How to make curved cover ?

[Steve1]

I need to make a couple of curved covers as shown below.  I will probably use plywood, and it will be covered with high pressure laminate. 
Best thought I have had to create the curved surface is to make a couple of profile rails, set up rather like a router slab flattening fixture, and carve away at it with my router.  And then some final handwork with my belt sander.

I don't really want to bend wood -- I have never successfully done that before, and the piece will be pretty much stand-alone, and if it moves over time, it will be very visible.

Anybody got a better idea than the curved slab mill ? 

 

[waho6o9]

Kerf the back of the ply wood every quarter inch or so more than half way deep and it will bend. 

Practice on some scraps, best of luck.

 

[waho6o9]

View attachment 1

 

[ChuckM]

Your diagram shows a flat back which can't be achieved by any bending method. Did you mean a curved front and back?

 

[Steve1]

Only one side curved.  Backside is flat.

 

[ChuckM]

Other than the router/sander method you outlined, I can only think of another solution: stand up the piece and saw off the curved parts on the table saw with the blade titled to the proper angle and in multiple passes, if necessary. To do it safely, make a high auxiliary fence that rides along the saw fence (example:https://www.instructables.com/id/Auxiliary-Fence-for-Table-Saw/  But use a full-length bracket, not the one shown in the link). Featherboards, too.

However, it's not clear from your diagram how much material needs to be removed towards the centre of the board, and whether the table saw method is workable as the blade height is a limiting factor. The table saw method, quicker than using a router, should be followed by some sanding.

I also assume you're working with a stack of plywood glued together.

Edit: I vaguely recall seeing something written about using a thickness planer and some jig to make curved parts, but I have had no experience with that method.

 

[Cheese]

I'd cut the profile on 2 strips that are 7.5" wide on a band saw. Domino & glue them together for the full 15" width and then finish the profile with a sander.

 

[Alanbach]

I was just about to start typing what Cheese just said so plus one on that!

 

[KelleyCrafts]

I think Wahoo has it on this one. You're using plywood so that's a solid solution. Not to mention it'll make both side bends even.

Cutting on the bandsaw then using a sander won't guarantee both sides are exactly the same, cutting kerfs and bending will.

 

[Svar]

This:https://www.lumberjocks.com/topics/47397
If not, than what Cheese suggested.
Kerf method makes the panel structurally weak. Gaps need to be filled, and it won't support any top load (it's a lid you are making).

 

[Cheese]

I think Wahoo has it on this one. You're using plywood so that's a solid solution. Not to mention it'll make both side bends even.

Cutting on the bandsaw then using a sander won't guarantee both sides are exactly the same, cutting kerfs and bending will.

[welcome] to the FOG.  [big grin]

However, Steve1 wanted the back to be flat...kerfing & bending will not allow that to happen. 

Hey Svar thanks for the Lumberjocks post...that's a pretty simple rig to fabricate. [smile]  That idea just went into the router sled folder.

 

[Bob D.]

"That idea just went into the router sled folder."

How much you wanna bet there will be a WP version for use with their slab or board mills out soon.

 

[KelleyCrafts]

I think Wahoo has it on this one. You're using plywood so that's a solid solution. Not to mention it'll make both side bends even.

Cutting on the bandsaw then using a sander won't guarantee both sides are exactly the same, cutting kerfs and bending will.

[welcome] to the FOG.  [big grin]

However, Steve1 wanted the back to be flat...kerfing & bending will not allow that to happen. 

Hey Svar thanks for the Lumberjocks post...that's a pretty simple rig to fabricate. [smile]  That idea just went into the router sled folder.

Thanks Cheese! I've been lurking for a couple years.

Ah, missed the back flat portion. However, it would be strong if kerfs were cut then bent and glued/clamped but it doesn't work in this scenario. The LJs link was a goods one for sure. Would be nice and even as well.

 

[xedos]

If you're worried about movement, I'd use MDF as the substrate.

 

[Longhair]

Use a tablesaw and cut kerfs on the face. Start at each edge with a 1 inch kerf, move in and cut a shallower cut, continuing until at the center with no kerf. Handplane the surface down to the bottom of each kerf and finish with sanding.

 

[StevoWevo]

you could make a template of the side profile and router out 18 or 20 pieces. Glue it up like a butcher block

 

[Don Corleone]

Why not swing it into a band saw? You are looking for a radius cut. Add a riser to your band saw and build a jig.

 

[Jesse Cloud]

I like StevoWevo's method.  I would also drill a few holes in the template to make a guide for drilling holes in the 18 or 20 pieces.  Use the holes to put in dowels for registration during glue-up to ensure that all pieces fit together perfectly and stay that way.  Should come out with both sides the same.  And a very economical method!

 

[zapdafish]

coopering
https://www.canadianwoodworking.com/finer-details/coopered-doors

 

[JRD]

If you make that door solid it will be very heavy. It is already almost twice as wide as it is tall. You might try making one curved piece 3/4" thick by your dimension. Use that as a  pattern to make 10 more the same shape. Space those piece equal distance apart with a 1" x 15" piece on each side to form a frame. Cover that with 1/4" plywood. Than you have a smooth surface to apply your laminate to. This is how I did the enclosed pictures both the interior doors and exterior frame.
Jeff