Bent panel

[Doug71]

I'm doing a wall panelling job and one of the panels is a push to open secret door to hide some electric boxes. There isn't much depth so I used 12mm MR MDF for the panel with a Tulipwood bead pinned around the edge to match the other panels, it was hung on a full length piano hinge. I know it's not really ideal mixing real wood and MDF like this but I have done it before successfully and I had both the Tulipwood and the MDF acclimatising in the room for a few days before I started and they were both perfectly straight before I made the door.

The door/panel

Just 1 day after fitting it the top and bottom had bent inwards by about 15mm, the hanging side was held straight by the hinge but it also bent the same as soon as I took the screws out.

I was surprised how much and how quickly it moved, it has also cupped slightly across its width, the wall behind the panelling is internal and vented to the rest of the room. Kind of reminds me of heating bi-metal strips over Bunsen burners back in my school days.

Having a redesign with some battens on the inside to hopefully balance things up, won't be risking making any more doors like this

 

[Sachakins]

Could have the tulip wood, being face mounted, caused the panel to bow?
Maybe try with the tulip wood being edge lipped onto outside all round.

 

[Doug71]

Could have the tulip wood, being face mounted, caused the panel to bow?
Maybe try with the tulip wood being edge lipped onto outside all round.

Yes I'm sure the Tulip being on the face caused the problem, I should know better......

My first plan is to kerf the MDF and use some tulip wood battens on the back to hopefully straighten things up. If that doesn't work it will be a total remake in the style of a proper door with the MDF in a groove so yeah kind of lipped all round.

 

[Cabinetman]

Shame Doug, but that did move a lot! The Tulip must have expanded along its length, yes I know it does but that’s still a lot, there was another post recently where it appeared to be the moisture from the glue that was the culprit, just wondering if it’s worth waiting a couple of days before trying to flatten it?
Ian

 

[porker]

I had similar happen on a thin door. I think it is the moisture from the glue that causes this. Because the glue is only on one side of the MDF it expands slightly on this side. I clamped a straight edge along mine (I have a long piece of aluminium extrusion I use) while the glue dried and it was OK.