Darryl Keil Last Activity 2025-09-09 11:09 AM
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Bill Pappas

Posts: 18

Joined: 2008-01-20
Location: The Villages, FL

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Subject : Design Question
Posted : 2008-01-20 4:01 PM
Post #34286
I need some help. I am designing my home office furniture (desk) and want it to have some curves. So I am considering laminating together 5 pieces of 3/8 inch bending plywood to serve as the legs. The legs will be about 2 inches thick and almost as wide as the desk top so they will be fairly substantial in size. I have never used bending plywood before so I have a couple of questions I thought someone might be able to help me with. A crude drawing is attached...

1. What kind of a radius might I be able to achieve with 5 pieces of bending plywood.

2. Should I try and laminate them all at once in the vacuum bag or laminate 2 pieces, then the 3 and finally put the 2 lamminated pieces together?

3. How strong or maybe better said how much weight would the laminated leg support when the force is applied from top which is shown in the attached picture as "Force - High". The top of the desk would sit on the laminated legs so it will have some weight to it and then all the stuff that goes on the top of the desk like a monitor, keyboard, etc.

Thanks,

Bill
Attached file : Laminated Leg009.jpg (30KB - 150 downloads)



 
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Darryl Keil

Posts: 1455

Joined: 2003-05-22
Location: Maine

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Subject : RE: Design Question
Posted : 2008-01-20 7:41 PM
Post #34289 - In reply to #34286
Bill,

Structurally I dont think you will have any problems with five layer. As far as the radius goes, I dont attempt 3/8" bending ply under 6". For all five layers at once I would probably go with 10" radius or better. You may get it tighter but this is what I would do.

Darryl


 
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Bill Pappas

Posts: 18

Joined: 2008-01-20
Location: The Villages, FL

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Subject : RE: Design Question
Posted : 2008-01-21 9:11 PM
Post #34299 - In reply to #34289
Thanks for the advice - it is greatly appreciated.


 
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Bill Pappas

Posts: 18

Joined: 2008-01-20
Location: The Villages, FL

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Subject : RE: Design Question
Posted : 2008-01-26 10:30 PM
Post #34330 - In reply to #34289
Darryl,

I was reading a book tonight that had an article you authored....it was great and very informative. The article mentioned the honey comb material vacupress sells. I was wondering what kind of a radius you can get with the honeycomb material sandwiched between 3/8 bending ply and just how much strength the piece would have. I was thinking I might be able to use the honeycomb and eliminate a few layers of bendy ply? I attached the picture of the desk leg I was considering this for.

Thanks in advance for any thoughts on the subject.

Bill
Attached file : Laminated Leg009.jpg (30KB - 132 downloads)



 
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Darryl Keil

Posts: 1455

Joined: 2003-05-22
Location: Maine

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Subject : RE: Design Question
Posted : 2008-01-27 10:45 AM
Post #34331 - In reply to #34330
Bill,

What is your tightest radius on this curve? What thickness of honeycomb were you considering?

Darryl


 
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Bill Pappas

Posts: 18

Joined: 2008-01-20
Location: The Villages, FL

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Subject : RE: Design Question
Posted : 2008-01-27 6:42 PM
Post #34333 - In reply to #34331
I am in the design stage so I have flexibility on the radius. I would like to keep it to about 10 inch radius, currently my drawing has it at 7 inches. As of the thickness of the honeycomb...I was hoping to use the 1 inch stuff...I am trying to get to 2 inch thick legs.


 
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Darryl Keil

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Joined: 2003-05-22
Location: Maine

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Subject : RE: Design Question
Posted : 2008-01-27 7:37 PM
Post #34334 - In reply to #34333
Bill,

I'm pretty sure you could get 10" but 7" would be pushing it for 1" honeycomb. Be aware that using honeycomb requires some additional work as you need to make 1" thick curved strips that match your radius less the 3/8" thickness of the final layer that will go against your form. What I would do is tack down a piece of 3/8" bending ply onto your form, lets say 3" wide. This would represent your inside skin. On top of this, glue together a combination of 3/8", 1/8" and veneer to get exactly 1" total thickness. I would make this about 2" or so wide. Once its glued up you can rip two pieces out of it to get your two curved perimeter strips.

When it comes time to make your panel, start by tacking down the 3/8" bending sheet to your form and then glue the four border strips around the edge of this sheet. I tack them down with brads and then let the vacuum press glue them to the 3/8". Doing this ahead of time makes it so the honeycomb is captured within the border strips. Trying to glue up both skins, four border strips, and the honeycomb all in one shot is very difficult.

Hope this makes sense.

Darryl


 
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Don Stephan

Posts: 825

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

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Subject : RE: Design Question
Posted : 2008-01-21 9:15 PM
Post #34300 - In reply to #34286
Can't offer an opinion re the strength, but you likely would have problems making a 2 layer lamination, a 3 layer lamination, and then trying to put the result together. I think it's very unlikely the curves would mate well, especially if assembled with rigid glue. If concerned with difficulty of working with five layers at once, glue up 2 or 3, and after cured add the remaining layers to the assembly. My 2 cents.


 
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Bill Pappas

Posts: 18

Joined: 2008-01-20
Location: The Villages, FL

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Subject : RE: Design Question
Posted : 2008-01-26 10:23 PM
Post #34329 - In reply to #34300
Thanks Don. I agree it will be easier to just do it all at once.
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