Laminating MDF

[JayStPeter]

I'm redoing my large MFT type worktable.  In the past, I've had problems with MDF deforming if I laminate just one side.  On my router table, I laminated both sides and had no problems. 

On this one, I don't want the additional thickness of two layers of laminate, so I'm thinking of putting polyurethane on the bottom side to seal it and hopefully prevent potato chip.  I'll also have several supports that should attempt to keep it straight also.  But, I'm looking for a very flat surface that'll stay that way.  Thoughts?

 

[galwaydude18@gmail.com]

You need to laminate both sides. If you only do one it will not stay flat

 

[Rob-GB]

galwaydude is correct both sides need to be laminated but normal practice is to use a good laminate for the face side and a cheaper balancer laminate on the other (most commonly a dull white and thinner one).

Rob.

 

[galwaydude18@gmail.com]

Ya Rob that is what I usually do unless the design calls for the same laminate to be seen on both sides.

 

[JayStPeter]

What do you ask for to get this thin laminate?  Using regular Formica on the top since it's easily available.

The cubicle I sit at has pretty nice flat, probably MDF or particle board, surface.  The bottom looks like brown paper bag with a clear finish.  Seems like a laminate of sorts, but clearly not the same material.  Like I said, more like an impregnated paper.

I think 3/4" MDF with laminate on both sides starts to get too thick for use with the Festool clamps.

 

[greg mann]

If you laminate both sides I would thinkg 5/8 material would be a place to start. The laminate will make the structure much stiffer than 3/4 mdf without laminate and your finished thickness would be pretty close to 3/4.

 

[JayStPeter]

If you laminate both sides I would thinkg 5/8 material would be a place to start. The laminate will make the structure much stiffer than 3/4 mdf without laminate and your finished thickness would be pretty close to 3/4.

While that solution sounds OK, I'd prefer a solution using commonly available materials.  Odd stuff like that requires a several hour drive, during the week, when I should be at work.  One of the few downsides to living a little off the beaten path.

 

[cje]

Regarding the Festool clamps & thick worktop: I've read somewhere about routing the holes at the bottom side of the worktop with a chamfer bit.

 

[Rob-GB]

What do you ask for to get this thin laminate?  Using regular Formica on the top since it's easily available.

The cubicle I sit at has pretty nice flat, probably MDF or particle board, surface.  The bottom looks like brown paper bag with a clear finish.  Seems like a laminate of sorts, but clearly not the same material.  Like I said, more like an impregnated paper.

I think 3/4" MDF with laminate on both sides starts to get too thick for use with the Festool clamps.

In the UK it is called a balance sheet or balancer and is bout 0.25mm thick if I remember right. Your supplier should understand what you want.
The "paper bag" stuff is a balance sheet used where it does not have to be good looking, much loved by big manufacturers  [wink]

Rob.

 

[RonMiller]

This material really IS just impregnated brown paper bag type stuff smashed together under tremendous pressure. Some of it has a thin printed paper over top which is the pretty design, but if not, then you get the plain look. But as long as the coating is there to make it laminate, it'll work. Just not look pretty.

 

[tiralie]

Formica sells several different grades of backing sheets including a  "Thick Phenolic Grade" for balancing panels.

Here is the list from their online brochure.

Grade 72 Cabinet Liner Grade (CLS, Nominal
Thickness .020" (0.5mm)) Non-decorative surface;
light-duty interior use cabinet liner for balancing and
moisture control of laminate panels. Available only for
Cabinet Liners.

Grade 87 Fire-Rated Backing Sheet Grade: (BLF,
Nominal Thickness .028" (0.7mm)) Non-decorative
surface; light-duty interior use, fire-rated backing
sheet for balancing and moisture control of laminate
panels. Available only for selected Fire-Rated
Laminate Backing Sheet items.

Grade 89 Fire-Rated Backing Sheet Grade: (BGF,
Nominal Thickness .048" (1.2mm)) Non-decorative
surface; general purpose interior use fire-rated
backing sheet for balancing and moisture control
of laminate panels. Available only for selected FireRated Laminate Backing Sheet items.

Grade 91 Backing Sheet Grade: (BKL, Nominal
Thickness .020" (0.5mm)) Non-decorative surface;
light-duty interior use backing sheet for balancing and
moisture control of laminate panels. Available only for
selected Backing Sheet items.

Grade 92 Backing Sheet Grade: (BKH, Nominal
Thickness .048" (1.2mm)) Non-decorative surface;
general purpose interior use backing sheet for
balancing and moisture control of laminate panels.
Available only for selected Backing Sheet items.

Grade C2 Backing Sheet Grade: (BKH, Nominal
Thickness .030" (0.8mm) Non-decorative surface;
general purpose interior use backing sheet for
balancing and moisture control of laminate panels.
Available only for selected Backing Sheet items.

Thick Phenolic Grade: Two-sided, decorative panel
suitable for interior horizontal or vertical surfaces.
Available only with black core.
S2: (CSL, Nominal Thickness .125" (3.175mm)
P7: (CSL, Nominal Thickness .250" (6.350mm)
S8: (CSL, Nominal Thickness .375" (9.525mm)
S6: (CSL, Nominal Thickness .500" (12.7mm)
P8: (CSL, Nominal Thickness .625" (15.875mm)
S7: (CSL, Nominal Thickness .750" (19.05mm)
R3: (CSL, Nominal Thickness 1.00" (25.4mm)

 

[Rob-GB]

There you go another item for the "separated by a common language " thread.....
Balancer = Backing sheet.  ;D ;D

Rob.

 

[JayStPeter]

Appreciate that.  Googling balancer, balancer sheet, etc. wasn't the right terminology for sure.

Do you apply the thinner backer/balancer sheet the same way as the decorative side.  Contact cement and a roller?  I imagine handling of that stuff at 0.5mm is tricky without cracking it.

I am considering different options for how to build this thing, so I am going to do some small mockups with scrap and see how it works out.  Maybe with a decent chamfer on the back the clamps will work.  Will report back once I figure it out. 

Materials just for the top are expensive.  2-sheets formica @ $45 each + 1 sheet MDF @ $35 = $125 (including tax).  Still trying to get some quotes for CNC also, but local shops aren't making that easy.  Sheesh. 

 

[Tim Morris]

Jay the backer sheet will install and trim the same as your decorative laminate. It isn't as fragile as one would think considering it's a fraction of the the thickness. It should also be much cheaper than the decorative sheet. As far as the CNC try a local plastic shop, the one I use is a fraction of what cabinet shops want to do small custom runs. Hope that helps.

 

[tjbnwi]

I call it balance sheet. Treat it the same as the finish sheet.

Tom

 

[JayStPeter]

Jay the backer sheet will install and trim the same as your decorative laminate. It isn't as fragile as one would think considering it's a fraction of the the thickness. It should also be much cheaper than the decorative sheet. As far as the CNC try a local plastic shop, the one I use is a fraction of what cabinet shops want to do small custom runs. Hope that helps.

Thanks.  Business around here leads to a lot of machine shops, which is where I run into $ and hassle.  Most will only quote off CAD drawings.  Might try some local cabinet shops and see what they would do.

 

[JayStPeter]

I call it balance sheet. Treat it the same as the finish sheet.

Tom

Just don't google "balance sheet" looking for it  [big grin]

 

[tiralie]

There you go another item for the "separated by a common language " thread.....
Balancer = Backing sheet.  ;D ;D

Rob:
At least you guys are consistent...People think Canadians are "nice" but really were are just confused. Not only do we have American & British spelling for some words but with the influence of the French and an imperial and metric system, we're just smiling cause we don't have a clue  [wink].
Tim

 

[lino-man]

Guys, if you are, on the other hand, working with melamine as opposed to mdf, is there any need to put plastic laminate over the back of the doors?

 

[Knight Woodworks]

Jay,

In the NorthEast the product you're looking for is sometimes refured to as 'vertical grade' plastic laminate.
Good luck.

John