Clear Acrylic with Standoffs Corners Cracking

[TeamOutlaw]

We have been installing 1/8" clear acrylic panels with standoffs for 10+ years and have recently noticed an increase in the # of call-backs we are getting for corners being cracked / broken out.

Doesn't seem to matter if they are installed on brick, block, sheetrock etc!? We have the holes pre-drilled 1" from the edges, and oversized by 1/16" or so from the standoff stud size for a little "wiggle room" etc. as well

We cannot 100% rule out that the panels aren't being "bumped" or pushed on while janitorial staff cleans etc. But it appears to be very random. Some in schools (bumping most likely), others in attorneys offices.

Anyone else have this happen? Any ideas on what could be done to prevent it in the future short of using polycarbonate vs acrylic?

 

[d fleming]

Try a thicker panel

 

[Gino]

Is there a timeframe involved ??

 

[TeamOutlaw]

Is there a timeframe involved ??

?
Meaning how long are they typically up before issues arise? If so...no, not really. Some are days after install...others years later. That's what has made it so tricky to troubleshoot. I could see a building "shifting" after new construction or something...yet other sites are old / existing buildings.

Has me wondering if the acrylic is being compromised during the hole drilling procedure or something prior to us even getting them from our plastic supplier. Something like a stress fracture that later breaks completely. Although there are no visual signs of any stress on the new panels when we receive them!?

 

[Gino]

If you say you have them over-sized, then there should be no reason for the breaking, unless someone has switched out what you WERE using to what you ARE using, now.

Are the areas climate controlled ?? Most of the time, where we use offsets, it's in a very air-controlled environment. If someone did do a switcheroo on you, you may need to make a bigger hole and try making it egg-shaped. There may be more expansion and contraction going on then you 're allowing for with 1/16". You have 1/6", which I took as a typo. If they're only oversized a 1/16", then you're only allowing a 1/32" play all away around...... not very much.

 

[TeamOutlaw]

?
Meaning how long are they typically up before issues arise? If so...no, not really. Some are days after install...others years later. That's what has made it so tricky to troubleshoot. I could see a building "shifting" after new construction or something...yet other sites are old / existing buildings.

Has me wondering if the acrylic is being compromised during the hole drilling procedure or something prior to us even getting them from our plastic supplier. Something like a stress fracture that later breaks completely. Although there are no visual signs of any stress on the new panels when we receive them!?

If you say you have them over-sized, then there should be no reason for the breaking, unless someone has switched out what you WERE using to what you ARE using, now.

Are the areas climate controlled ?? Most of the time, where we use offsets, it's in a very air-controlled environment. If someone did do a switcheroo on you, you may need to make a bigger hole and try making it egg-shaped. There may be more expansion and contraction going on then you 're allowing for with 1/16". You have 1/6", which I took as a typo. If they're only oversized a 1/16", then you're only allowing a 1/32" play all away around...... not very much.

Yes, all are interior office spaces (climate controlled).

We have spec'd the same acrylic from same supplier for years, so I can't imagine they are trying to pull any "switcheroo" on us.

The standoff "studs" are 3/8" (0.3750). I typically spec the holes to be 15/32" (0.4688). Should I be jumping that hole size up to 1/2 (0.5000) for more wiggle room?

 

[rjssigns]

Top or bottom corners? If it's top corners out of the way of human body parts there might be an issue with material, clearances, etc...

May want to look into Makrolon Hygard. Expensive, but cheaper than doing the job twice.

Since I have no control over people in the facility I don't warranty anything years after install.

 

[Marlene]

.125" is pretty thin. How large is the sign? If larger than a 6" x 6" it might be an issue with a large sign done in thin material. I have a lot of 18" high signs out there and never have had an issue. I use ..187" thick. (sorry for the .375" mistake, I was thinking dibond thickness, ooops)

 

[TimToad]

Just looking at the photo, that is an impact crack starting from the edge and going inward. If it was pressure from your standoff stud, too tight of a hole or faulty drilling, you would see lots of little cracks and craze marks emanating outward from the hole. Somebody is probably removing the panels to clean them and the wall behind them and is mishandling them.

You didn't say what size the panels are, but I would be using .177 at the very least for anything over a small panel under 1 square foot.

 

[KMC]

looks like it was dropped on its corner (by the photo supplied) and fractured up to the hole

 

[Gino]

Oops, I didn't notice il the last two posters chimed in. We never use 1/8" for this sort of scenario. Usually, nothing less then 1/4". We too, have used 3?16" but that's not common. Besides, 1/8" doesn't seem like it would have any rigidity to it. Do these things bow/bulge ??

 

[DoubleDiamond]

We switched to polycarbonate because the drilling became a problem and it seems like the acrylic has become more brittle over the last 10 years. We do this sometimes to small sized panels and drilling 3/4" - 1/2" in is a problem with acrylic making it almost impossible. The polycarbonate is only slightly more expensive and way worth it in so many ways. Try to stay away from off the roll though as these will retain that curl for a very long time. We keep a 4x8 that actually measures like 52x100" in stock and a typical job costs us like $10 more and is so worry free, not to mention that in a school you have a shatterproof and less likely to be vandalized option.
If you sell them on that they will be more than willing to pay more too. It's a WIN WIN!
Just my opinion.
JM

 

[TeamOutlaw]

The pic I attached is just ONE example of many that I just happened to have lying nearby when I posted this. Doesn't seem to matter...top, bottom etc. Sometimes there are multiple corners on a single panel cracked / broken.

A LOT of our panels sizes are in the 24"H x 18"W size area. Some slightly bigger, some smaller. Typically not much over 30" or so.

I considered switching to Poly, but it is more $, and I was under the assumption you CANNOT polish the edges!?

Thanks everyone for the comments...appreciate the discussion!

 

[letterman7]

Nope, you can't polish a polycarb edge. That one photo though looks like an impact crack as another poster mentioned. Could be cleaning staff getting exuberant with a cleaning wand or something. Or, it just may be that you've tightened the caps too much. I don't use anything less than 1/4" acrylic for stuff like this, but I still back off the cap a half turn (and use the plastic washers on both sides) to ease the expansion/contraction issue.

 

[ikarasu]

Are you polishing the edges by flaming? I don't know the brand offhand... But one brand we used, we had a bunch come back cracked from different vendors. We'd send them out and they'd look perfect... but over the course of a 1-7 days they'd end up cracking, some all over the edges, some just in the corners where theres "pressure". We thought they just got damaged after the install... But one set of panels wasn't even installed yet, just sitting in their office waiting for the install date... then when we unpackaged them, spider cracks everywhere.

Turns out they changed their formula, or started to put some oil residue on it that caused the heat to fracture the material. We were told to use lower heat... which we did, and still within a few days the same thing happened. We ended up switching our supplier and the problem fixed itself.

 

[The Sign Goddess]

How is this being cut? The edges look rough in the picture, maybe just the picture? The roughness in my experience often means micro cracks that turn into big cracks when any pressure is applied later. Could be as simple as a bump and they'll show up anywhere in the panel.

We have all of our acrylic laser cut. Smooth edges and no nicks that later turn into cracks.

 

[JHeard]

We had a similar issue a little less than a year ago. Switched suppliers and haven't had problems since. We think they changed something in the way the acrylic was made, but I'm not sure what exactly was changed. I would suggest a different supplier and see if the problem improves.

 

[eahicks]

If you are getting the acrylics flame polished, remember DO NOT apply alcohol to them to clean. They WILL crack around the edges.

 

[CanuckSigns]

Is the acrylic cast or extruded? How are they finished? Saw or router or laser?

I agree that the 3mm acrylic is far too thin to use with standoffs, our bread and butter is interior signage like this, I would never use 3mm in this application, 4.5mm as a bare minimum. I bet someone either leaned against the sign or bumped it while walking past, the thin acrylic flexed and cracked around the fixed standoff.

 

[Johnny Best]

I use green edge acrylic in 1/4" thickness with polished edges using compound and polishing wheel.
Has the look of glass and not plastic.
Like was mentioned those cracks come from the corner, back to the hole.
And you can polish the edges of polycarb, so you could stick with the thinner material. It just does not look nice and clear as acrylic does when polished.