Smooth finish on MDF
 

Hi all,

I'm trying to achieve a smooth painted finish on MDF.

I have a project where I'm cutting rings out of 3/4" sheets (each ring
has a 17" external, 15" internal diameter). The rings are then glued
together to create a tube.

My previous experience of finishing MDF was priming (with a brush) a set
of loudspeakers, sanding down and then spraying them with tins of paint.

I had huge problems with the primer (International MDF Primer) as it
never seemed to dry properly - attempting to sand it would result in
dragging off tiny rolls of primer and it clogged the paper. I even
bought a second batch, thinking the the first was contaminated, and left
the piece to dry for a week. It still wouldn't sand.

As I don't have a HVLP spray setup, could anyone recommended a primer
that I can paint/roll onto the outside of these rings, that will sand
well, so I can produce a perfectly smooth finish that I can spray paint?
I'm in the UK BTW.

Many thanks.

"sploo" wrote in message
...
Hi all,

I'm trying to achieve a smooth painted finish on MDF.

I have a project where I'm cutting rings out of 3/4" sheets (each ring
has a 17" external, 15" internal diameter). The rings are then glued
together to create a tube.

My previous experience of finishing MDF was priming (with a brush) a
set
of loudspeakers, sanding down and then spraying them with tins of
paint.

I had huge problems with the primer (International MDF Primer) as it
never seemed to dry properly - attempting to sand it would result in
dragging off tiny rolls of primer and it clogged the paper. I even
bought a second batch, thinking the the first was contaminated, and
left
the piece to dry for a week. It still wouldn't sand.

As I don't have a HVLP spray setup, could anyone recommended a primer
that I can paint/roll onto the outside of these rings, that will sand
well, so I can produce a perfectly smooth finish that I can spray
paint?
I'm in the UK BTW.

Get a primer made for auto bodies...sands wonderfully.

--
dadiOH
____________________________

dadiOH's dandies v3.06...
....a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at http://mysite.verizon.net/xico

Prime with a Zinzer BIN. It is shellac-based rather than latex. It sands
well. An oil-based primer would probably work well too, but it would require
more time to cure before sanding.

-steve



"sploo" wrote in message
...
Hi all,

I'm trying to achieve a smooth painted finish on MDF.

I have a project where I'm cutting rings out of 3/4" sheets (each ring
has a 17" external, 15" internal diameter). The rings are then glued
together to create a tube.

My previous experience of finishing MDF was priming (with a brush) a set
of loudspeakers, sanding down and then spraying them with tins of paint.

I had huge problems with the primer (International MDF Primer) as it
never seemed to dry properly - attempting to sand it would result in
dragging off tiny rolls of primer and it clogged the paper. I even
bought a second batch, thinking the the first was contaminated, and left
the piece to dry for a week. It still wouldn't sand.

As I don't have a HVLP spray setup, could anyone recommended a primer
that I can paint/roll onto the outside of these rings, that will sand
well, so I can produce a perfectly smooth finish that I can spray paint?
I'm in the UK BTW.

Many thanks.

Thanks dadioH.

I'm only familiar with spray cans of automotive primer (which I know don't
work well on MDF). What type of product do you mean?


Get a primer made for auto bodies...sands wonderfully.

--
dadiOH

I used an automotive sprayer in the past to spray latex primer. The
can specified no need to thin and it worked great. I ended up brushing
the topcoat on because for this project the finish was too smooth. I
would expect a little water added to latex paint and it would spray
just fine.

Of course an automotive sprayer creates a TON of overspray so be ready
for a mess.

A Zinzer BIN... interesting (sounds like a character from a sci-fi movie ;)

The primer I was using was water based, so I'll have a look into these
(Zinzer and oil) products. What are the brand names of these products in the
US?

Cheers,

Sploo.

"Stephen M" wrote in message
...
Prime with a Zinzer BIN. It is shellac-based rather than latex. It sands
well. An oil-based primer would probably work well too, but it would
require
more time to cure before sanding.

-steve

That's a bit of a problem - I can buy the paint in spray cans (for the
topcoat), but I have no equipment to spray a tin of primer. I suppose a HVLP
system for home use shouldn't be *that* expensive...

Cheers,

Sploo.

"Ray" wrote in message
oups.com...
I used an automotive sprayer in the past to spray latex primer. The
can specified no need to thin and it worked great. I ended up brushing
the topcoat on because for this project the finish was too smooth. I
would expect a little water added to latex paint and it would spray
just fine.

Of course an automotive sprayer creates a TON of overspray so be ready
for a mess.

Zinzer is the manufacturer, BIN is the product.

As far as oil-based goes, anything that says "oil-based primer" or "Alkyd
primer" should do. Just be prepared to wait a couple days for it to cure
completely.

-Steve


"sploo" wrote in message
...
A Zinzer BIN... interesting (sounds like a character from a sci-fi movie
;)

The primer I was using was water based, so I'll have a look into these
(Zinzer and oil) products. What are the brand names of these products in
the
US?

Cheers,

Sploo.

"Stephen M" wrote in message
...
Prime with a Zinzer BIN. It is shellac-based rather than latex. It sands
well. An oil-based primer would probably work well too, but it would
require
more time to cure before sanding.

-steve

"sploo" wrote in message
...
That's a bit of a problem - I can buy the paint in spray cans (for the
topcoat), but I have no equipment to spray a tin of primer. I suppose a
HVLP
system for home use shouldn't be *that* expensive...


There is no need to be buying spray equipment to prime a little MDF. That's
like using a Hummer to pick up a quart of milk at the corner store. It only
makes sense if it's already parked in your driveway.

-Steve

on 8/2/2005 12:02 PM sploo said the following:
A Zinzer BIN... interesting (sounds like a character from a sci-fi movie ;)

The primer I was using was water based, so I'll have a look into these
(Zinzer and oil) products. What are the brand names of these products in the
US?

Zinzer is the brand, BIN is one of their trade names, along with, I
think, BullsEye which is a shellac. Good products. Last time I bought
any it was at a Menard's but any of the big box stores (or local paint
stores for that matter) will have it. It's a national brand rather than
regional AFAIK.

just to make it easier to find...the company the makes BIN and other
shellacs and primers is ZINSSER

" wrote in message
ups.com...
just to make it easier to find...the company the makes BIN and other
shellacs and primers is ZINSSER

If you go to the nearest auto store you will find automaotive preimers in
spray cans just like the paints you are using . Generally speaking the
automotive end of finishes is years ahead of the furniture people ......I
have been using a major finishing materials manufacture here [in the US]
for years and still have big problems that they have no explanation or
solutions for .....mjh

on 8/2/2005 12:45 PM said the following:
just to make it easier to find...the company the makes BIN and other
shellacs and primers is ZINSSER

You're correct, I didn't catch the misspellng when I penned my reply.

To make it even easier....

http://www.zinsser.com

All you'd want to know about their product line and then some.

"sploo" wrote in message
...
Hi all,

I'm trying to achieve a smooth painted finish on MDF.

I've been using spray can insert brand here enamel for the finish and
spray can primer with great results.
SH

"sploo" wrote in message
...
A Zinzer BIN... interesting (sounds like a character from a sci-fi movie
;)

The primer I was using was water based, so I'll have a look into these
(Zinzer and oil) products. What are the brand names of these products in
the
US?

Zinser.

Thanks all, I'll see if I can find Zinzer products in the UK.

Screwfix's MDF primer is OK and cheap. I've never been impressed with
International's paint products.

Stick with MDF primers though. If you use something inappropriate and
water based then it raises fibres on the surface and you'll never get
it smooth again.

Thanks dingbat.

I was considering trying Screwfix's product. It certainly can't be worse
than the International stuff.

You can get Zinsser B-I-N in the UK, so I've sent them an email asking about
suitability.

I've previously also tried spray cans of automotive primer (Halfords), but
it's just absorbed by the MDF and doesn't actually do anything useful.

Sploo.


wrote in message
oups.com...
Screwfix's MDF primer is OK and cheap. I've never been impressed with
International's paint products.

Stick with MDF primers though. If you use something inappropriate and
water based then it raises fibres on the surface and you'll never get
it smooth again.

"sploo" wrote in message
...
Thanks dadioH.

I'm only familiar with spray cans of automotive primer (which I know
don't
work well on MDF). What type of product do you mean?

One in a can so that it can be brushed on. Get one with a lacquer base,
dry rapidly.
_____________

Get a primer made for auto bodies...sands wonderfully.



--
dadiOH
____________________________

dadiOH's dandies v3.06...
....a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at http://mysite.verizon.net/xico

In article O6LHe.27801$Tk6.7916@trnddc02,
"dadiOH" wrote:

Get a primer made for auto bodies...sands wonderfully.

I have used automotive spot-putty (is lacquer based) on the end grain of
MDF with great success. It is thin enough to crawl into the MDF a bit
and sands like a dream.
One of the brand names is 'Green Stuff'.

OK, I'll have a search thanks. I'm also looking into Zinsser B-I-N (which
I've found I can get in the UK).

Do you know of any products (brand names) of the primer type you mean? That
way I can search for it (or similar products) in the UK.

Cheers,

Sploo.


I'm only familiar with spray cans of automotive primer (which I know
don't
work well on MDF). What type of product do you mean?

One in a can so that it can be brushed on. Get one with a lacquer base,
dry rapidly.

"sploo" wrote in message
...
Thanks dingbat.

I was considering trying Screwfix's product. It certainly can't be
worse
than the International stuff.

That rather depends upon *which* stuff. International make a primer
that is the best I have ever seen (for your purpose). It was originally
formulated to fill the grain on Phillipine mahogany in marine
applications...dries fast, sands very easily. Don't recall the ID# but
the last time I checked (couple of years) it was running about $80/gal.

--
dadiOH
____________________________

dadiOH's dandies v3.06...
....a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at http://mysite.verizon.net/xico

The only product I could find here in the UK was "International MDF Primer".

I used it to prime some MDF loudspeakers I built (with a brush). I left the
primed boxes for a couple of days (at roughly 68 degrees F and low
humidity). When I tried to sand it the primer clogged the paper, and came
off in little rolls - basically it hadn't fully dried and was still slightly
plastic.

I (tediously) sanded all the primer off with a powered sander, and bought
another batch (with a different batch code).

This time I used a roller, then left the boxes in a drying room (around 80F)
for a week. Guess what happened when I sanded it again? Yep. Same result.

I did contact International to work out what went wrong. They sent me a
catalogue. Thanks.

What was the primer you've seen?

Sploo.


That rather depends upon *which* stuff. International make a primer
that is the best I have ever seen (for your purpose). It was originally
formulated to fill the grain on Phillipine mahogany in marine
applications...dries fast, sands very easily. Don't recall the ID# but
the last time I checked (couple of years) it was running about $80/gal.

"sploo" wrote in message
...

What was the primer you've seen?

Sorry, but as I said I don't recall the number. Been too long.
"International #62" sticks in my mind but I have no idea if that is
right or not.

I used to use it a lot when I had a yacht, both on it and other wood
projects, but that has been a while back. Nowadays, I just use auto
body primer if I want one that sands well.

--
dadiOH
____________________________

dadiOH's dandies v3.06...
....a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at http://mysite.verizon.net/xico