MDF painting

[gad5264]

Good morning all, I am looking for information on the best sealing practices for MDF before I spray paint it. I cut some letters out this weekend and am placing them on a sign and want to spray paint them. I am assuming that the edges will be like sponges and suck up the paint.

This will be an inside sign for an office.


Any thought and insight?

Attachments:

[stevem]

I use unwaxed Schellac! It's a Zinzer product, but it's available in many other brands.
I mix mine 50/50 with denatured alcohol and MDF really soakes it up.
Put 2 coats on then lightly sand then another coat or two and you should be ready for paint.

[gad5264]

Aug 24, 2020 12:37:35 GMT -5 stevem said:

I use unwaxed Schellac! It's a Zinzer product, but it's available in many other brands.
I mix mine 50/50 with denatured alcohol and MDF really soakes it up.
Put 2 coats on then lightly sand then another coat or two and you should be ready for paint.

Thanks Steven

[dustypilot]

I agree and the quick dry time is a real bonus when you are trying to get the project out the door.
Tim

[christcrosscrafts]

I'm a huge fan of the Mohawk vinyl sealer.  It goes on easy and dries quick.  Plus, it won't raise the grain and allows for natural wood movement without cracking the topcoat finish.  I get mine here:  
www.woodworkingshop.com/product/m1028000/

If you are using water-based paints, then the shellac is best.  I've used the thinned shellac and had good results with it as well.  Zinsser actually makes a version of what was previously described  that's already thinned called "SealCoat".  
www.woodworkingshop.com/product/zr00854/


I'm always looking for better/faster, so I'm constantly testing finishes.

[jackoat]

If you are in the UK then try some 'Mylands Knotting' (or any other similar knot sealing.
We make MDF sculpture display plinths and use this product as it is deep penetrating and fast drying.
Because it dries fast it can be rubbed down soon after so cutting production time.