How to seal the cut ends of MDF before painting? (1 Viewer)

[Bill**H]

I want to paint my Tempest AA box this weekend. How do I seal the cut ends of the MDF so they will stop soaking up all the paint? I never could get the cut edges of the MDF top plate of my speaker stands to look good because it kept soaking up paint. I didn't use a primer on them. Will a filling primer for cars seal the ends so my paint job will come out looking good? I'm just going to spray paint the box. My speaker stands came out looking great but they were all Oak except the top plate.

Bill

 

[Jeff shark]

I just used a sandable primer on my MDF towers....
2 coats of primer, & the ends didn't seem to soak in any paint at all.

 

[Wayne Ernst]

As far as primer goes, you could use the Zinnser Bullseye 1-2-3 which is sold at most home centers. Plus, the primer can be tinted, so tint it close to the color you are going to be painting your MDF.

 

[Brian_J]

Sanding sealer works well too.

Brian

 

[TimForman]

Here's what I did my last go:

1. I used Bondo Dynatron Glazing and Spot Putty on all the seams and other imperfections I saw. Sanded with 120 on an orbital sander.

2. Used Benjamin Moore Fresh Start 100% Acrylic Primer. Hand sanded with 400.

3. Repeated 1 & 2 two more times.

 

[Geoff L]

Regrdless the approach you take, and many have different way/aproaches to this, sanding and recoating is just a (major part in MDZ finishing in oredr to get a high quaility finish.

There ar different products out their and many approaches to using them, but no matter which you chosse to try/follow, time and allot of sanding is required when finishing RAW mdf. Thats why you see many now moving and or always using veneers, vinal, real wood, or veneered (plywood void free is best) to finish their projects.

Bottom line, a perfect glasss or satin finish dose not comes arm strong free..

You could always go with the ever growing truck bed liner finsh, which is now coming in colors by some manufactures.

I use a process very simalar to Tim F, except I use the newer expoxy 2-part primers, fillers and puttys. Will not shrink in time and dries quicky so you can get started sanding ASAP...
Very fortunante to have a friend with a top line body shop and access to his goodies when needed...

Regards
Geoff

 

[Dean T]

Hehehe others beat me to it...

I use a sandable filler when working with MDF. You can use anything from the 2-part epoxies that are mentioned, to the basic wood putty that you can get at the same place you got the MDF. nice thing about the wood filler is that it can be thinned with only water, so no fumes to deal with, and it then can be brushed on to seal the entire piece to get that super smooth surface ready for primer or paint once it's been sanded (for some reason not all MDF surfaces are the same, heheh).

Either way you go, there will be some arm exercising going on, hehehe!!

 

[Denis P]

I've had good succes with a 50-50 mix of regular wood glue and water. Paint it on and let dry then sand. You still need to sand a fair amount but you can get a very smooth finish.