PVC Thickness

[NMES]

Hi Guys,

I'm new to sign making and have a basic question. I'm making some letters to hang on the outside of a building. The size of each letter is 3' tall. I'm planning to mount each letter in four places, two fasteners at the top two at the bottom.

I had been planning on cutting the letters from .5" komatex. Now I'm concerned that .5" is too thin and that I need to go to .75". Can anyone offer advice here?

I'm mostly nervous about warping and thermal expansion.

Thanks,

Nick

[robtown]

For letters that size you will most likely need more mounting points. Not because of the weight, but because PVC will want to warp because of being outside. Thicker would help.

[NMES]

Here's a proof of what I'm doing. You can see the two rails, one at the top, one at the bottom. Would you suggest having a third rail in the middle?

facade.jpg

[joe]

Here's a job where I'd order Pre Coated Red Dibond and screw the letters directly to the building. Even if I needed to create a second drop shade this would be faster and more profitable that using PVC. Your method for attaching PVC is almost guaranteed to bend.

I like to make money!

Joe

[NMES]

Thanks Joe. The 'customer' wants the letters to have some depth and standoff from the building a bit which is why I kind of dismissed Dibond. Does that make you see things any differently?

This is more of a favor than a job...

[joe]

I'm sorry but it confirms what I was thinking. This customer has little or no idea about the materials. One better option is to order the letters from Gemini and put them up. They will outlast anything you can make. You can't buy the materials and paint it for what they will charge. They will even send you the patterns to put them up. Because you have a CNC doesn't mean you can out do the market.

I sure like to make money.

Joe

[bleeth]

For great product that you can't duplicate in your shop the Gemini suggestion is the way to go all the way.
You can get vacuum formed poly letters that will last forever.

If you are dead set on cutting them yourself you are better off with foam a couple inches thick. I know someone who has done a bunch of these in upstate New York.
Also, it would amaze you, unless you already know, how many decorative elements on building exteriors today are pretty low density foam (including columns in front of my house for 14 years and three hurricanes).
They use insulation foam, seal it with shellac, and then paint it. There are also hardcoats out there that make them hail proof. Do some research here on the forum and the net for hardcoat ideas from those who have used them personally.

[bobmoore]

I would make them if it was me. You are apparently new to cnc as you only have 4 posts. An excellent learning experience and pvc will hold your paint so warpage is your only real concern. Hopefully your buddy is appraised of the risk that comes with a new sign guy. PVC has to move like vinyl siding so keep that in mind with your mounting system and have some fun.

[robtown]

Gemini is the best bet for speed and durability. If you choose PVC, then yes a middle rail and .75 thick at least.

Foam would be a good choice as well, I'm not sure if bleeth was referring to HDU or a lighter foam, but HDU would work well, the stuff ain't cheap though... PVC and HDU foam both both cut well.

[rb99]

I hope you don't plan to position the letters where you have them.