Does MDF Move?

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Hiya Folks, I built a little table a while back for our laundry room using Maple and MDF. I basically used the Maple for the legs, stretchers, rails, and drawers. I used the MDF for the top. I then put plastic laminate on the MDF given it's utilitarian purpose and the fact that I got a great price on some close-out stock. This was my first time laminating with plastic laminate. 9 months later, the laminate appears to be buckling at the back edge. I should also say I ran maple edging around the table to enclose the laminate (ie. flush with the laminate). I'm now thinking I need to trim the laminate and re-glue it but that's for another day. My biggest question at the moment is why did it lift/buckle? I thought MDF stayed constant in it's size? Cheers, cc
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I'm no expert on these matters but I'll take a stab at it... Is there any chance something spilled between the lam and the maple? I don't think MDF is conducive to warping etc. but it's very sensitive to moisture and will swell.
-Brian
: Hiya Folks, : I built a little table a while back for our laundry room using Maple and : MDF. I basically used the Maple for the legs, : stretchers, rails, and drawers. I used the MDF for the top. I then put : plastic laminate on the MDF given it's utilitarian : purpose and the fact that I got a great price on some close-out stock. : This was my first time laminating with plastic : laminate. 9 months later, the laminate appears to be buckling at the back : edge. I should also say I ran maple edging around the : table to enclose the laminate (ie. flush with the laminate). I'm now : thinking I need to trim the laminate and re-glue it but that's : for another day. My biggest question at the moment is why did it : lift/buckle? I thought MDF stayed constant in it's size? : Cheers, : cc : :
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I thought of that as well but no, the table has not seen any spills nor did it during construction. Being the first time putting laminate down, I'm a bit leery that it was something I didn't do correct but can't figure out what. Cheers, cc

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James, Two or three key points . . . 1) You said 'laundry room'. Toward the end of your comments you said, " . . . lift/buckle . . " This seems to point to a POSSIBLE cause. MDF is basically paper dust & glue. Heavy, relatively hard, stable {NO 'GRAIN'} . . . as long as it is DRY. Depending on the humidity of your 'laundry room', or if some wet items were placed on the table, there is the possibility that water/moisture was trapped between the wood edging and the MDF. Over time it saturated and the MDF deteriorated. Maybe only the top surface, which lost integrity and separated along with the laminate.
2} Another possibility - the same type of 'error' that happens with a 'cheap' artwork framing job. MDF is stable, but 'tensions' caused by the different expansion/contraction rate of the laminate are tremendous. If you put the laminate ONLY on the TOP - the very slight movement of the MDF {again, due to moisture absorption from the atmosphere - via the bottom side} will be greater than the strength of the adhesive. WHATEVER you do to the TOP you have to do to the BOTTOM. There is even a type of 'blank' laminate specifically for this. In the case of artwork attached to 'Foamcore' board . . . if a large photo, or paper print is attached to the front . . . an equal size piece of paper must be attached to the back. If not the board will actually BOW and pop out of the frame. This will simply be due to the difference in humidity between the summer and winter.
Regards & Good Luck, Ron Magen Backyard Boatshop
----- Original Message -----
Subject: Does MDF Move?

SNIP
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On Mon, 27 Dec 2004 10:31:29 -0700, "James \"Cubby\" Culbertson"

What do you think might happen if you poured water onto the edge of your MDF? If not sure, take a small piece and give it a try. Let the water sit a while.
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The table has not seen spills. There's the possibility of additional humidity being in the laundry room but no spills.

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Did you laminate the bottom of the MDF? When you lay up ply or any surface for laminating you need to do top. Bottom and the edges or the piece absorbs moisture from the exposed areas. max

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Well I have workled a lot with MDF, both for desks, etc and for models. As MDF is recostituted pulp, basically it acts differently to 'real' wood. Moistures, even in the atnostphere does affect it. Even when painting the MDF toys I have made they absorb the paint unless i have sealed the wood. I dont NOTICE any difference, but the moisture HAS to go somewhere and swelling would seem logical.
In your case i would look to trying ot get a dehumidifier into teh room wheile you investigate, while the laundry isnt being done, and then removing the venir, seal the entire unit in special MDF sealing varnish, paying special attention ot any worked edges/bevels. At least 2 coats and then reapply your venir finish.
On Mon, 27 Dec 2004 10:31:29 -0700, "James \"Cubby\" Culbertson"

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Seems we may have found the problem. I only laminated the top of the MDF. Didn't realize I needed to do the bottom and sides as well. Thanks for the help! Cheers, cc

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About five years ago, I made a frame for an air mattress(high end, not camping type). The entire frame and six large drawers are made from MDF covered with plastic laminate. Only one side is laminated and looks as good now as it did when new.

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It is NOT necessary to laminate both sides, in fact, even suggesting that in this case is just crazy. If you think about all the manufactured laminate kitchen countertops in this country, NONE are laminated on both sides. More than likely, the bond between the laminate and the MDF failed. Did you put two coats of contact cement on the MDF? One coat is just not enough to provide good adhesion as the first coat is mostly absorbed by the substrate. However, one good coat on the laminate is usually sufficient. Also, make sure the contact cement is not wet when you adhere the laminate, it should be slightly tacky, but not wet, or it won't stick. Once joined, roll the hell out of the thing with a good j roller starting from the middle and working out. --dave

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Hiya Dave, Yeah I got to thinking more about it and realized, I've never seen laminated tables with laminate on the underside. Your comments about the glue was where I was headed next. I put down one real thick coat on the MDF and no cement on the laminate. Didn't realize I needed to. I'll bet that's what's going on there. Now, how to remove and replace it. I may have to scrap the maple edging and just peel it off as best I can and re-glue another piece on there. Is there anything I need to do to the MDF before re-cementing? Thanks for the help! Cheers, cc

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On Mon, 27 Dec 2004 23:31:00 -0700, "James \"Cubby\" Culbertson"

James, try this link for a general 'primer' (pardon the pun), noting the first eight words <g>
http://www.woodcentral.com/bparticles/contact1.shtml
I use thin dowels - 3 mm diameter - as spacers, and pull them out one at a time, this lets me position it perfectly.
Greg
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James "Cubby" Culbertson wrote:

I have removed a lot of laminates over the years and have found the following to be the best. If you want to use the existing laminate again. Carefully pry up a corner with a flat knife (I use a Putty Knife) Fill a plastic sauce bottle with thinner and squirt a bit into the gap. As the laminate lifts slowly insert the knife and cut away any adhesive. Squirt more thinners in the now bigger gap and keep on going. Once the laminate has been removed wash the glued side down with thinners and leave it a couple of days to dry. Using a belt sander or a random orbital with atleast 80g paper give the mdf a good sanding. You do not have to remove all of the contact but it should be SMOOTH. Also give the underside of the laminate a sanding until it to is smooth. Apply contact evenly to both the laminate and the mdf and leave until it wont stick to the back of you hand when you touch it. Now for the tricky part, Aligning the two pieces. Get yourself some 3/8" dowels or thin pieces of timber wider than the top. Lay them across the top about 6 - 8" apart. Lay your laminate on top of these rods. A line one corner and edge, and press gently together. Remove the rod closes to this join and press the two faces together. Carry on up the length removing each rod as you come to it. All things being equal, the laminate and mdf should now be in position. Use a roller if you have one to press the two surfaces together If not, a block of timber wrapped in a rag, place on top of the laminate and belt the hell out of it, moving it slowly around until the whole surface has had a good hiding. Pay particular attention to the edges. Before you replace the timber edges it always a good idea to coat the edges of the top with a layer of contact. This helps to water proof the edges. hope you can make some sense out of this :) Good luck John
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John, <snip> A big drum of lacquer thinners is the best ticket I've always used solvent based CC and cleaned up with laquer thinner, but he mentioned using water based CC on this project. I'm thinking the laquer thinner may not work very well on the water based CC, simply because chemistry teaches that likes dissolve likes. Any experience removing water based CC with laquer thinner? Just curious if it works as well as on solvent based. --dave

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Dave Jackson wrote:

Dave, that'll teach me to read things properly. I missed the bit about water based contact. (I've never heard of it) And after all the effort I put into that masterful essay on laminating :(. To be quite honest I don't know if it would dissolve with thinners or not. Would be worth a go though as Water based acrylics can be washed of with thinners. John

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Well, removing the laminate may prove to be futile at this point. I would suggest flipping the top over and laminate the backside (just for the sake of reusing what you already have made.) if possible. If not, hopefully you have enough laminate and MDF laying around to construct a new top. --dave

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Dave, quality countertops are laminated on both sides. You may notice on the underside of these tops the dark choclate color. If you look hard you will see this is a very thin lamination of backing paper. Comes in large rolls, glued with contact cement same as laminate that shows. That being said, any good sealer will work,shellac, varnish etc.A counter top that is only laminated on one side has a great chance of looking like a banana in a few days.I once installed a L shaped top like this. I got it flat with clamps and braces from upper cabinets.Screwed well from bottom, looked good when I was done. Went back next week to remove and trash tops. The tops pulled the corner blocking out of the base cabinets.Got a new supplier that day. mike
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James \Cubby\ Culbertson Wrote:

Hi James,
MDF is pretty darn stable due to the fact that it is composed o sawdust (no grain) and that the glue that binds it together is more o less resistant to moisture (but not waterproof).
The problem with the laminate lifting near an edge probably had more t do with your laminating technique. I'm going to guess that either yo did not get a sufficient coat of adhesive on either the laminate or th substrate, or you had a wet patch of adhesive (too much adhesive in on spot/too thick of a coat in a spot) and the contact adhesive didn' work properly.
You might be able to fix the problem with some Gorilla glue carefull squeezed into the void and some clamps.
Are you using solvent-based contact adhesive or a water-based adhesive I personally prefer the water-based product as it is easier to clean u and doesn't leave you with a raging headache.
Good luck
-- makesawdust
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Yeah, Just replied to Dave up above. Looks like my gluing of the laminate was the culprit. I used the water based contact cement but didn't realize I had to put a coat on the laminate as well. Thanks much for the help! Cheers, cc

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