Best Primer for MDF?

[phototec]

What is the best primer for MDF edges?

I cut some shapes out of MDF and I know you need to use some special NON-water based sealer on the edges before painting.

What do you guys use?

 

[Gino]

Basically, you're talking end-grain and if you wanna do it right, you should shellac the ends after sanding them smooth. Something called glue-size is also good. Afterwards, sand again, then apply your prime and top coats.

 

[phototec]

Basically, you're talking end-grain and if you wanna do it right, you should shellac the ends after sanding them smooth. Something called glue-size is also good. Afterwards, sand again, then apply your prime and top coats.

Thanks Gino, I'm off to get some animal skin for boiling:

http://en.wikipedia.org/wiki/Glue-size

:ROFLMAO:

 

[Gino]

Thanks Gino, I'm off to get some animal skin for boiling:

http://en.wikipedia.org/wiki/Glue-size

:ROFLMAO:

It easier than that, nowadays. Glue size is basically a solution of PVA glue and water [dilute the glue by about 90%].


Serioulsy, you asked for the best.

We generally use a good wood putty... straaight, like Elmers, stuffed in the entire way around and let the voids build up. Sand them down and use like Cooke's Primer/Sealer.... then the top coat.

 

[Techman]

The best and only sealer for MDF is shellac. It dries within 10 minutes. It penetrates deep into the MDF and seals of perfectly. Do two coats and its done. If you want a super smooth surface sand it and shellac it again. Shellac is water proof. The only thing that will hurt it is alcohol.

Watered down wood glue as as sealer dries way to slow and is not waterproof. It can cause the MDF to swell a little. Any swelling will cause a failure in the future. It is a complete waste of time..

I cut MDF into products all the time and would never use wood glue as a size for MDF under any circumstances. Shellac is the magic bullet.

 

[skarekrow]

http://www.sherwin-williams.com/homeowners/products/catalog/fast-drying-primer/
I've been using this with great results the past few years... Really like that it dries in 10 or 15 minutes.
I like to seal the edges with a latex caulk... not one with silicone. Sometimes even oil (alkyl) based paint will crawl over silicone products. Also, be sure and prime the MDO before sealing the edges. Most often, I finish coat with Rustoleum oil-based baint.

edit... my error. OP metioned "MDF" not "MDO". ~nevermind~

 

[artbot]

one other tip, you might want to mix the shellac with black transtint. transtint is wood dye. the black is super concentrated. blacking out the edge of mdf gives it a high end look. much more attractive than black pvc. it's almost impossible to paint mdf black because it just sucks it up and gives a mottled charcoal color. the transtint will be a wipe on mix and will be pitch black and deeply stain the fibers in one pass and also disperse uniformly.

http://www.homesteadfinishingproducts.com/htdocs/TransTint.htm

 

[phototec]

Thanks guys, lots of good info.

Artbot, I never heard of transtint, I will look into that.

 

[artbot]

a single bottle is $19. india ink, and other things are not the same. it's a solvent based dye. it can be thinned with glycol for large area (slow dry), water, alcohol, acetone, etc.

this project was done with transtint-ed veneer.

http://www.flickr.com/photos/alldredge/sets/72157626473720326/

 

[phototec]

a single bottle is $19. india ink, and other things are not the same. it's a solvent based dye. it can be thinned with glycol for large area (slow dry), water, alcohol, acetone, etc.

this project was done with transtint-ed veneer.

http://www.flickr.com/photos/alldredge/sets/72157626473720326/

Alan, very nice work as usual, I wish I had 1000th of your talent.

So, what is the process of the wood panels, you used the Transtint die to color the wood, how did you put the graphic designs onto the wood panels, is that silk screen or did you use a flatbed printer?

Again, very nice work!!!

 

[player]

I bet it is CNC work.

 

[artbot]

thanks, i lost my arse on that order. client just kept upgrading and i didn't know what i was getting into (it was my first large custom dyed veneer project). then they complained about
the $800 install in quoted. so i accepted $600 and $200 in a gift certificate (the food is amaaaaazing there. crazy good). but my luck, my wallet was stolen off a restaurant table a week later and
i never got to stuff my face with mediterranean food with my gift card.

this project was mostly ash and white oak. when dying large pieces of veneer, i use transtint and straight butyl cellosolve. it gives lots of open time for getting the
overlapping values out. takes a day or more to air out. just smell it to see how it's coming along.

stain is nothing like dye. with dye the flash of the wood is much better preserved. also, there's no pigment per se, so the grain doesn't fill with
color. just soaks up the color. takes practice to learn to mix dyes. one drop can shift the color a lot.

as for printing, i then sprayed them with bright rubbed effect SW Cab acrylic clear and then printed black/brown ink (solvent) with my, then, kooky jv3 160sp flatbed rig.
then mount on mdf, stain the sides, etc.

 

[Techman]

woodcraft sells transtint as well. Multitudes of colors.

 

[synergy_jim]

ML Campbell Clawlock paint / primer. I've used 50 gallons of this stuff on various POP displays. Its amazing. High solids and typically seals in one coat. You can also buy it tinted so all you have to do is a base coat then clear.

sands super smooth also...

http://www.pondcovepaint.com/content/page/catalog_product/id/1856/Clawlock_Primer_M_L_Campbell_Finishes.html

 

[Sven]

We use painter's caulk. Nice to work with but not sure about durability.