Finishing LDF

[john_hartman]

I really don't do this even often, but I have made up a mixture of wood glue and water. About 75% glue to 25% water to seal the edges with a couple of coats. Sanded between coats followed by a couple coats of primer then paint. This works but the results are never as smooth as the unbroken skin. Is there a better way to do this? I'm thinking about offering cabinet doors in Trupan using the "Free Doors" program. Does anyone have any experience with this program and finishing MDF?

[ron_moorehead]

Hi,

I just did a larger project with MDF and it had exposed edges. I did the water and glue at about 50% each, two coats of glue with no sanding bewteen coats. Then sanded primed and painted. It came out just as smoothed as the uncut front. From what i have read your glue to water mixer should be about 50/50 or 60% glue to 40% water. You may have to much glue to real soak in.

[beacon14]

Trupan is pretty porous and soft for cabinet doors. Most door makers use a harder, denser grade of MDF. There are a few brand names. One local supplier calls it "A Grade" MDF. Since it's denser it's easier to finish, especially the routed areas. With sharp bits a light sanding may be enough depending on your finish materials.

[Gary Campbell]

Another thing to consider is, due to the amount that MDF/LDF swells with water... use a non water based product. You will reach acceptable results much quicker. We find close to .020 swelling near glued butt joints.

Agree with David on the grade, buy the densest, heaviest that you can find, it will make your life easier. Trupan or other UL or LDF materials are much too porous.
Gary

[toddmaci]

I use titebond III full strength then prime and paint.

[Gary Campbell]

We use ML Campbell Clawlock post Cat Primer.
Sand 120
Prime
Dry 1 hour
Spot with lacquer putty if needed
Sand 180
Prime
Dry 2 hrs
Sand 320
Paint 2 coats
Drill hinges & mount in the AM
Gary

[john_hartman]

Great info guys. I actually have never used the Trupan for this, but wanted too because of its lightwieght. I see your points on the density. I have done the ratio 50/50 but found 25% more glue did cover better and faster as well as sanded better. I guess I was just on another quest to make things easier and turn out better...
Thanks, all, for the feedback.

[dubliner]

If using MDF for 3d, would it be practical to rough cut, coat with Titebond 3 and then do a finish pass, would that yield a harder material & a sharper cut?

[john_hartman]

Neville that makes a lot sense to me. Perhaps using something that would really penetrate would be even better. Something like shellac...?

[dubliner]

You know, I use spray shellac when I take the piece off the machine & then sand. I think I'll try brush on and then do the finish pass.

[tmerrill]

Minwax makes a product call Wood Hardener and I remember reading somewhere that it works great with MDF. Haven't tried it myself, but might be worth visiting the Minwax site and reading up on it. I think it's readily available at the big box stores.

http://www.minwax.com/products/wood_maintenance_and_repair/high_performance_wood_hardener.html

Tim

[dlcw]

Another product that I've used for indoor and outdoor application is Daly's Benite. It not only preserves and protects the material but also eliminates splotchy stain and paint finishes.

http://www.dalyspaint.com/

Don
www.diamondlakewoodworks.com (http://www.diamondlakewoodworks.com)