Which flexible non shrink/crack filler to use?

[ED65]

I try to minimise screw holes where possible so minimum filling but recently I fitted some pine architrave and the knot fell out and a decent filler would have been ideal.

Well for something like a lost knot you can glue in a small piece of dowel, that can work quite well. But you can make a very decent filler as needed from sanding dust or fine sawdust and some glue. Epoxy is much favoured for this these days and it works really well, without an excessively long hardening time.

I think your main requirement for filling on the toy chest is strength rather than flexibility, and wood dust + epoxy has that in spades too. It's not what you'd call flexible like caulk if flexible, but it does resist movement enough that it won't crack like many standard wood fillers.

 

[skipdiver]

How much filler? People will buy any old tat nowadays. My niece paid a packet for 2 hand painted wardrobes, "shabby chic" they call it. They were just those horrible old brown 60's jobbies with a slapped on paint finish, most of which had scraped off by the time her hubby and mate had manhandled them upstairs. They are fashionable though, so i've been told.

 

[petermillard]

P.s. when you cut MDF and you get the fluffy cut surface, to make it smooth would you sand and then seal or fill, sand and then seal or something different?

Use MR MDF if you can - much better board for not much more money and minimal 'fluffiness'. I use a water-based primer/undercoat straight onto the cut surface applied with a foam roller; rub it smooth once dry and apply a second coat, followed by your usual process for topcoating, once dry. That's it.

Never had an issue doing the above, and I've painted a *lot* of MDF over the years for some very picky clients.

HTH Pete

 

[skipdiver]

P.s. when you cut MDF and you get the fluffy cut surface, to make it smooth would you sand and then seal or fill, sand and then seal or something different?

Use MR MDF if you can - much better board for not much more money and minimal 'fluffiness'. I use a water-based primer/undercoat straight onto the cut surface applied with a foam roller; rub it smooth once dry and apply a second coat, followed by your usual process for topcoating, once dry. That's it.

Never had an issue doing the above, and I've painted a *lot* of MDF over the years for some very picky clients.

HTH Pete

That's the process i use too, with MRMDF being much better for finishing. Some like to also put pva on cut edges and i have tried that as an extra precaution but can't say it made a massive difference. My process is to plane cut edges with a nice sharp plane, then a good sanding once assembled, before the painting starts.

 

[ComfortablyNumb]

if I was making those boxes I'd mitre every joint so would negate the need of filler.