Hi everyone, I am working on a large (24in x 34in ) shadow box that needs to
be painted gloss black. It needs to be done cheaply so I used some MDF that
I had laying around. I'm using cheapo spray paint from WalMart and am
having trouble with the rounded edges not taking the paint. The flat
surfaces are fine but where I used a round over bit the MDF is behaving like
end grain-it's just sucking up the paint. I shot a primer coat and three
top coats and still cannot get a nice finish. Before painting I also sanded
to 220 grit so it should be smooth enough. Can anyone shed light on this
problem?
Thanks,
Gene

--





This message has been scanned by Norton Anti-virus software

In article ,
"Gene T" wrote:

Hi everyone, I am working on a large (24in x 34in ) shadow box that needs to
be painted gloss black. It needs to be done cheaply so I used some MDF that
I had laying around. I'm using cheapo spray paint from WalMart and am
having trouble with the rounded edges not taking the paint. The flat
surfaces are fine but where I used a round over bit the MDF is behaving like
end grain-it's just sucking up the paint. I shot a primer coat and three
top coats and still cannot get a nice finish. Before painting I also sanded
to 220 grit so it should be smooth enough. Can anyone shed light on this
problem?
Thanks,
Gene

Think sponge.

You need to seal the porosity. I use lacquer-based automotive finishing
putty.

Gene T wrote:
Hi everyone, I am working on a large (24in x 34in ) shadow box that needs to
be painted gloss black. It needs to be done cheaply so I used some MDF that
I had laying around. I'm using cheapo spray paint from WalMart and am
having trouble with the rounded edges not taking the paint. The flat
surfaces are fine but where I used a round over bit the MDF is behaving like
end grain-it's just sucking up the paint. I shot a primer coat and three
top coats and still cannot get a nice finish. Before painting I also sanded
to 220 grit so it should be smooth enough. Can anyone shed light on this
problem?
Thanks,
Gene

The spray paints (Pressure Packs) are just to thin for MDF edges. Get
out a brush and give them a coat of acrylic Black or undercoat-sealer.
Sand back nice and smooth and then spray. All should be OK.
Regards
John

"Gene T" wrote in
:

Hi everyone, I am working on a large (24in x 34in ) shadow box that
needs to be painted gloss black. It needs to be done cheaply so I
used some MDF that I had laying around. I'm using cheapo spray paint
from WalMart and am having trouble with the rounded edges not taking
the paint. The flat surfaces are fine but where I used a round over
bit the MDF is behaving like end grain-it's just sucking up the paint.
I shot a primer coat and three top coats and still cannot get a nice
finish. Before painting I also sanded to 220 grit so it should be
smooth enough. Can anyone shed light on this problem?
Thanks,
Gene


An article in FWW and/or FHB showed sealing the cut edges of MDF with
thinned drywall taping compound. Fills, smooths and pretty much seals the
edges. Use before priming.

Or so I'm told. I use very little of the stuff, personally.

Patriarch

"Gene T" wrote in message
...
Before painting I also sanded to 220 grit so it should be smooth enough.
Can anyone shed light on this problem?
Thanks,
Gene


When ever I finish MDF with paint I prime the hell out of it. I use Krylon
spray primer and lay it on until it looks like it will run, then I let it
dry, and put on one or two more heavy coats, with a light sanding in
between. Keep laying on the primer until it quits absorbing into the MDF.
Greg

Thanks for all of the useful info guys. I didn't realize how porous MDF
was. Now I wish I had used polar instead!!!
Gene
"Gene T" wrote in message
...
Hi everyone, I am working on a large (24in x 34in ) shadow box that needs
to be painted gloss black. It needs to be done cheaply so I used some MDF
that I had laying around. I'm using cheapo spray paint from WalMart and
am having trouble with the rounded edges not taking the paint. The flat
surfaces are fine but where I used a round over bit the MDF is behaving
like end grain-it's just sucking up the paint. I shot a primer coat and
three top coats and still cannot get a nice finish. Before painting I
also sanded to 220 grit so it should be smooth enough. Can anyone shed
light on this problem?
Thanks,
Gene

--





This message has been scanned by Norton Anti-virus software

In article ,
"Gene T" wrote:

Now I wish I had used polar instead!!!
Gene

....working with that stuff can give you a disorder.
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
I seldom make fun of a typo..sorry 'bout that.

You can also buy special primer for MDF too
Most big box tool stores should have it.

--
Regards,

Dean Bielanowski
Editor,
Online Tool Reviews
http://www.onlinetoolreviews.com
Complete our tool survey, Win $200!
------------------------------------------------------------
Latest 6 Reviews:
- Sherwood OS-100 Oscillating Spindle Sander
- Porter Cable NS150A Narrow Crown Stapler
- Book: Popular Mechanics Shelving & Storage
- Betterley Tru-Cut Insert System
- Digital Calipers & Height Gauge
- Delta SS250 Scroll Saw (Review Updated)
------------------------------------------------------------

"Gene T" wrote in message
...
Hi everyone, I am working on a large (24in x 34in ) shadow box that needs
to
be painted gloss black. It needs to be done cheaply so I used some MDF
that
I had laying around. I'm using cheapo spray paint from WalMart and am
having trouble with the rounded edges not taking the paint. The flat
surfaces are fine but where I used a round over bit the MDF is behaving
like
end grain-it's just sucking up the paint. I shot a primer coat and three
top coats and still cannot get a nice finish. Before painting I also
sanded
to 220 grit so it should be smooth enough. Can anyone shed light on this
problem?

Unfortunately I work with MDF all too often, I find no joy out in working
with it whatsoever.

I make a light wash of PVA and water and "pre-prime" (hey, did I just invent
a new term?) the MDF edges with that, let it dry and then prime & paint
normally. Occasionally I may also need to do some filling but I do that
after priming and usually add a second coat of primer over the filler.

It works for me, anyway.

- Andy

I used shellac for this purpose and found that it did a good job of
sealing the surface. After each coat (did several) I sanded the
surface to make it smooth. Has anyone tried shellac as a primer? Have
you found that the other methods mentioned did a better job?

I have used it ith success.

I like shellac for it's quick-drying, and it "sandability".

-Steve
wrote in message
oups.com...
I used shellac for this purpose and found that it did a good job of
sealing the surface. After each coat (did several) I sanded the
surface to make it smooth. Has anyone tried shellac as a primer? Have
you found that the other methods mentioned did a better job?

Oh yes, I forgot that you can add some sandarac (about 10% or so) to
shellac and it makes it less "gummy" and more friable so it sands a lot
better. Sandarac is a gum resin that can be purchased from some
finishing suppliers.

In article .com,
wrote:
I used shellac for this purpose and found that it did a good job of
sealing the surface. After each coat (did several) I sanded the
surface to make it smooth. Has anyone tried shellac as a primer? Have
you found that the other methods mentioned did a better job?


I haven't used plain shellac, but I have used Zinsser BIN primer,
which is a shellac based primer with white pigment added. It worked
very well for me.


--

Larry Wasserman Baltimore, Maryland

Andy McArdle wrote:

I make a light wash of PVA and water and "pre-prime" (hey, did I just invent
a new term?) the MDF edges with that

A.K.A. "Glue Size".

Andy McArdle wrote:

Terminology's one of the problems with being self-taught...


I know the feeling.

"B a r r y" wrote in message
.. .
Andy McArdle wrote:

I make a light wash of PVA and water and "pre-prime" (hey, did I just
invent
a new term?) the MDF edges with that

A.K.A. "Glue Size".

Ah. Thank you. Terminology's one of the problems with being self-taught...

- Andy

Terminology's one of the problems with being self-taught...

I know the feeling.

Lessee... glue sizing isn't about wallpaper, tenons go in mortises instead
of chucks, and if a plane flies you're doing something wrong? Next I'll be
told a jig is not when you hit your thumb and lathing doesn't involve
plaster.

No. No, I'm not getting the hang of this. I'm going back to pointy sticks.

- Andy