MDF cabinets ruined by tiny amounts of mositure (can you protect it?)

[Paulh Tremblay]

About 5 years ago I build a European-style cabinet from MDF. I like the way MDF takes paint and its smooth finish. But I now notice that almost every single shelf has been ruined because of small leaks from stuff (jars, cans, etc.) I have stored there.

I painted the cabinets with a primer and a high quality oil based paint. I used the same paint for a pantry I built from pine. Although we use the pine pantry more often, none of the spills ever ate through the paint to the wood. In contrast, all of the spills in the MDF ate through the paint, and of course, once MDF gets wet, it swells and becomes almost useless. I can't figure out why so many minor leaks corroded the paint on the MDF. When I saw that a can of soda had leaked and eaten away the paint, I thought "well, that's just the acidic nature of soda (such as coke)." But I now I just notice all four shelves suffered from the same type of damage. I believe that some of the damage resulted nothing more that pooled water.

Is there any way to better protect MDF in future projects? When I search on the web, I note that almost no one has had the same experience. Yes, serious exposure to water will ruin the MDF, but most people state that paint will protect it from normal exposure (and it will, so long as the paint remains intact). I wonder what high quality MDF cabinets use to protect the material. I know melamine is often used, but melamine looks awful, and I know some cabinets are actually painted.

[Wade Lippman]

I expect some penetrating epoxy would protect it from anything.

[Greg Hines, MD]

I read that if you paint the edges of an MDF panel with glue, and let it dry, it will make it take paint well and make it waterproof if you use Titebond III or some other glue like that.

Doc

[Todd Burch]

Hi Paulh.

I don't understand why the paint on the pantry shelves is outperforming the same paint on the MDF shelves. Were they painted differently or by a different person? Was different primer used?

There are different grades of MDF. Do you know what grade MDF you used, or, perhaps where you bought it might give a clue.

I have had MDF garage cabinets for 20 years, in a humid environment. I don't particularly care for MDF myself, but at the time, it was an good solution to my need for cabinets. They are still together, functioning just fine, so I have not replaced them.

I try not to use MDF for shelves because they are so prone to sagging, as compared, length to length, with pine.

How long have the MDF shelves lasted? (As an aside, now that they are ruined... did you save any money going with MDF shelves? ;) )

And, ... there's no such thing as a high quality MDF cabinet. There are expensive MDF cabinets, mind you.

Todd

[Steve Kohn]

Todd's note made me think of something......It's a shot in the dark but could the increased deflection of the MDF over the pine pantry shelves be cracking the paint coating and allowing moisture penetration into the MDF?

[glenn bradley]

This one will be interesting to figure out. Like Todd, I have MDF shop cabinets. They were shellacked and paste waxed and have taken all sorts of abuse. My workbench top is MDF with BLO and pastewax; it will show if it gets wet. I would expect a good primer and paint to do as well if not better than shellac. As far as cracking, I haven't run into a paint for the home that wasn't extremely flexible including enamels(?).

[Art Mann]

Recently, I have been looking at a lot of older houses for rental property. I noticed that every single kitchen that had cabinets made of MDF had exactly the kind of damage you describe at least to some degree. I don't mean to be too pessimistic, but I do not think that common grade of MDF is suitable for any kind of cabinets that will be wet. It doesn't matter what finish you apply. Eventually, water will get through and the MDF will swell and dissolve like cardboard.

[Paulh Tremblay]

I painted the the two types of cabinets the same way; that's what puzzles me. Deflection probably did not cause the paint to wear, since the paint was worn on the bottom shelf, dado-ed into the sides; plus, the damage occurred on the end, and you would expect deflection in the middle.

There are at least two ways to solve my problem: use plywood for the bottoms and shelves, or use shelf liners. I would like to stay away from making the whole carcass from plywood, since it will not give as dead flat a surface as MDF.

Most cabinet pros swear by MDF if you are going to paint them, or if you want a modern look. No other material is supposed to take paint so well or be so dead flat. As I type this, my coffee mug sits on a mid-century modern piece that is at least 20 years old and very well made. It has a veneer on top. My girlfriend couldn't believe it was MDF until I flipped it over. I say all of this to explain why, on the one hand I have an affinity for MDF, and on the other, and starting to rethink using it again after what i discovered tonight.

[johnny means]

And, ... there's no such thing as a high quality MDF cabinet. There are expensive MDF cabinets, mind you.

Todd

Why not?

Anyway, a good varnish or lacquer would protect your MDF from moisture. Although, I doubt that's really your issue. Pictures of the damage would be helpful. Are you using real oil based paint or some low voc oil based light?

[Paulh Tremblay]

I read that if you paint the edges of an MDF panel with glue, and let it dry, it will make it take paint well and make it waterproof if you use Titebond III or some other glue like that.

Doc

It's not really the edges that got the damage, but the faces. However, I have come across several threads on painting MDF that suggest doing just this. It is called glue sizing. You can either buy the substance, or make it by mixing glue and water. You are supposed to apply it to the surface, sand, and then paint. I guess if you could use a waterproof glue to seal the surface.

[Todd Burch]

Why not?

Because you can't put lipstick on a pig and call it a beauty queen.

MDF is sawdust and glue. It is not made to pass the test of time. It's a product for a disposable society. Its popularity exists because it's cheap, dead flat, dimensionally stable, and takes paint and glue well on it's surface (and not the edges, without a lot of other prep). It wasn't made for beauty, grain or longevity. Proper screws for its joinery (confirmat) are large and ugly.

But, perhaps I'm being too hard on it. Perhaps there are some "high quality" MDF cabinets out there. (High quality is not equal to good looking) Perhaps it depends on your definition of high quality too.

[Art Mann]

Some folks learn from their mistakes or the experience of people who have been doing it for a long time. Others don't.

[Rick Potter]

Just wondering if it was regular MDF or Light Weight MDF? Maybe someone more expert than me could tell us if it would make a difference. I know the light weight stuff sure dents on the edges easier.

Rick Potter

[Jay Jolliffe]

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[David Weaver]

If I was using MDF for cabinets, I'd use an impermeable drawer liner on all of the shelves.

Won't solve any issues with big spills, but it will eliminate issues from small ones, leaks, wet dishes, etc
..

[Bill A Hagen]

Sounds like its more particle board than MDF, but either the same thing will happen to. MDF is a little better as the grain size is smaller and there are less voids.

If you want to redo the shelves to hold up better, laminate them with formica. The paper face of most stock cabinets is crap and will absorb water once it's used a little while, once there are small scratches in it, it seems to act like a sponge.
I built my workbench with mdf and laminated each side with formica, and edged it with hardwood and its holding up well.

[Yonak Hawkins]

Jay, as far as you know, does this MDF come in Ultralight ?

[Jeff Duncan]

"Most cabinet pros swear by MDF if you are going to paint them, or if you want a modern look."

Who are these pro's? I would say the opposite, mdf is the last material you want to use for cabinet parts! For door panels and flat slabs it's great! But for parts not so much. I would put ply as the top performer as it holds fasteners well, resists moisture, has a lot of strength......and b/c it's light:) However it's expensive, which is why most pro's actually use melamine, (particle board), it's as flat as mdf, comes with a fairly good surface that wears well, accepts fasteners fairly well and is.....well, cheap! I can offer customers a wide variety of colors and woodgrains that I can simply cut, band, and send out without having to touch the spray gun. MDF is last on my list, it's does not play well with the majority of fasteners, it has to have some type of coating, veneer, or finish applied to it, and it's heavy as lead! OK maybe not quite, but it sure feels like it some days:o

However I think we need to back up a bit first.....before addressing the issue of materials, I think maybe the issue of why you have so many leaking containers in your cabinets needs to be looked at? If this is a common thing, (which by all the shelves being damaged it sounds like), I would think about resolving this issue first. If you can't keep your containers from leaking then I suggest a more durable material needs to be used as a liner. This also brings up another point that should be understood....paint does not prevent the transfer of moisture! General paint, and most wood finishes merely slow the transfer of moisture they don't fully prevent it. Of course there are exceptions, but for our purposes we need to understand that painting or finishing wood with most off-the-shelf coatings does not prevent moisture from penetrating. Your pine shelves don't "show" this transfer since the pine itself is not affected like the mdf is by moisture.

My last point is that most storage cabinets don't need to be dead flat. In a kitchen for instance you have a series of boxes attached to each other and usually have a panel for finished ends. So the box itself does not have to be perfectly flat. Even plywood which is the least flat of the 3 we're talking about is usually plenty flat enough for most cabinets. Now if your building Euro boxes you may prefer to have something a bit flatter to start with, (though I've done plenty of those with ply as well),.....which is why melamine is the most common material for Euro boxes. Of course if you just plain don't like melamine just b/c, and don't want to spend extra for ply, well then your stuck with either making the box out of solid or mdf. In which case I'd go mdf and either use liners, or consider the shelves disposable after several years;)

good luck,
JeffD

[Peter Froh]

Top coat with a hard clear finish (like Target coatings EM9000 super clear poly) and you should not have any problems.

[Peter Aeschliman]

I wouldnt use MDF in situations where moisture could come into contact with the piece.

For the same reason that heavily-finished solid wood pieces still expand and contract with humidity changes, moisture can pass through the finish to some extent.

For some things, MDF is great. But in my experience, it's not as good as the woodworking magazines say.

Cons:


Heavy as heck
Dust is super fine and toxic (you need impeccable dust collection)
Sags under weight (how many MDF sheets you get from the big box stores are actually "Dead flat"? they sag/bow big-time if they're poorly stacked)
worthless when it comes to moisture of any kind
edges need lots of extra prep for paint (to be fair, same goes for most plywood)
horrible at holding fasteners (have to take extra precautions because it blows out when screwes pass through- i.e., countersinking the "exit wound" side of the hole)
edges are prone to breaking and splitting (especially when fasteners are close to edges)


Benefits:

Faces take paint really nicely
Cuts smoothly with no tearout
Relatively inexpensive


I use it for door panels for painted pieces or veneers that have no reasonable chance of exposure to moisture. I also use it for sacrificial shop surfaces and cabinetry. My router table is MDF with no veneers- just lots of poly and wax. It has its place, but I rarely use it for nicer furniture anymore. I've learned too many hard lessons with the stuff...

[Paulh Tremblay]

272460

Here is a picture of the damage. You can see two spots. The one on the top shows the raised wood, as well as where the paint wore off.

[Paulh Tremblay]

I used this cabinet unit for food that would not fit in my pantry--canning salt, a six pack of sprite, canning jars. Those three items apparently did the damage. I agree that all parts of the cabinet do not have to be flat. As I stated before, you could use MDF for all but the bottoms of the units, giving a perfectly flat surface for all but the bottoms, which mostly are not visible.

The only metal in my cabinet are the Blum hinges and handles; both have seen to hold up fine.

Thanks for your input.

[Paulh Tremblay]

Most of the cons don't really matter to me, personally. I don't mind the weight, and I can handle the dust with dust collection *and* a respirator. (Not that I particularly like MDF dust!) I put my cabinets together with dadoes and or dowels, so I don't have a problem with metal fasteners. However, the inability to handle moisture is a major drawback for me.

[Paulh Tremblay]

"test of time ..It wasn't made for beauty, grain or longevity. Proper screws for its joinery (confirmat) are large and ugly." The coffee table on which my coffee table rests is at least 50 years old. I don't see any reason why it wouldn't last another 50. You don't need confirmat screws to join MDF; it joins very, very nice with just glue and dadoes, or, if you really want to make sure a join will never fail, dowels.

I understand MDF isn't for everyone, but it has its place in quality furniture.

[Paulh Tremblay]

Thanks! Will check that out.

[Art Mann]

"test of time ..It wasn't made for beauty, grain or longevity. Proper screws for its joinery (confirmat) are large and ugly." The coffee table on which my coffee table rests is at least 50 years old. I don't see any reason why it wouldn't last another 50. You don't need confirmat screws to join MDF; it joins very, very nice with just glue and dadoes, or, if you really want to make sure a join will never fail, dowels.

I understand MDF isn't for everyone, but it has its place in quality furniture.

I doubt very much that the material used in your coffee table is the same material that is sold in big box stores today labeled as MDF. I don't think the low grade material we know as MDF today even existed 50 years ago. There are many types of materials manufactured from compressed cellulose fibers and adhesives. Mdf is just one of them.

I doubt if many of the members of this board or fine furniture makers in general would agree that MDF has much of a place in quality furniture. As someone already said, it depends on your definition of quality.

On a different subject, the post with photos you posted mentioned that you stored bulk salt on the shelf. Salt is highly hygroscopic, meaning it attracts and retains moisture. I suspect that is at least onew reason for the moisture damage.

[Joe Hillmann]

Could the cabinet have been more humid than the pantry? Due to lack of ventilation or storing vegetables in there? That could have lead to quicker deterioration of the finish.

Is it on an outside wall and sees larger temperature changes than the pantry?

[Paulh Tremblay]

Woops. Missed this yesterday. I thought sawmillcreek had put an ad here!

The only problem with medex is that it is hard to get, so far as I can tell. A search on line didn't relieve any distributors except on the west coast.

[Paulh Tremblay]

Follow up:

I note that the paint on my bottoms has worn away in other places, but no water has caused damage. So it looks like some failure of the paint. Don't know why. Maybe I applied it too thin.

I have a lot of options to protect my bottoms in future projects:

1. Use plywood for the bottoms, and MDF for everything else (or just use MDF for the fronts).

2. Use melamine. Disadvantage: it is ugly? Or maybe you can buy some really attractive melamine and apply it yourself? Anyone have experience with this?

3. Apply a protective layer over the paint.

4. Use a water resistant MDF, such as medex. Disadvantage:hard to find?

I think almost any of the four would work pretty well. I am incline to (1), or maybe (3). Options (2) and (4) depend on my being able to get the material.

Thanks everyone for your feedback.

[Paulh Tremblay]

"I doubt very much that the material used in your coffee table is the same material that is sold in big box stores today labeled as MDF." Are you confusing MDF with particle board? The stuff in the big box stores doesn't strike me as any less of quality than what my coffee table is made of. If the table is veneered, as this is, why wouldn't it hold up?

[Paulh Tremblay]

As a matter of fact, yes. The MDF piece was in the hall outside of our living spaces, so subject to much greater variation in temperature. Also, maybe I just put the paint on too thin. Next time I'll know better.

[Jeff Duncan]

As far as melamine goes not sure why it's more "ugly" than white painted shelves? Of course that's a matter of opinion so there's no right answer.....just personal preference. I prefer melamine as it holds up better as shelving than a painted shelf in my experience. Paint gets ugly over time and gets to a point where it's just not as clean. Melamine lasts for many years with normal use and cleans easily. As far as different looks there are hundreds of melamine colors and woodgrains out there. Problem is most are special order and not practical to a small shop doing a couple cabinets:( So then you probably only really have access to several dozen colors/woodgrains to choose from. Something like a natural maple wood grain might be a good choice? Though again, it's going to come down to what you personally can live with for your cabinets and whether or not you like the look as compared to paint?

good luck,
Jeffd

[Paulh Tremblay]

As far as melamine goes not sure why it's more "ugly" than white painted shelves? Of course that's a matter of opinion so there's no right answer.....just personal preference. I prefer melamine as it holds up better as shelving than a painted shelf in my experience. Paint gets ugly over time and gets to a point where it's just not as clean. Melamine lasts for many years with normal use and cleans easily. As far as different looks there are hundreds of melamine colors and woodgrains out there. Problem is most are special order and not practical to a small shop doing a couple cabinets:( So then you probably only really have access to several dozen colors/woodgrains to choose from. Something like a natural maple wood grain might be a good choice? Though again, it's going to come down to what you personally can live with for your cabinets and whether or not you like the look as compared to paint?

good luck,
Jeffd

I wonder if melamine can look good? The cabinets that I associate with melamine are very bland and ugly, situated in a cafeteria.

But I am starting to reconsider, especially when I see most European style cabinets are done with melamine. I came across the same obstacle you mention, though: finding melamine sheets. Then at Lowe's I noticed that a search for laminate seemed to indicate that the box store sold laminate by the sheet. I assume laminate is the same as melamine. Do you know any other sources?

[Curt Harms]

Laminate IMO would be more durable than the other mentioned choices. However, if it's subject to water and is not sealed very well, the water will get between the laminate and substrate and swell the substrate. We just replaced countertops because of this happening around the sink. I made a jig for a planer to form clapboards. I figured to use melamine (from a borg) because it was slick. The melamine wore through in short order. I replaced the melamine jig with one faced with laminate strips. I found the laminate much more resistant to abrasion. Laminate is more work but as long as you keep the substrate dry or use water resistant substrate, it seems quite durable and yes the borgs sell it.

[Jeff Duncan]

I wonder if melamine can look good? The cabinets that I associate with melamine are very bland and ugly, situated in a cafeteria.

But I am starting to reconsider, especially when I see most European style cabinets are done with melamine. I came across the same obstacle you mention, though: finding melamine sheets. Then at Lowe's I noticed that a search for laminate seemed to indicate that the box store sold laminate by the sheet. I assume laminate is the same as melamine. Do you know any other sources?


No, laminate is very much different than melamine, and FWIW if your seeing them in a cafeteria those cabinets are likely laminate. Laminate is a thick paper based sheet that is very durable but a bit different to work with. Think of kitchen counters as they've been using laminate for those since at least the 50's. Laminate is usually bought in sheets and applied in the shop onto whatever substrate your using. If done properly it is very tough and water resistant.....again think vanity tops and kitchen counters! For shelves it would be a very good and long wearing surface. Downsides of using laminate is now you have to buy the sheet of laminate and the sheet of substrate to apply it to as well as the glue. So it's much more costly. You also have more labor involved as you have to cut the laminate and glue it.

Melamine on the other hand is a film applied to a sheet of particle board, so your just buying the sheets ready to go. It's fairly durable as well, just not nearly as durable as laminate. I've seen plenty of melamine kitchens 30 plus years old that while dated, are are still in good condition. As I mentioned before melamine comes in many, many, colors and wood grains though what's available to you will depend on your specific location. Trying to find anything other than white or black will require going to a wholesale sheet goods supplier, or finding a local shop willing to sell you a few sheets. Some reasons so many kitchens are made with it is that it provides a hard flat durable surface for maybe half of what plywood costs. Additionally it's thickness is consistent, it's easy to drill and machine, and there's no additional labor involved in finishing. The only real downside I can think of is most of the banding is PVC and needs to be put on a by a bander.....you cannot iron it on. Though some guys use Fastcap double sided tape to get around this.

If your interested I would try posting your location and seeing if any local guys can help you out finding some melamine. There are more than a few pro's that post here and if someone is close to you they may be willing to help you out. Alternatively you could call some local shops or even post a WTB on CL? Or if you want really tough shelves......you could try doing your own laminate shelves;)

good luck,
Jeffd

[Yonak Hawkins]

The only problem with medex is that it is hard to get, so far as I can tell. A search on line didn't relieve any distributors except on the west coast.

FYI : I called my supplier in Atlanta yesterday about the availability of Medex and he said they have been carrying it for awhile. ..So at least in the Atlanta area it's available.

Also, I asked him about Ultralight Medex and it doesn't come that way, unfortunately for me.

A question for users of Medex : Are the bundles protected on the sides ? My supplier has gone to a source that doesn't protect the sides of the MDF I currently get and it often comes with dings and dents on the corners and edges.

[Larry Edgerton]

Don't use MDF.

Larry

[J.R. Rutter]

Primer? OP never mentioned if he used any or what he used. On some surfaces, you can get away without but MDF isn't one of them.

[Jim Matthews]

But, perhaps I'm being too hard on it.

No, I don't think so.
Anybody that's done repairs on hideously expensive loudspeaker cabinets has said more or less the same.

A highball glass full of ice, on a damp napkin can forever ruin a seriously expensive cabinet - with no easy repair possible.

This stuff was invented to handle intricate machine cut patterns, not daily use in a wet environment.

[Brent Ring]

Just an observation - a couple of years ago Norm Abrams did a rebuild of a kitchen where he wanted a paint type finish, - In most places. 3/4" Prefinished Maple plywood for carcasses and shelving, and Poplar for face frames, and poplar/MDF for the doors and Drawers. I like the prefinished maple in the cabinets for sure. Just a thought. If you want the painting all the way through, then your other options are available.

[Brian Jarnell]

Worth considering in future.http://www.melteca.co.nz/product-tool.php