 
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Don Stephan

Posts: 825

Joined: 2003-07-18
Location: Cincinnati, Ohio

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Subject : RE: Tricky little corners.....
Posted : 2008-04-12 6:36 PM
Post #34494 - In reply to #34493

If you are building a complete whatchamacallit, you could use cauls and deep throat clamps on every opposing pair of surfaces, one pair at a time.


 
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Brian Gray

Posts: 339

Joined: 2004-01-21
Location: Sandusky, OH

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Subject : RE: Tricky little corners.....
Posted : 2008-04-12 8:38 PM
Post #34495 - In reply to #34494

I'm not a fan of PVA's for veneering. I've tried your ironing method, and I hate it, unless it's for very small applications....not large surfaces. That being said, some people do PVA with an iron with no problems. My experience is that the heat of the iron makes the veneer split. And then overall, PVA's are simply a poor choice compared to Unibond. (my opinion)

My first vote is with Anton for more precise table-saw set-up with a very sharp blade, and zero clearance. I would get plenty of MDF for test scraps. Do you have a friend with another table-saw? Once you get one angle set PRECISE AND DEAD ON....you don't want to change it. So maybe you can have mutliple saws set up with your needed angles?

If you would rather abandon that and veneer after assembly, then I also agree with Don - long-reach clamps would be nice.

Another option....

It might be worth your time to make a custom manual press.

You could create a custom frame with screw-presses.

If you plan on making multiples of this design, then a custom manual press is probably the way to go, my 2 cents.

Question - is there any internal support inside the box? If you put full pressure on the box will it collapse?

If so, then Anton's suggestion of more precise sawing and veneering beforehand is probably the only way.


 
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Christof

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Joined: 2008-04-12
Location: Windy City

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Subject : RE: Tricky little corners.....
Posted : 2008-04-13 12:30 AM
Post #34497 - In reply to #34495

Thanks for the input. The panels are 2.25" thick mdf. There is internal bracing inside the enclosure. I'm using zero clearance Corian inserts on my saw with a sharp Forrest WW2 40T blade.

I am using Unibond800 when bagging the large panels, it's mainly the little 3-1/2" triangles that I'm having trouble getting to line up perfect...there are just under 50 joints to fit on one of these enclosures, I'd like to say I could get this many joints to line up without error but....back to the drawing board.







 
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Brian Gray

Posts: 339

Joined: 2004-01-21
Location: Sandusky, OH

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Subject : RE: Tricky little corners.....
Posted : 2008-04-13 9:57 AM
Post #34499 - In reply to #34497

If the box is internally supported, then I would either try long reach clamps, or build a custom manual press, as mentioned above.

This way, your joints can be a tiny bit off. You can then fill some minor gaps with epoxy, bondo, whatever, and then veneer over them.

Now obviously, these gaps need to be few and minor...otherwise you will compromise the the integrity of the box (as well as sonic performance). So there has to be a certain allowable slop on your gaps during construction.

By the way, congratulations on not using contact cement. My (granted limited) experience with speaker builders is that they put lots of work into design, electronics, components, etc...and then when it's time to veneer the box, they just use a press-on veneer, or contact cement.

If you are interested, here's a neat little speaker project of mine...

http://www.briangray.net/projectdetail.cfm?ProjectID=26

Obviously, this was much easier to construct the carcass and glue than your project!

When you are finished with your speaker, please post completed pics. I would really love to see it.


 
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Christof

Posts: 3

Joined: 2008-04-12
Location: Windy City

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Subject : RE: Tricky little corners.....
Posted : 2008-04-13 12:27 PM
Post #34502 - In reply to #34499

Brian

I've seen pic's of your speakers before, not sure where...I like your inlay work very much. I'm familiar with quite a few speaker designers and very well may know your brother inlaw.

Here is a gallery with some of the enclosures I've done.

http://www.audiocircle.com/gallery/index.php?cat=12241

Thanks
Chris


 
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Anton Gerner

Posts: 45

Joined: 2003-09-04
Location: Melbourne, Australia

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Subject : RE: Tricky little corners.....
Posted : 2008-04-13 5:01 PM
Post #34503 - In reply to #34502

Hi Chris,

Nice work with your various speakers !
I noticed you used some Seas drivers in some.
I made the Seas Thor a few years ago - **** nice.
I really should post some photos......


 
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Brian Gray

Posts: 339

Joined: 2004-01-21
Location: Sandusky, OH

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Subject : RE: Tricky little corners.....
Posted : 2008-04-13 8:23 PM
Post #34504 - In reply to #34503

Great work, Chris!


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