Cheers. I don't tend to get on with the cut edge of MDF. What is your method for sealing and finishing?
Years ago when I worked for a cabinet maker, we used to use a (clear) two pack product from Morrells to seal routed end grain MDF and then spend ages sanding it back. After a few years, he decided that it was too expensive and realised that few other cabinet makers bothered using it.
As a decorator (who for many years specialised in hand paint MDF units), if faced with, for example, a bull nose finish on a MDF window board, I sand it with 80 grit Abranet and work my way through and up to 180 grit Abranet. I then apply a coat of cheapy Leyland acrylic primer and sand it with 180 grit. I keep sanding until I see a uniform colour- that is to say, I sand 60% of the primer away. I then apply 2 or 3 coats of oil based eggshell.
I have to say Medite is better than cheap MDF and MR MDF has less grain swell when applying the Leyland primer. To be honest though, I prefer painting regular medite rather than MR MDF. The reason being that the first coat of oil based eggshell. soaks in deeper and enables me to apply a more evenly coloured first coat. With the MR the paint slides (albeit, very slightly)
The primary reason for using the Leyland waterbased primer is that it is a dream to sand. More expensive waterbased primers tend to clog the abrasives.
Contrary to what many will tell you, MDF is not perfectly smooth. There are visible (parallel) sanding lines in the face finishes. Hence the extent to which I sand it after the primer.
The above isn't the best photo, but hopefully you can see the parallel lines.
