Plywood vs Marine plywood

Hi guys

I've been browsing the net looking for info on plywood as i'm building a skateboard halfpipe ramp.

I'm going to use treated pine struts along a 17mm plywood structure for the curves of the ramp but I need the actual ramp surface to be somewhat waterproof

I was advised that marine plywood is a possibility?

Is there any measures of waterproofing standard plywood so that I could get some extra life out of it?

The ramp will be 5 feet high, 22 feet long and 8 feet high so I'm trying to find a balance between quality and price

I live in Adelaide, South Australia so if anyone knows of any suppliers for the products I need please let me know

All info is greatly appreciated


Cheers

As far as I know, marine ply isn't waterproof. It's made differently to standard ply, so that it doesn't have any voids in the structure, which makes it more capable of withstanding wave motions. I'm sure it's got a good water-resistant glue, but it would still need some other form of waterproofing.

I'm sure others here will have more experience with skate ramps, and will be able to tell you what is needed.

Good luck.

ajw

Quote:

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Originally Posted by Jonnyiswalking

Hi guys

I've been browsing the net looking for info on plywood as i'm building a skateboard halfpipe ramp.

I'm going to use treated pine struts along a 17mm plywood structure for the curves of the ramp but I need the actual ramp surface to be somewhat waterproof

I was advised that marine plywood is a possibility?

Is there any measures of waterproofing standard plywood so that I could get some extra life out of it?

The ramp will be 5 feet high, 22 feet long and 8 feet high so I'm trying to find a balance between quality and price

I live in Adelaide, South Australia so if anyone knows of any suppliers for the products I need please let me know

All info is greatly appreciated


Cheers

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When I rebuilt my balcony deck a few years ago I researched this and found that exterior ply uses the same specification adhesive as marine ply but is a lot cheaper. The difference is that marine ply is selected wood with fewer voids which is not a consideration for your application.

I tiled the deck over a waterproof seal (because it is over the living area). The guy who put on the waterproof gunk told me he preferred exterior ply because the compound stuck to it better. That was about 8 years ago and so far so good.

Just for a skate ramp I would grab some construction/form ply it has a plastic skin on it and is very resiliant to water and stress and not too expensive. I have made sand pits and other outdoor item from it and it seems to hold up well, you should still seal ends and edges where you cut them.

Yep you will need to make it from several layers of thinner ply 4.5~6mm should bend enough for your purpose. Make a test ramp frame to see which thickness you need before lashing out on the ply.

Ps, buying ply by the pack full is much cheaper per sheet than singular, a 22' long 1/2pipe will use a stack of sheets.

Beautiful

Thanks for the info guys. Going to build the structure this week and then decide on the ply once ive got the base.

Thanks again...will update photos/info as the project as I go

GLENNET and AJW are correct...marine ply uses the same wood, and glue as exterior H3 grade construction ply...you can get marine ply that isn't treated as treated wood can react with marine glues for weaker bonds...but marine ply has the garrantee there are no voids between the edges of the veneers within the sheets...voids tend to collect and hold water that inevitably finds its way in...and causes the veneers to swell excessively and delaminate.

If you choose to go with laminateing thiner sheets together...use the black resorcinol marine glue (the black stuff)...it'll be the cheapest for the quanity you'll likely use...it come in cear but thats dearer.

marine plywood has no viods in the inner laminates and has a minimum of 5 laminations.
It is glued with the same glue as exterior ply ( resorsinal glue, the only glue that can withstand boiling without failing ) Plywood that is thinner than 4.5mm (3/16" to us older people )with 5 laminations or more, is considered to be aircraft ply.Formply will not do the job you require, as it is designed to have no flex. i.e. very rigid. exterior grade ply is what you need.You can waterproof it with epoxy, but epoxy hates ultraviolet light and breaks down, the best thing that you could coat it with is some form of water proofing paint, the end grain being the most important thing to protect as that is where water will ingress the most.
I remember those skateboard things from the early 70's, but then it was a rollerskate screwed to the bottom of a piece of wood. I think I still have a few scars from my attempts to ride one. take my hat off to the people young and old that ride these things today.
|Hope this has been of some help. Cheers, Grump.

I have also been researching plys lately but for a slightly different reason. I have been building some longboard skateboards. I have also come to the conclussion that exterior ply is (for me) going to be better than marine ply. Is almost A-grade quality and uses the same glues etc.

A while ago I was building a ramp for my boys and from my research I found that there is a product called "Skatelite" that is used extensively for skateramps (is waterproof etc) but is very expensive. A lot of people have also use masonite as the skate surface but can be slippery. I didn't end up using either of these but went some cheap structural ply and just put it away each night.

Have a look at the cost of marine ply. I am sure that will shape your decision :-

regards,
Jill