I’m building a custom mantle for my house. In order to keep the weight of the mantle down, I’m using MDF crown moulding for it. The crown is also what I used for the room so it will all match up.
The top shelf will be a clear 1″x8″x7′ long piece of pine. What are you recommendations for glueing the mdf to the pine (the pine is unprimed and the mdf is preprimed)?
The glue I have elmers and titebond fast set wood glue both absorb into the cut ends of the mdf. I was wondering, for the non-cut edge (that contacts the prime) is wood glue even the right thing to use?
I also have used Locktite’s Grabit(?) latex construction adhesive to mount small pieces of trim. Would this be the right adhesive to use along with some brad nails?
Replies
I use tightbond III for that kind of stuf. you get an 8 minute working time. They also have a molding glue that works pretty good, doesent run as much and has a little better initial tack.
If you need more working time than that, try gorilla or elmers polyurathane glue. They give you 30 minutes to get it clamped or tacked.
If the ends are soaking up all the glue, use more.
Why are you using MDF if you have weight issues? It's much denser than comparable pine molding.
that was my first thought
Hmmm...maybe this particular moulding I'm using is thinner in MDF. The equivalent paint grade pine with the same profile was definitely heavier...maybe because it's slightly thicker? Not sure. I never held the two up together to compare. Also, the reason I used the MDF crown for the room was because I could get affordable AND straight pieces of trim. In order to get true and straight pieces in pine, I would have to special order from the lumber yard and the cost put it out of my justifiable cost range.
Edited 10/18/2005 9:16 am ET by emaxxman
If you want to use a yellow glue you'd have to remove the primer on the mdf to get a proper bond. A ureathane like gorrilla will bond very well from pine to primed mdf. As far as the glue being absorbed, I always glue, mate the two pieces by hand for a few seconds, then seperate and re-apply because the first glue always soaks in and nearly disappears on mdf. If you don't add more you'll have a very poor joint with almost no strength... BUIC
My usual glue-of-choice is Weldbond. It comes with instructions about how to seal end-grain with diluted glue (dries clear).
Phill Giles
The Unionville Woodwright
Unionville, Ontario
I like PL Premium. I love Gorilla glue but you have to be so careful as to how much you put on as it expands so much and you don't want to be scraping it off finished work like crown. I'm pretty good with it at this point but if you're not used to using it I'd steer clear of it till you are. PL Premium has good holding power and doesn't drip.
Be well
andy
The secret of Zen in two words is, "Not always so"!
When we meet, we say, Namaste'..it means..
>>> I like PL Premium. ...PL Premium has good holding power and doesn't drip.
Andy,
I do too, but was wondering which one you're talking about here, the syrupy stuff in the bottle (like the Gorilla) or the construction adhesive tube. (I've used both depending on the situation with good results). thanks.
In the tube...doesn't expand like the bottled glueThe secret of Zen in two words is, "Not always so"!
When we meet, we say, Namaste'..it means..
I honor the place in you where the entire universe resides,
I honor the place in you of love, of light, of truth, of peace.
I honor the place within you where if you are in that place in you
and I am in that place in me, there is only one of us.