sihollies":rzkfsfyp said:
Hi I am using PVA, as usual, but on this attempt the veneer hasn't adhered to the substrate and has left a rippled effect on about a 2 square inch area.
Simon
You can use an iron to stick veneer to a ground. I've used the technique many times over the years, primarily to attach veneer edging to various panels. In those cases, I usually cut strips of veneer, ~25 mm wide to attach to an 18 mm thick panel veneered in the same material. I apply the PVA or aliphatic resin to the panel edge, position the veneer edging, and run over this with a warm iron.
There's another related technique some people use for laying veneer on the wide ground where they apply PVA/ aliphatic resin to the ground, let it dry, position the veneer on top of the dried adhesive and apply heat using an iron to stick the veneer in place. I've only ever experimented using this methodology with odds and ends of veneer offcuts just to see how well it works. To be honest, it's not a technique for which I've developed much confidence, and I've always had other methods available that I do trust, e.g., hammer veneering, bag press, vacuum bag veneering, mechanical presses, and so on. However, I'm aware that quite a few people report good success using the heated iron technique on dried glue method so I won't and can't say it's a poor method, primarily because I haven't experimented enough with it to form a good opinion.
So, as profchris has said, you have nothing to lose by trying, and I can report I've successfully rescued veneering jobs with similar problems using the warm/hot iron technique. But it might be worthwhile adding a wrinkle and try to find out the cause of the bubbling veneer. It could, for example:
*1. too little glue
*2. a contaminant, e.g., oil or wax for example on either the ground or the veneer, or both
*3. lack or no pressure on that spot
*4. particularly strongly wrinkled veneer that perhaps ought to have been softened and flattened before attaching it to the ground
If it's 1 or 3 above, you might even be better to make a slit with the grain, or lift up edges of your marquetry and feed some extra glue in before you apply heat in an attempt to fix the problem. If it's 2 or 4 you're much less likely to have success, and you'd need to address those problems, which would probably be fairly difficult in an already glued down pattern, meaning you might have to take more drastic repair measures. Slainte.