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Sealing and flattening your MDF bench

by hiswillus
posted 04-29-2013 02:34 PM


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51 replies

51 replies so far

View redSLED's profile

redSLED

687 posts in 647 days


#1 posted 04-29-2013 03:19 PM

Lacquer.

I really don’t think any finish can “strengthen” a top. Are you talking about “losing the flatness” in terms of 1/1000 of an inch? The same would apply to a solid wood or plywood top. Unless I’m misunderstanding your situation.

-- Perfection is the difference between too much and not enough.

View TobyC's profile

TobyC

484 posts in 630 days


#2 posted 04-29-2013 03:20 PM

Lacquer based sanding sealer.

Toby

-- Cigarettes and squirrels are completely harmless until you put one in your mouth and light it up.

View brtech's profile

brtech

714 posts in 1677 days


#3 posted 04-29-2013 04:32 PM

There is flat, and then there is flat.

You don’t want a smooth surface, you want a “dead flat” surface. That’s a few thousands of an inch if you can get it, but I think those who hand plane their top probably are happy with 1/32”, which is a few hundredths.

The MDF is flat, period, if it’s supported. It may gouge, but it will stay flat if it doesn’t warp, but it won’t warp if you keep it dry and support it well. Any coating on the top isn’t going to affect the flatness, and short of a poly build up like a bar top, it won’t stop any tool from gouging. Sometimes, you put a piece of hardboard on top of the MDF, which you can replace when you need to.

How thick is the MDF, and what is underneath it?

Don’t second guess yourself too much – plenty of beginning jocks have MDF bench tops to start. It’s an inexpensive way to get a flat surface.

View ksSlim's profile

ksSlim

1011 posts in 1644 days


#4 posted 04-29-2013 06:36 PM

I put a piece of Masonite on top of mine years ago. When it get too rough and gouged up, I replace it.

-- Sawdust and shavings are therapeutic

View byerbyer's profile

byerbyer

109 posts in 727 days


#5 posted 04-29-2013 06:50 PM

I applied (2) heavy coats of Johnson’s paste wax to my MDF bench top. Glue and finish will scrape off (easily) after curing and you can always re-apply as it wears. The only draw back I’ve seen is the surface becomes rather slick, so when you’re sanding small parts with a ROS you’ll need some tool box / rubber shelf liner to keep parts from skittering about.

-- Byer-- "Comparison is the thief of joy" -- T.R. Roosevelt

View SCOTSMAN's profile

SCOTSMAN

5594 posts in 2339 days


#6 posted 04-29-2013 06:58 PM

mdf is about (,so they tell me) as flat as it gets don’t worry about the future just enjoy.Alistair

-- excuse my typing as I have a form of parkinsons disease

View hiswillus's profile

hiswillus

70 posts in 703 days


#7 posted 04-29-2013 08:43 PM

Thanks to all of you for your input. One of my major concerns is that I’m a heavy water drinker and tend to slop it about quite a bit. I’ve seen what happens when it gets wet and it’s not easy to get it back to flat again without tearing it up. I actually have 3 layers laminated together on top of an old metal desk frame I found in the basement. The bench is about 5 feet long and has two metal cross bars supporting it. I don’t think we have to worry about support.

Oh I’m not real concerned with 1000th’s of an inch, just looking to keep a decent reference surface. So I guess it’s either put something over it or the wax idea which I liked for my particular concern. Unfortunately I was dumb and laminated all 3 pieces together to the frame as well, so I can’t really see any easy way to peel and replace.

Thanks again guys and any other input is appreciated by me and probably any others in a similar situation.

Thanks,

Jeff

View brtech's profile

brtech

714 posts in 1677 days


#8 posted 04-29-2013 08:51 PM

I’d probably seal it with shellac and/or poly. Take the faces off if you can and seal the edges of the MDF. If you can raise the edges 1/8”, then I’d probably drop the hardboard on there, and seal that the same way. I might even put something in the poly to give the surface some grip. I think wax is not such a great idea on a benchtop – you don’t want things sliding on it. There are folks that “tooth” their bench surface to get more grip.

View BurtC's profile

BurtC

91 posts in 1884 days


#9 posted 04-29-2013 09:02 PM

I just brushed on a couple coats of Danish Oil on my MDF bench top. Do not sand the MDF. How is your bench top going to loose flatness?

View hiswillus's profile

hiswillus

70 posts in 703 days


#10 posted 04-29-2013 09:06 PM

Drops of water cause the MDF to swell and deform…

Man, am I really that bad of a communicator. I can not disassemble any of the current top without destroying it. It is glued into one solid piece I think the MDF was about 3/4 inch x 3 leaving the frame a little lip on the bottom to hold the top from sliding side to side in any direction. I can lift the whole thing up and remove it all as one solid piece and that’s about it.

View bondogaposis's profile

bondogaposis

2765 posts in 1105 days


#11 posted 04-29-2013 09:43 PM

I like to thin out spar varnish 50/50 with mineral spirits and apply it to MDF. It really drinks it in and provides some good protection I think. Give it a couple of coats.

-- Bondo Gaposis

View Tedstor's profile

Tedstor

1507 posts in 1387 days


#12 posted 04-29-2013 10:06 PM

Ever considered gluing a piece of formica laminate on the top?? It would make it waterproof. They even make laminate that has a wood-like pattern.

View Viktor's profile

Viktor

448 posts in 2173 days


#13 posted 04-29-2013 10:15 PM

View Cosmicsniper's profile

Cosmicsniper

2199 posts in 1913 days


#14 posted 04-29-2013 10:16 PM

Jeff, can you disassemble any of the current top without destroying it? :) jk

MDF is fine. Makes for a great work bench top. It takes a lot of water to really deform the MDF. Do you slobber like a camel? ;)

If you are concerned about it (like for spills), I’d seal it off with oil-based poly and then affix hardboard to the top.

I think you have a very fine workbench…and I think many people around here have a false sense of what is truly needed in a workbench. Having an heirloom workbench is somewhat of a rite of passage, but it’s not a necessity.

-- jay, www.allaboutastro.com

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hiswillus

70 posts in 703 days


#15 posted 04-29-2013 10:45 PM

Cos, that was hilarious!!! And yes I do slobber like a camel sometimes…lol What is “hard board” do you mean Masonite or an actual piece of hard wood? Here is a pic of my water “jug” for your entertainment. If that tipped I think that would be considered a camels slobber ;)

View bbasiaga's profile

bbasiaga

112 posts in 749 days


#16 posted 04-29-2013 10:54 PM

I put the cheapest piece of formica I could find on my mdf top. It was flat finished…not stippled. Worked great. If you but the spray can contact cement it is very easy to put a uniform coat with no humps in it.

Brian

-- Part of engineering is to know when to put your calculator down and pick up your tools.

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hiswillus

70 posts in 703 days


#17 posted 04-29-2013 11:00 PM

Do you think maybe just a flat spray paint may offer suitable protection?

View waho6o9's profile

waho6o9

5304 posts in 1331 days


#18 posted 04-29-2013 11:02 PM

I don’t think you’d be happy if some paint stuck to one of your fine
projects.

Oops.

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hiswillus

70 posts in 703 days


#19 posted 04-29-2013 11:03 PM

Good point!

View woodbutcherbynight's profile

woodbutcherbynight

1311 posts in 1163 days


#20 posted 04-30-2013 01:21 AM

Tedstor +1 I have 4 laminate covered MDF top for more than 10+ years, all are flat and laminate does not care if it gets wet at times if done correctly. The colors and options are endless, working it is fairly easy even if you have to use a file to finish it as I did.

-- Live to tell the stories, they sound better that way.

View padawan's profile

padawan

21 posts in 955 days


#21 posted 04-30-2013 01:40 AM

I am certainly no expert as far as a finish goes but I can recommend a good water bottle that only dispenses water when you suck on the tip (and yes I know how bad that sounds). The first thing that came to mind was the movie airplane where he throws the drink in his eye after he said “he had a drinking problem”

http://www.camelbak.com/en/Canada/Sports-Recreation/Bottles/2012-eddy-1L.aspx

View gfadvm's profile

gfadvm

11555 posts in 1444 days


#22 posted 04-30-2013 02:08 AM

Another vote for covering it with Formica for a lot of reasons: stays flat and smooth, glue pops right off, and if you use white like I did you can write notes/measurements on it. AND it’s immune to camel slobber!

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View RogerInColorado's profile

RogerInColorado

310 posts in 708 days


#23 posted 04-30-2013 04:41 AM

I’ve had a workbench with an MDF top for more than 35 years. I’ve spilled gallons of coffee on it. When I first built it I put two coats of polyurethane paint on it. The first coat was sort of a beige. About 10 years later I sanded it up a bit to give it some tooth and gave it another couple of coats of polyurethane paint. That one was yellow. Another few years passed and after some more sanding I gave it another couple of coats of the same yellow. Glue won’t stick to it. Motor oil won’t penetrate it. Roubo, it ain’t but neither am I. Whenever I get the urge to build a new bench. I have a cup of coffee and think about the other things I want to build. Pretty soon the “new bench urge” goes away.

View Lee Barker's profile

Lee Barker

2169 posts in 1604 days


#24 posted 04-30-2013 04:50 AM

If you guys were cooks we’d all be beyond hungry. You’d still be fussing about the table cloth and the napkins and the salad forks a week from yesterday.

Just build something, Jeff. It’s a workbench, not a Master Table for the U.S. Bureau of Standards. Be a job creator, and put that pretty flat, pretty, flat, surface to work!

Go for it!

In a year, or five, it will be a testament to your efforts, a rosetta stone of all the skill dialects you have learned. It will have sustained the whacks of miss-aimed mallet shots and will have survived slopped H20 and will still be your silent and loyal partner in every project you do.

Fret no more about that surface. Do not strip its lovely mitered sides. Do not douse it with this or drown it in that. Elevating the humble work surface to something otherworldly won’t make your work any better; in fact, your subconscious efforts to not harm the surface while you are building something truly beautiful and achingly tactile will enhance by a factor of 3.14159 the likelihood of something going awry at the end of the chisel.

Leave your tuxedo in the closet, put on some real clothes and get with the tools and bring on the wood!

Kindly,

Lee

-- "...in his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

View waho6o9's profile

waho6o9

5304 posts in 1331 days


#25 posted 04-30-2013 05:18 AM

LOL

” a factor of 3.14159” waxing eloquence from Mr. Lee.

Thanks for the laugh.

View Rick M.'s profile

Rick M.

4518 posts in 1134 days


#26 posted 04-30-2013 07:34 AM

Jeff, you asked what is hardboard and I don’t think it was answered.
hardboard = high density fiberboard
It’s about 1/8” thick and will have at least one smooth side, sometimes both sides and is made with some kind of resin that makes it really tough.

-- http://thewoodknack.blogspot.com/

View Lee Barker's profile

Lee Barker

2169 posts in 1604 days


#27 posted 04-30-2013 02:58 PM

Adding to Jeff’s clarification, it comes in other thicknesses including 1/4. It can have one finished side or two; the unfinished side being kind of an embossed look of window screen. It is the same material in which holes are created for pegboard.

It can be regular or tempered; the tempered is hard stuff, resistant to fasteners which aren’t preceded by a pilot hole. Air driven fasteners can penetrate but they leave a raised area around the scar.

Thanks for the note, Waho. I am hoping my post was taken as light hearted encouragement, not criticism.

Kindly,

Lee

-- "...in his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

View waho6o9's profile

waho6o9

5304 posts in 1331 days


#28 posted 04-30-2013 03:03 PM

You’re welcome Lee. You do leave impressions in the positive vein

which is appreciated by all.

View Smitty_Cabinetshop's profile

Smitty_Cabinetshop

10395 posts in 1372 days


#29 posted 04-30-2013 05:08 PM

^ Lee, in the threads I frequent that would be called a Manifesto. And a damn good one at that. Thank you for the reminder of what is important about this hobby: Getting the work done!

-- Don't anthropomorphize your handplanes. They hate it when you do that. -- OldTools Archive

View TOM's profile

TOM

71 posts in 745 days


#30 posted 04-30-2013 05:32 PM

Why not attach a hardboard top to the bench?

If it ever gets warped or chipped or whatever, simply replace it with a new one.

View Cosmicsniper's profile

Cosmicsniper

2199 posts in 1913 days


#31 posted 04-30-2013 07:00 PM

Yeah, hardboard is what they said it is. The virtue of it is cost…maybe $13 for a 4×8 sheet of it. That makes it almost disposable and easily replaceable. I’d pre-drill and countersink some holes to put it down, or build a skirt with the right height to accommodate the 1/4” thickness and just wedge it on. It’s durable, hard stuff and will sit pretty flat.

Formica is great for assembly tables. It’s fine on a workbench too, but it does get cemented down and can crack or chip during rough handling activities. I just don’t care much for it aesthetically.

-- jay, www.allaboutastro.com

View Rick M.'s profile

Rick M.

4518 posts in 1134 days


#32 posted 04-30-2013 09:53 PM

When I moved into this house, I covered the workbenches in the shop with 1/8” ply but I’m going to pull that up and recover with 1/8” white melamine/masonite paneling. Easier to keep clean and it will reflect more light.

-- http://thewoodknack.blogspot.com/

View TOM's profile

TOM

71 posts in 745 days


#33 posted 04-30-2013 09:56 PM

I do love the way MDF looks – nice and smooth/neutral color.

A sheet of 3/4” 4×8 MDF is not really all that expensive – around $30 or so at Lowes/Home Depot. So it seems to me that even if you just worked on your raw MDF bench top for a time – which, from what I read above, will likely be a decent length of time – it’s not too much of a bank-breaker to replace it if need be.

View gfadvm's profile

gfadvm

11555 posts in 1444 days


#34 posted 05-01-2013 12:14 AM

Rick M., I made a new table for my RAS from white melamine and wore all the white finish off of it the first day I used it. I was NOT impressed with melamine. Your mileage may vary.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View Rick M.'s profile

Rick M.

4518 posts in 1134 days


#35 posted 05-01-2013 06:05 AM

Unless you attacked it with an angle grinder, I doubt it was melamine. Something else I’ve been thinking would make a good bench covering is laminate flooring. I have an extra box in the shed, about enough to cover one bench.

-- http://thewoodknack.blogspot.com/

View Lee Barker's profile

Lee Barker

2169 posts in 1604 days


#36 posted 05-01-2013 01:16 PM

Yes, I think gfadvm got into a pretender to the Melamine throne. Not that it’s iron, but it would last a heckuva lot longer than a paint product.

That said, we used to get a product here called Kortron which was chipboard with a very high gloss paint applied that was somehow zapped in the process. It was very durable and glue would not stick to the surface at all. It makes for a nice place to let glue drip.

As for the laminate flooring, Rick, I have worked in a friend’s shop where there are two such benches and I don’t like them at all—too slippery, and just not flat because it is pieced. Plus all the joints are chamfered. It doesn’t have any attributes that I like.

My work surfaces are chipboard—not even MDF. They have served for over 25 years without replacement.

Kindly,

Lee

-- "...in his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

View Lee Barker's profile

Lee Barker

2169 posts in 1604 days


#37 posted 05-01-2013 01:19 PM

Oh, and Smitty—Thank you. And in many cases, most all for me, the word “fun” could be appended to “work.”

We are so fortunate to have a profession or hobby that allows us to see the results after time invested. Think of the people you know who go to work day after day and never see an end result that is tangible.

Kindly,

Lee

-- "...in his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

View BurtC's profile

BurtC

91 posts in 1884 days


#38 posted 05-01-2013 01:43 PM

I like your bench Jeff. Much like mine. I sunk a few T-tracks in the MDF top. The MDF top can be removed and replaced because it is screwed to plywood layer underneath.

View waho6o9's profile

waho6o9

5304 posts in 1331 days


#39 posted 05-01-2013 01:52 PM

A fine looking bench BurtC!

View Tedstor's profile

Tedstor

1507 posts in 1387 days


#40 posted 05-01-2013 03:59 PM

Yep- Rick is right about the flooring. I’ve used laminate and engineered flooring on various shop fixtures. Easy to work with, durable, and doesn’t react much to temp/humidity changes (within reason). Its also fantastic stuff for fences and jigs.
Leftover and/or half-used boxes of flooring can be had for a song on CL or in the clearance section of any big box store.

View DS's profile

DS

2132 posts in 1174 days


#41 posted 05-01-2013 04:11 PM

gfadvm, what you probably had was cold-rolled, or cold-pressed melamine. It is an inferior product which is sensitive to moisture and very fragile. (It costs less though)

On the other hand, Thermo-fused Melamine is baked onto the substrate and is far more durable and has excellant moisture resistance.
Most of my work surfaces, router table, assembly bench, etc. are made from TFM panels that somehow got mis-cut or damaged and then got re-purposed in my shop.
They take a real beating and are still holding up.

If I had a raw MDF worktop, I’d be considering a HPL high pressure laminate (like Formica) on top.
In most cases, it will cost the same or less than the sealers and/or topcoat you plan to put on the top.

If you do any laminate work, chances are, you already have a leftover scrap that will fit the bill nicely.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View stefang's profile

stefang

13633 posts in 2088 days


#42 posted 05-01-2013 04:18 PM

I would just give it 3 coats of poly and be done with it. I would use high gloss poly which is very strong and just sand the 3rd coat to a satin or even rougher texture. This will protect against water, oil and whatever else you throw at it. If it gets damaged you can repair it good enough without refinishing the whole thing and still keep it flat enough for normal woodworking.

-- Mike, an American living in Norway.

View Rick M.'s profile

Rick M.

4518 posts in 1134 days


#43 posted 05-01-2013 05:53 PM

I probably should have mentioned the laminate flooring would go on a wall (garage style) bench, not a proper woodworking bench, so flatness isn’t really an issue. I go back and forth between wanting to tear out the wall benches to make room for a woodworking bench or fixing them up.

-- http://thewoodknack.blogspot.com/

View Smitty_Cabinetshop's profile

Smitty_Cabinetshop

10395 posts in 1372 days


#44 posted 05-01-2013 05:58 PM

Lee, +1 to “fun,” so moved!

RE: Laminate flooring, I have an assy bench that had such stuff glued down to the real (old) T&G/breadboarded top. After some consideration, I pulled the screws from underneath the bench and turned the whole top over. Flooring is out of sight, out of mind, and wood returned.

So, I’d seal it w/ Watco’s and move on. Or 3 coats w/ sanding as Stefang suggests if durability is preferred.

-- Don't anthropomorphize your handplanes. They hate it when you do that. -- OldTools Archive

View gfadvm's profile

gfadvm

11555 posts in 1444 days


#45 posted 05-02-2013 12:05 AM

My “melamine” must be the el cheapo economy version so my apologies to the “real Melamine”. The crap I used soured me on ever using melamine for anything (now I may have to rethink this). How do you know whether you are getting crap or the good stuff?

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View Rick M.'s profile

Rick M.

4518 posts in 1134 days


#46 posted 05-02-2013 01:51 AM

Good question gfadvm, I don’t know. Melamine is tough stuff though, I’ve worked on it much of my life. Cut on it, used acetone and xylene on it, set hot pans on it, all sorts of stuff. I’m not an expert on plastics but I know that you could drag wood across real melamine all day, every day for a decade and might not wear it out. We used melamine covered shelving for printing platens and abused the hell out of it. Your post made me question whether the paneling I wanted to use is melamine or something else.

-- http://thewoodknack.blogspot.com/

View mandatory66's profile

mandatory66

102 posts in 885 days


#47 posted 05-02-2013 05:13 AM

I have a table very similar to yours except it is built on top of a old oak table. I have been using it for 7 years and have recently notice a sag of about 1/8 inch in the center. I used 2 sheets of 3/4 inch MDF but they are not glued together. They sit on top of a 1 inch oak top. Your iron frame should be a lot better. The table is 6ft long and I finished the top twice with oil based poly in the 7 years. I have no idea why it is now low in the center section. I will be checking out the reason and replacing the MDF soon. The table sits in the basement with humidity about 60% most of the time, I run a small dehumidifier about 9 Mo. of the year.

View DS's profile

DS

2132 posts in 1174 days


#48 posted 05-02-2013 10:49 PM

With cold-rolled melamine the edges can usually be flecked off and only remove the melamine layer. With TFM, you won’t be able to seperate the melamine from the PB substrate. The PB may fleck off, but the melamine is inseperable from it.

Thermofused melamine also has a distinct texture to it and feels slick to the touch. Cold Rolled is usually smooth without much texture.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View hiswillus's profile

hiswillus

70 posts in 703 days


#49 posted 05-14-2013 05:30 PM

Thanks BurtC, but yours is much more beautiful!

View RonInOhio's profile

RonInOhio

720 posts in 1618 days


#50 posted 05-14-2013 05:36 PM

I have a utility bench with MDF top. I read someplace where coating the top with wood glue would protect it
from spills and such. So thats what I did. Rolled on some wood glue over the top. The hardboard sounds like
a good way to protect it from gouges and such.

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