Mitered trim corners

[PeoplesElbow]

Anyone that does trim work in their house has known that molding can be frustrating. I have gotten pretty good at it with one exception. The mitered corners that I make seem to pull apart very slightly making a small hairline crack. Does anyone have any tricks to keeping them together in the winter months, this is even using the MDF stuff that shouldn't be too affected by humidity changes.

 

[desertrat]

Anyone that does trim work in their house has known that molding can be frustrating. I have gotten pretty good at it with one exception. The mitered corners that I make seem to pull apart very slightly making a small hairline crack. Does anyone have any tricks to keeping them together in the winter months, this is even using the MDF stuff that shouldn't be too affected by humidity changes.

Hmm, glue and clamp?

 

[glhs837]

Pins..... 23 gauge, I think. Adhesive also. (I used some trim adhesive only to lay 1/4 round in the bathroom 2 years ago and it's still tight.

 

[Midnightrider]

Anyone that does trim work in their house has known that molding can be frustrating. I have gotten pretty good at it with one exception. The mitered corners that I make seem to pull apart very slightly making a small hairline crack. Does anyone have any tricks to keeping them together in the winter months, this is even using the MDF stuff that shouldn't be too affected by humidity changes.

Inside corners should be coped instead, and both outside and inside miter should get caulked.
Allowing he wood to equilibrate in the house longer before installation will help some too

 

[PeoplesElbow]

Inside corners should be coped instead, and both outside and inside miter should get caulked.
Allowing he wood to equilibrate in the house longer before installation will help some too

I'm talking flat trim around windows and doors, the MDF stuff not wood.

 

[Midnightrider]

I'm talking flat trim around windows and doors, the MDF stuff not wood.

If it was tight when you put it in it has to be shrinking. The only answer would be to time your install and make sure your trim sits for a couple weeks in the room you plan to install it. You are probably still going to see some hairline cracks. Which takes you back to caulk. It is the trim carpenters best friend.....

 

[BOP]

I heard one of our forumite regulars is pretty handy with caulking stuff. Showers and whatnot, mostly. Plus she's a world-class chef, so there's that.

 

[PeoplesElbow]

My brick molding, that is made from PVC, around my garage door also did it. My solution would normally be to screw those pieces together but the interior of that PVC brick mold is not strong enough to hold screw threads. I suspect this is the wood underneath responding seasonally. I just put it up this past summer.