do you fill the "end grain" of MDF before spraying?

[Jeff@G]

Quick question... I want to make some furniture using MDF as the main material, but with that sprayed on, deep wet grand piano style finish.
There will necessarily be some edges (I know MDF has no "Grain", but you know what I mean) of the MDF that are to be finished surfaces.
So what needs to be done to "seal" the edge so that paint isn't absorbed and that the edge accepts paint and give the same perfect finish as the MDF faces?

Any info on spray finishing on MDF would be appreciated.
Thanks all.

[echnidna]

Apply a coat of auto primer surfacer first and rub it back with wet & dry

[Harry72]

I use fibre glass or epoxy resin, although I tried some of ubeauts dewaxed shellac the other day but I havent put any top coats as of yet.

[martink]

I Use a schellac mix, and if I want it really smooth, rub in a bit of pummice at the same time. It works every time for me when I need to end fill either MDF of plywood and I can use any top coat after I'm done.

Ciao,

M.

[Big Shed]

I use a slurry made from waterbased undercoat and polyfilla or gyprock filler. Just brush it on, let it dry and sand it off.

Latest Australian Woodsmith (#55) has an article on finishing MDF and the edges.

[MurrayD99]

I "polish" it with a ROS.

[Pulse]

Mirotone recommends timbermate filler. I found it works best slightly thinned with water to a pancake batter thickness, dries out a bit on the spatula but just remix with water.

Works really well

Cheers
Pulse

[jmk89]

Mirotone recommends timbermate filler. I found it works best slightly thinned with water to a pancake batter thickness, dries out a bit on the spatula but just remix with water.

Works really well

Cheers
Pulse
That's what I do. It works well on MDF, blockboard and ply.

[Greg Q]

I have used shellac, thinned white pva glue, polyfilla crack filler, surplus oil paint and gesso.

They all get the job done...I'd use the cheapest, easiest to sand thing that I could lay my hands on. In my case that's gesso. You can get it at art supply stores, but its frankly not worth going out of your way for if you can get plaster grack filler easier.

Cheers

Greg

[Shedgirl]

Gyprock joint compound. Cheap, in big buckets!

[Jeff@G]

I "polish" it with a ROS.
Pardon my ignorance but what is a ROS?

Thanks for the response all...

[jmk89]

ROS = random orbital sander

[Jeff@G]

Gyprock joint compound. Cheap, in big buckets!
Hmmmm... I've got some of that stuff... Do you need to then Seal the sealer though?
CHeers
J.

[Christopha]

Some interesting replies there but what if a clear finish is required?

[Greg Q]

Some interesting replies there but what if a clear finish is required?

Then I guess you are stuck doing two coats on the edges before the top coat(s). Anytime I have done that its been shellac, and time consuming. I haven't yet tried grain filler, but it might be better...it dries slower but fills better, and sands easily.

I've only ever done this on jigs and shop things, and one table for a friend. His wife grew tired of the clear MDF look within a few weeks anyway.:cool:

[Jeff@G]

Apply a coat of auto primer surfacer first and rub it back with wet & dry
Do you use the wet& dry "wet"? Don't you run the risk of water damage to the MDF? Doesn't the stuff swell up easily when wet?