vaneering over core
Varneering can be trickey over a core.
Points to remember: 1; the core has to be as smooth as a , pardon the expression, babys ***. Otherwise any imperfections may telegraph through. Close your eyes and run your fingers over it, if you feel a surface discrepency correct it. fill or sand
2; depending on the type of varneer used, its usually suseptable to cracking when curvers are not gentle enough. In otherwords the larger and gentler the curve the better. Now that said you will also have to weigh this change in box shape with the possible ramifications related to the sound waves propagation.
3; the use of contact adhesive would be advisable, as you will have no way to press the varneer on to avoid bubbles when applying to a predetermined shape(unless you are privy to a vacuum press). Leave lots of overage to trim off later, as small bits of varneer are quite hard to align. A large piece allows for slippage or line of site misqueues and this happens with contact cement(unintentially). Varneer that you do not want to see the edge of should be applied first(trimmed flush) so that your major pieces covers the edge.
When applying the varneer hold it up above the box select an edge try to get the registration as close as possible to your requirements, gently lower work methodically(remember varneer has no strength over holes!) from the edge and propagate out, finish one face then continue arround, smoothing as you go(you are looking for a smooth transition to avoid air bubbles) with something that will not mar the surface or catch the grain of the wood. eg. dense white packing foam blocks ......anything you use to hold the varneer up has to be dust and partical free....... any dirt under, bubbles the finish even a spec.
4; keep a bottle of contact adhessive thinner nearby just in case(to release the adhessive; you may have to soak the joint to open it up) and a long sharp knife to cut the bond....... work slowly so that you can see your progress is not going to be a waste of time later....
In case you are not aware....applying varneer in any situation is seriously challenging........and if you slip, even once, can be a discouraging proposition(start from scratch, clean the box off(all off) allow to dry reapply adhesive etc)......done correctly its beautiful.
Caution; if you dont want to get high better to do it in wide open spaces with lots of ventilation..........
OH by the way dont smoke while doing this, not only are the vapours flamable but the combination of high heat of the ciggy and the vapours sucked through creates one of the most deadly mixes of carcinagins you could be exposed to ..deadly..
Hope I have given you a little insight into the application of varneers.
Do a little investigation check out the libruary, the internet, see whats involved....the more aware of the total job etc the less likely you will be to encounter an unexpected SUPPRISE in the middle of the process ..which is not what you want...