Mountboard as a Spacer

[RobM]

I'm doing a small job where the client has asked just for the glazing to be replaced (wanting anti-UV glass) in a frame for a watercolour painting.

Just with regards to leaving a space between the glass and the artwork, there simply isn't enough room to install a conventional spacer, so I'm looking to insert strips of mount board, as shown on these pictures.

My question is, for those of you who have used this method, would you ordinarily glue these strips to the glass? I'm just concerned especially with the top horizontal one dropping down over time if it isn't. Are there are any other considerations I should take into account for this method?

Thanks

[Justintime]

First of all I've remove the old eyelets and clean up the back with a blade scraper and possibly a quick sand. Then I'd cut some 20-30mm barewood spacer and glue and pin the mitred pieces to the back of the frame in order to increase the frame depth by the required amount. This way you're not compromising what's inside the frame. There'll now be room for some proper spacers. Incidentally the way to hold the top spacer in place is to cut and position the top and bottom spacers first and then cut the side pieces to hold the top and bottom ones in place. He common method to hold spacers in place is to put dots of self adhesive tape along the spacer and apply dabs of Eva/PVA. The self adhesive tape dots will hold then in place whilst the glue dries.

[Justintime]

Your mountboard spacers are unlikely to offer the required protection to the work. If the work warps or cockles at all then it's likely to touch the glass. I would always recommend a minimum 5mm for spacers.

[JKX]

With that amount of support and depth it’s highly likely the artwork will touch the glass, so I agree, extend the rebate, or sell up to a deeper rebated frame.
I’d always try and turn partial reframes in to complete ones!

The spacer method Justin describes, I call the Stonehenge method, it’s my favourite but requires very accurate cutting.

Many prefer the pinwheel method, which doesn’t, play is left (shown in red) to allow you to butt spacers together easily. As long as it depends on wet adhesive and not DS tape, it’s fine, and probably better on deeper spacers when the ends also have to be a perfect 90 degrees on the Stonehenge method.