I am helping a friend build some large window frames to close in a screened-in porch for the winter. It is a big old victorian and the openings are large – about 5′ by 3′ each. The plan is to have each window divided into four equal sized panes and use plexi (lexan?) to keep the weather out. The frames will be painted. If someone could help me with a few questions I would be grateful (I build some furniture as a hobby so I am supposed to be the expert).
Questions are: 1) type and thickness of wood to use? (we are in the Boston area re weather) 2) what joinery (I was thinking mitered end joint with biscuits but will they be strong enough given that the windows will be removed for screens in the spring and will get banged around some?) 3) technique to rabbet for the plexi?
Any other considerations would be appreciated.
Replies
Hi Will, you do not give an idea of the tool you have so I am assuming some basic hand tools. Circular saw, hammer, chistel
For the joint, I beleive you will not be happy with the biscuits over time. Your windows are very large and when removed they will flop around. My first choice would be to use a mortice and tennon joint. Second choice is a half lap. A variation on the half lap could be as follows: If you want the frame to 3/4 inch thick start with 3/8 material half lap it to make a frame, do it again, then glue the two together to obtain the 3/4 inch stock. This would create alot of glue surface and should hold together well.
As you are asking how to make the rabbit, I am assuming you do not have a tablesaw. As these windows will need to shed water, you will have to caulk the plexi to the wood frame. In some ways this is in your favor as you can hide some minor imperfections in your construction. If you decide to mortice and tennon or a half lap, you could use a circular saw to cut the rabbit in the edge. You would want to use a guide to keep the saw cutting straight. If you select nice stock to work with the small peice you cut out can be placed behing the plexi and nailed in. If you do not feel comfortable cutting the 3/4 on edge then sawing on the flat, you can many passes while the board is on the flat - actually making sawdust of the total rabbit. Then cut a filler later.
With the suggestion of using two ply 3/8 half lap stock to make the frame the rabbit is even simpler. Just cut the one ply smaller before you glue it up.
As for what wood to use for Boston, I cannot help there but I beleive you will get suggestions for Fir and Redwood. Does the frame need to be wood or could it be aluminum or plastic. You might see what the local glass shop has to offer. They might even make the wooden frames for you. I have seen extruded plastic (probably PVC) at the local Home Depot for use with PVC lattice in the shape of C and H. It might work.
SB - thanks for the quick reply. I should have mentioned tools. I have just about everything shy of a bandsaw. Does fir take paint well? Also, do you think I need to go thicker than 3/4" given the size of the frames (also, can I do a sound M&T joint with wood that thin?)
Lap joint sounds logical - would you cut it using a dado blade on a table saw or with a router and jig? Need to re enforce with wooden pin/dowel?
I was less than clear with my rabbet question. Cut it with a router after frame assembly or prior to assembly on a table saw?
Again, thanks for the advice.
Plexiglas yellows, fades, scratches, etc. Why put so much work into something that will look like****?
Use glass or have the glass shop build frames and all. There are some very good looking storm panels framed with white or brown extruded aluminum frames.
Excellence is its own reward!
glass sounds like the right choice
More an add on question: I see poplar used as exterior trim around here with some frequency. Granted, it's pretty clean and takes paint well, but I wonder about how well it would hold up in adverse weather - whether that be Boston, Dallas, or here. Any perspectives on it's exterior use?
Not good idea, IMO.
Excellence is its own reward!