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

 
Subject : Ripples in Curly Maple Table Top - What did I do Wrong?
Posted : 2005-12-03 10:40 AM
Post #32606
Folks,

I am having problems with ripples appearing along the centerline of a dining table top I am making. It's a real bummer cause the veneer was really $$. Any help or advice on how to prevent these ripples forming would be apprecitated, I am ready to give it one more try but dont want to make the same mistake again. Pictures of the problem are attached. Details on my proceedure are below. - Thanks for any advice.

- I am suspicious of the glue size proceedure - it caused the maple to distort quite a bit even though I had it taped down to a flat table during appllication and drying.


Tabletop substrate: 1" particle board
Top Veneer: curly maple
bottom balancer veneer: plain maple
Top dimensions (2 pieces) 44" wide x 44" long x 1" thick

Glue: unibond 800 with blocker
Glue size applied to underside surface of both veneers to stop bleed through - dried 4 - 24 hours (both sides differnt dry times, the 4 hour dry time veneer sheets rippled badly during pressing)
Pressed each table top piece in vacupress bag at 20" vacuum for 6-8 hours -used 3/4" platten on base and 1/8" mdf as top caul

Attached file : TableTop2.jpg (48KB - 478 downloads)
Attached file : TableTop1.jpg (47KB - 454 downloads)



 
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Don Stephan

Posts: 825

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

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Subject : RE: Ripples in Curly Maple Table Top - What did I do Wrong?
Posted : 2005-12-03 7:49 PM
Post #32609 - In reply to #32606
If I understand correctly, you pressed the veneer first to one piece of MDF, then removed that from the bag and pressed the second piece. I'm presuming you taped together two or more sheets of veneer to have a skin wide enough for each piece of MDF. The distortion and rippling only occurred on what would be the inner edge of each piece of MDF where the two meet, and not at any of the taped veneer joints or along any of the other edges of the pieces of MDF.

Could you elaborate a bit on the glue size, distortion and rippling? My first thought is that the veneer was still wet from moisture in the glue size. Were the veneer skins flat when you pressed them to the substrate, or buckled? If you were using a commercial glue size, what is the name; if you made the glue size yourself what were the ingredients and proportions? Second, could you describe what you meant by "distortion" and "rippling?" I'm not being tedious, I just don't want to interpret incorrectly, and the pix weren't definitive for me. Third, were you using raw veneer or paperbacked? Finally, did you use solid veneer tape on the show face and nothing on the glue face?


 
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tdanaher

 
Subject : RE: Ripples in Curly Maple Table Top - What did I do Wrong?
Posted : 2005-12-03 9:09 PM
Post #32610 - In reply to #32609
Hi Don,

thanks - here are some more details:

Substrate was 2 x 1/2" sheets of particle board pressed together to make 1" thick substrate, then cut to rough size for veneering. allowed to dry for 2 days before veneering.

3 sheets of raw curly maple veneer were needed to cover the table top width. The rippling occured in the center of the top (in the middle of a veneer sheet), not at the joins of the veneer. sheets. The ripples are raised ridges that run down the center length of the middle sheet on the table top. They are about 1/8" to 1/4" wide and about 1/16" deep.

The Glue Size was commercially made from CP products, I did not thin it with water.

I used solid veneer tape on the face and 3-hole on the glue face joints.

hope this provides the details you are looking for.

thanks
Tom...


 
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Darryl Keil

Posts: 1455

Joined: 2003-05-22
Location: Maine

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Subject : RE: Ripples in Curly Maple Table Top - What did I do Wrong?
Posted : 2005-12-04 7:38 PM
Post #32615 - In reply to #32606
tdanaher,

I will first say that all maple veneers are notorious for wrinkling and I am always extra careful about this when using them.

I have never used this glue size you used so its difficult to say if this added to the problem. Very well could have.

A few questions for you. Did you apply glue to the veneer as well as the substrate? Was the curly veneer face up under the 1/8" caul or face down towards the platen? Did you take a long time to get the panel in the bag after the veneer was on the panel? Did the plain maple veneer wrinkle as well?

Answer these question and I may have a better sense of what went wrong.

Sincerely
Darryl Keil


 
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tdanaher

 
Subject : RE: Ripples in Curly Maple Table Top - What did I do Wrong?
Posted : 2005-12-05 11:28 AM
Post #32616 - In reply to #32615
Hi Daryll,

Answers to your questions are provided below:

I will first say that all maple veneers are notorious for wrinkling and I am always extra careful about this when using them.

I have never used this glue size you used so its difficult to say if this added to the problem. Very well could have.

A few questions for you.
Did you apply glue to the veneer as well as the substrate? - No, just the substrate.

Was the curly veneer face up under the 1/8" caul or face down towards the platen? - Face up under the 1/8" caul.

Did you take a long time to get the panel in the bag after the veneer was on the panel? - Approxmately 5 minutes. it went in pretty fast.

Did the plain maple veneer wrinkle as well? - yes - in exactly the same place as the curly maple - along the "centerline" of the table top.

Answer these question and I may have a better sense of what went wrong. - thanks.

Tom....




 
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Darryl Keil

Posts: 1455

Joined: 2003-05-22
Location: Maine

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Subject : RE: Ripples in Curly Maple Table Top - What did I do Wrong?
Posted : 2005-12-05 8:53 PM
Post #32618 - In reply to #32616
Tom,

Always interesting to sleuth out these problems. At first I considered that your 1/8" cover sheet was not sufficiently thick enough to stop the wrinkling but the fact that the other side that was face down did it too makes me think in another direction. I would still recommend a thicker caul when pressing maple but I'm wondering if you ended up getting a gasketing affect. This can sometimes happen when the air does not fully evacuate from the center of the panel while putting down good pressure around the edges. This usually happens if the bottom caul is bigger than the panel and the top caul is melamine coated effectively sealing off the center area of your panel. This is easily fixed by using some form of a simple bleeder fabric draped over your panel. This condition doesnt mean its a sure thing but it can happen.

I'm not really sure if this is whats going on but its odd that your problem is in the center on both sides of the panel. Its not like there's anything that jumps out at me here.

I also did not ask you what vacuum level you are pressing at. I assume you are 20HG or above. This could make a difference as well.

It could still be all about this sizing agent you used, and another full sized panel without it would tell a lot, although I'm sure your not keen on loosing another one.

I'm unfortunately not giving you firm answers here only educated speculation. You could always call me as we might find out something else through a phone conversation.

Sincerely
Darryl Keil


 
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Don Stephan

Posts: 825

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

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Subject : RE: Ripples in Curly Maple Table Top - What did I do Wrong?
Posted : 2005-12-14 7:47 PM
Post #32635 - In reply to #32618
Tom:

Did you ever identify the cause of the mid-line rippling?

Don Stephan
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