Pedestal interlude

As part of my initial build some months back, I put together the shell of the pedestal. This is the bit of any cockpit that sits on the floor between the seats and is usually integrated into the MIP. It’s roughly analagous to the corresponding bit on a car where the gear lever is (on a European-style, rather than US stick-shift style, vehicle). Controls you’ll usually find there include the thottle quadrant, flaps, speedbrake, CDU and radio stack. Other stuff can go there too depending on whether this is a Boeing or an Airbus or Some Other Kind Of Plane. Indeed, the pedestal on a big Boeing or Airbus is a very large thing with many switches and buttons. Just ripe for the sim nut to have all kinds of fun with.

Given the slightly truncated width of my console (1.2m as opposed to the 1.5m or greater of most airliners), I decided up front that my pedestal would have to be somewhat thinner that you’d find on a really big jet. It’s not going to be blade-thin, you understand. It’ll be wide enough to accomodate a four-lever throttle quadrant. But not all those blingtastic buttons that the Airbus has going on.

For the last few weeks the pedestal has been lurking in the corner of my build room acting as a shelving unit for the many off-cut pieces of MDF that I use up from time to time. This weekend, having a couple of hours free, and having recently painted the main console shell and glareshield assembly, I decided to paint the pedestal frame. This gives me a good excuse to spend some time talking about the perils and pitfalls of painting MDF.

(I rotated the above image so the pedestal is oriented the right way; don’t worry about it hanging out in space like that. The rather peculiar shape is designed to fit snugly against the console in the right places – only the first half or so from the left, up to the peak, will be visible in front of the console, with the rest fitting underneath and providing support for the weight on top of the console as well.)

I had to use small blocks of softwood as a joining element in the load-bearing parts of the structure, because screwing into MDF along the side tends to split it and the joins are weak:

When painting MDF, you have a number of choices. Wood paint will work reasonably well, as will hobby spray-paint (in fact spray-painted MDF, done well, provides a high-sheen surface akin to painted metal, which is excellent for cockpit work. Done badly, it sucks, as I found out on my glareshield prototypes). You can buy a specialist MDF primer to use as an undercoat if you like, although the shiny surface of most MDF sheets will take paint directly without the need for primer. I use a general house paint intended for kitchen and bathroom use, which will be somewhat moisture-resistant, is odour-free, and dries very quickly (touch-dry in about 10 minutes; fully dry in about an hour). I tried the primer but found I didn’t need it in the end. Two coats usually does for a good even covering, and with this paint being so quick-drying you can usually start applying the second coat just after you’ve finished the first.

To get a nice painted-metal texture, without using expensive metallic paint which wouldn’t look very good anyway, I use a mini-roller rather than a brush or larger roller. The sleeve for this is designed for use with gloss paint and is made from foam. The pores in the foam give the painted surface the correct texture. Traditional roller sleeves do not leave this texture and the end result is, to my eyes at least, less pleasing. I did need to use traditional brushes in certain less accessible areas, but these are in areas largely hidden away from view, so I can live with a less pleasing finish.

Before painting, I went over the pedestal frame and used wood filler on some areas where screws had to be moved after initial construction. Little dings and dents are common, and a decent filler will cover them over more or less entirely so you won’t notice them when painted.

All of that done, the actual painting was, well… uneventful. I mean, it’s just painting. Here’s the post-painting article.

Leaving the insides and bottom edges unpainted was deliberate, BTW – no need to paint what can’t be seen (once all the panels are in place), and the bottom edge will be joined to a base panel eventually anyway. Which leads me nicely onto the topic of painting MDF edges.

Thing is, the faces of MDF are designed to be painted. They’re sealed, shiny and non-porous. The edges are very a different matter. An MDF edge is a plane through numerous layers of what amounts to dust bonded together with glue. It’s very porous. Very. It will slurp up your paint like a thirsty plant slurps up whatever water you give it. In general, I try to leave MDF edges invisible or cover them up, but if you must have one exposed and must paint it, use primer or a very viscous paint. I have heard good things about using some form of varnish to cover the edges before painting, but I haven’t tried it.

Also, be aware that when MDF is exposed to moisture – including the solvent in which your paint particles are dissolved – it swells. This is because the small grains of wood dust that make it up are dry when they’re glued, but swell up under the influence of moisture and the glue cannot contain this expansion. The faces are non-porous so it’s not an issue there. Again, use of a viscous paint which has less moisture in it to begin with, and a quick-drying one where the solvent evaporates quickly, will help. Even so, I had a few exposed edges on my shell balloon up and require trimming or sanding (and this in itself causes more problems – sand the shiny surface off MDF and you’re into the fuzz underneath which will just swell again when painted).

With all basic elements of the phase 1 shell now painted and in place, it’s time to turn to the installation of the computing power. That’s a story for an upcoming post.