Darryl Keil Last Activity 2025-02-12 2:48 PM
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tim borys

Posts: 7

Joined: 2006-02-02
Location: Winnipeg, CANADA

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Subject : Veneering cylinders
Posted : 2006-04-25 11:57 AM
Post #33013
Does anyone have any advice on veneering cylinders? I have cylinders (actual they may be slightly oval) approximately 16" tall and 16"-20" in diameter. I will construct the cylinders with a bendable ply and a cylindrical torsion box but how can I apply the veneer around the entire cylinder and get enough clamping pressure? Maybe this is an application for hammered veneer which I've never done? Any comments, guesses, or experienced advice will be appreciated.



 
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Darryl Keil

Posts: 1454

Joined: 2003-05-22
Location: Maine

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Subject : RE: Veneering cylinders
Posted : 2006-04-30 9:49 PM
Post #33022 - In reply to #33013
Tim,

I'm assuming you don't have a vacuum press as that would be a solution. Another option would be to get phenolic backed veneer and use contact cement with yellow glue at the return seam.

Hammer veneering is of course an option but not a particularly friendly one unless you're experienced with this method.

Sincerely
Darryl Keil


 
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tim borys

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Joined: 2006-02-02
Location: Winnipeg, CANADA

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Subject : RE: Veneering cylinders
Posted : 2006-05-02 12:34 AM
Post #33026 - In reply to #33022
I do have a vac bag Darryl. I just couldn't visualize how I would use it to press the veneer all the way around the cylinder. What am I missing?


 
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Darryl Keil

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Joined: 2003-05-22
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Subject : RE: Veneering cylinders
Posted : 2006-05-02 8:19 PM
Post #33027 - In reply to #33026
Tim,

You do it in two steps. Apply glue to three quarters of the cylinder with the unglued area face down on the platen with the veneer overlapped in this area. Press this making sure the bag is tucked beyond the point where the glue stops. Then cut through both layers of the veneer to create the seam, apply glue in this area, and put it back in the bag with this section face up.

Hope this gives you a general idea.

Sincerely
Darryl Keil


 
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tim borys

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Joined: 2006-02-02
Location: Winnipeg, CANADA

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Subject : RE: Veneering cylinders
Posted : 2006-05-02 11:52 PM
Post #33028 - In reply to #33027
Gotcha! Thanks!
I was concerned that a partial press would leave a hardened glue line right where the glued area ends but I see now that ensuring the bag is pressing well past the end of the wet area should keep that flattened out. I imagine it will be a bit tricky getting glue all the way back in to the point of where the first glue ends without bending the veneer out so much that I risk cracking it. But is that really so terrible if I have a thin strip between the two areas where it's not glued?

Thanks again, I'm going to give it a try.


 
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Don Stephan

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

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Subject : RE: Veneering cylinders
Posted : 2006-05-03 8:00 AM
Post #33029 - In reply to #33028
Tim:

Veneering a cylinder is demonstrated in the 2nd Vacuum Pressing video.

I'm curious as to how you made up a torsion box oval with smooth seams.

Thanks.


 
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Darryl Keil

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Joined: 2003-05-22
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Subject : RE: Veneering cylinders
Posted : 2006-05-03 4:23 PM
Post #33030 - In reply to #33028
Tim,

Once you apply glue as close as you can get to the previous glue line use compressed air to drive the glue in all the way.

Sincerely
Darryl Keil


 
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tvsp

Posts: 11

Joined: 2006-02-10
Location: OH

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Subject : RE: Veneering cylinders
Posted : 2006-05-05 8:21 AM
Post #33032 - In reply to #33030
A critical item not mentioned in this thread is that the cylinder will implode in the bag without a form or bladder bag inside it to prevent it from crushing.


 
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ray

 
Subject : RE: Veneering cylinders
Posted : 2006-05-07 6:48 PM
Post #33039 - In reply to #33032
I have also had a problem with deflection on a 16" drum even with a air bladder bag. Another thing is I don't think a 20 diameter will fit inside the bag. The bag will pull apart at the seems. Someone mentioned away of doing this, but I tried everything I can think of. If someone knows how to do large diameters 20 or 22" please take a picture with the cylinder in the bag under pressure.


 
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Don Stephan

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

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Subject : RE: Veneering cylinders
Posted : 2006-05-07 7:13 PM
Post #33040 - In reply to #33039
Since you are pressing the veneer to a form you don't need a platen for a flat reference surface. Could you use the bag without a platen? If so, the maximum diameter assuming a 96" long bag, would be slightly less than (96+96)/(2*pi) = 30" radius.

Alternatively, someone might be able to explain how to use a single sheet of plastic taped to a smooth surface, with evacunet and a continuous vacuum.


 
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tvsp

Posts: 11

Joined: 2006-02-10
Location: OH

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Subject : RE: Veneering cylinders
Posted : 2006-05-23 8:40 AM
Post #33066 - In reply to #33040
Hey Don! I'm in Cinti, too - Mason actually.
I've been waiting for an answer to your question, "could you use the bag without a platen?" when vacuum pressing a form (or bladder) filled cylinder.
I veneer snare drum shells & saw someone do this using a homemade vacuum bag WITHOUT a platen & he has no problems. Of course I assume this will permanently stretch the bag out of shape?


 
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Darryl Keil

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Joined: 2003-05-22
Location: Maine

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Subject : RE: Veneering cylinders
Posted : 2006-05-24 9:34 AM
Post #33067 - In reply to #33066
tvsp,

You can definitely press without the platen. All you need is some method to get the air down to the exit port and out of the bag efficiently. A bleeder fabric of some kind like EvacuNet is all you need for non-platen pressing.

Sincerely
Darryl Keil
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