Veneering methods

[Bob Barkto]

Ironing raw veneer can be a challenge.
My best results with troublesome veneer came this way...

Coat the veneer lightly, one light coat of glue. I use a short-nap trim roller.
Do Not Thin the glue! This only adds extra water that must be removed before glue-up.

Put two regular coats of glue on the substrate (mdf).

Let the veneer and substrate dry thoroughly, ~24 hours seems to work in a rather dry, warm room.

Sometimes light pre-heating of the veneer with the iron will help. Just hover the iron a few mm over the surface of the veneer a few seconds before you apply pressure.

Work from one edge to the other in small overlapping passes, about 1/4 the width or less of the iron.

Use the lowest heat setting that will adequately bond. Testing on scrap is the way here.


I've never had good results with filling cracks with PVA glue and sawdust. It's difficult to sand and always is darker than the wood. And it can leave the surrounding area impermeable to other finishes that are later applied.

I've used that method with thin CA glue, very carefully applied, to fill tiny hairline cracks. Results were mixed.

You can widen cracks with a veneer saw or the back edge of a sharp hobby knife to fit an edgewise piece of matching veneer glued in. In most cases the repair is nearly invisible.
Highly figured woods (burls, quilted's, etc.) are more difficult to repair. A normal wood filler close to the finished color and some artists brushes and oil or acrylic colors or pigments will probably be required for the best results.

Hope this helps.

Originally posted by KennyBradley
I made a start with my veneering last night.
...

I started with one of the sides of the cabinet which is the biggest panel (400x1000mm). Bond seems very strong but the 0.6mm raw veneer has shrunk onder the heat of the iron and one or two cracks have appeared (about 0.5mm wide and 100mm long).

Is there any way to avoid this on the other panels?

What can I do about the cracks? I've had one suggestion of filling the crack with PVA and then sanding over it and the dust will stick to the PVA????

Cheers Kenny

[KennyBradley]

Thanks Bob and suzy,

I had a go at the other side last night. This time I applied an extra coat of PVA to the substrate and only coated the outside edge of the veneer (about a 1" strip). Before applying the glue to the veneer I Ironed it and I also Ironed the centre of the veneer imediatley before applying it to the substrate.

Results where much better this time.

I had another look at my first attempt. The crack is't as bad as I thought and I'd rather not remove it if I can avoid it. The veneer is Black American Walnut and the coulor varies quite a lot in vertical strips which should make it easier to fill since colour match is less critical. I'll experiment with a thin strip of veneer. .

Thanks again. Kenny

[fgroen]

Hi Kenny,

Did you humidify (slightly dampen with plant spray) and press the veneer between two sheets of MDF for 24 hours prior to glueing?

I found that by doing so the veneer becomes very flexible, hence reducing risk of cracks considerably.

Best is to put a 10-20kg weight on top of the MDF-veneer sandwich while pressing (e.g. a bucket of water) to increase pressure a bit. Not too much weight, otherwise the veneer might crack.

Regards, Fokke.

[kec]

Originally posted by 69stingray
Great thread everyone. There is a lot of good information here.

Bear-

Can you apply a water-based poly over a Danish Finsih? Will the Danish still yellow and the poly stay clear? I am thinking of Minwax's Polycrylic.

Make some samples and try it. I've never tried water based over oil.


-Ken

[KennyBradley]

Speakers are finally finished. Thanks to every one for your help and advice. They're not perfect but I'm fairly happy with them.

Although the iron on PVA method was simple I found it did have it's problems. I had to ensure the raw veneer was as dry as possible before starting because shrinkage was causing cracks to open up. Thankfully this was only on the first panel and It is now filled with filler wax and is almost indistinguishable.

I also found a lot of pressure had to be applied to the iron to ensure a bond. I worked a small area at a time and went over it with a veneer hammer while still hot. I have just noticed one small area (about the size of a thumb nail) which has not bonded. Not sure what I'm going to do with it now. I fear the iron will damage the oil finish?

Here Is a photo, unfortunately it doesn't really do the beauty of the grain justice but you get an idea.

Thanks again for your help, Kenny

[AMV8]

Hi Kenny

Your speakers look great. It is spurring me on to finish mine which are working but not finished off as yet.

If it helps you my father was a cabinet maker and I used to help him a lot with furniture making. The usual method for removing bubbles was to cut the bubble along the grain, then squeeze glue under each half and then leave wuth a weight on untill the glue had dried. Any cracks were filled with wax - which I think you are doing - as you can adjust the colour of the wax easily to suit the grain of the wood.

Hope you enjoy the speakers and that they sound as good as they look.

Don