The Framers Forum

Hello all,
I'm looking for some advice... I have an old painted (acrylic I think) canvas which was previously stuck down to a very curvy piece of 3mm hardboard. I've managed to get it off without it tearing but now I need to stick it to a new board to get it flat. The paint is very dry and cracky so I don't think it would handle stretching over battens. What do people think is a good adhesive to use? And what sort of board... Is plywood a good idea? How thick?

The canvas is 105x85cm and I'll need to frame in an L-shaped tray frame afterwards.

Any advice much appreciated!

cover the board with watered down PVA and put weight on top and leave over night

What Steve said.... A good tip is to use a foam blanket (and release paper) to equalise the pressure if the painting is 'lumpy'.
This helps to ensure there are not sections that don't bond firmly.

I would avoid plywood. It can delaminate and also has a tendency to twist and bend. MDF if preferable as long as
you seal the back with PVA or varnish. Don't go too thick. To allow fixing in a floater frame, glue battens to the back
to stabilise the board and to allow enough depth to screw into.

That's quite a reasonable size and might be appropriate for sticky down onto a cradled plywood panel to give the job an appropriate level of longevity. I am asumming that the age of this canvas issuggesting that it may be intended to be preserve with the long term in view. I am not always regarding MDF as something that has a great deal of long term durability.

Cheap hong kong oils often are stuck down on MDF, but maybe you should discuss this with the customer, before proceeding.

An alternative to a rigid wood (solid or plywood) backing is "aluminum composite material" (ACM) with brand names such as ALUCOBOND, DIBOND, ALUCORE, KAPA, FOREX.

The material is 2 thin layers of aluminum with a foam core. The material is used conservation, sign making, motor home, bus and trailer manufacturing.

Watch out for distortions in the canvas caused by pulling it off the original board. There may be areas that will not lay flat or will crease if forced flat.

I use a veneeer vacuum bag for this sort of job.

Thanks everyone for you replies - all really helpful and has given me lots to think about and research.

Preservation/longevity is definitely desirable as it has sentimental value although the customer is not too precious and seems happy for me to do what I see fit. Eek. I am nervous of using MDF as in the past people have told me its not the best material to use - didn't realise about the ply delaminating but will look into the cradled panel - I know Harris Moore make these so that could be a good place to start.

Does anyone have an alternative adhesive suggestion to PVA? Again people have told me its not great from a conservation perspective but I'm more that happy to be corrected.

As GeoSpectrum suggests a little bit of distortion has occurred from removing it from the other board. A more alarming problem is that the paint is cracking off in some areas. Its very dry and is coming away from the canvas and where I've manipulated it to remove it this has exacerbated the issue and the surface is now extremely fragile. I wish I had had the foresight to turn the job down!

Thanks for all your wisdom!

Plywood is not all the same. Some is better than other. I varnished a oil on ply for a lady recently and there was a huge
bump in the middle where the top layer had separated. This was not noticeable until the shiny varnish went on.
It also bent to the extent that it wouldn't sit in the frame properly. Just saying......

MDF will deteriorate rapidly if it gets damp. But so will plywood. That's why it needs to be sealed.

** If the work is as fragile as you say, a restorer would line the canvas (stick it to the new piece) and it can then be
mounted on stretcher bars. Once mounted the flakey paint could be stabilised and any missing sections be retouched.
Not a cheap procedure, but better than trying to bodge it. Might be worth enquiring along this route before doing anything.

if you are going to stick it to ply or mdf, it is a good idea to stick a piece of canvas (ideally the same weight) to the reverse of the board. This is called a balancer and will counteract any bending of the board due to sticking two pieces of together and absorbing moisture at different rates. this is quite often done in carpentry when veneering or using laminates.

I can help with cradled panels or Baltic birch panels if you need something. I sell loads to artists.