Veneer Bleed Through
#11
I recently did some veneering work using white oak veneer. It will likely be no surprise to those of you who are experienced with veneer that I had lots of adhesive bleed through. I'm dealing with it on this project, but what is the best way to prevent it the next time. Is there a good way to seal the back side of the veneer before gluing it down. I usually use plastic resin glue for veneer.
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#12
Is this commercial veneer? I have done limited veneering but never with oak. I imagine the porous grain of oak would make it more susceptible to bleed through. I've always used plastic resin glue too but most of my experience has been with shop sawn veneer which usually doesn't have this problem because of the thickness. I'm interested in seeing the comments from people with more experience with the process.
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#13
Sounds to me like you're using too much adhesive.  I'm assuming you're using plastic resin glue, since you mentioned it, but didn't conclusively say that's what you're using on this project.  White oak isn't a porous wood (red oak is), so I'm wondering if your veneer might be red oak.  I've not experienced this kind of issue with veneering.
Still Learning,

Allan Hill
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#14
(09-25-2017, 10:29 AM)AHill Wrote: White oak isn't a porous wood (red oak is), so I'm wondering if your veneer might be red oak.  I've not experienced this kind of issue with veneering.

Don't see too many red oak whiskey barrels
Big Grin

I wondered the same thing Allan. All depends how a person looks at Oak, White often isn't, and red sometimes is, and that throws a lot off. I can't tell the times I have seen people selling lumber mistake one for the other. Tough to check end grain on veneer though, so if the seller messed up........
Worst thing they can do is cook ya and eat ya

GW
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#15
Lightbulb 
Not sure about this?

Years ago most veneers were sliced 1/28" thick.  

With modern machinery they have been getting thinner and thinner.  Now so thin and gossamer like they have to have a paper backing.  

This (I guess) should help your glue penetration of the face veneer.

Are you using the common 4 x 8 sheets?

I think they are designed to be applied with sprayed or rolled-on contact cement, which doesn't penetrate.

My highest quality veneer jobs were using 8-foot long sequentially bookmatched veneers I got from some company in Europe.  Of course that required edge joining first and then gluing down with a bag press after spraying on UF glue.  

Unfortunately my photo portfolio is all analog so I cannot include digital examples here.

But then if you want to come down here, the door is always open and I shall be happy to show you, over an adult beverage or two!



Big Grin
A laid back southeast Florida beach bum and volunteer bikini assessor.


Wink
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#16
Yes. It is commercial white oak veneer (less than 1/32" thick) and, at this thickness, it is quite porous.
Yes. I did use plastic resin glue.

Quote:Sounds to me like you're using too much adhesive.

So far, this is the only reason I can come up with. I tried to minimize the amount glue by using a small detail paint roller with very short nap. However, my habit has always been to put glue on both surfaces when gluing anything in order to assure that both sides are wetted. So, that is what I did this time. I can only assume that this resulted in too much glue. Since my OP, I've read that you should not put glue on the back side of the veneer. But, I'm always concerned about not getting a good bond without doing so. I understand that it is possible to seal the back to partially correct the problem. I don't know the best process/material for this (spray shellac, spray lacquer, other?).

I've heard/read about paper backed veneer, but have never used it. I can see how that would correct the bleed through problem. But, doesn't that result in a weak bond? I know that contact cement is not generally recommended for veneering, but I wonder if for the thin white oak it would be good. I've used it to glue down plastic laminate counter tops and it works very well. Why not wood veneer?
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#17
Most common things now seem to be directed at cheap-shot solutions to solve
the deficiencies of relatively inferior products available.

(Ikea for instance is apparently now considered to be good and acceptable as quality furniture.)

Back to your situation = even if you get a perfect bond, then what about finishing?

Sure can't use anything penetrating to reveal and enhance the character of the wood I would think?

But then I am an old guy who has been spoiled for decades
with much better options.

You have the same of course but just have to look a little harder
searching among all the garbage and learning how to identify which
is what.
A laid back southeast Florida beach bum and volunteer bikini assessor.


Wink
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#18
(09-25-2017, 02:11 PM)Willyou Wrote: Yes. It is commercial white oak veneer (less than 1/32" thick) and, at this thickness, it is quite porous.
Yes. I did use plastic resin glue.


So far, this is the only reason I can come up with. I tried to minimize the amount glue by using a small detail paint roller with very short nap. However, my habit has always been to put glue on both surfaces when gluing anything in order to assure that both sides are wetted. So, that is what I did this time. I can only assume that this resulted in too much glue. Since my OP, I've read that you should not put glue on the back side of the veneer. But, I'm always concerned about not getting a good bond without doing so. I understand that it is possible to seal the back to partially correct the problem. I don't know the best process/material for this (spray shellac, spray lacquer, other?).

I've heard/read about paper backed veneer, but have never used it. I can see how that would correct the bleed through problem. But, doesn't that result in a weak bond? I know that contact cement is not generally recommended for veneering, but I wonder if for the thin white oak it would be good. I've used it to glue down plastic laminate counter tops and it works very well. Why not wood veneer?

Yes, your putting glue on both surfaces was almost certainly the problem.  I've never had a bonding problem using PRG as long as I follow the recommended coverage of 40 sq. ft/lb of resin.  I've done it so often that number is stuck in my head.  I use a foam roller and apply the glue to the substrate, never the veneer.  I've made test specimens so that I could test the bond and have never been able to peel off the veneer; it's always "one" with the substrate.  Not to sound like a jerk but the directions are pretty clear on the bucket of PRG on how to use it.  

John
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#19
Quote:I use a foam roller and apply the glue to the substrate, never the veneer.
I appreciate your experience and advice. I will nervously follow it the next time with my fingers crossed. I must resist my gut that tells me to put glue on both sides which has worked well for me with non-porous and thicker veneers.
Thanks
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#20
I use better bond cold press veneer glue, and  unibond, applied to the substrate only, even if the veneer is thick (even 1/8").  If I want to stain the piece and the veneer is porous then I use a backed veneer (like from Oakwood Veneer Company).  I get bleed through on lots of veneer but if the finish is natural it's not a problem if you match the glue's color to the venner.
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