MFT table warped.

[Peter Hamilton-Scott]

Chaps, because of the lack of space in the house and not having a garage I have no choice but to keep my MFT table in the small shed outside. Unfortunately, like all small sheds it suffers from extremes of temperature and humidity. I need to use the MFT to do some cutting but I noticed that the MDF has warped and has bowed outwards from the table frame. I've brought the whole thing back into the house in the hope that if I let it dry out naturally it might settle back to its original flat surface.

Do you think I'm being too optimistic? My experience with other bits of MDF suggests that once it gets warped it tends to stay that way. Right now, it looks like I might have to buy another slab of the MDF from the local Festool dealer.

Any advice, as usual, will be much appreciated.

 

[DKurzweil]

If it's not too warped, and you have access (or a friend with) a large format planer you could send it through.  It will be thinner, but you won't pay the ridiculous price for a new top.

Daniel

 

[PA floor guy]

Peter,
  I do not have an MFT.  YET...    But my experience with MDF is that it's a great product to work with.  But not stable whatsoever with moisture..   It will swell something awful. Maybe you can wet it a little and put some good weight on it.  Or kerf cut it and pull it back down with a fastener of some type. Again, I have never seen an MFT so I dont know what fastening options there are..  I wish you luck though.      Sam

 

[semenza]

Is it proud on the top or depressed?  How much is it warped?  How about a picture?

Seth

 

[Peter Hamilton-Scott]

Is it proud on the top or depressed?  How much is it warped?  How about a picture?

Seth

Seth,

If my photos make it through you'll see the warped MDF. On one side, it has bowed so much you can see straight through between the MDF and frame.

Edit: In reply to your original question, it's bowing proud off the top. I was wondering if I removed the MDF insert from the frame it it would improve the chance of it "righting" itself? It looks like a replacement insert would be about £80 UK.

 

[Alan m]

i would take the top off the mft. then get 2 good qualtity pallets (the smaller ones ) and put one on the ground adn the mft top on top  of that then put the second palltet upsidedown on the mft. then put as much weight onto the pallet (evenly)  as posible.
i would maybe leave it there for a few days and see how its going.

 

[Peter Hamilton-Scott]

If it's not too warped, and you have access (or a friend with) a large format planer you could send it through.  It will be thinner, but you won't pay the ridiculous price for a new top.

Daniel

Daniel, I don't have access to or a friend with a planer who could shave it back to a reasonable profile. Another option is to source a piece of MDF and get a shop to drill the holes for me but I reckon that'll cost more than a new slab from Festool directly?

 

[ajones]

Peter you are right if you take the top out of the table and weight as required in a dry enviroment there is every chance it will flatten out enough to use.

you could also use a new plane piece of mdf if you did not need the holes or you could use the old top as a template to produce a new top with holes using a bearing guided cutter

good luck

 

[peter halle]

Can't you turn it over and see if that flattens it?  My MFT is 20 miles away so I can't see if I just made a stupid suggestion.

Peter

 

[tiralie]

Did your tops get wet only in the middle somehow?

Hmmm, until recently I have stored mine outside through 4 seasons and they have never warped at all.
They are under an eve and covered with a BBQ cover and have never warped like what you are showing.
While the edges have gotten wet and have swollen a bit they have not distorted as much as yours.
I think it would be worth it to take them off the frame and sticker them and lay them flat in a dry place for a week of so and see if they dry out flat.
Tim

 

[PeterK]

If none of those ideas work, I would just add some cross pieces of ruler straight hardwood and screw into the bottom of the MDF top. Yes you will loose a few holes for clamp usage but just mark the top to remind yourself of what holes are not available. My experience with MDF has shown me that reflattening MDF is near impossible without permanent braces installed.

 

[panelchat]

maybe keep the eventual replacement top inside and just install it when you use it? if the mdf hasn't expanded like a sponge from water and is only bent, applying that beam underneath might work well. i wonder if there's a Trespa or Richlite top available anywhere? that might solve the moisture exposure issue.

 

[monte]

Typically, when you seal wooden or mdf shelves one always does the same to both sides to prevent warpage.
What if you would seal only the concave side?
Over some time it could possibly correct itself.
As any moisture within would only have one way to go.

It could work,
or not.
It may be worth a try, try at least a couple of coats.

 

[Peter Hamilton-Scott]

I've removed the MDF insert and at the moment it's lying on the floor in the lounge, which isn't exactly to Mrs. Wife's liking, but she understands. I've layed it down "bum up" if you'll forgive the analogy (first recorded use of Festool Porn?) and I've placed a 3/4" piece of scrap at each end. I put a very heavy storage box on the "bum" and it's depressed it downwards quite nicely. [laughing] My thinking is that if the insert is ruined I've nothing to lose. Even if the weight bends it the other way I think the bolt on each corner that secures it to the table might possibly correct it by pulling it flat. It's worth a go if nothing else.

When it got damp it wasn't the result of direct water contact, rather the high ambient humidity caused it to warp. I have an old towel in the shed and that's really wet so it's understandable the MDF took it badly as well. I might have been okay if I had some ventilation in the shed but there isn't. Just as soon as I can, I'll cut some holes in the panels and use fine wire mesh to keep the pesky spiders out. It's a tiny shed, 6' x 8' and there's a bit of mould growing in the roof apex so temperature and humidity is well and truly shafted. I might have to keep the table in there but remove the MDF insert and keep it inside somewhere, which again, won't please Mrs. Wife.

Project ongoing. I will report back in a day or two and let y'all know what the MDF looks like.

 

[tiralie]

Just as soon as I can, I'll cut some holes in the panels and use fine wire mesh to keep the pesky spiders out.

That would be good, other wise you might have to rebuild that shed in a couple years as it just might fall down from rot  [big grin].
Tim

 

[Harvey]

Here's a thread on moisture sealing the tops:

Sealing MFT top

 

[Roseland]

+1 for Peter Halle's suggestion - just turn it over and let the bolts pull it flat against the extrusions.

Andrew

 

[MrToolJunkie]

I had a desktop warp before I had a chance to install it.  I clamped cauls across it's width and pulled it flat.  Left it that way for some time and it worked.  When flat I quickly finished and installed it.  3 years later and it is still flat.  If the floor does not work you might try that.

Scot

 

[semenza]

+1 for Peter Halle's suggestion - just turn it over and let the bolts pull it flat against the extrusions.

Andrew

Ditto

Seth

 

[Peter Hamilton-Scott]

Reasonably good news. After a day and a bit of heavy weight sitting on it the MDF insert has flattened out quite well. It's not 100% but it's certainly much better. The only problem is that it's slightly too long to fit comfortably in the frame as the MDF obviously expanded with all the moisture it absorbed. I'll take my TS55 to it and trim off 1cm to get it to fit again. I've cut ventilation holes in the shed and that has made a big difference to (a) the dampness, and (b) the smell.