Help with finishing MDF and Maple

[Lewis Cobb]

Hi there -
I've started to build some shop wall cabinets and tool holders and they are basically MDF with an edging of maple. I did not think too much about the finishing when I started and after hanging the first one and admiring it today I realized it looks a little on the bland side. So I tried a test piece of MDF and maple with water based polyurathayne and it looks the same blandness (if there is such a word). I would like the MDF to darken down to a more deeper brown - almost like hardboard / masonite and I would like a slight amber tint to the maple. Maybe a tung oil on them would work? Or maybe an oil based polyurathayne ?

Any suggestions are welcomed. I'm a bit of a buffoon when it comes to finishing and don't like staining at all after a blotching disaster some time back...

Thanks
Lewis

[Jim Becker]

An application of BLO will darken the MDF and add a little amber to the maple. You can then top coat with varnish or shellac to get the effect you desire. There is no need to use anything with polyurethane in it, although if you are buying at mass retailers, that tends to be all they have on the shelf. There is also no reason to use tung oil (the real stuff) as it's major expensive compared to BLO (boiled linseed oil), takes at least a week to cure before you can top coat it and you will not be able to tell the difference between it and garden variety BLO.

[Lewis Cobb]

An application of BLO will darken the MDF and add a little amber to the maple. You can then top coat with varnish or shellac to get the effect you desire. There is no need to use anything with polyurethane in it, although if you are buying at mass retailers, that tends to be all they have on the shelf. There is also no reason to use tung oil (the real stuff) as it's major expensive compared to BLO (boiled linseed oil), takes at least a week to cure before you can top coat it and you will not be able to tell the difference between it and garden variety BLO.


Hi Jim - thanks for the advice. I was going to ask you "what's this BLO stuff" (thought perhaps it's not the stuff used in the old Miami Vice shows). But reading further on I see it explained. This leads to my next question - where does one get this BLO - is it normally available at the home centers or should I be looking at mail order places? Hopefully I don't have to start cooking this stuff up on the stove. I'm on thin ice with my wife for spending so much time in the workshop these days already....:o

Cheers,
Lewis

[glenn bradley]

Hi Jim - thanks for the advice. I was going to ask you "what's this BLO stuff" (thought perhaps it's not the stuff used in the old Miami Vice shows). But reading further on I see it explained. This leads to my next question - where does one get this BLO - is it normally available at the home centers or should I be looking at mail order places? Hopefully I don't have to start cooking this stuff up on the stove. I'm on thin ice with my wife for spending so much time in the workshop these days already....:o

Cheers,
Lewis

Not Jim, but yes, Boiled Linseed Oil is available at most home stores. It will be with the Mineral Spirits and Lacquer Thinner, Paint Thinner, etc.

[Lewis Cobb]

Not Jim, but yes, Boiled Linseed Oil is available at most home stores. It will be with the Mineral Spirits and Lacquer Thinner, Paint Thinner, etc.

Thanks Glenn - I'll check it out tomorrow on the way home from work.

[Jon Crowley]

I second the BLO suggestion. It makes it almost hardboard dark, and gives an even color. Something like an oil based poly/varnish directly on MDF looks extremely blotchy... DAMHIK. :)

[Jim Becker]

Honestly, the MDF surfaces in my shop (my miter station primarily) only have BLO on them. Same with my maple workbench. I just put a little more on a few times a year to clean up the dings. The cabinet under my drum sander, made of birch plywood with a poplar face frame also only has BLO on it. Everything looks just fine and in an area where dings and cuts are a normal thing, quick renewablity is a nice thing.

[Lewis Cobb]

I second the BLO suggestion. It makes it almost hardboard dark, and gives an even color. Something like an oil based poly/varnish directly on MDF looks extremely blotchy... DAMHIK. :)


Thanks Jon - I notice you are from Cincinnatti - I get there from time to time on business and last time I visited Mueller's - as a result I am getting ready in a few weeks to buy some machines from them.

Cheers,
Lewis

[Prashun Patel]

You can also just use amber shellac alone.
I don't see the use in doing BLO AND shellac. They both seal. Shellac'll dry much quicker, though, so it's a tad trickier to apply. But once you get the hang of it, you'll appreciate how fast this lets you recoat (you can cut with ethanol or IPA to make it more workable)

Beware of shellac on mdf, though, it'll make it amber. This effect is beautiful (IMHO) on wood, but is a matter of taste on mdf; it won't just 'darken' it as you're looking to do.

[Lewis Cobb]

I found some BLO at a local hardware store today and just finished wiping some on a scrap of MDF and maple. Impressions are a bit mixed on the results.

The MDF sure darkened down nicely and as was pointed out earlier it's almost like hardboard. The color is a little bit on the greenish tint - ever so slightly but in general it's to my liking. Could be the fluorescent lighting - but that's what I will have in the shop anyway. The surface remained nice and smooth as well and color is very uniform indeed.

The maple however I am not that happy with at all. It's a little too yellowy looking for my tastes and the test piece I used seemed to have some blothcing as well. Is maple prone to blotching with BLO like it is with normal stains?

I will wait for the stuff to dry completely and then re-evluate to be sure, but I am starting to think the blond look of the waterbased poly looked better on the maple against the contrast of the BLO MDF panel.

This leads to another question - can I poly the maple and BLO the mdf and not risk some "interaction" or problems at the seams where the 2 materials meet such as a 90 degree corner? Most of the planned cabinets and wall hanging items I am going to build are with a removable MDF panel so this does not matter, but there is one that's MDF glued into grooves of a maple edging and that one I will have to mask and be very careful with - if it's even advisable to try it.

I'll get some shellac in a few days and try some tests on top of the BLO treated pieces as well as bare pieces to see how I like that look. Maybe it won't change much.

Anyway, thanks for the advice and comments - I am getting closer to something I like.

Lewis

[Lewis Cobb]

Well I have another follow up. Strangest thing. I went into the basement to have a look at the mdf that was so evenly stained with the BLO and lo and behold it had developed a bunch of darker brown "freckles" all over it. I came back about 2 hours later and they were bigger. Now the surface is mostly the darker brown color and there's freckles of the original color. Maybe this is the curing process at play here, but I just might end up with a nice deep brown by tomorrow morning at this rate. Interesting....