any advice on applying veneers? (Off Topic)
by fu_man 
, Wednesday, July 18, 2007, 03:45 (6126 days ago)
I’m about to try to apply a paper backed veneer to my speakers. They include a curved (in one direction) wall.
The supplier of the veneer recommended using a good quality (3M) contact adhesive, noting that if something goes wrong it can be heated and removed.
But because of the tricky curving I am worried that I can not place it accurately first go, so am worried about using a contact adhesive. I was thinking maybe a good PVA glue? Tight clamping will be difficult too.
Has anyone got any advice from your experience with such things. I have been building these for almost a year now and the thought of stuffing it up on the home straight has got me **** nervous….
Thanks
any advice on applying veneers?
by Bert , Wednesday, July 18, 2007, 09:24 (6126 days ago) @ fu_man
Hi fu_man,
The supplier of the veneer recommended using a good quality (3M)
contact adhesive, noting that if something goes wrong it can be
heated and removed.
Exciting! 
But because of the tricky curving I am worried that I can not
place it accurately first go, so am worried about using a contact
adhesive.
Cut the veneer enough wider than you need (5cm on each side or so) and use several lath (without adhesive...) to keep the veneer away from the wood so that you can align the veneer with applied glue before it makes contact with the wood. While pressing the veneer to the wood you can remove the lath one by one and press the veneer further and further alnog the way.
I do not know if these words make the tip clear to you, if I would have a picture then I would have shown that.
It has to be done rigth in one go though...but when done then it is in place and you can cut and sand away the edges. Using PVA glue only works if you can clamp 100% of the surface as the veneer gets "wet" by it and starts bubbling.
Bert
--
BD-Design - Only the Best!
any advice on applying veneers?
by MikeH , Wednesday, July 18, 2007, 12:13 (6126 days ago) @ Bert
Stick on the least visible part first, then work your way around to the most visible part last. the paper shows on edges of the paper backed veneer.
PVA will be a nightmare. don't do it.
Buy very, very good contact adhesive, many cheap ones will be falling apart in a few years.
Let the contact adhesive get a lot dryer than you think it needs to be. follow directions precisely.
once the adhesive is ready place some dowels on the box about every 20cm, depending on how stiff your veneer is.
Get an assistant to help you place the veneer on the dowels in the right place.
once the position is correct lift that end slightly and remove the dowel, stick it down, an unplugged, cold clothing iron with a cloth tied over it helps you press evenly, "Iron" it on from the edge pressing firmly. working your way along SLOWLY, do not go in big circles and trap bubbles.
once the edge looks like it has started off well get your assistant to lift the far end of the veneer, just enough for you to remove the next dowel ONLY. work your way along slowly with them still holding the end up so you dont trap any bubbles. they can place it back down for a rest when you get near the next dowel.
You want to be gently pulling the veneer down onto the wood with the iron, if you put it down by its own weight you may get bubbles.
work in arcs from the centre out, so the centre is advancing first.
look for bubbles once you finish the first side, stick a thin sewing needle through any bubbles and "iron" towards the needle to squeeze the air out. then remove the needle.
let the first side cure, trim the veneer close with scissors then sand the edge flush with fine paper on a solid wooden block.
But don't take my word for it, do some research to see if you are comfortable first, I suggest buying extra veneer and practice on something else first.
any advice on applying veneers?
by fu_man , Wednesday, July 18, 2007, 12:41 (6126 days ago) @ MikeH
Mike... thanks for the wonderful reply.
I'll do more research and play around a bit...
any advice on applying veneers?
by fu_man , Wednesday, July 18, 2007, 12:39 (6126 days ago) @ Bert
Thanks Bert,
Not quite sure about the word "lath"? Maybe equivalent to dowel as Mike describes?
Man, if i sent a picture you would know how much trouble I am in! Maybe I will see if I can find a friendly cabinet maker... otherwise i better find out how many friends I have got... and get them all around to lend a helping hand.
any advice on applying veneers?
by Bert , Wednesday, July 18, 2007, 12:57 (6126 days ago) @ fu_man
not quite sure about the word "lath"? Maybe equivalent to dowel as
Mike describes?
Yes, or anything else to keep the glued veneer from the wood so that it does not stick when you do not want to! 
Man, if i sent a picture you would know how much trouble I am in! Maybe
I will see if I can find a friendly cabinet maker... otherwise i better
find out how many friends I have got... and get them all around to lend a
helping hand.
With the help of the dowels you do not need friends.... unless it is a big surface you want to veneer, then some extra hands might come in handy...
I do the Swing system the same way with a 2,5m long strip of veneer to glue in one go... :scared1:
You'll manage, just play with a piece of extra veneer and wood first to see how all feels. :wink:
Bert
--
BD-Design - Only the Best!
any advice on applying veneers?
by MikeH , Saturday, July 28, 2007, 13:05 (6116 days ago) @ Bert
Search the internet for "Vacuum Bagging".
14.7 pounds per square inch clamping pressure in all directions.
You will need to blank off any driver holes, wrap it in cloth to cover any sharp edges, stick it in a "Space bag" from the supermarket used to compress winter clothing for storage.
Be careful, a domestic vacuum cleaner does not mix well with flammable glue fumes. Kaboom! It also does not generate a lot of suction but it might be enough. A low performance low mileage Petrol motor car engine generates quite a lot of vacuum at idle. About 1/2 to 1/3 of normal atmospheric pressure and it is tolerant of flammable gases.
any advice on applying veneers?
by Bert , Saturday, July 28, 2007, 13:20 (6116 days ago) @ MikeH
Hi Mike,
Nice idea! But what if....knowing speakers having sharp, hard and square edges.... :nah:
Bert
--
BD-Design - Only the Best!
any advice on applying veneers?
by PeterSt. 
, Netherlands, Sunday, July 29, 2007, 08:37 (6115 days ago) @ MikeH
Better do not mount the drivers ... 
Bert, I have such bags here. They are from very thick transparent "plastic" (could be 2mm or so), and it really can stand the "sharp" things you pointed out.
You just can connect a vacuum cleaner to that, which obviously has to be set in reverse mode (most can, I think).
I'm not sure what comes from it in the end, because the pressure won't be equal in all places, just because the bag's material will be folded in many places, and then contains twice or triple the thickness with more pressure. Shouldn't be a problem really, as long as the pressure isn't sideways.
I'd say it is dangerous to apply because it is out of your control how the pressure is devided. Instead of spreading pressure (which you would do by hand) it might just burst the veneer BECAUSE the pressure is equally devided (the bump can't go anywhere). Otoh, assuming you started off properly, it should be able to take it, and the pressure is gentle and sufficient enough to have the decent contact for the glue (etc.).
Oh well ...
Peter
any advice on applying veneers?
by MikeH , Sunday, July 29, 2007, 13:34 (6115 days ago) @ PeterSt.
For more information have a look here:
http://www.tapeease.com/vacuum_bags.htm
Peter: The bubbles _should_ get pressed out the edges of the veneer by the atmosphere pressure.
A vacuum cleaner likes to have airflow to keep the motor cool. If you use one you will need a non return valve and switch it off after the air is out of the bag.
If you are using a proper vacuum pump many cabinets can not resist the pressure and will be crushed by the atmosphere. A good vacuum pump at sea level can easily apply five hundred kilograms per square foot!
any advice on applying veneers?
by Bert , Monday, July 30, 2007, 08:23 (6114 days ago) @ MikeH
Hi Mike,
If you are using a proper vacuum pump many cabinets can not resist the
pressure and will be crushed by the atmosphere. A good vacuum pump at sea
level can easily apply five hundred kilograms per square foot!
That would be "fun"! Still, it is a good idea for certain applications but thinking about it a bit more...it won't work for me.
Having cut the veneer larger than needed (sticking out to create clean edges after) won't look nice after as that extra veneer will break and pressed into another side where you do not want the extra veneer to be...
I'll do it the old fashion way...works well too if you work around the possible problems and prevent them to occur.
Bert
--
BD-Design - Only the Best!