Hi All,

I spent 10 years working in steelworks, and now I no longer do that I develop properties and do all the work myself! (No I am not Nuts, but am too picky to employ someone when I am sure with some practice I could do it myself!)

Rather than replace some stunning 1930's art deco architrave with rubbish ogee, I recreated it using my router out of MDF. It is a really good match, but the problem is the ammount of finishing I have to do prior to painting.

I suppose the only way to describe the finish is furry! and requires a hell of a lot of sanding to get flat, the problem with this is that the detailing is a mix of radius and straights, and really has to be done by hand, and is very labour intensive.

Is there anyway I can change my technique to correct this?

I am using a Bosch GOF 2000CE 1/2" Plunge Router 2000w, so better than an average DIY'er, with trend cutters.

And please, nobody say use a detail sander!! I just need to know if this is normal, or if I am doing something wrong.

Thanks in advance

Don,t use rubbish MDF and you will get a better finnish

Wow, how useful.

I am sure there are enough debates on here about the benefits/disadvantages of MDF, and I dont want another one. Normally I only use Oak/Elm/Ash. but as this is painted, and the quality of pine and the likes from a local DIY store (which is the only thing within a 40 mile round trip) is crap, MDF will surfice.

I just want to know if I am doing something wrong or not?

Hi Iron

I don't think you are - that is what happens to me - I have both more expensive and less expensive cutters and doesn't alter a great deal - I have variable speed routers and that makes some difference but the furry edges can still happen - I assumed it was the routing process lifts the fibres - but higher speeds reduces the effect - it is greater with rounded cutters - straight edges or vee cutters don't do it

Regards

Peter

Thanks Peter!

That's good to know it's not just me. My personal trick now is before sanding, I give it a coating of diluted emulsion, both to seal and prime the MDF. When it dries it makes sanding a hell of a lot easier! and takes a coating of trade one coat gloss beautifully.

Thanks again

Iron sorry my advice wasn't usefull, next time you ask a question maybe you should specify the answers you want beforehand

I think that the OP misread the first reply, which I hope was meant to say "Don't use poor quality MDF" rather than "Don't use MDF which is rubbish."

This advice is very true, because the "fluffiness" you experience is caused by low-quality core material, typical of low-priced, DIY store sheet goods. Try using really good-quality water-resistant MDF (Medite, for example) and the vast majority of your problems will disappear immediately.

Medite is a little harder on the cutters, but not disproportionately so. WR MDF is denser, finer (usually greener, too!) and takes a profile very well. Sharp, clean cutters are a must, of course, the best you can afford. There are better than Trend, I mostly use Wealden. PM for more details, as UK cutters won't interest many!

Ray

MDF has very different absorbtion characteristics between the faces and the edges. By routing profiles into the material, you are extending this problem into a lot of the visible surface. One known solution is to coat the exposed raw fibre areas with plasterboard jointing topcoat compound to fill the surface, then sand with appropriate profile sanding blocks. This results in a surface with similar absorbtion characteristics to the normal face of the sheet. As a byproduct, the topcoat sands very easily and reduces the amount of sanding required.