another mft question

[martin.pearson]

When I move into my new workshop I will probably want to build a couple of worktops & at least one of them will be with the MFT style hole pattern. The one I am currently using I made from Baltic birch ply & would probably have just done the same with these if it were not for the price of birch ply just now.
I know people use MDF for these tops so if I decide to do that do I need to do anything to seal the MDF as the workshop is not a temperature controlled environment? Maybe I am over thinking this but I wasn't sure if the MDF would absorb moisture from the air & my nice 20mm holes would suddenly be to small if it weren't sealed in some way.

 

[PerryGunn]

Use MRMDF as it's moisture resistant - as far as sealing goes, I sealed mine with a few coats of sanding sealer, others have used wax or Zinsser BIN ( or 1-2-3) or varnish so I'd say, if you want to add a coat of sealer, use whatever you have available, it doesn't have to look pretty

 

[Alli]

I've had the mft3 for donkey years, it has lived out in a shed that is unheated and gets damp in winter. I've not had any problems with the holes changing shape, the 20mm dogs I have got always seem to fit snuggly.

 

[Distinterior]

I have a Festool MFT that's still got it's original top (6 years old now...)...It has expanded to the point where it is a REALLY tight fit within the alloy frame but its accuracy hasn't been affected as far as I can tell. Every now & then, I just use up any oil or sanding sealer that I have left over from a project and apply it to the top of the MDF.
Admittedly, the diameter of the holes in it have always seemed a bit bigger than I would have liked and they are certainly larger than the holes that I had CNC machined Into my 2440 x 1220 MRMDF MFT cutting table.....Its never had any sealer applied to it and its holes are still nice and snug with any dogs that i use.

Put it this way,....If I fitted any of my dogs or "20"mm fittings in the Festool top, turned it upside down, they would all fall out.
If I did the same with the larger top, none of the dogs would fall out.....They need to be firmly pushed in and very firmly pulled out.

 

[martin.pearson]

Use MRMDF as it's moisture resistant - as far as sealing goes, I sealed mine with a few coats of sanding sealer, others have used wax or Zinsser BIN ( or 1-2-3) or varnish so I'd say, if you want to add a coat of sealer, use whatever you have available, it doesn't have to look pretty

Haha, use what ever I have.....
Fairly new to woodworking but I knew finishing was a very big part of any project so I have bought a huge range of different sanding sealers, oils, waxes polishes & anything else I could think of to experiment with, got a large percentage of Chestnut Products wood finishes lol

 

[Bojam]

I built mine out of good quality 18mm marine grade ply. I live in the tropics and work outside on a covered driveway where the bench lives permanently. After 2+ years there is no noticeable change to the holes or the surface. Not a cheap option as you say but definitely durable even in very moist humid conditions.

Edit: BTW, I didn't apply any finish to the top. Hasn't needed it.

 

[Sideways]

I bought a CNC'd top in MDF and waxed it. Bad idea, it made the holes too tight.
MRMDF is the way to go.
If you want to wax, do that first then drill your own holes.
I have a sheet of 6mm mrmdf as a top sheet if I want to do glue ups or not have stuff fall through the holes. Sealed this with thinned, wiping, varnish. I'm pleased that that stayed flat although I didn't seal the opposite face to balance out any tension.

 

[Ollie78]

The official festool one is actually HDF like valchromat but that won't be cheaper than birch ply anyway. MR MDF is definitely better than the regular stuff.
Trouble is, if you seal it once you have cut the holes it shrinks the holes up. If you seal it before cutting the holes this might be better. To be honest I don't bother as it will just get battered anyway on my mft as I use it for everything and it gets abused.

Ollie

 

[martin.pearson]

The official festool one is actually HDF like valchromat but that won't be cheaper than birch ply anyway. MR MDF is definitely better than the regular stuff.
Trouble is, if you seal it once you have cut the holes it shrinks the holes up. If you seal it before cutting the holes this might be better. To be honest I don't bother as it will just get battered anyway on my mft as I use it for everything and it gets abused.

Ollie

When I made the birch ply top I sealed it with Chestnut Spirit based shellac sanding sealer after the holes were cut & then once it was fully dry ran an expandable reamer through the holes until the dogs were a nice snug fit, seems to have worked OK.
Funny because I built it when I got a track saw & really only expected it to be used with that, I put it on top of a centipede pop up frame as I thought it would spend most of the time packed away in the corner. That never happened as once I had built it I found lots of other things that I could use it for so pretty much the same as you it gets used for everything lol