finishing the edge of MDF

[will_89]

Hi all,

First time posting so hopefully I get this right.

I've recently made some built in alcove units in MR MDF with oak tops and shelves. One problem I had was getting a nice finish on the sawn edges of the MDF, even though I used moisture resistant and sanded the edges to 400grit the finish wasn't great. I suppose edging the mdf with solid timber would be one way of solving this but wondered if anyone uses a different method, maybe some sort of sealer?
Thanks
Will

 

[Random Orbital Bob]

There is a tape you can buy...I've not used it myself as I generally trim them with hardwood. If you search around a bit you'll find some recent posts on it.

 

[marcros]

There were some comments on one of my threads that you may find useful.

knotting-solution-t71333.html?hilit= knotting

 

[Chrispy]

So long as you have prepared the MDF first to remove all saw marks and then sanded between coats of finish the edges should end up as good as the faces.
Perhaps you can explain why your not happy with your results.

 

[katellwood]

I rub car body filler into the edges prior to sanding, works for me

 

[Bradshaw Joinery]

Either apply PvA or even better end grain sealer using a sponge/stiff brush, or paint with a suitable MDF primer after sanding to 180-240 grit, I used sayer lack primer and it was perfect after one coat and sanding.

 

[MrYorke]

Firstly, how are you currently finishing the edges?

As mentioned in other posts, I use Zinnser BIN (shellac based) sealer NOT the water-based version. It's expensive but is the best out of a lot of finishes I've tried. One of the main things is it dries very very quickly.

 

[johnf]

I use zinsser bullseye 123 works for me this is the water based one so brush cleaning is easy

Zinsser bin needs meths for brush cleaning but does the same job

 

[will_89]

Thanks for the replies,

I used movac PU paint spray applied and sanded between coats. The finish wasn't bad just not as good as the face.
I'll try sealing it next time.

 

[longinthetooth]

I use pva thinned with water (possibly 1:1 as a wild guess but I just go by the texture) - let it dry, then sand. It both binds the soft fibres and blinds their absorbency.

 

[Leif]

I made a little corner piece to go above my boiler and hide the pipes. I used MDF offcuts, primed with a couple of coats of Zinsser 123 followed by emulsion paint. It looks good, the join is invisible, the ends look as good as the faces. It was cut using a jig saw, produced a perfect cut. Not keen in Zinsser bin as it dries quickly and is messy to clean.

 

[WurliTzerwilly]

Hi all,

First time posting so hopefully I get this right.

I've recently made some built in alcove units in MR MDF with oak tops and shelves. One problem I had was getting a nice finish on the sawn edges of the MDF, even though I used moisture resistant and sanded the edges to 400grit the finish wasn't great. I suppose edging the mdf with solid timber would be one way of solving this but wondered if anyone uses a different method, maybe some sort of sealer?
Thanks
Will

If you have the right equipment you could do what a professional finisher friend of mine does and what I'm currently learning.

Use a thixotropic grain filler and fill the faces as well as the edges. It just wipes on with a cloth and excess is removed with a cloth. Then go over it all with 240 grit sandpaper, by hand and very lightly or it clogs.
Then apply suitable acrylic primer/undercoat with a pressure sprayer. Then two coats of appropriate coloured acrylic paint. You have about three hours to complete the two coats. Dried rock hard. There are also rag-rolling techniques for grained finishes.
The finish looks really great. MDF can be made to look like veneered walnut etc.

Call Mylands (London) and they'll send you a fact sheet and give advice on what you need. 020 8670 9161

 

[promhandicam]

There is a tape you can buy...I've not used it myself . . .

I have. You can get it here. Iron it on trim it back and you're done. If you have a decent saw - panel saw or track saw with a sharp fine blade - then you don't need to sand it at all with the strong possibility of rounding over the edge.

NB. No affiliation to edgeband.co.uk, just a satisfied customer.

 

[mailee]

I will have to add to this that I have just tried the Zinnser bin and it works great (Spirit based one) I applied one coat with a brush and then sanded it with 150 grit it dries very quickly. I then spray the panel with my usual Morrells primer one coat and then sand with 320 lightly and on with the top coats. Not cheap stuff but it works great. :wink: