sign face question

[gabagoo]

I am building a sign face using ex12 extrusion. How much bigger than the acrylic does the finished frame have to be to allow for expansion and contraction? This one is just a frame with no box and is about 12' x 30". Would 1/4" be enough?

 

[ams]

I always do 1/4" all the way around myself.

 

[gabagoo]

Thanks, I don't do these often and never remember.

 

[Z SIGNS]

1/4" should be good enough.
Knowing how much something will expand and contract is important especially when joining dissimilar materials.
Most sign materials like acrylic come with a spec sheet that has all the physical properties that list expansion and contraction.

 

[Billct2]

Maybe I'm misunderstanding, but if the face is 1/4" smaller all the way around that means the face is cut .5" shorter. Doesn't the face sit on the bottom of the frame? So the 1/4" may be distributed evenly on the sides but on the top its 1/2"(unless you're using a hanger bar)

 

[S'N'S]

Maybe I'm misunderstanding, but if the face is 1/4" smaller all the way around that means the face is cut .5" shorter. Doesn't the face sit on the bottom of the frame? So the 1/4" may be distributed evenly on the sides but on the top its 1/2"(unless you're using a hanger bar)

I agree, I would have thought 1/4" on top and 1/4" on one side would be enough.

 

[Gino]

You'll still have an inch behind the retainer lip, but I agree, a 1/4" all the way around is a little sloppy. 30" × 144" shouldn't be too bad, but I wouldn't make that my rule of thumb.

 

[gabagoo]

I guess I meant an 1/8" all around but 1/4 all together.

 

[J Hill Designs]

I guess I meant an 1/8" all around but 1/4 all together.

dont forget to take into account the thickness of the extrusion. a finished size 30"x144" would only accommodate 29.75"x143.75" max if the extrusion is 1/8"wall