Wood...cracking...painting...anyway to stop it?

[marksandygill]

I'm hoping to start building a new floating tv cabinet soon, I'm thinking about a wooden frame with sheet wood (MDF/Chipboard/Plywood etc) on top and then shiny white cabinet paint and an enamel finish.

The issue I think I will have is the wood expanding and cracking the paint/enamel, does anyone have any tips or hints (I've seen some people use car body filler to cover the wood as it stops moisture from the paint etc) or is it just inevitable that the wood will crack along the joints?

 

[RobinBHM]

The best solution is to design the cabinet so that there are no flush joints.

 

[marksandygill]

Yeah...original idea has everything flush but knowing how long it will take to paint and get it right I don't want to have to see it all crack after a couple of months!

Think I might leave a 1-2mm uniform gap between all of the sheets, could just pretend its a 'design feature'...?

 

[rafezetter]

There is a practice in woodworking called a "Shadow joint" - whereby the mating face edges have been chamfered a small amount creating a V-groove. This is used for several possible reasons; for design effect, to visually hide less than perfect flush joints, r if the item is to be painted, any hairline cracks forming over time will occur at the base of the V-groove and thus be hidden in shadow.

This article look like it should give you all the info you need : http://www.lautsprecherbau.de/Practical-guide/Design/Shadow-joint/8602,en

They have used a router bit to assure evenness of depth and angle of bevel - a V grooving bit would work just as well as the one they use but would require you use a clamp guide as they don't have a runner bearing.

You might wish to consider what level of finish you'll want as that will be dictated by the material you use. A high gloss laquered finish on MDF can be hard to achieve at home without the use of 2pack paints (which are extremely toxic and should not be used without a full setup for it) which as you may be aware is an epoxy paint and completely seals in the MDF as you mention. Normal oil paints are fine on MDF but the edges will require special prep beforehand so they don't end up looking like garbage.