Bending 1/8" ply

[Jim55]

When one bends 1/8 ply, like in Del's Jellybean or when making a hatch, do you need to moisten the ply first?

How small radiuses can one bent before running into trouble?

Thanks

Jim

[halfdome, Danny]

When one bends 1/8 ply, like in Del's Jellybean or when making a hatch, do you need to moisten the ply first?

How small radiuses can one bent before running into trouble?

Thanks

Jim

Jim, It depends which way your putting the sheet on and what kind of 1/8" ply. Luan is crap in my opinion. The best plywood would be Baltic Birch. It bends best going with the grain and never moisten plywood. I've bent Baltic Birch as small as a 4" radius. Danny

[James & Avisia Flohr]

Keep in mind that you can get Baltic Birch which is manufactured to bend either from the length ends or from the width ends. For instance, if you are covering the roof and it's width is greater then let's say 4 feet, you'll need the ply to bend from the width ends. Hope this helps, Jim

[Jim55]

For an aircraft that I built I used Norwegan birch ply.
--- Excellent stuff! Due to the small radii we always steamed the ply with good results, the glue never gave. That is the reason for my question.

And thanks for a great forum!

Jim

[ErikF]

Hi jim. hope you dont consider this a threadjack.

in terms of grain. to me it would be easiest to run the grain parallel with the ground.

is this correct? cause u see pics of people with grain runnung perpendicular to the ground?

pros cons of each?

[asianflava]

It's plywood so there technically isn't a grain. Some plywood is more flexible in one direction because there are more that run in that direction (or fewer plys in the other depending on how you see it).

I bent the baltic birch ans luan around the tight radius of my hatch, no heat, no steam, and no water. I think I got lucky though.

[doug hodder]

Whatever you decide to do...Luan just might be a crap shoot to get the results you want. Sometimes it works well, sometimes it doesn't, results may vary depending on the batch of material. You may have good results, but if you don't, you've blown money and a bunch of time. I used luan on the exterior on the Rocketear and a fairly mild bend caused it to explode, creating a bunch of extra work. The piece was only like 14" wide and was on the front of the tear, cracked completely across. The core was full of knots at that point.

On the new tear...1/8" baltic birch doing 2 layers on the curves as there is no aluminum skin on it. This will allow it to really appear smooth with the epoxy on it. I have a tight enough radius that the 1/4" alone might be too tough to make happen. The rest of the roof will be 1/4"...Also...just a note, 1/4" in baltic birch is 1/4". Not the same for the luan...it's only like 3/16, so if you mix, there will be a step. Doug

[del]

When one bends 1/8 ply, like in Del's Jellybean or when making a hatch, do you need to moisten the ply first?

How small radiuses can one bent before running into trouble?

Thanks

Jim

I used 1/8 mahogany and did not moisten the wood. That said there is one way they bend easier (3 layer ply) and two pieces cracked (bent the hard way). So should I have moistened the wood?

del

[Classic Finn]

When one bends 1/8 ply, like in Del's Jellybean or when making a hatch, do you need to moisten the ply first?

How small radiuses can one bent before running into trouble?

Thanks

Jim

Jim, It depends which way your putting the sheet on and what kind of 1/8" ply. Luan is crap in my opinion. The best plywood would be Baltic Birch. It bends best going with the grain and never moisten plywood. I've bent Baltic Birch as small as a 4" radius. Danny

Amen.. Baltic Birch

Why do I say so .. I live in the Land of Baltic Birch

Classic Finn

[markhusbands]

I am going to use 1/8 red oak ply - to match the wood type, at least on the interior. It seems that if I cut the 4x8 sheet in half and bend it parallel with the face grain it will go very easy. I'll just have to tolerate more seams. But I'm leaning that way to avoid a struggle and possibly breaking a sheet.

[markhusbands]

I did use 1/8 red oak. It worked. There was really no struggle getting it to accept a 16.5" radius and i'd call the affair perfect except that I missed some shots with the pneumatic stapler.