Backlit, routed ACM

[3Dsigns]

Contemplating routing an ACM panel, routing the letters out, so that it can be a solid background with light passing through the letters. I'm wondering if I can put a piece of white polycarb behind this, and glue the panels together and also glue pieces like the centers of "a's" and "o's" to the polcarb. Is this doable? Thanks

 

[Zendavor Signs]

Yes, we make signs like this all the time. We use solid 1/8in alum instead of ACM. Solid alum is stronger and you can get cleaner edges, but ACM would probably work OK. Just don’t use the cheap stuff, you want at least 0.2mm, preferably 0.3mm, skin faces.

 

[Gino]

That will end up being so flimsy, I doubt it will withstand much of anything in the elements. Not to mention the ugly edges. You might wanna check with U/L and see if it's even allowable.

 

[3Dsigns]

That will end up being so flimsy, I doubt it will withstand much of anything in the elements. Not to mention the ugly edges. You might wanna check with U/L and see if it's even allowable.

Ok, any suggestions for a better way to do this?

 

[3Dsigns]

Yes, we make signs like this all the time. We use solid 1/8in alum instead of ACM. Solid alum is stronger and you can get cleaner edges, but ACM would probably work OK. Just don’t use the cheap stuff, you want at least 0.2mm, preferably 0.3mm, skin faces.

I'm open to using 1/8 aluminum if that's what you recommend. Then, how do you attach your polycarb to the back of it?

 

[gnubler]

Yes, we make signs like this all the time. We use solid 1/8in alum instead of ACM. Solid alum is stronger and you can get cleaner edges, but ACM would probably work OK. Just don’t use the cheap stuff, you want at least 0.2mm, preferably 0.3mm, skin faces.

Any chance you can post an image of what these look like, both day and night? Curious how they look lit up.

 

[Moze]

I'm open to using 1/8 aluminum if that's what you recommend. Then, how do you attach your polycarb to the back of it?

Aluminum would definitely be preferable.

You can use VHB tape and Lexel (Lowes) or Dap UltraClear (Home Depot) to attach the polycarbonate to the back of the aluminum as well as the aluminum 'islands' to the polycarbonate.

These are typically referred to as route-out show-through (ROST) faces.

If you use thicker acrylic and extend the letters through the routed portions in the face, it's typically referred to as a route-out push-through (ROPT) face. These are often fastened to the back of the aluminum by stud welding to the back of the face. The studs extend through the acrylic flange and it's held in place with nuts and lock washers. If there's a large enough surface area of the flange, it's possible to use VHB and adhesive instead of the studs.

 

[Gino]

Basically, you weld pins on the back side of the face and drill the holes out where the two come together. Preferably threaded pins so you can screw them fast. The push-thru looks the best.

Haven't worked on one..... or furnished one with only tape on it. I've seen others with tape and the centers eventually slide all over the place.

 

[MJ-507]

Aluminum would definitely be preferable.

You can use VHB tape and Lexel (Lowes) or Dap UltraClear (Home Depot) to attach the polycarbonate to the back of the aluminum as well as the aluminum 'islands' to the polycarbonate.

These are typically referred to as route-out show-through (ROST) faces.

If you use thicker acrylic and extend the letters through the routed portions in the face, it's typically referred to as a route-out push-through (ROPT) face. These are often fastened to the back of the aluminum by stud welding to the back of the face. The studs extend through the acrylic flange and it's held in place with nuts and lock washers. If there's a large enough surface area of the flange, it's possible to use VHB and adhesive instead of the studs.

I've never heard the term "route-out show-through faces" before. I've worked in places where the terms "routed & backed faces" and "routed aluminum faces" were used, but never "ROST". Maybe it's a regional thing. Where are you located?

 

[Moze]

I've never heard the term "route-out show-through faces" before. I've worked in places where the terms "routed & backed faces" and "routed aluminum faces" were used, but never "ROST". Maybe it's a regional thing. Where are you located?

Dallas. I've worked for and with some of the largest companies in the Country and it's commonly used.

 

[Boudica]

We are currently working on a project like this. The letters/logo are CNC cut out of ACM, then the letters/logo are CNC cut out of acrylic, but not all the way through, a thin portion is left on the back side. The letters will slide through the holes cut out of ACM, and that thin portion will be glued to the ACM. For color, I've printed on clear vinyl, which will be applied to the acrylic. We are about to put it up on the production table to be finished. I'll try to get some pictures.

 

[JBurton]

Then, how do you attach your polycarb to the back of it?

Magic!

Production Stud Welding Systems | CNC Stud Welding Systems

www.studweld.com

But really, this machine is critical if you want to do push through copy that will last. Glue and tape are really only temporary solutions, epoxy works but is hard to deal with, especially with smaller parts like insides of A's. Though at least with push through, you have the edge of the acrylic helping to keep the piece in place. When it's just backed up it tends to sliiiiiiide downward. We route out of .75" clear, leaving a small lip, then add a sheet of .177" white poly behind that. It is feasible to glue acrylic to poly with channelbond, but if you don't have a very uniform coating between the two, it will distort the light where the glue is leaving dark spots.

For color, I've printed on clear vinyl, which will be applied to the acrylic.

Please tell me it's white acrylic or you're backing it up with a panel of white acrylic/poly. Clear acrylic, even with white trans applied, will hot spot unless the led's are mounted to the face of the can pointed backwards.

Here's one of our sample boxes, one side 'push through', the other is just 'backed up'. Forgive the rough edges and nicked vinyl, it was done with our old router and has been hauled to many banks since then. (We don't have to use the 'routed out' notation because some suit came up with ROST so he could speed through spreadsheets faster. Surprise mr suit, it's all routed out!!!).

 

[Boudica]

Here are some pictures... Boss was just getting started as I was leaving. We dry fit the acrylic first, then he used a clear epoxy. Once it's set, we'll flip it over and apply the color.

 

[signbrad]

Routered faces backed by acrylic have been around a long time and they can be very durable.

The industry standard for the face is .080", or even 1/8th", with studs welded to the backs for attaching the plastic. Holes in the plastic to accept the studs should be twice the diameter of the stud—holes smaller than this may not allow enough room for movement of the plastic. Fasteners can be "speed nuts." Just push them on and don't tighten.

ACM is unsuitable for a routered face. You can't stud-weld to it and you may have delamination of the paper-thin aluminum from some of the pieces, especially the pointy ones. Most of the ACM products we typically use are only rated for five years anyway. Plus, ACM is not really rigid enough. This type of sign is not inexpensive to build. Why cheap out on the face?

On the other hand, why use polycarbonate? 3/16" acrylic is plenty strong for this application. Plus, it's easier to work with and it stays white.

Using tape and silicone to hold the plastic backer, instead of studs, is inviting the plastic to separate from the face, in my opinion. And in the event of breakage, replacing a stud-mounted backer is easier than one glued on. I also like using smaller, multiple pieces for backer, rather then one large piece of acrylic that backs the entire face. Assembly is easier and the movement of the plastic from expansion, especially long ways, is less.

Brad in Kansas City

 

[Boudica]

ours is going into a frame, an existing light box, . Admittedly, we don't normally do this type of signage, it's a first for me, but my role so far has been printing and sending cut files to the CNC guy, who has done this before. So he knew exactly what to do... though even he admitted he cut it a little thin on the backing of the acrylic part. anyhoo... learning lots from this thread! though this project is not my brain child, but my boss is a smart and capable guy, and I'm really curious about this endeavor of his, and how it works out. Sorry JBurton , it is clear acrylic, going into some sort of thin backlit lightbox/frame currently on the building... replacing what is currently there. They are rebranding with a new logo, and we are trying to replicate what ever is there, but with a newer logo. IDK who make the first sign, or anything about exactly how it's lit. If something goes wrong, hot spots etc... I'll be calling you. but it will be a prank call, acting like a robocall, updating you on how you were right.

 

[3Dsigns]

We are currently working on a project like this. The letters/logo are CNC cut out of ACM, then the letters/logo are CNC cut out of acrylic, but not all the way through, a thin portion is left on the back side. The letters will slide through the holes cut out of ACM, and that thin portion will be glued to the ACM. For color, I've printed on clear vinyl, which will be applied to the acrylic. We are about to put it up on the production table to be finished. I'll try to get some pictures.

What thickness ACM? And what thickness acrylic? Thanks Also what bit and speed do you use on the router? Thanks!

 

[Boudica]

What thickness ACM? And what thickness acrylic? Thanks Also what bit and speed do you use on the router? Thanks!

3mm ACM, and the Acrylic is 5/8" - we don't have a CNC router in-house, we send it down the street to our CNC guy (I can't answer those questions). We just finished moving it from the big table to another work table in another room, and having done that (it's really flimsy), we are going to try to back it with a sheet of thin acrylic - what ever we can get away with and still have it fit in the light box.

 

[3Dsigns]

Routered faces backed by acrylic have been around a long time and they can be very durable.

The industry standard for the face is .080", or even 1/8th", with studs welded to the backs for attaching the plastic. Holes in the plastic to accept the studs should be twice the diameter of the stud—holes smaller than this may not allow enough room for movement of the plastic. Fasteners can be "speed nuts." Just push them on and don't tighten.

ACM is unsuitable for a routered face. You can't stud-weld to it and you may have delamination of the paper-thin aluminum from some of the pieces, especially the pointy ones. Most of the ACM products we typically use are only rated for five years anyway. Plus, ACM is not really rigid enough. This type of sign is not inexpensive to build. Why cheap out on the face?

On the other hand, why use polycarbonate? 3/16" acrylic is plenty strong for this application. Plus, it's easier to work with and it stays white.

Using tape and silicone to hold the plastic backer, instead of studs, is inviting the plastic to separate from the face, in my opinion. And in the event of breakage, replacing a stud-mounted backer is easier than one glued on. I also like using smaller, multiple pieces for backer, rather then one large piece of acrylic that backs the entire face. Assembly is easier and the movement of the plastic from expansion, especially long ways, is less.

Brad in Kansas City

Hi Brad, I think I remember you from Letterville. Our Buddy Michael Boone came to visit my shop once, good man. What type studs do you weld to the back the aluminum and how close together? So, if the sign is 14'' x 96'' long, would you use like 3 pieces of 3/16'' acrylic instead of one piece? I have a new spool gun for my welding machine and a bottle of argon. WIll that work well for this?

 

[gnubler]

Nice work there! That looks awesome.
These are the kinds of signs I want to make but no one seems to have the budget. Or, I'm not a good enough salesperson.

 

[JBurton]

we don't have a CNC router in-house, we send it down the street to our CNC guy

Tell that poor guy he doesn't need to pocket out the whole sheet, a .25" lip around the perimeter is plenty, if you're backing it up with a separate sheet that is. That's the main reason we add another sheet, so that fewer studs have to be placed and less strategically. We used to have to run around the perimeter of letters putting studs just so, so they held but didn't show on the copy.

though even he admitted he cut it a little thin on the backing of the acrylic part

Looks about what we leave behind, between .25 and .125 will be plenty. You gotta imagine, for the letter to fall out, you have to push the whole thing through the metal (in this case acm) face. (wait, are those two pictures from the same piece? The one with paper looks to have much more thickness than the one in sign already...
Even better if you can coordinate mounting vinyl before cutting acrylic, though it has to be a cast colored vinyl, most printed laminated products will lift or seperate too much.

On the other hand, why use polycarbonate? 3/16" acrylic is plenty strong for this application. Plus, it's easier to work with and it stays white.

Resilience, and I always have drops of lexan on hand, very rarely do I order any acrylic under 3/4".