Will this sign warp?

[pkirby]

Hey guys,
I'm about to start a v-carved sign that will be hanged by 2 chains from the building's soffit. It will be 3/4" thick PVC and V-carved. Do you think I will have any problems with it warping or am I going to need some kind of back support?

22456

[steve_g]

Paul…
I’m envisioning high school boys running, jumping and seeing who can slap it the highest/hardest… If for no other reason, I’d back it up with something!
Is it V-Carved on both sides?
SG

[pkirby]

It will be v carved on one side and it will be hanging about 10' in the air so I'm not too concerned about teenagers. LOL

[Kyle Stapleton]

That is what they thought about the rim in BBall.

[pappybaynes]

Hey guys,
I'm about to start a v-carved sign that will be hanged by 2 chains from the building's soffit. It will be 3/4" thick PVC and V-carved. Do you think I will have any problems with it warping or am I going to need some kind of back support?

22456
I would think 5/4 would be better...I use 5/4 all the time for exterior - EXCEPT, mine are screwed to the building...
Dick

[jdwykrent]

In my experience with a product called "Azek" (http://www.azek.com/), which is a PVC product, it bends very easily. You might want to try hanging it before you make the cuts and see what happens.

Are you worried about it cupping after the cut is made? I might not understand your concern fully... Correct me if I'm wrong.

[blackhawk]

I think that I would put one or two aluminum angles on the back to keep it straight. Be sure to slot bolt holes in the aluminum and don't fully tighten the bolts. This will allow the PVC to expand and contract.

[pkirby]

Dick,
When you screw your signs to the building, how do you allow for expansion/contraction?

Jeff,
Maybe warping is the wrong term to use. I'm more concerned with it flexing a lot over it's 8' length. So if you were to look at the sign from a top view, then I would worry about it flexing in a snake/zig zag because the PVC I've dealt with has relatively flexible compared to say plywood.

Brad,
I have thought about doing it this way but I wanted to avoid seeing the aluminum on the back. I had also thought about placing another sheet on the back and sandwiching the aluminum between them, but am not sure of a good way to mount both sides with keeping the fasteners hidden.

[jdwykrent]

What about a piece of material for the top that is of the same thickness cut a half lap down the 8' length and attach it to the top? that would solve any sag or zig zag if it were something rigid... I'm thinking maybe even cut a piece of flat bar stock hidden by cutting a rabbet into the back of the sign.

[jerry_stanek]

We have made signs like that but we used 2 sheets of 3/4 sintra with a square tube routed in and the bolts go through that. The tube keeps it from warping

[pappybaynes]

Dick,
When you screw your signs to the building, how do you allow for expansion/contraction?



Jeff,
Maybe warping is the wrong term to use. I'm more concerned with it flexing a lot over it's 8' length. So if you were to look at the sign from a top view, then I would worry about it flexing in a snake/zig zag because the PVC I've dealt with has relatively flexible compared to say plywood.

Brad,
I have thought about doing it this way but I wanted to avoid seeing the aluminum on the back. I had also thought about placing another sheet on the back and sandwiching the aluminum between them, but am not sure of a good way to mount both sides with keeping the fasteners hidden.


Fortunately I don't have to hang the signs (the historical society is getting a hell of a deal)...it is my understanding that the screw hole is larger than the diameter of the screw giving it room to expand and contract...they then put a pvc cap in the counter sink

[cabnet636]

If it is cut on both side fairly equal it should balance, if it is a "Face" only then we usually cut a relief in the back of say 1/4 leaving a few inches full depth at the perimeter

[pkirby]

Thanks guys for all the help. I met with the lovely city government today:rolleyes: ,and they are forcing me to mount it to the side of the building instead of letting it hang.

[joe]

Interesting; I've read through this post and if I'm not mistaken we haven't got a peek at what this is all about.

I've found it helpful when asking questions to show what the job looks like. It's easy to do.

One of the major advantages to a sign that swings, it takes the pressure off the substrate. But the architecture of blade signs is almost an art within itself. Here in Oklahoma where we often get wind of 60mph it's important to a refined structure with the movement in mind.

Joe Crumley
www.normansignco.com (http://www.normansignco.com)