Box beam....

[Dr. Jim]

Greetz all,

1st, I wasn't sure where to post this, since it really didnt seem like there was an area for posting 'help - how to'...? And since this is 'part' of a remodel,...thought I would post here. (unless I should have put in my other thread?_)

Box beam......for the joining?...butt or miter joint? Seems like a miter joint that long could get tricky,...and show more than a butt?......the goal ofcourse is to have it look pretty natural.


Thoughts?

[Terry Mac]

Hey Dr. Jim, are you talking about encasing the two support studs on your second floor? If so, what are they, 10' or 12' tall?

If that's the case, then I would do butt joints with finishing nails. Then inset the nails with a punch.

Doing miters on pieces that long isn't that bad on a table saw; just have to be careful and have plenty of support for both ends while cutting. An extra person would come in handy to assist.

[Jammin]

Are you painting a or staining. If painting then butt togehter sand smooth and paint. If staining, can you build it in butt form and put the seam in a hard to see area. If you can see it from all sides then I would miter on table saw. If you can see it from only 3 sides, then build a U that is big around beam with miters. Shim, liquid nail to beam and slide inside U on back side a butt filler piece to complete box

[Dr. Jim]

Actually, I will be doing those posts you mention as well,...but it will be part of another project.

I am creating a box beam that will span the entire horizontal length right below the loft ledge. This beam will serve to be a visual 'drop soffit' if you will to divide the new wooden ceiling of the kitchen and under loft area.
I think this could look nice and help break up some of the contemporary lines everywhere.
So this box beam will be 20+ feet long.
I was going to build some 2x blocks every couple feet off the ceiling at the edge and fasten to them on 3 sides (front, bottom and back) to create the beam.
I will be staining (er waxing) the beam, so again,...the idea is to get as best a look as possible.

Ofcourse I could go for the 'obvious' butt joint,...where I even inset a little to make it appear intentional?.....But I would prefer to get more of a seamless beam look.

[Dagster]

Here is an easy way to do a box beam, it hides joints and has a little bit of a stylized look to it. It can be easier than plain butt joints and much easier than a miter (not recommended for such a long joint)

http://www.garagehobbies.com/images/temp/boxbeam.jpg

[Dr. Jim]

Yes,.....I am seriously considering that look.

The other option I may go for is a butt joint,...but with the seams on the bottom,...no the sides,.....sand it down really good,....

Thanks guys,.......I too am thinking a miter joing that long will prolly show the seam pretty well and look obviously worse than any of the other options..

[Dr. Jim]

Considering this beam will be long,....and I doubt I can get a top grade board at 20+ feet in length,....I will need to use more than 1 board for each span.
I would assume a scarf joint to be the best option in this case?

Any thoughts from you guys?




(and yes, I know these projects are pretty silly by pro standards,....but it's all I got right now ;-)

[Dagster]

Yes, I'd definitely use a scarf joint unless you have a finger joint bit for your router.

[Dr. Jim]

More exciting totally simple questions to test you pro's knowledge of the utmost basics:

I have made 2 scarf joints in my day. Both on short lengths,...and I made them, glued everything and THEN worked with the resultant piece.

In this case,..where I am building this box beam,...building and fastening around 2x blocks for support............I am thinking it would be better to do the cut and all,...amek sure everything lines up perfect, yet construct the actual joint as I have the facades of the beam. Sort of building it as I install the beam,...instead of scarfing a 24 foot 1x6 and THEN trying to work with it?
My goal here is ofcourse the most invisible seam possible.

Thoughts?

[Dagster]

The easiest way would be to constuct each plank with a scarf joint then build the beam. You will find that trying to assemble two beams with a scarf joint will be extremely difficult while getting a good joint.

Once each plank scarf joint is dry you will realize it ain't breaking... if done correctly and accurately that joint will be as strong or stronger than the surrounding wood. Just be sure to use minimal clamping pressure and a nice even coat of wood glue. Clamp hard enough to get a little squeeze out but not a flood.

Something to consider... you can sister up a piece on the inside of each scarf joint to provide added strength to the joint. Nobody will ever see it and it will add good strength while you assemble the beam.

[Dr. Jim]

Hmmm.....

My previous scarf joints (all 2 of them) were done with a short length ratio.
Maybe a 2-2.5 inch cut on a 1x board.

I have read online (just about everywhere) that a normal 'starting' ratio is 1:8!
So.....I should have an 8 inch cut on a 1x board?

Sitting here at work,.....but is that possible on a miter saw? That seems like really long, very precise angle cut..............

[Dagster]

You could get away with a 45 degree cut really but I'd just max out the miter saw and go with what you can accomplish. If it is glued appropriately it should hold fine.

The main goal here is to avoid seeing gaps and creating a nice fairly hidden joint. Since the box beam won't be structural you can bend the ratio to what works for you.