Attaching a Thick Base to a Box - Help!!

[RobM]

My latest crisis...

Continuing with this box frame, I've unfortunately progressed so far without fully appreciating how I will attach the base to the box. Let me explain...

The base of what is to be contained within this box consists of two sheets of MDF, a sheet of perspex, and two sheets of mount board (I won't go into full details as to why, but it's essentially part of an art project for a client).

The combined parts of the base come to about 25mm thick, which I will attach together with screws. This base will therefore protrude out of the box by about 20mm. Please see Pic 1 (which also shows how I plan to make and attach a spacer frame around this protrusion).

The plan would have been to simply use the yellow gun to attach Multipoints, which would go through one of the sheets of MDF - as per Pic 2.

The concern with this is two-fold:
1. The way the MDF lines up, the multipoint would be less central, and you might see that from Pic 3, this is causing a split in the wood.
2. Because I'm putting a spacer/frame surround around the protrusion, it would have to sit on top of these multipoints and wouldn't look too great.

And so I was wondering if there was any mileage in attaching the base to the box solely by applying glue within the rebate, as Pic 4.

Or perhaps glue and Multipoints is the way to go.

What do you all think?

[RobM]

Regarding centralising the multipoint within the middle of the MDF, I imagine this could of course be done, and would just push the base back from the rebate by a couple of mm, rather than sit comfortably within it.

[vintage frames]

I would just glue it all into the rebate, as you were thinking, and then glue the spacers to the sdes.
Use masking tape to hold everything whilst the glue dries overnight.

If you wnat things to be not so permanent, only use a few inch long beads of glue all around.
It should then crack open if ever need to.