Darryl Keil Last Activity 2024-10-10 3:42 PM
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Paula

Posts: 37

Joined: 2004-05-22

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Subject : EvacuNet
Posted : 2005-02-08 3:02 PM
Post #32042
The product description for evacunet makes it sound like it can be used for flat projects, although it doesn't specifically say this, and the examples you show are for curved pieces. Can it be used to replace the upper and lower cauls for flat projects? This would sure be a lot easier to manage than having to keep cauls of different shapes and sizes for different projects.


 
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bgray

 
Subject : RE: EvacuNet
Posted : 2005-02-08 5:13 PM
Post #32043 - In reply to #32042
I think that I would still use a caul.

The evacunet will surely leave it's imprint on most soft veneers, and even some harder ones....



 
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Darryl Keil

Posts: 1453

Joined: 2003-05-22
Location: Maine

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Subject : RE: EvacuNet
Posted : 2005-02-08 5:28 PM
Post #32044 - In reply to #32042
Paula,

The EvacuNet is a substitute for the platen not the cauls. Although we show its use mainly for curved work you can definitely use it as a flat platen.

Sincerely
Darryl Keil


 
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Paula

Posts: 37

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Subject : RE: EvacuNet
Posted : 2005-02-09 11:16 AM
Post #32045 - In reply to #32044
Darryl,

After reading these posts I went back and looked at your videos again, and I've got a couple of questions.

On your video on curved work you used evacunet on a curved cherry piece. Will only the inside of this piece show? Based on the last post by bgray, I assume you only use evacunet on sides that won't show. What if you have two face sides?

Is this why you didn't use any evacunet on the stair stringer you did in the video?

Also, this got me thinking about the fact that you didn't use any cauls in most of the curved pieces you did on the video. When do you use or not use cauls?


 
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Darryl Keil

Posts: 1453

Joined: 2003-05-22
Location: Maine

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Subject : RE: EvacuNet
Posted : 2005-02-10 1:36 PM
Post #32047 - In reply to #32045
Paula,

I dont recall using cherry on any of the curved pieces in that video, Its been a while. What piece did I use cherry on.

The evacunet goes on the side that has the nipple on it. It's really irrelevant which side will be the show side in respect to the evacunet, it's only a platen substitute.

You use cauls whenever you can on raw or paper backed veneer. Some of the veneering in the "Working in a Vacuum" video were on such tight radiuses a caul couldn't be used, and on two ply its not needed.

As far as the spiral staircase goes, I did use the evacunet. Go back and review that section and you will see it.

Sincerely
Darryl Keil


 
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Paula

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Subject : RE: EvacuNet
Posted : 2005-02-10 3:38 PM
Post #32048 - In reply to #32047
You made an arch from 4 3/16" pieces of cherry. It was a piece where you demonstrated using a form that is outside the bag. What I'm confused about now is the comment the bgray made about the evacunet leaving an impression on the veneer. Are you saying this doesn't happen, or is it something you just scrape or sand off?

What is it about a two-ply that makes a caul unnecessary?

I'm sorry for being dense, but at this point I'm confused about the reason you need the top caul. I can see that you need a bottom caul to keep the veneer from being sucked into the grooves in the platen, but although I've been using top and bottom cauls without thinking much about it, I don't see the function that the top caul serves.


 
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Darryl Keil

Posts: 1453

Joined: 2003-05-22
Location: Maine

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Subject : RE: EvacuNet
Posted : 2005-02-11 4:55 PM
Post #32049 - In reply to #32048
Paula,

Yes, that arch jam was cherry. Like I said it was some time ago.

The evacunet will not leave an impression on solid wood but will on veneer. Veneer gets somewhat soft from the glue during pressing which makes it susceptable to the evacunet.

Let me explain about veneer, cauls and the bag. When glue comes in contact with veneer, especially water based ones, veneer wants to swell and buckle. As soon as veneer has been pressed to even another piece, hence the creation of two ply this condition no longer comes into play. As far as the bag goes, although it clearly applies sufficient pressure, it will not stop the veneer from wrinkling. The surface rigidity of a caul in combination with vacuum pressure assures good pressing. This is why you need a caul between the veneer and bag unless its two ply, shop sawn veneer, or thicker materials.

One other point. The veneer doesnt actually get sucked into the platen grooves. The problem is the glue sensing the lack of pressure there and migrating towards the grooves leaving a grid work of raised ridges on the veneer surface.

Hope this clarifies things.

Sincerely
Darryl Keil


 
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Larry Root

 
Subject : RE: EvacuNet
Posted : 2005-02-14 6:29 AM
Post #32050 - In reply to #32048
Paula,

Envision a small bubble in the vereer being pressed. The bag on the veneer follows the surface -- the bubble only gets pressure from the limited area that's in contact with it. But, with a rigid platten between the bag and veneer, the platten takes the pressure from a large area of the bag and places it all in the only spot that's making contact -- the bubble: The platen "concentrates" the pressure.

If you've ever stepped on a cracker bare foot, it breaks. Step on it in flat soled dress shoes and its powdered. The skin gives, the shoe concentrates your weight.

Larry


 
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Paula

Posts: 37

Joined: 2004-05-22

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Subject : RE: EvacuNet
Posted : 2005-02-14 9:44 AM
Post #32051 - In reply to #32050
Darryl and Larry,

Thank you very much - your posts helped a lot!
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