Thread: Veneering with a Vacuum bag

I'm not sure about veneering on the compound curve, but I think it would be OK if not too 'compound'. As for the bag, I made one from vinyl from Bunnings, and sealed the edges with vacuum bag sealant tape. I think you'd need a stronger pump than a shop vac - they are high volume low vacuum, you want high vacuum low volume. I've heard of people using the motor & pump from an old fridge.

Originally Posted by graemet

I am about to venture where I've not gone before.
I want to veneer a harp soundboard with something like Silver Ash. The board face surface is flat, while the reverse has a (very gentle) compound curve, but enough that a flat caul would not work. Would the suction from a shopvac be sufficient to clamp the veneer with an appropriate caul on the face, or will I need a vacuum pump?
Second, is there an Australian supplier of suitable vacuum bags? - Google has definitely NOT been my friend in this instance.
Third request - is there a local supplier of fancy veneers who will sell less than $100 minimum?
Any input would be appreciated.

Hi Graeme

Usually a vacuum pump will be required, you need 18 to 21" of vac to press effectively with a bag.

In the Aus. Wood Review there are Aus. suppliers of veneer and vac equipment, (in the advertising).

As an alternative for a gentle curve sandbags might be worth a look, they conform to a shape, getting enough wieght might be trial and error.

If it's a compound curve will the veneer conform without crinkling, just thinking out loud!!!.



Pete

Hey graemet,

yes you will certainly need something stronger, but more importantly more consistent and reliable pressure than a shop vac. I have an appropriate set up with bag and pump that I would be happy to let you/show you how to use - I also have a supply of Silver Ash which may be appropriate for you - I believe we could cut a suitable veneer, or I have some pieces of ripple Sycamore that may also do the trick. I am in Northmead - so I thinks that's pretty close for you. Just PM me to work out a mutually convenient time.

cheers

pete

Originally Posted by graemet

I am about to venture where I've not gone before.
I want to veneer a harp soundboard with something like Silver Ash. The board face surface is flat, while the reverse has a (very gentle) compound curve, but enough that a flat caul would not work. Would the suction from a shopvac be sufficient to clamp the veneer with an appropriate caul on the face, or will I need a vacuum pump?
Second, is there an Australian supplier of suitable vacuum bags? - Google has definitely NOT been my friend in this instance.
Third request - is there a local supplier of fancy veneers who will sell less than $100 minimum?
Any input would be appreciated.

you need 18 to 21" of vac to press effectively with a bag.

Yep. The one I've used supplied about 70% vacuum ~ 21" Hg.

Another thing to consider is the duty cycle of the pump & motor. Some don't allow 100%. The one I've used did, which was good, because if you couldn't hear the pump going, you knew there was a problem.

Thanks Alex, Pete & Pete. All the information I can get helps to avoid disaster.

All the information I can get helps to avoid disaster.

Ya think?

Like Alex is aluding to, the fun is just beginning, simple things like haven't mixed up enough glue (if using a two part), getting the veneer where you want it, not where it wants to be after it's slipped, a flat surface can be tricky enough, a curved surface adds to the fun and then you have a compound curve which further, umm compounds the problems, just thinking about that I wonder if you might have to cut a curved strip of venneer just like wine barrel (staves?). Have fun!!!!



Pete