Weathering MDF buildings, any suggestions?

[Cessna]

I bought a few MDF buildings that I'd like to use for an old west game. I'd like them to look like old, weathered wood instead of fresh MDF.

I suppose I could paint them, but are there any better alternatives that would retain the "bare wood" look somehow? Perhaps I could use some sort of wood stain to give them a greyish or patchy brown look like the old wood in the pics below?

Any tips or suggestions would be helpful.

[SupremeLittlenessDesigns]

I'd recommend using a smooth acrylic paste applied with a wooden cocktail stick (tooth pick). Use the length of the stick rather than the point to apply and lift off the paste and create long grain lines that provide highlights for the paint to pick up.

[Pattus Magnus]

Similar idea, but may be a bit quicker if you are covering large areas of boards - get a tube of artist acrylic paint in the colour you intend to use as your undercoat colour, and apply it with a square tipped bristle brush (the ones made using coarse pig hair). The bristles will leave tracks similar to the toothpick but will cover much more quickly. You can use a toothpick or similar to add some irregularity or knot hole impressions. If you are lucky, you may find a brush about the same width as the planks you intend to texture.

Once the artist acrylic is dried, you can lighten up and weather the surface with drybrushing.

[FifteensAway]

PM's idea seems more workable.

But first - do the models have those ghastly 'ends' showing that shout MDF?  If so, need to do something to hide that first.   Have to ask others for advice - I shun MDF like it is a plaque because of those ends though some people have done great jobs in making them look terrific and hiding those parts somehow.

That first photo you posted - if you can get close to that look you will have incredible buildings.  Artist water color pencils might help getting to that look.  Or, stain as you mentioned but you will want to vary the tones to get that sort of look.  Not sure I'd try it but some people use shoe polish - seems too messy for my tastes. (more of a model railroad thing than miniatures).  If you stick with paint, then the basic colors of raw and burnet sienna, raw and burnt umber, yellow ochre will all help - with some white mixed in to tone them down, probably too strong straight on.  And gray.  There are also weathering powders you can use but not sure they will handle much handling (model railroading again).

[Cat]

I've built quite a few mdf kits.  I always take a shop file to the burnt edges and file away the hard burnt crust (leaving little streaks is OK, that works to add a bit of weathering to the finished painting).  This completely solves the burnt end syndrome.  If left as is, the burnt crust will not absorb paints the way the rest of the surface does and will always be off-colour.
 
I spray prime, mdf can soak up an amazing amount of paint. 

If it's going to be wood colour, I prime with a woodish colour, this doesn't have to be a solid coat.  This can even be the final coat and it looks better than leaving raw mdf. 

For any other finish, I prime in white or light grey.  Normally, I prime in whatever predominant colour a model will be, but mdf really works best with with a white or grey undercoat.
 
If you want to try a stain, test it on a bit of scrap first.  I had some protective stain from my old wooden cross country skis that worked perfectly on boat models that were cut from pine wood, but that was actual wood.  I tried some on a scrap of mdf too to see if that might work.  It didn't — layers of mdf separated and curled up.
 
For weathering, I drybrush like crazy.  Whenever I'm cleaning a brush, I look for a surface to wipe that colour on!
 
Lots of photos in my Sleepy Hollow thread:
https://leadadventureforum.com/index.php?topic=106615.0

[Malebolgia]

One of the things you can do is to first score the wood with a metal wire brush. This adds texture and will make the mdf less flat and adds a bit of texture.
For painting I recommend starting out with a very dark brown and then switch to warm greys for drybrushing. This will give that typical dried wooden look you get with those buildings.
And if you want coloured fronts, one thing you can do is to sponge on masking fluid after painting the wood. After this dries you can paint the colours (and letters) to the fronts. Once dried, you can rub off the masking fluid and paint, giving an awesome weathered and flaked paint look.

[Johnny Boy]

Sarissa precision have published a book on how to assemble and paint their buildings which Wargames Illustrated printed an abridged version of. Obviously most types of their buildings are covered. But in the Old West chapter artists pencils were used to great effect. Well worth a look IMHO
JB

[Cat]

One of the things you can do is to first score the wood with a metal wire brush. This adds texture and will make the mdf less flat and adds a bit of texture.

Yes, that was a bit I forgot to mention.  I scrape a razor saw along the mdf to give it a wood grain.  This also catches dry brushing very nicely.
 
Mdf kits that come with etched-in wood grain tend to have very comic-book style very wiggly lines, and sometimes like this for edges between what are supposed to be rough board blanks.  I use an XActo to straighten these out as much as possible to get a somewhat more realistic look.