Moisture Prevention on MFT Table?

paulkane1

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Joined
Jun 24, 2014
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17
I'm considering buying a MFT Table,the problem I have still at the moment,is some condensation in my workshop,although,I'm taking measures to cut it out,The MDF could be vulnerable to movement,in such a environment,is,there anyway I can treat the table with some product on the market,that will counter the moisture in the air?something I can paint on? All advise would be appreciated,I live in Belfast,Ireland,so it would have to be a product I can get here.
 
Hi Paulkane1, what I use on my mft is Minwax oil based polyurethane. I just brushed it on and the MDF just absorbed the polyurethane like a sponge. I applied several coats and very happy with the results. Hope that helps.
 
Hi Paul

Like Geoff above, I have used Osmo on a number of MDF tops that I have made and it is excellent. Remember to do the underside as well. Not only does it help with moisture but it makes it very easy to wipe excess glue off and PVA usually comes off after it has gone hard.

Peter
 
Peter,
Do you also apply the osmo to the interior of the dog holes? Is there any particular reason you prefer osmo over lacquer or shellac? Also, how many coats of the osmo do you apply? I would suspect it would be best to remove the MDF from the MFT and thoroughly apply the osmo, right? Many thanks for all your great advice and very informative videos! Happy New Year!
Thank you!
 
With mdf being so absorbent how uniform is the coats, blotchy or ?

Was thinking of trying some min wax water based poly since polyx appears a bit harder to get.
 
Yes, I took the top out of the frame to do the edges, which seem to be the most vulnerable bit - like end grain on solid wood.  I also tried to do the dog holes for the same reason.

PolyX is not too bad, I think I used a rag to apply it.  I was surprised by the consistency, having only used oil before, but it is fairly workable and you can get an even coating.
 
I started applying Osmo to my MDF tops at the end of an oiling session just to get rid of the excess oil on a brush or pad. I then had a tiny bit left over at the bottom of a small can and used that to complete the top and underneath. I have only ever deliberately applied one coat of Osmo but, again, at the end of an oiling session I still get rid of the excess on a bench top.

I have always avoided allowing any oil go into the 20 mm holes although some will go in no matter how hard you try. Now I am able to make really accurate custom tops I try to remember to oil the MDF before I cut the 20 mm holes.

Peter
 
I've had all 3 mines in a uninsulated garage for the passed 3.5 years with no issues what so ever. I didn't use anything to protect the tops
 
Peter,
I'm curious to why you purposely avoided the dog holes. As Geoff pointed out, I would think that they are vulnerable to moisture and swelling. But as jobsworth reported, many people never have any issues with untreated MFTs. What to do, what to do?  I found and just ordered Osmo on Amazon for $45 for 25 oz, so expensive, but not ridiculous.
 
Rhino1789 said:
Peter,
I'm curious to why you purposely avoided the dog holes. As Geoff pointed out, I would think that they are vulnerable to moisture and swelling. But as jobsworth reported, many people never have any issues with untreated MFTs. What to do, what to do?  I found and just ordered Osmo on Amazon for $45 for 25 oz, so expensive, but not ridiculous.

It is not an issue with an MFT3 as the dog holes are often just a dash over 20 mm. With the 20 mm cutter that I use to make holes for my Parf Dogs there is very little wiggle room. My worry with the oil (or any other finish) is that a "blob" of it might make a hole a little tight. So, no need to worry, just go ahead and you will be fine.

Peter
 
In the states a persueder is slang for a hammer,

Happy New Year to you to buddy
 
I live in Houston, Texas on Galveston Bay.  It is hot and humid in the summer and in the winter we get marine fog often and it's the kind of fog that makes you think of Adrienne Barbeau.  Genuine Fog Monster fog, complete with marine fog horns and a few years ago a collision between a chemical tanker and a container ship.

My untreated MFT top is in an unconditioned garage and it is unaffected by humidity.

The moisture in Belfast, Ireland is coming from the Gulf Stream that goes by my house before it get's to yours.

I guess it is possible that the warm water condenses on cold equipment in your shop more than mine, but it does get cold here and I still haven't had a problem with an untreated MFT top.  I think it is made from a better grade of MDF specifically made to resist atmospheric moisture.
 
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