Is 1" Thick PVC Gonna Warp?

[tuck]

Folks,

I have a client that is wanting high end 2-sided routed signs for his remodeling business. The signs will be placed in front of homes that they are remodeling and they need to look top-shelf as well as hold up to a lot of handling (put 'em up, take 'em down, put 'em up). He wants to start with an initial order of 8 signs with more to come. (The remodeling business is booming, I reckon!)

The client wants wood panels (clear 1.5" cedar), but I am doing my best to talk him into 1" sheet PVC, which I know will cut cleaner and hold up better over time.

Now, looking at my design, the panels will be about 23" in diameter with the black areas to stay black, routed down (hollowed-out) into the substrate maybe 1/4". I want to use 1" thick black PVC with Oneshot metallic paints for the painted finish for the areas not routed. (The raised sections of the saw blade logo would be painted metallic silver, for instance.)



If I use 1" black PVC, routed both sides, is there any chance these panels might warp in the hot sun, even painted with lighter colors? (Black absorbs heat). The panels will be hanging from chain from the post arm.

Thoughts and suggestions much appreciated!

Mark

[letterman7]

It'll be ok as long as you don't rout any deeper than that since the sign is relatively small. Just did a couple larger size signs (2' x 3') for a company that wanted to do the same thing - remove and install at different places. Now, that said, the black pvc isn't UV protected - it will turn grey anywhere it's been cut. What I've done in the past is spray the entire thing in a UV clear (in my shop it's an automotive clear) and let it soak into the pores. Two coats is enough to keep it from turning. Don't use OneShot metallics... they have a very poor life even if clear coated. Better choice: sheet the entire sign in metallic vinyl of your color choice, then rout through the vinyl. Finish with clear over the vinyl. Best choice: prep and paint the pvc with your choice of metallic urethane paint, rout then clear.

[joe]

Greetings Mark,

What I'm about to say is my own take on this job. O, congarts on the job.

I agree that pvc will be an excellent choice but it does have it's down sides. First off, black pvc warps because of it's chemical structure. It's nothing like white. The second concern, is it by nature looks stiff and mechanical. This can be overcome but it's a factor. I think you could do some texturing and stuff to it and come out well.

You know me, I'd go with wood, probably MDO and have a black steel bracket as the carriage and incorporate some design with the metal. It wouldn't cost much with MDO.

Joe Crumley
www.normansignco.com

[tuck]

Thanks for the prompt feedback, guys.

Rick,...the client has stated that he won't settle for any vinyl under any circumstances. I myself prefer a painted finish in a case like this and have used the Oneshot paints in the past and they've held up well with some spray-on UV clear-coat.

Joe,...MDO? Really? If I rout down into the plywood, I'll get into the layers of thin plys, right? I'm not questioning your expertise, no sir, but I've never in all these years routed a 2.5D sign out of MDO or any other kind of plywood.

I don't HAVE to use black PVC. White would be fine since the entire panel(s) would have to be painted. Rick has reminded me that black PVC turns gray when routed anyway, so I could use white. (The idea with black was to not have to paint the routed-down sections.)

As for "stiff and mechanical", I think the saw blade logo kinda warrants that, but I can dress up the panels easily enough, like maybe a chamfered edge around the outer perimeters and a nice color scheme.

Whatdaya think?

[joe]

I wouldn't ever try to carve in MDO. I'd either pocket or apply decorations to surface.

Joe Crumley
www.normansignco.com

[tuck]

I wouldn't ever try to carve in MDO. I'd either pocket or apply decorations to surface.

Joe Crumley
www.normansignco.com

I didn't figure you would, Joe. (MDO).

But as described with 1" thick (white) PVC, routed down 1/4" on each side, you reckon I'd be safe with no chance of warpage?

Another thing I could do is use 1/2" thick PVC (separate panels) and sandwich them to a center core of 3/4" MDO with some Gorilla Glue and I know that will never warp. Thoughts?

Edit to say, and I repeat,... one riding concern is that these little panels will be handled a great deal over time, like taken down for temporary storage or moved to another location, whereas they will be tossed into the back of a truck with God knows what else and transported. They need to look good but be as tough as possible and that's one reason I want to rout the copy and graphics down into the substrate, rather than having raised letters, numbers, etc., which would be just begging for damage, and it's another reason I wanna use PVC instead of wood. It's much tougher for something like this. I reckon a determined vandal could damage it, but you can't hardly break sheet PVC.

[tuck]

Ok, what would you think about this?

Black = black

Light gray = Metallic Silver

Dark Orange = Metallic Copper

Green = Hunter Green



Whatdaya think?

[letterman7]

That looks nice Mark. Even with white pvc I don't see any warpage issues. And, for the record, I've never had a piece of 1" black warp at this size - ever. I was almost going to suggest just using HDU for this, but I don't think it would hold up to the rough handling. As it is, the paint is going to get chipped if it gets thrown around. That's why I'm suggesting a urethane clear - it'll give you a little more protection than a generic UV clear.

[tuck]

Thanks Rick, and thanks for the tips. Yeah, the paint will be the weak link, but what are ya gonna do? Anyone can take a car key and ruin the finest, hardest and best protected finish on an automobile that money can buy.

These will be easy enough to touch up, though.