# Arched pergola beams - how to make them?



## Loren

A client wants me to build a pergola with arched beams.

The sample pics I've seen of the sort of thing they want are
glue-laminated out of shaped curved parts, lotta waste and 
a lot of clamping to make just 4 or whatever.

So I've got a question of whether: (a) can I outsource these
glue-lams at any kind of reasonable cost?

and (b) would I be real stupid to glue up perhaps 2"x18" 
blanks from 2×6s (for example) and just saw them out?

Weight load is not going to be more than a few hundred
pounds on all the posts but I'm looking at spanning about 14
feet between posts with the curved beams.


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## waho6o9

You wouldn't be stupid at all for making them yourself. Plan b seems to me like normal thinking.

Make a template, use the flush cut router bit, and have fun.


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## bhog

What kind of heigth are you trying to be at ?How severe of an arch? You could always use LVL and wrap it with what ever you are building with- cedar,redwood,cypress etc.


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## madts

A pictrue would be good to be able to give a decent answer.


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## Loren

Like 8 feet tall and maybe a 10" rise in the center of the arched
beams. Not bearing a lot of weight.


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## higtron

You don't need to waste all that much material if you glue and spline your laminated material together like in pic.


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## Loren

Ok. Splining, that makes sense. Thank you.

Other ideas still welcomed of course.


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## Sawkerf

I made these with redwood 2×8's.

First, I made a full size pattern from 1/4" ply, then determined the number of pieces of redwood I needed and the angles to cut the ends to cover the pattern

I laid the pieces out and traced the pattern onto the pieces and marked for biscuits - making sure that no biscuits would be exposed on the edge of a joint.

I cut my biscuit slots, tacked cleats at each joint, and assembled the whole thing using the cleats to clamp the joints.

When it was dry, I cut the arches on my bandsae, sanded everything and rounded the edges.

That was 10 years ago and - except for turning grey with age and exposure - the arbor is rock solid.


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## a1Jim

Here's how I would do it Loren ,close to how sawkerf suggested but doubled up with splines and overlapping sections and cut it out with a router.


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## Sawkerf

I considered splines Jim, but didn't want anything peeking thru the edged of my joints which might provide a path for water.

I forgot to mention it earlier, but I used gorilla glue.


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## LeeBarker

I question the need for splines when you've got a flat grain to flat grain glue joint.

Kindly,

Lee


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## a1Jim

Sawkerf
My job was paint grade so I just used bondo in the little bit of kerf that showed primer and painted. I like the splines because they had more glue surface(I made them 1/2" deep on each side of the joint ,I used resin glue for the spline joinery and construction adhesive to join the two layers together.


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## LeeBarker

I've been mulling about my comment regarding splines, and I'm thinking they are a sensible addition to this project structurally.

The representative from Oregon changes his vote to Yea for splines.

Kindly,

Lee


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## a1Jim

Us Oregonians have to stick together Lee )


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