I am building a headboard that requires an arched border along the top
edge. The border is 3 1/2 inches tall (the side that faces outward)
and 1 1/2 inches thick (top edge). So it's not the type of arc that
can be bent.
My plan was to piece 5 wide straight segments together with angled
joints then cut the arc from this. The segments would be 22" long for
the center and 2 14" segments on each side. I started worrying,
however about the integrity of the joints. First, they would be end
grain to end grain - I could do a lap joint or a dado to help with
that (I don't think biscuits would be enough). Second, I was worried
about the wood movement. As the segments swelled, on the convex side
of the arc the joints would grow apart, and on the concave side they
would push toward each other. I thought this might make the joint
break.
Does anyone have experience with something like this? Is there any
other way to do it? Should I have smaller segments between joints?
Is there enough movement in 3 1/2 inches to cause any problems?
This is my first commissioned piece for someone else, so I really want
to get it right.
Thanks for any advice you can give.
Jodi
Jodi,
You might consider "brick-laid" construction. Use 1/2 inch thick pieces
the same height and width that you are considering, (but approx. 3x as
many). You get long-grain to long-grain glue joints. A garden arch I
built with this method has lasted several years with no apparent separation.
Steve Stripling
Jodi wrote:
>I am building a headboard that requires an arched border along the top
>edge. The border is 3 1/2 inches tall (the side that faces outward)
>and 1 1/2 inches thick (top edge). So it's not the type of arc that
>can be bent.
>
>My plan was to piece 5 wide straight segments together with angled
>joints then cut the arc from this. The segments would be 22" long for
>the center and 2 14" segments on each side. I started worrying,
>however about the integrity of the joints. First, they would be end
>grain to end grain - I could do a lap joint or a dado to help with
>that (I don't think biscuits would be enough). Second, I was worried
>about the wood movement. As the segments swelled, on the convex side
>of the arc the joints would grow apart, and on the concave side they
>would push toward each other. I thought this might make the joint
>break.
>
>Does anyone have experience with something like this? Is there any
>other way to do it? Should I have smaller segments between joints?
>Is there enough movement in 3 1/2 inches to cause any problems?
>
>This is my first commissioned piece for someone else, so I really want
>to get it right.
>
>Thanks for any advice you can give.
>
>Jodi
>
>
Steve wrote:
>
> Jodi,
>
> You might consider "brick-laid" construction. Use 1/2 inch thick pieces
> the same height and width that you are considering, (but approx. 3x as
> many). You get long-grain to long-grain glue joints. A garden arch I
> built with this method has lasted several years with no apparent separation.
>
> Steve Stripling
It's one of the two preferred methods for constructing banjo shells,
which must withstand a lifetime of tension without failure.
>
> Jodi wrote:
>
> >I am building a headboard that requires an arched border along the top
> >edge. The border is 3 1/2 inches tall (the side that faces outward)
> >and 1 1/2 inches thick (top edge). So it's not the type of arc that
> >can be bent.
> >
> >My plan was to piece 5 wide straight segments together with angled
> >joints then cut the arc from this. The segments would be 22" long for
> >the center and 2 14" segments on each side. I started worrying,
> >however about the integrity of the joints. First, they would be end
> >grain to end grain - I could do a lap joint or a dado to help with
> >that (I don't think biscuits would be enough). Second, I was worried
> >about the wood movement. As the segments swelled, on the convex side
> >of the arc the joints would grow apart, and on the concave side they
> >would push toward each other. I thought this might make the joint
> >break.
> >
> >Does anyone have experience with something like this? Is there any
> >other way to do it? Should I have smaller segments between joints?
> >Is there enough movement in 3 1/2 inches to cause any problems?
> >
> >This is my first commissioned piece for someone else, so I really want
> >to get it right.
> >
> >Thanks for any advice you can give.
> >
> >Jodi
> >
> >
[email protected] (Jodi) wrote in message news:<[email protected]>...
> I am building a headboard that requires an arched border along the top
> edge. The border is 3 1/2 inches tall (the side that faces outward)
> and 1 1/2 inches thick (top edge). So it's not the type of arc that
> can be bent.
>
> My plan was to piece 5 wide straight segments together with angled
> joints then cut the arc from this. The segments would be 22" long for
> the center and 2 14" segments on each side. I started worrying,
> however about the integrity of the joints. First, they would be end
> grain to end grain - I could do a lap joint or a dado to help with
> that (I don't think biscuits would be enough). Second, I was worried
> about the wood movement. As the segments swelled, on the convex side
> of the arc the joints would grow apart, and on the concave side they
> would push toward each other. I thought this might make the joint
> break.
>
> Does anyone have experience with something like this? Is there any
> other way to do it? Should I have smaller segments between joints?
> Is there enough movement in 3 1/2 inches to cause any problems?
>
> This is my first commissioned piece for someone else, so I really want
> to get it right.
>
> Thanks for any advice you can give.
>
> Jodi
If it were me I would do it pretty much as you are planning. I would
lay out the boards, rough draw the arch and then attach the boards
together with dowels or mortises and loose tenons making damn sure
that they are well within the arch area so that they do not get cut
into when cutting out the arch. Is there any way do incorporate a
design pattern at the joints so they look like they were desired, not
just necessary? The other option, as I see it, would result in
significant waste, but I think I saw in an another post that the arch
is either 6" or 9". You could glue up a panel large enough to
accomodate the arch and just cut it out. This would look best in my
opinion. I don't know if there are other aspects of the headboard that
could be made out of the scrap that would result or if there is room
in the commission budget to waste this much wood.
Dave Hall