Smooth finish on MDF

[sploo]

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.

[dadiOH]

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

[Stephen M]

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]

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?

[Ray]

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.

[sploo]

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.

[sploo]

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.

[Stephen M]

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

[Stephen M]

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

[Unquestionably Confused]

on 8/2/2005 12:02 PM sploo said the following:

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.

[eag111]

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

[mike hide]

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

[Unquestionably Confused]

on 8/2/2005 12:45 PM [e-mail] said the following:

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

To make it even easier....

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

[Slowhand]

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

[CW]

Zinser.

[sploo]

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

[dingbat]

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]

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.

[dadiOH]

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

-- 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

[Robatoy]

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'.