Ripping long miters

[jim price]

Got a question.

Background: I need to box in five 5x5 cedar posts on our front porch. The guy at the lumber yard talked me into some 8" wide "Weather Wood" for the job (which is an oriented strand board with simulated wood grain primered on one side) The posts are about 7' tall. His suggestion was, because of the rough open edges of the "Weather Wood" , to make the "boxes" by mitering the long edges on my table saw and caulking the seams.
I have a bosch 4000 table saw.

Question:

Given the above, what's the best way to make the miter cuts?

[Peter Quinn]

Use good in feed and out feed support, use a feather board to hold the stock to the table, and rip um. I'd rip each miter a bit over the first time, perhaps 1/8" over, to make the finish cut easier on your saw. Not much more to it. A power feed is a nice option on a cabinet saw but I doubt that would work on a portable. Use a good blade, probably thin kerf for yours.

Also, a tape miter will help you build the first three sides of that box pretty well. Are you familiar with tape mitering?

[Kevin Groenke]

Just tilt the blade to 45 and rip cut to ~7.625" (the post + "weatherwood"x2 + ~1/16") on the long side of your bevels. Being a longish board, you'll want an outfeed table or an assistant supporting the stock behind the saw.

I don't know that there is convention, but I'm inclined to call such a cut a bevel cut. If I'm cross cutting something at an angle (ie picture frame) I call it a miter cut.

Attach the boards to the posts with brad nail and/or construction adhesive: apply adhesive to the corner bevels as you go. Once its all up, you can wrap the box with shrink wrap or bungee cords to hold it all together until the glue dries (much easier than clamping IMO).

If you can assemble the boxes separate from the posts (and slide them over later) you might be able to employ the masking-tape-box-assembly-technique.

Peter may have beat me to this, but mine is ILLUSTRATED!!

http://www.woodworkersjournal.com/Media/PublicationsArticle/MOW/194_2009_MarApr/194MOWMiter8.jpg
http://www.woodworkersjournal.com/Media/PublicationsArticle/MOW/194_2009_MarApr/194MOWMiter9.jpg

g'luck
-kg

[jim price]

Fandangtastic!! GREAT suggestions you guys!!

interesting. I posted the same question on Craigslist. You don't want to see the results.

I'm now sold on this forum! Course I was partial before, but hay you guys are GOOD!

[phil harold]

I would not miter / bevel for this exterior trim job with solid wood or OSB

Movement from temperature and moisture is inevitable and the joints will open.
I would butt the boards

Rip two boards approximately 1/2" wider than the posts

Rip the other two boards approximately 3/4" wider than the post plus the thickness of the two narrow boards you just ripped

Make an "U" out of the two narrow boards and one wide board add a small 1/8" reveal when assembling

Install on the post with shims then install the last wide board

Since the boards are going to move it is better to have it designed to allow movement and hide the discrepancies in the butt joint with the reveal

Miter / bevel joints like to open up in exterior environments

That’s just my 2¢

[Russ Boyd]

I would not miter / bevel for this exterior trim job with solid wood or OSB

Movement from temperature and moisture is inevitable and the joints will open.
I would butt the boards

Rip two boards approximately 1/2" wider than the posts

Rip the other two boards approximately 3/4" wider than the post plus the thickness of the two narrow boards you just ripped

Make an "U" out of the two narrow boards and one wide board add a small 1/8" reveal when assembling

Install on the post with shims then install the last wide board

Since the boards are going to move it is better to have it designed to allow movement and hide the discrepancies in the butt joint with the reveal

Miter / bevel joints like to open up in exterior environments

That’s just my 2¢
A very emphatic second to this suggestion. Miters on this type of product WILL open up. At the very least, use the glue as suggested.

[Phil Thien]

I would not miter / bevel for this exterior trim job with solid wood or OSB

Movement from temperature and moisture is inevitable and the joints will open.
I would butt the boards


I don't think I'd want exposed OSB edges outside in a butt joint. You may as well start delaminating the stuff yourself.

[phil harold]

I don't think I'd want exposed OSB edges outside in a butt joint. You may as well start delaminating the stuff yourself.

true
Unless you can design the box to be 7.25" (or the width the 8" board")
wide then the sides would be factory sealed...

I am assuming that he is using LP smartside trim which is a decent product if all the edges are sealed, but warranty will be voided if ripped

LP had some issues with thier osb siding products growing mushrooms and delamenating prior to 1997, but that has been adressed now

http://www.lpcorp.com/Literature/LP_SmartSide_Trim_and_Fascia_Installation_Instruct ions.pdf

[Russ Boyd]

I don't think I'd want exposed OSB edges outside in a butt joint. You may as well start delaminating the stuff yourself.
While this is a very good point, you can seal those exposed edges so that it would not be a problem.

[Peter Quinn]

I have my doubts that an 8" wide OSB box is going to move enough to cause a problem. I would use type III glue, and I use thread reinforced heavy duty packing tape instead of masking tape on long miters. It has more strength and applies great clamping pressure if done correctly. Try a test piece if you are uncertain of the technique or its longevity.

Last ones I did were polyurethane trim boards like Azek. I like to put a 1/4" shim the length of the post tacked on the edges of two faces to create an air gap and let the box move a bit, sort of like an isolation joint. That PT post is not going to grow in most cases, its going to shrink. I like to let it shrink, or grow if it wants to without blowing the box apart. But joints on textured OSB? Might as well source some different material, ain't no way to make that look like much more than junk without mitered corners.

If it were real wood I'd go with a tongue and rabbit box, not so much with OSB. Maybe try gluing up a small sample of each, seal the ends, and throw them out side in the rain, or hose them down if necessary. Nothing like the scientific method to add clarity.

[jim price]

got side tracked on boxing the posts, but I'll look all this over again before I make a move.

thanks to you all for taking the time to respond!

Jim

[Vic Damone]

A contractor just did this to my next door neighbor's remodel using that rough sawn prepainted thicker than 2"x6" material that's typically used for outdoor trim. The idea was to add a mission flavor to an early seventies construction.

The columns get most of the days sun. Unfortunately I didn't pay much attention to his method. What caught my attention was that the pieces were narrow at the top tapering down and the edges were mitered. Not your average cut. Last I saw they were using a pneumatic nailer for the assembly.

They've been up for about a month but the house was painted yesterday. I'll take closer look when I get the chance.

And If your wondering who can afford to remodel in these times, my neighbor works for Standard Oil.

[phil harold]

Last ones I did were polyurethane trim boards like Azek. .

So is that woodworking or plasticworking when you use that stuff.

I get to use smartside trim, cedar, or clear pine how is Azek to work with?

Any tips or tricks?

thanks

[Paul B. Cresti]

I am in the process of replacing all the windows and residing my house using hard-board and azek. While the azek is very nice for simple trim I am not sure I will be using it for the beveled column enclosures for my new portico. The azek uses PVC glue and trying to use that stuff without making a mess is tough....and when you do get it on it does not come off. You can buy premade items in azek like the corner boards which are welded togehter at the factory. One can also order columns both structural and decorative...so that could be an option. I hva emade wood columns for interior use many times but always use a locking box cutter on my shaper to ensure a perfect fit. In this case for me I will most likely be making them out of cedar butt jointed and simply have to maintain them

[Lee Schierer]

If you decide to rip the boards, take the time to recheck your blade and fence alignment before making the first cut. Also having a digital angle gauge will make the corners fit much better than eyeballing the 45 degree angle withet h saw's built in angle scale.