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Iron-on PVA Veneering

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andrewm

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I have just had my first stab at veneering. Ash veneer on a MDF substrate. I have seen mention here on several occasions of using PVA glue and a hot iron, most recently here so this was the method I used.

I put two coats of dilute PVA on both the veneer and the MDF (which was sanded first) and then the following evening applied the veneer to the MDF with a hot iron, pressing down with a cloth as it cooled. All seems to have gone well and the veneer is nice and flat which surprised me as it had been stored rolled up for some time (years, see previous thread about bleaching).

However I notice that it is inclined to start lifting at the slightest provocation although responds to a further attack with the iron. It seems better now that I have trimmed the edges but I am concerned about how long it will last. Is this to be expected or am I doing something wrong?

Andrew
 

MikeW

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Hi Andrew,

Don't know how to help at this point. If the edge banding or veneering is begining to lift now or down the road, it is going to.

fwiw, I don't thin the glue 50%. I have found it doesn't have a good enough bond, but others have, so it is probably the anount of heat I use or something else I do differently.

The banding should be applied with a day or two at most after the glue has been applied, else my understanding it is not softened by the heat enough. Which it seems you did, so that's not the problem. It could be too much heat which softened the glue too much and as such the veneer wanted to loose contact before it redried? Maybe that was my problem.

A thicker mix seemed to cure my problem. I would say that if it continues to want to left off, I would try to iron it back on, being careful not to scorch the veneer. Which is also what you have done.

So, does the piece you reiron seem to hold better?

Mike
 

Chris Knight

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Andrew,
Basically, wot Mike said - try a thicker glue mix and/or somewhat hotter iron. I don't know what PVA glue you are using but the trick is to get it thin enough that it can be painted on the veneer easily but not thinner. The sanding of the MDF is done with a coarse (80grit or so) to get rid of any glazing, not to make it smooth or shiny.

You can always paint on another coat without problems. I have had no trouble ironing on my veneers treated this way even with a delay of a couple of weeks, as long as I used white PVA like Evostick. With Titebond Type I, I find you need a hotter iron and not leave it so long. If you are using Type II Titebond you need an even hotter iron and don't leave it more than a day before ironing - never used Type III and would not reckon to do so for this application.

My gut feel is that you need more glue. I also recommend a roller in addition to the iron - follow the iron with eg a wallpaper roller.
 

andrewm

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Using a steam iron at maximum heat and maximum steam. Is that right?

Thinking I might just pull off what I have and try again with a bit more and thicker PVA. My concern at the moment is that all will go well with what I have but that it will start lifting after it is all finished. That would not be a good outcome so I would rather get it right at the outset.

Thanks for you help. At least I now know that I am doing it right.

Andrew
 

Chris Knight

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NO NO NO!

No steam!!!! - No wonder it ain't sticking :roll:

not max heat - but hot enough. Try a wool setting, then cotton if need be. Heat is a trade off with speed and potential burning - comes easily with a bit of trial and error.
 

andrewm

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Ahhh. I've not had problems with burning but its the no steam bit that I have missed. I was imagining that a bit of steam to dampen the veneer and make it a bit more plyable would. I'll try it dry then.

Thanks,

Andrew
 

Chris Knight

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Andrew one of the great benefits of this method is precisely that you don't work with damp veneer, so it doesn't shrink much after applying it as moisture evaporates - as would be the case with glues containing water. It thus doesn't split nor does it try to warp the substrate like veneers applied with a wet glue can.
 

andrewm

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waterhead37":148qt04k said:
Andrew one of the great benefits of this method is precisely that you don't work with damp veneer, so it doesn't shrink much after applying it as moisture evaporates - as would be the case with glues containing water. It thus doesn't split nor does it try to warp the substrate like veneers applied with a wet glue can.
You know Chris, it is all so obvious when someone explains it. :)

Andrew
 

Adam

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DaveL":2mpouqwm said:
Thanks for this thread, I learned a lot from it. :D
Ditto

andrewm":2mpouqwm said:
You know Chris, it is all so obvious when someone explains it. :) Andrew
Indeed, but I hadn't thought it through before either - I'd never thought about shrinking before, I merrily lash on the PVA and spray down the outside with oodles of water. :oops:

Adam
 

Chris Knight

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Guys,
I am glad this thread is proving of interest. All I know about this method of veneering is in this book plus what I learnt from doing it. I cannot recommend the book highly enough. The author is exceptionally practical with zero bullshit and he shows how to veneer the most difficult things - bombe chests for example!

It is one of my two favourite woodworking books.

http://www.amazon.co.uk/exec/obidos/ASI ... 50-6306033
 

Chris Knight

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Good Grief!!

I hadn't noticed the price!!!!!

You can borrow mine with personal collection and return 'cos if it's that rare, I ain't trusting it to the post!
 

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