Sealer for MDF

[mrwireless]

I know, i know.....this topic has been done to death, however....

....having read all the posts, the many posts, there really isn't any clear advice on what's good to seal MDF cabs before priming and painting. It can't just be me scratching their head over all the different options.

So what are people currently using to seal MDF? What have you settled for at this moment in time?

Epoxy?
Polyurethane?
Urethene?
Wood hardeners?
Gelcoat?
Acrylic?

If any UK based people can gives links to products i can buy here, that would be very very appreciated.

[evanc]

BIN shellac based white primer. dries fast and sands easily. scuff the surface of the med before you paint it no matter what you end up using.

[mrwireless]

I read the data sheet. An interesting product that seems to tick the boxes.
I wonder why it hasn't had more mention.

Most threads are concerned with ensuring joints don't show through. That is a concern of mine, but i am unlikely to do a "piano" shine finish. I prefer matte.

[pinkmouse]

I use sanding sealer, works a treat. The other thing you can do is finish up the woodwork, seal, then before doing the final finish leave the boxes to acclimatise to your house for a month or so. The wood will then settle down to the humidity in your house, then you can do a final sand and finish.

[joe58]

Originally Posted by pinkmouse

I The other thing you can do is finish up the woodwork, seal, then before doing the final finish leave the boxes to acclimatise to your house for a month or so. The wood will then settle down to the humidity in your house, then you can do a final sand and finish.

To be fair I think that happens anyway as probably quite a few builds go with out paint for a while, as you just want to listen to them.

On a serious note I will for a non speaker build, be trying to seal MDF with some Wilko's PVA mixed with water tomorrow and will let you know how that goes. It is stated on it that this can be done, but we'll see.

[simon7000]

PVA doesn't sand well. It will however allow you to use a water based filler over it.

If you want to cheat, mix joint compound with water to fill the surface. Sands nicely but what a mess!

There are lots of products called sanding sealer, the actual brand is quite important. DuPont makes a good one for wood but it is hard to find. Automotive gray primer works well but you have to spray it.

[mrwireless]

Originally Posted by simon7000

There are lots of products called sanding sealer, the actual brand is quite important.

I quite agree. There are just so many different products you could use, and variations thereof.

Can i ask if anyone is suggesting a product they like that they specify exactly which brand and type they're referring to. I hope that makes things clearer for everyone. Is there a particular Automotive primer or Sanding Sealer etc. in mind?

At the moment Zinsser BIN Shellac primer sealer is has been suggested.

[pinkmouse]

Okay, this stuff

[marce]

I use this on MDF, started using it when it was all I had, so I thought I'd test it. Takes a while to dry but does do a good job on the edges.
Ronseal Wet Rot Wood Hardener | Wood Filler Products | Ronseal
Also used chestnut cellulose sanding sealer and melamine lacquer.
All dry to a veryvery hard finish, which I think is necessary for MDF.

[evanc]

Another advantage of the zinsser product is the fact that it is alcohol based. It is less toxic then any other thinner based product, and you can top coat with whatever you want....thinner based or water based.....