Woodworking Talk banner
1 - 9 of 9 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter · #1 ·
g'day just wanted your help with an issue i have! we are currently building a skate ramp and need to know how to bend ply to the shape of the ramp. we were thinking of purchasing 9mm marine ply. We were told soaking the ply before installation was one way of doing it! If you could please respond any help would be greatly appreciated.
 

·
Registered
Joined
·
25 Posts
Good luck with bending 9mm ply, you will need it.

Better to buy 3 sheets of 3mm ply, bend them to the shape that you need and glue them together, this way they will stay in the shape that you want.

Or you can go the dodgy way and cut grooves in the back of the ply to help with bending, but the chances are that it will break, also it makes the ply weak.

Go with the thinner sheets glued together :thumbsup:
 

·
Registered
Joined
·
419 Posts
For sure, the best way to GIT-ER-Done is to laminate thinner sheets over your framework. Gluing may not be necessary but recommendable. An advantage of laminating thinner material is that you will be able to stagger the overlap joints and produce smoother transitions from sheet to sheet. I have two sons and speak from experience.
 

·
Registered
Joined
·
8 Posts
bending plywood

g'day just wanted your help with an issue i have! we are currently building a skate ramp and need to know how to bend ply to the shape of the ramp. we were thinking of purchasing 9mm marine ply. We were told soaking the ply before installation was one way of doing it! If you could please respond any help would be greatly appreciated.
I read somewhere a while back, that the best, easiest way to bend
plywood or any other wood is to make a series of fairly close spaced
narrow and shallow saw kerfs across the sheet of plywood and that
will allow the flexing needed to bend and form it to a curved surface.
hope this helps,....eezlock
 

·
Registered
Joined
·
419 Posts
Kerf cuts are not really an alternative in this application. First off, you are talking about 4' x 8' sheets of material with continuous curves. That translates into a flamin lot of kerf cuts. The other issue becomes the fact that you are significantly weakening the plywood by doing this. The skate wheels will be splitting tthe kerf cuts without too much trouble. The clear path here is laminating thinner plywood to accomplish the thickness you need.

Ed
 

·
Registered
Joined
·
116 Posts
I'd vote laminate the thinnest you can get.
Glue between layers,, titebond 3.
Lots of ventilation underneath to keep it dry (this is a biggie).
Screws in the frame, not nails.
Engineer the frames to take the stress (glued/screwed plywood gussets at the joints is nice and made from scraps).
Spray underside with Outdoor deck preservative would be real nice.

Its hard enough to design and build things, so try not to build light or cheap.

No kerfing. That would weaken the situation, and invite the kerf side to rot quick.

be safe,,, you'll last longer.
that's the object of life,,, to last long.
jim
 

·
Registered
Joined
·
1 Posts
I have to agree about the kerf cuts. This is only something you want to use when there will be little ot no stree put on the boards. This is a common technique used when pouring concrete. You use the kerfing to allow the boards to bend and produce curves, but very little force is placed on the boards when used in this situation so breakage is not a big issue. If you are building a skate ramp you want as much strength as you can get. Good luck and be safe.
 

·
journeyman carpenter
Joined
·
333 Posts
on the skate ramps i have built, we used multiple layers of masonite rather than ply. much smoother, and easy to bend.

oh wow. i did not realize how old this thread was.
 
1 - 9 of 9 Posts
Top