MDF architrave

[wellywood]

I want to round over one edge of some mdf profile. Problem is, when I've done this in the past, the resulting surface won't paint smoothly (it becomes 'furry', a bit like end grain on wood).
Does anyone have any tips on treatment to the cut surface that will allow me to sand it smooth before painting? I was thinking of a water/PVA solution brushed on the cut surface. Would this work or any other ideas?

 

[carlb40]

Try the moisture resistant mdf, other members use it as it isn't furry like normal mdf.

With normal mdf in the past i have sanded the rounded over part up to 400g or more and applied plenty of primer first. Anything up to 5 coats then glossed it.

 

[Random Orbital Bob]

But also if you give it a pass or two with 44 grit paper it will neaten it up and then you can give it a coat of cellulose sanding sealer that will bind the fibres. De-nib with 4-600 grit and then paint.

EDIT: That should read 400 grit paper of course and not 44...apologies for the typo

 

[wellywood]

Thanks guys. Unfortunately this is proprietary mdf profile and not available in mrmdf. I'll try both suggestions on some offcuts and see which gives best results.

 

[carlb40]

If you sand between each coat, every time you apply a coat of primer it will act almost like a sanding sealer. I will be in my workshop tomorrow after work so if i remember i will take some pics of my mdf thicknesser stand. That has rounded over corners and is painted.

 

[hansonread]

Morrells mdf sealer, you have to buy 5 litres of the stuff but its a worth investment. If you only want a small amount I can send you some for some beer tokens

 

[fiveeyes]

shellac works well for me

 

[wellywood]

Thanks for all the suggestions. Hansonread - what the heck is a beer token? Don't you guys use real money any more? :lol:

 

[Silas Gull]

I use pva with good results. If the workpiece is profiled, then sanding back with a fine steel wool will help maintain the shape.