Joints - Glass smooth or sanded?

[Randy Redding]

I'm making several large picture frames using oak. The frames are 3/4" stock about 4" wide. I'm mitering and doweling the corners. I use a razor miter trimmer to get the miters accurate. This leaves a glass smooth surface, except for the wood pores.

My question is: Does anyone know if regular yellow wood glue holds better leaving the joints glass smooth or should I sand them a little with fine paper to rough the surface? I'm not expecting a problem either way but I just started wondering about long term strength.

[Joe Spear]

End-grain glued joints aren't real strong anyway, whether or not you sand them. However, the fact that you're doweling them ought to make them plenty strong enough to last.

[Wade Lippman]

I'm making several large picture frames using oak. The frames are 3/4" stock about 4" wide. I'm mitering and doweling the corners. I use a razor miter trimmer to get the miters accurate. This leaves a glass smooth surface, except for the wood pores.

My question is: Does anyone know if regular yellow wood glue holds better leaving the joints glass smooth or should I sand them a little with fine paper to rough the surface? I'm not expecting a problem either way but I just started wondering about long term strength.

I've never heard of anyone sanding a joint, except perhaps to correct a problem. Feel free to be the first and tell us about it!

[Cliff Rohrabacher]

The problem with Glassine surfaces and glue arises subsequent to dull jointer and planar blades. It's not that they cut so finely it's that they burnish the surface closing it off which prevents adequate absorption of the glue.

The fine surface the trimmer makes isn't the same thing and isn't an issue.

[Joe Chritz]

Not sure what your definition of large is but on every one I have done up to 16x20 or so just glue has been sufficient. It took a surprising amount of force to break them.

Wider material is more glue surface and a dowel should be plenty strong.

I would surmise that a clean shaved surface (like a lion trimmer) would be the best joint with a joint from very dull blades on the bottom. That is just a guess on my part.

Joe

[Randy Redding]

Thanks for your thoughts. I'm going to leave them smooth and not worry about it. I'll worry about things such as getting them the right length instead!

[mark page]

I use an 80 tooth blade for crosscuts on picture frames which leaves a glass smooth surface. I haven't had any problems with glue-ups without dowels or biscuits. My frames are plenty strong for what they are designed to do. With the addition of dowels or biscuits, I don't think you will have anything to worry about.