Darryl Keil Last Activity 2024-10-10 3:42 PM
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Don Stephan

Posts: 825

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

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Subject : Veneering with Polyurethane
Posted : 2016-06-17 1:14 PM
Post #37499
Anyone know of any instructional text or video on using polyurethane in a vacuum press for veneering?


 
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Darryl Keil

Posts: 1453

Joined: 2003-05-22
Location: Maine

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Subject : RE: Veneering with Polyurethane
Posted : 2016-06-17 3:56 PM
Post #37500 - In reply to #37499
I don't think you'll find any info about using polyurethane glue in a vacuum press. Personally, I'd be wary of the stuff. It foams considerably and it's the one glue that will stick aggressively to the bag.


 
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david haig

Posts: 1

Joined: 2016-06-06
Location: Nelson New Zealand

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Subject : RE: Veneering with Polyurethane
Posted : 2016-06-21 4:15 AM
Post #37501 - In reply to #37500
I can vouch for polyurethane glue being a poor choice...I used the stuff on the very first project I ever undertook with my brand new bag and pump all the way from America (I'm in New Zealand). Those beads of glue are still on my bag 12 years later, it's like they're welded on.
BTW, thanks Darryl for your suggestions re getting the pressure dial-gauge to work on the pump..all good now!


 
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Jeff Patrick


Joined: 2004-04-15
Location: Bainbridge Island, WA

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Subject : RE: Veneering with Polyurethane
Posted : 2016-07-21 4:50 PM
Post #37517 - In reply to #37499
I've used poly glue in my press on a few occasions. These are usually when I bond XPS foam to plywood. The foaming of the glue isn't a problem because I take pains to wrap the bundle of foam/plywood in plastic. So far I've been successful in keeping the glue off the bag. Other than the plastic wrap, I follow the usual procedures for veneer pressing. Just like a pva glue, the poly glue wants a thin glue line and plenty of pressure.


 
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Dave S

Posts: 4

Joined: 2012-07-02
Location: Westfield, IN

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Subject : RE: Veneering with Polyurethane
Posted : 2016-12-16 12:10 PM
Post #37544 - In reply to #37499
I agree - a very poor choice. I just went thru hell and back with a burled table top, remaking the top to replace the one we made with Urethane glue in a vacuum bag.

Easy to use and spread, and good adhesion, but it will not lay flat. The glue foams and lifts the veneer away from substrate or whatever. You end up with a rolling landscape of hills and valleys of 30 thousandths or more. Plenty enough to have sand throughs. You can feel it in the top as it comes out of the bag, even after pressing with a 3/4" thick MDF caul.

I have clamped up small parts with clamps (handscrews) and had no trouble using urethane glue, but then I am sure I am getting many more psi than the vacuum makes. .


 
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Darryl Keil

Posts: 1453

Joined: 2003-05-22
Location: Maine

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Subject : RE: Veneering with Polyurethane
Posted : 2016-12-17 8:27 AM
Post #37545 - In reply to #37499
I have a saying with polyurethane that when your absolutely convinced you have not put on enough glue then its just right. Its just not like other glues when it comes to coverage.
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