Sandwiching 2 12mm Mdf panels

[Wilson joinery]

Hi, I need to create a decorative frame round some cabinets I’ve just built and because I’ve got a couple of sheets of 12mm mrmdf left over I was planning on glueing up and clamping to create a 24mm deep sheet. I’m just wondering if anyone has tried this (I’m guessing yes, lots of times!) and whether the join is visible when sanded (240 grit?) and painted? I’m potentially going to be adding a chamfer so I could try and get this to end at the join which might make the join even less visible.

Thanks
Pete

 

[eribaMotters]

Hi, I need to create a decorative frame round some cabinets I’ve just built and because I’ve got a couple of sheets of 12mm mrmdf left over I was planning on glueing up and clamping to create a 24mm deep sheet. I’m just wondering if anyone has tried this (I’m guessing yes, lots of times!) and whether the join is visible when sanded (240 grit?) and painted? I’m potentially going to be adding a chamfer so I could try and get this to end at the join which might make the join even less visible.

Thanks
Pete

There is no reason why you cannot double up the mdf, as long as you have sufficient [deep throat] clamps that they clamp up well. Finish absorption on the edge of mdf is always a pain as it's like blotting paper. I've found that at best of times edges can take 4 or 5 coats of mdf primer undercoat where the flat/face surfaces are happy with 2 or 3 coats.
If you could get the chamfer to line up with the joint you would definitely be OK.

Colin

 

[baldkev]

It also depends on the mrmdf. Is it caberwood trade or pro? Medite ?

Pro and medite are better to machine and finish due to higher resin than in the cheaper trade sheets, which are fluffy when cut

 

[Spectric]

What size frame are you looking at? Maybe rather than sandwich two whole sheets it might be easier to just sandwich two of the required frames, be easier to clamp.

 

[petermillard]

I made some ‘faker shaker’ MRMDF doors a while back to ‘show’ why I prefer making them with loose tenons. I edgebanded one on two edges, and left the others bare, and after painting the only way I could tell which was which was because I knew the edgebanding was on the hinge side. As others have mentioned, aslong as you’re using decent MRMDF you’ll be fine, and if it’s a square edge, just edgebanded it to be sure.

 

[Wilson joinery]

Thanks all. As spectric suggested I did end up just glueing narrow widths of the Mdf together and it worked a treat. Especially as the frame was then secured to batons in the wall with 64mm nails .

 

[Spectric]

I think MDF joinery is a unique branch of woodworking that can be very different from using other materials and even require a different range of tools. The most obvious difference is the amount of dust, it really is a filthy material to work with and a respirator is essential. I don't use a lot of MDF, for me it's main use is worktops with 20mm holes, jigs and templates but even joining it has it's downside. I use a lot of dowels with no problems but in MDF you have to clamp the MDF when inserting a dowel otherwise the MDF just opens up, this is probably the glue and something I had not thought about with domino's and the sloppy setting when drilling, it not only allows alignment but also an escape path for the glue. Then of course finishing, it soaks up primer like a sponge and I think getting the right finish on it is also an art.