Sealing MDF can it be done?


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Depends in your definition of 'sealed'. I'm partial to shellac, but a poly if some sort will be more durable for a working surface. I suggest thinning it well, and applying multiple, thin coats.

What sort of activity will this bench be used for? For some things, MDF may be a less than ideal choice.

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18 minutes ago, Skjohn98 said:

I am just getting into wood working and building a work bench with some MDF, can it be sealed, and what would you use

john

Something other than mdf

that sounded crass and didn't mean for it too but I wood consider another material.

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3 minutes ago, Pug said:

I've had a triple layer mdf bench top for years.  I used water based poly on it, and its been pounded relentlessly.  Still holding up just fine!

Its edge banded with 3/4" by 2.5" hard maple.

I stand corrected. Thanks Pug!

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My first bench was three layers of mdf, edge banded with oak and topped with a layer of hardboard. The hardboard is cheap and can easily be replaced when it gets too beat up. Plus if protects the mdf in the event of a spill. It obviously had its limitations, but it was pretty heavy and did well enough until I got further into woodworking and started getting the Roubo itch.

Sent from my iPad using Tapatalk

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If you are going to use MDF follow Pugs example and use solid wood around the edges. Support  the top not only around the edges but at least every 12 to 16 inches in the middle too. MDF will sag if not supported .Use several coats of poly on all sides ( especially the bottom) water based is fine and dries faster usually . This will prevent the MDF from absorbing moisture and swelling.

Its dense and heavy which is good for a bench.  If it's what you already have started with it will do pretty good if sealed, edge banded with solid wood and supported.

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29 minutes ago, Skjohn98 said:

I understand MDF is not the best but this is my first project, I can always replace the top, but lack of experience and proper tools tells me to start with the MDF. Learn and get better and more knowledge with each project

i got the basic plan and idea for that bench from FWW. you can prob find it on their website.

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51 minutes ago, Pug said:

I've had a triple layer mdf bench top for years.  I used water based poly on it, and its been pounded relentlessly.  Still holding up just fine!

Its edge banded with 3/4" by 2.25" hard maple.

image.jpeg

image.jpeg

OK pug so let's see the bench today, not the day it got done  * )

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7 hours ago, Brendon_t said:

OK pug so let's see the bench today, not the day it got done  * )

I'll take a pic later today for you.  Or you can check out any of my projects in the journal section.  I used it for all of them.

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When I built my work benches, I approached it with the mindset that the tops are disposable and can be replaced. They will naturally get a lot of wear. 

I did one layer of plywood with one layer of MDF and topped it with countertop laminate. 

Your MDF top will be fine if you edge it with hardwood like PUG did and seal it. The edges take a beating and that is where MDF will break down quickly. 

You can seal it as PUG did or also apply a sheet of laminate. That stuff is tough! If you use white or light colored laminate you can draw all over it with a pencil and "erase" it all with a wipe down of lacquer thinner or mineral spirits. 

Sometimes I draw things out in full scale right on the laminate top. 

I have been using my tops for a good 10 years professionally and they still are going strong.

 

SV103727.jpg

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6 hours ago, RichardA said:

So it get's beat up over time, isn't that the definition of a "work"bench?  If you make a bench that looks like furniture, you will go out of your way to keep it pristine, Somehow that just doesn't seem like a place to "work" .  When you look a the pics of Roubo's benches, they look like they are getting beat to hell by all the children doing all the rough work for the craftsmen.  No one is sitting back admiring how beautiful the bench's are, their being worked on by ham handed young'uns!  Jeez, build what you feel works, and make the pretty go out of the shop, not into the shop!

Clearly the wink was lost in translation.  I forgot we can't rib each other on here any more. 

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1 hour ago, Brendon_t said:

Clearly the wink was lost in translation.  I forgot we can't rib each other on here any more. 

Sorry my friend, there was no wink in that diatribe! Just truth!  That wasn't a dig on any bench, just my feeling about a workbench!

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7 hours ago, toddclippinger said:

When I built my work benches, I approached it with the mindset that the tops are disposable and can be replaced. They will naturally get a lot of wear. 

I did one layer of plywood with one layer of MDF and topped it with countertop laminate. 

Your MDF top will be fine if you edge it with hardwood like PUG did and seal it. The edges take a beating and that is where MDF will break down quickly. 

You can seal it as PUG did or also apply a sheet of laminate. That stuff is tough! If you use white or light colored laminate you can draw all over it with a pencil and "erase" it all with a wipe down of lacquer thinner or mineral spirits. 

Sometimes I draw things out in full scale right on the laminate top. 

I have been using my tops for a good 10 years professionally and they still are going strong.

 

SV103727.jpg

Do you find the laminate slick?  Is the work moving around any concern?

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Just now, Pug said:

Do you find the laminate slick?  Is the work moving around any concern?

I have not found it to be a problem at all. There is a very light texture on basic white laminate.

It is extremely durable. I also used laminate on my miter saw table for use working on job sites. I can make notes on it and mark lines for repetitive cuts. It provides a lot of protection if there is mild rain or snow. (if it rains too much I am packing it all in.) 

  

 

SV103817.jpg

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6 minutes ago, Skjohn98 said:

Guys thanks for all the info but just wondering what and how would you seal it

john

Over the years I have sealed MDF with water base, oil base, and pre-cat lacquer, they all work.

Actually, if you frame out MDF with maple and seal it, the maple frame not only protects the edges but the contrast of the light maple against the darker MDF looks great. 

 

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9 hours ago, Skjohn98 said:

Guys thanks for all the info but just wondering what and how would you seal it

john

Staying on original topic is rare around here. :) It's fine though, good conversation to be had.

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On 3/3/2016 at 9:01 PM, Skjohn98 said:

...this is my first project, I can always replace the top...

MDF is so cheap it really doesn't matter if you seal it right now or not. Make the bench and use it for a bit. I'd leave the top bare, and just wrap the edges as Pug has done... Be sure to leave some small access holes, so you can push the old top off when it needs replacing.

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11 hours ago, Skjohn98 said:

Guys thanks for all the info but just wondering what and how would you seal it

john

I think the question was answered.  You can use pretty much anything to seal MDF.  Shellac, lacquer, water borne poly, oil based poly.  I'd probably use shellac or General Finishes High Performance waterborne poly.  

 

 

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Like Pug, I had an MDF bench; 4 layers of 3/4" laminated together.  I treated it with BLO followed by paste wax.  I would have to refresh the wax every few years.  Glue popped right toff and it took a load of use without problems.  If I did get a serious ding I would just fill it with leftover epoxy the next time I was using some and then pare it flush with a chisel prior to full cure.

I did make the mistake of trying to save a bit of cash by using BORG kiln-dried fir for the frame.  Despite being stickered in my shop for a couple of months the material continued to shrink and distort.  I was able to work around it but, after accounting for the waste due to poor product, I could have used some poplar or other inexpensive wood from a reputable lumber yard and spent no more money; lesson learned. 

Here's the surface after about 5 years of use:

More Dog Holes 6.jpg

I thought of this bench as an intermediate step in my journey and it was just that.  The surface worked so well, I stayed with it for my next bench. I wanted a longer span between supports although a shorter overall length) and so went with 2 layers of 3/4" BB ply laminated to two layers of 3/4" MDF on top.  I used poplar for the base this time and maple for the balance of the vise jaws and trim.  I used the same BLO followed by paste wax method that worked so well for so many years.

TNNW (68).jpg

It has been in use for under a year but, I am already very pleased with the shorter length (I kept the 30" depth).  It has remained dead-flat which provides a nice reference surface for many tasks. The twin screw is a joy after dealing so long with vises that rack. Once I decide on the end vise (designed for another twin screw but the jury is still out) I will add more dog holes for that function. 

You can see the original bench in the lower right corner of the pic.  I gifted this to a woodworking acquaintance who was in need  . . . good bye old friend.

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