When you think of finishing MDF, does it leave you feeling flummoxed?
Seemingly every kind of wood finishing product gets suggested as a great ‘waterproofing’ finish for this engineered wood.
And paste wax is one such highly recommended finish. Especially since paste wax can make MDF more water resistant.
But, is paste wax alone really enough to make this notoriously water-wicking material 100% waterproof?
Well, in this post, you will learn why modern MDF can be really durable stuff (even without the help of any kind of sealing coat). You will also find out why paste wax alone isn’t going to be enough to seal over those exposed MDF edges.
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How Do You Finish MDF Wood?
Well, surprisingly enough, modern-day MDF material comes already finished. Made from recycled hardwood fibers, this fairly material is rather durable and stable without any added wood preservative or sealers.
That’s not to say that this manufactured wood doesn’t ever need a sealer (especially when it comes to those difficult-to-seal MDF edges).
Why ‘Raw’ MDF Can Be Durable
MDF is heavy, (heavier than pine or plywood), and very dense. In fact, MDF registers a density range of around 700–720 kg/m3. Which makes the surface of MDF about as tough as European Oak.
And it is a very stable material too, especially for a wood by-product. Most natural solid wood will tend to shift around with changes in temperature and humidity, even long after wood has been seasoned.
Related Post: How To Season Wood (7 Tips)
But not so with MDF. From summer to winter and back again, MDF won’t move around, shift and twist. And only certain types of natural wood, (such as Douglas Fir), are anywhere near as stable as MDF.
Why MDF Needs Some Kind Of Finish Anyway
MDF has one fairly big flaw… it soaks up water like a biscuit dipped in gravy. What’s more, once enough water gets absorbed into it’s hardwood fibers, MDF will warp and bow.
Related Post: Why Is My MDF Board Warping? (+ How You Can Fix It)
Basically, MDF will last a good long while without any finish… but only if you can keep it away from water and high humidity environments. Which is why you won’t go too far wrong by coating it with a water-resistant film.
Can You Use Paste Wax On MDF?
Yes, you can. Paste wax is a thick wax finish that is smooth enough to be wiped onto MDF using a lint-free cloth.
This finish is made from a blend of natural waxes (such as Beeswax or Carnauba). And then mineral spirits (or other solvents) get added to help thin out these otherwise tough and/or hard natural waxes.
And How Do You Apply Paste Wax Onto MDF?
The same way you would apply it to a natural wooden surface.
This wood finish is incredibly easy to apply. A simple lint-free rag will coat on (and polish out) a paste wax finish.
You don’t need to apply on a lot of this finish either. Only 2 coats are needed, if you put paste wax directly onto bare MDF.
Plus, there’s no prep work needed to get paste wax to adhere to MDF’s smooth planed surface.
Is Paste Wax The Best Way To Seal MDF?
Well, paste wax isn’t a waterproof finish. In fact, it isn’t even all that water resistant.
Sure, paste wax can repel small water spills or liquid stains. But, just like natural wax, paste wax is susceptible to water damage. However, unlike other water-damaged finishes, paste wax is pretty easy to repair.
So, using paste wax to seal those MDF edges isn’t going to work. Instead, you should use a different type of wax product on MDF.
Waxed shellac is a faster and more effective way to make the surface of MDF fairly water resistant.
Waxed shellac is fast-drying and brushes on with ease. And it is more water resistant than beeswax or other natural wood wax products and blends.
But, full disclosure, waxed shellac should be used as a final finish. In other words, you will struggle to get a top coat sealer or paint to adhere over a waxed shellac finish.
Related Post: Can You Put Shellac Over That Off-Gassing Polyurethane?
Is Paste Wax Water-Resistant Enough To Use On MDF Edges?
A paste wax finish alone is far from one of the most water-resistant finishes on the market.
Waxed shellac, or even epoxy resin, are both more water-resistant than paste waxes. However, if you want to seal MDF edges, then you are much better off edge banding.
Edge Banding MDF: A Quicker (And Simpler) Edge Sealer Than Paste Wax
Edge banding involves using a thin strip of waterproof material, (such as plastic or vinyl), to seal over the side of exposed engineered wood, (such as Plywood or MDF).
These self adhesive thin strips have glue on one side of them, so that they can easily be applied onto those edges. That way you don’t need to seal MDF sides with any primer, sealer or wood glue. You can just tape over them instead.
Edge banding tape, (also called edging tape), can be purchased from your local hardware store. Or you can buy Melamine Edge Banding tape by Woodpress.
This high quality edge banding tape has been specifically designed to be ironed onto the sides of MDF. And it is both flexible and wide enough to cover a 8” by 4” side of MDF panel.
To Sum Up, Here Are The 3 Main Takeaways From This Post…
- 1). You can apply paste wax onto MDF. Just 1-2 coats of paste wax will give MDF surfaces full coverage.
- 2). Paste wax alone is not water-resistant enough to be reliably used to seal over MDF edges.
- 3). Instead, use water resistant edge banding tape to seal over MDF edges.