Darryl Keil Last Activity 2024-10-10 3:42 PM
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David Zaret

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Joined: 2016-01-09
Location: ann arbor, MI

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Subject : unibond 800 and waxed hardboard
Posted : 2016-01-21 2:29 PM
Post #37428
i have a number of flat panels to veneer that are all the same size, and i'd like to use thin cauls between the panels so they don't stick together. if i used heavily waxed hardboard panels between the veneer, should i expect the unibond to stick to the waxed surfaces?

thanks.



 
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Don Stephan

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

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Subject : RE: unibond 800 and waxed hardboard
Posted : 2016-01-21 6:55 PM
Post #37429 - In reply to #37428
What will be the substrates and how thick are they?


 
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David Zaret

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Subject : RE: unibond 800 and waxed hardboard
Posted : 2016-01-21 10:07 PM
Post #37430 - In reply to #37429
substrate is 1/4" MDF, veneer is pommelle sapele.


 
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Enrico Konig

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Location: Vancouver, BC

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Subject : RE: unibond 800 and waxed hardboard
Posted : 2016-01-21 11:39 PM
Post #37431 - In reply to #37430
You might want to test first before committing a pile to the press. Pommelle sapele will have quite a bit of bleed through, even if you use the blocker (and you probably want to use some blocker to limit the bleedthrough), and that can really affect how badly your cauls stick to your veneer. Nothing worse than having to pry a caul off and realizing it's taken a chunk of your show veneer off a panel.

Plastic sheeting always works if it does prove sticky when you test. I like using vinyl-coated mdf for cauls myself, in 1/4" and 1/8" thicknesses. Sometimes can get it where both sides are coated, which would be preferable in your situation.

Good luck.


 
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David Zaret

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Subject : RE: unibond 800 and waxed hardboard
Posted : 2016-01-22 12:23 PM
Post #37432 - In reply to #37431
i ran a test yesterday, my first test ever with unibond. i'll call it a failure. the glue cured, but the veneer peeled off in areas, probably because i didn't use enough. there was no bleed through at all, which tells me (given the species) that i didn't use enough glue. so, i ran another test this morning, with what is certainly too much glue - namely because i want to see the effect of the bleed through on the finished sapele to determine if it's an issue.

when you say vinyl coated MDF - that's a product i'm not familiar with. i'll check with my supplier, but do you have a brand name? thanks.

-- dz


 
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Darryl Keil

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Location: Maine

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Subject : RE: unibond 800 and waxed hardboard
Posted : 2016-01-22 5:44 PM
Post #37433 - In reply to #37432
If you got no bleed through on Sepele you definitely did not use enough glue. Also make sure you're above 70 degrees, (a common problem this time of year). Also, don't test the glue line until at least 12 hrs later, 24 hrs even better.


 
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Don Stephan

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Subject : RE: unibond 800 and waxed hardboard
Posted : 2016-01-22 6:39 PM
Post #37434 - In reply to #37432
David

A common guideline is to spread the glue out evenly, then drag your finger through it. If a slight ridge is left on each side, there is often enough glue. Do this every time to develop a sense of how much is enough.


 
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David Zaret

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Subject : RE: unibond 800 and waxed hardboard
Posted : 2016-01-22 6:58 PM
Post #37435 - In reply to #37434
thanks for your help.

my most recent test came out of the bag a few hours ago, with great success. had about 15% bleed through. popped right off the waxed hardboard cauls. the glue sanded flawlessly.

results attached shortly...

--- dz



 
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David Zaret

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Subject : RE: unibond 800 and waxed hardboard
Posted : 2016-01-22 7:00 PM
Post #37436 - In reply to #37434
https://www.icloud.com/sharedalbum/#B045ZhN2vGfVl38;3F405F39-6D92-4E2E-8755-1022C75CDA9C

and the pommelle:

https://www.icloud.com/sharedalbum/#B045ZhN2vGfVl38;389342AF-315A-4491-A51F-472934602C3D


 
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Don Stephan

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Joined: 2003-07-18
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Subject : RE: unibond 800 and waxed hardboard
Posted : 2016-01-22 7:25 PM
Post #37437 - In reply to #37436
Generally it is a good idea to veneer both sides of a substrate, especially one as thin as 1/4". Normally I wait 12 hours after taking out of the bag before I sand, so the glue cured. One trick to see when sandwich can be pulled from the bag is to pour a couple tablespoons of excess glue into a small zip lock bag. When the glue in the bag is rubbery, can take sandwich from the vacuum bag. When the glue in the baggie is rigid I'll start sanding.


 
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David Zaret

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Location: ann arbor, MI

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Subject : RE: unibond 800 and waxed hardboard
Posted : 2016-01-23 8:16 AM
Post #37438 - In reply to #37437
don, both sides are always veneered - what you're seeing in those pictures are the two sides of the same panel. i learned the hard way that there's no shortchanging veneering both sides.

the baggie trick is a good one - i'll do that, thanks.

i have the bag sitting on a piece of 2" insulation foam, and a heating blanket over the bag, and it was very toasty for a good 4 hours. the glue was almost certainly cured long before i popped it out.

thanks for the help,

-- dz



 
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David Zaret

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Joined: 2016-01-09
Location: ann arbor, MI

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Subject : RE: unibond 800 and waxed hardboard
Posted : 2016-03-31 7:54 AM
Post #37468 - In reply to #37428
just to close the loop on this... the waxed cauls worked quite well. i used 1/8" MDF, waxed on both sides. my cauls and panels were pretty large, so i ended up using a torch to melt the paste wax in the can, added a little mineral spirits, and it made it much easier to spread the wax and have it soak in to the MDF. the cauls were used multiple times and exposed to the unibond, and other than a little sticking to the very edges, they performed perfectly.

i found it difficult to spread the wax without "softening" it a little with the torch.

darryl, have you heard of anyone using commercial release agents? i worry a bit about contaminating the wood surface, but a liquid release agent sure would save time....

thanks for the guidance.
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