Wavy sign face in frame – what could cause this?

[Gil Johnson]

A few reasons :

Not enough room for expansion in the frame (it’s black substrate so it’s going to absorb more heat)

The frame has been fit too tightly on the sign face, therefore it can’t move in temp variations.

You have not stated what substrate has been used, but if it’s an expanded plastic then it’s never going to sit in a frame without lots of movement.

Usually first reason is to blame for this type of issue.

Hope this helps,

Gil 😀

[Desiree]

Thanks Gil,

It’s Lexan or Makrolon polycarbonate.

Would it be a space issue due to expansion on the height and width or from the depth(so the face is being pinched at the front on the retainers)? Or both?

[Gil Johnson]

The sign will be expanding all round but more on the horizontal (along the length of the sign).

All depends on the size overall, but an estimate would be to allow a 1/4 inch per panel, and use some panel locks to keep the panels together, that they will expand and contract together.

A sign like this is better hung along the top edge, this enables free movement.

Hope that makes sense?

[Desiree]

Definitely makes sense. Thanks a bunch! We’ll trim down the face a bit to start and see if that fixes the issue.

[Robert Lambie]

quote Desiree:

We’ll trim down the face a bit to start and see if that fixes the issue.

I do not see that working…
As Gil has said, everywhere the sign has been pinched/held by the frame due to a tight fit, preventing an even expansion/contraction of the panels. even once you free them up it will still sit buckled.
Maybe an idea to revert to a composite panel but do still allow for board movement. best of luck.

[Desiree]

Maybe I misunderstood what he said but didn’t Gil say that it was the overall height and length causing the wave? (most likely). Not the depth.

Maybe I wasn’t clear either. This is a backlit sign box with LED lights. It’s not in panels. It’s one full 25ft length of Lexan (translucent white plastic).
With printed/laminated vinyl laid on top.

[Kevin Flowers]

Hi
is this on a hanging strip if not that will be causing some of your problems

Kev

[Martin Pearson]

Think what Robert is trying to say is that now the panel has been distorted so badly it is unlikely to return to being a flat panel, as Kevin says would have been better with a hanging strip at the top. You will also need to be careful if you intend to try trimming some off, take off to much & you run the risk of the panel being sucked out of the frame during high winds.

[Desiree]

Thanks 🙂
The sign does have hanging strips. I referred to them as retainers in my previous post.

We definitely won’t trim off enough for the face to come out of the frame.
We might as well try that and see if the sign smooths out because the only other alternative would be to replace the face and graphics. Trimming it was my original plan but I wanted to get some other opinions first.

Unless you all have any other suggestions/questions that might lead to another option…

[Kevin Flowers]

Desiree
this may help expansion on Makrolon is approx 1.3mm per meter per 20-degree change in temperature.

[Desiree]

Thanks! I’ll have a look at it.

[Robert Lambie]

quote Martin Pearson:

Think what Robert is trying to say is that now the panel has been distorted so badly it is unlikely to return to being a flat panel.

Exactly…

Also, i should have read the part it was an illuminated sign or i would have not suggested the composite.