Fixing small holes & joint lines in Exterior Shutters

[Nate Secrist]

Hi Everyone,

I am building some exterior raised-panel shutters for the house - 8 of them in all.

I am using Douglas Fir for the stiles and rails, and MEDEX (outdoor-grade MDF) for the Raised Panels
I will be gluing and using pocket holes so that the glue and screws hold up over time - they should last a good long time.
I will be using primer and exterior latex paint to match the trim color of the house.

My question is about "filling" the joint lines - some of my stile-and-rail connections arent the "smoothest".
I don't think the normal interior spackle putty will hold up outside - I am certain it will shrink and not look good over time.

What would you all recommend for "filling" small dings and joint lines before priming and painting?
The only thing I could think of would be the exterior-grade silicone caulking, but that is a pain to sand smooth, since it is essentially rubber.

Any other thoughts?

Thanks

[John Lankers]

How about Bondo, it's been used on cars for many years.

[Wayne Lomman]

Nate, John is correct. Just use car bog. If your joint lines are going to be a bit average, slightly bevel the edges of the joint so that when you assemble the joint, it has a vee that breaks the visual change in the alignment of the surfaces. Cheers

[Jerry Miner]

If it's tiny, just use an exterior spackle (prime first).

[Charles Lent]

I used Bondo when I made my shutters out of Fir. I've had no problems with any of it coming loose in the past 7 years, but all of the shutters were primed completely with good quality latex primer followed by two coats of exterior latex primer. I also made up some aluminum flashing pieces to completely cover the top edges of the shutters to improve their Weather resistance. These pieces were the thickness of the shutter plus a 1/4" 90 deg edge on the front and the back, attached with silicone caulk and then painted. I used the flashing with the white outer surface and just painted over it. My raised panels were made from Fir, and I'm wishing that I had used an exterior MDF instead.

Charley

[mark mcfarlane]

I don't have any experience or knowledge of exterior woodworking, but ....

I suspect the douglas fir may move over time, cracking a bondo-based joint and perhaps eventually ejecting the bondo. I would expect wood and metal to respond differently to seasonal temperature and humidty changes.

I do like Wayne's idea to 'celebrate the joints', either with a v-shaped bevel or some other kind of reveal, then the stiles and rails can move seasonally and the joint will still look purposeful. If the shutters are already assembled, you can add a reveal with a sharp chisel and a few minutes per shutter. If you are painting the shutters, and really feel a need to hide the joints, perhaps consider carefully applied paintable 30- or 45-year silicon caulk, using blue tape to minimize the amount of caulk going outside of the joint. Wipe it in with a spit-on finger, remove the tape. The silicon caulk should move with the wood.

Yet again, I will disqualify myself based on lack of experience. Isn't the Internet great, "I know nothing but here is my opinion anyway".

[Lee Schierer]

I've used the Minwax 2 part Wood filler in exterior applications and have not had any problems with it failing.

[Paul F Franklin]

I suggest WoodEpox exterior epoxy filler. It's two parts that you knead together and then apply. It doesn't shrink, sands easily and takes paint beautifully. I haven't used the minwax two part filler, but I imagine it is similar.

[John TenEyck]

Never done it, but I think Bondo would work fine, too. Metal expands a lot more than wood, so if Bondo sticks to that (and it does) I see no reason it won't stay stuck to wood. A prior poster indicated it's been fine on his shutters for 7 years, so that's pretty good empirical evidence it works. I use Bondo for all kinds of interior wood repairs. Great stuff.

John