Cedar Pegola question

[Junkyard Engineer]

After seeing this pergola design (see plan P012) at

decided to buy that plan. Let's say I'm just a week-end woodworker with a couple of tools. I thought that would be a nice winter project. So, nothing real difficult with the plans in hand except for the arc of the treillis. (I already put the double post at the end of the summer) It's 1x5 lamination with a 2x2 in the inside. 48" hemispherical curve dimension. I will use red cedar.

I've browsed in the woodworking newsgroups and internet and I can already tell you that I don't intend to invest in a steam box. From what I gathered so far, it would be almost impossible to bend a 2x2 or a 1x5 in one piece without splitting it. Or is it ?! At first, I thought doing a jig and put everything in a water bath. I also saw somewhere that putting a metal strap outside would help and I need a really sturdy jig.

Can somebody point me to a site where I can find detailed instructions to achieve that ? Or better yet, detailed instructions in this reply ?

tia

[TWS]

What are the dimensions of: the width of the arc (radius x 2)? the thickness of the curved piece (not the depth but the difference between the inside and outside radius)?

Also, are you painting the wood or do you want to use a stain that shows the wood grain? (paint/opaque stain can hide a myriad of construction tricks).

These three factors will be necessary to provide the appropriate advice.

TWS

[loutent]

We have been looking to put a pergola in our garden also, so thanks for the link - these are some spectacular designs.

As far as the curves, I think that lamination is the best (if not only) choice from the looks of the picture. Slice off 1/4 inch strips in whatever width you need (plus a little extra for trimming off later). Make a jig out of MDF or plywood. When you cut the circumference of the circle, save both pieces so you can use these to apply even clamping pressure. Cover the MDF/plywood with plastic/wax paper so the glue does not stick.

I would use poly glue or a good exterior glue of course.

Thanks again for the link.

Lou

[Junkyard Engineer]

the arc is actually half of a circle so it's 48" in diameter (outside). The internal radius is then 24" minus 1" to account for the 1x5 and minus 2" to account for the supporting 2x2 which will be 21" inside radius. Just to be clear, the 1x5 is bend in the 1" plan and the 2x2 is bent inside as a supporting structure where the 1" is glued or/and nailed to the 2x2. Hope this is clear.

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[Junkyard Engineer]

ooops, forgot to say that I will use a natural stain to show the redness of the red cedar.

tia

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[Junkyard Engineer]

thanks for the tips and no problem !

Yes, I've looked around internet including local fine woodworking shop and they probably have the nicest design of treillis and pergolas you can buy. Local shop makes it really expensive to buy it as is though (20k$ for a 40 feet). That led me to the path of making it myself. Can't wait to assemble everything in the spring !

[TWS]

I haven't tried poly glue for bent wood laminations. I have used Plastic Resin Glue with success. Weldwood has a good one. This will allow you to stain the wood and see the color but you will also see the glue seams as well. These are typically pretty thin if you use enough pressure but you will still see them. The glue is dark brown so won't be that obvious if the wood stain is dark red.

Plan on doing slightly wider than your finished width because you will have to machine off the squeeze out. Also plan on your form being slightly smaller than the finished dimension due to springback of the wood after you release the clamps.

TWS

[Junkyard Engineer]

ok thanks for the tips !

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