Carpentry and Woodworking - Exterior Plywood

I need to buy exterior plywood (sanded one side). When I go to buy them, do I need to know anything else or is this as basic as it gets? Just want to make sure they don't start asking me additional questions that I don't know. I do know the size I need. That's about it.

Generally s1s plywood is not used on the exterior applications. What are your plans? Products like T1-11 and RB&B are designed with exterior glues and are made for such use. It will have to be painted, regardless, so let us know what the plans are.

I'm planning on building a Skateboard Halfpipe. Was thinking of painting it or attaching tar paper for the surface.

You might try CDX, it is cheaper and rated for exterior but it will have knots and voids in it. You can fill the voids with durham's rock hard putty or some other filler and then paint. I know very little about skate boarding but assume it would tear up roofing felt in short order.

If you use rock hard putty, apply it neatly - it is a real bear to sand!!

:o Just noticed I put this in the wrong topic! Durrrh...

Sorry guys and thanks for the info. So now I guess T1-11 and RB&B would be out of the question right Larry?

I've heard about CDX and found some free ones available but didn't know what it was. I'm trying to figure out why the plans would call for s1s (I guess that's the technical term for that?). I guess if I go with the CDX maybe I could use something like Bondo?

Hmmm...something that costs less but more work (applying something to fill knots and voids and then sand) OR something more exspensive and less work. Guess I have to weigh out the costs. *Sigh*

I've thought about the tar paper as well. I don't see how you can skate on that. Roof felt and tar paper is the same? I think I'll stick to painting it.

There apparently IS more to it than just going and buying! :(

Halfpipe = curved, doesn't it?

Since you are asking about plywood, I'm guessing that it must be for the sides of the halfpipe?

Yep. Curved. It'll be for the sides and the decking part. For the decking part it I'd have to wet the unfinished side of the plywood so it'll curve.

LOL...I guess that just answered my question about why it has to be s1s... ?

You're not going to get plywood to curve very much unless it's very thin. 4 layers of 1/8" tempered hardboard applied one at a time, and glued together, would prove to be a much better choice for a barrel-like curve.

I've been thinking about building one for my nephews. ;)

It calls for 4 x 8 x 3/8". That's pretty thin isn't it? For the decking it'll have 2 layers. The 4 layers of 1/8" tempered hardboard would still be better? As far as it curving, right?

3/8" plywood would produce a very gentle curve. How much will this half-pipe curve? (vertical drop from top to bottom of curve)?

I've never looked at plans yet.. was just thinking about it in my head. I imagined that if I made one, I'd use many layers of tempered to get a nice curve. (the 1/8" bends easily, yes, and its smooth as a baby's bottom) Not saying it would be better than your plan, since i don't know what the plan looks like! ;)

Are the plans on the web?

I shoulda thought about that...

Here are the plans:

http://www.rickdahlen.com/hpplans/Halfpipe.pdf

WOW! That thing is way bigger than what I was imagining! I was imagining the plywood curving the opposite direction. 3/8" ply will bend easily in the direction shown. My nephew's would absolutely flip if I built something like that for them! Course I'd need a small fortune first, and their mom's permission... LOL

:D Yeah, I can't wait to build this thing and ride on it! I mean...have my son ride on it. :D

So..I'm good to go on s1s? And that's all I need to know when I go to buy the plywood?

You're more than welcome to come to La La land, CA and build it FOR me. You have my permission, my small fortune and you can invite your nephews.

Careful... I've been known to work for beer, room, and board! LOL

Almost all plywood sold anymore is exterior glue. Finding that shouldn't be a problem. You will likely want BC plywood, where the B stands for a good quality of sanded plywood that will have very few imperfections or fillers.

AC plywood would be the highest grade, and if the price doesn't scare you off, that would be the best plywood you could get for this project. The A stands for the best quality plywood, sanded, no blemishes. The C is the back side, and it will likely have football shaped imperfections that are filled but not sanded smooth.

Well, if you're gonna work on it while drinking beer... :thumbdn: :D

Thanks so much for the info especially explaining in detail the AC and BC stuff.

I've just been reading the responses, and you are getting excellent advice, so I stayed back. But, yes, T1-11 and RB&B are out of the question. Good luck with it!

I'm assuming the sanded side is for when the youngin's fall flat on their faces, at least they won't get splinters?

That would be good! :thumbup: I guess most s1s plywood is less work too so you can paint them or whatever else?

We used to use masonite for the surface of the curved half pipe.

What's masonite? I've done a quick search and I think I'm looking at the wrong stuff. Expensive? Can you link me to a pic of it?

Masonite is a misnomer for the 1/8 or 1/4" 4x8 sheets of tempered hardboard that I was referring to earlier. Masonite is actually a name brand that most often refers to lap siding (and other siding products) that became famous for failure and class action lawsuits. When used in the generic sense, masonite has come to refer to items that are made of compressed paper, which is what kcxj was referring to.

Well, just so you guys know, I went ahead with the AC plywood. :) I need to make a correction that it's 3/4" plywood for the decking part. The 3/8" is for a different part of the project. :rolleyes: