# Curved Lighted box / plexiglass frosting - how do I do this



## DannyDepac (Jan 29, 2018)

Hello Everyone, 

Today I started building a small stage platform for our upcoming musical Sister Act and then I found a cool picture online (after I had built it of course) that would def help "jazz it up" 

I can definitely adjust the desired design to my current build but I'm just not sure of the method or material - 

I need a flexible plexiglass / acrylic material that is not very transparent but I want to light it with colored lights... 

Should I use frosted glass spray ? Sand plexiglass? Slightly heat the plexiglass? Or does something exist that is curved and not completely transparent like film?

I attached a picture - My version is a curved semi circle is that helps. I can take a picture tomorrow if need be. 

Thanks in advance guys


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## RonHebbard (Jan 29, 2018)

DannyDepac said:


> Hello Everyone,
> 
> Today I started building a small stage platform for our upcoming musical Sister Act and then I found a cool picture online (after I had built it of course) that would def help "jazz it up"
> 
> ...


 @DannyDepac Perhaps add a few approximate dimensions regarding Circumference, bend radius, uninterrupted length required / desired between joints (Basically how long a continuous length are you hoping to find without having to piece it together where sections end?) This will allow folks to appreciate how tightly you're hoping to curve your translucent material. To be clear [Pardon my inadvertent pun] this is for illumination purposes only, correct? You're not hoping for this material to be structural in the sense of supporting any walking surfaces and live loads, right? 
*EDIT:* The first thing coming to my mind is the pebble-ized translucent panels Home Depot used to sell for laying in T-Bar ceiling grids below incandescent and / fluorescent ceiling lights. These used to be readily available in nominal 1' x 4' and 2' x 4' sizes and were often stocked in pebble-ized clear and milky white colors. If you're hoping to wrap around 20' or 30' feet in a continuous, uninterrupted, length with no light-leaking cracks or ugly, shadowy, seams, obviously 4' lengths aren't going to be to your liking. If what I'm describing sounds like a possibility and you're on an extremely tight budget, you may be able to find some of these panels in a second-hand building material store for very little cost. 
Toodleoo!
Ron Hebbard.


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## Amiers (Jan 30, 2018)

4x8 sheets of 1/8” cheap clear plexi/acrylic/lexan plastic. ( Its not cheap ) Then take the orbital sander to it with a 60 grit. Don’t push hard you want to try to get it as even as possible. 

Then push it through a saw with 120 teeth blade or more. If you feel like it will chip you can tape your line but an even push of the saw or sheet will get a perfect cut. 

Personally I prefer a table saw for plastic vs a panel saw but that’s me. Use whatever you are best at.


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## RonHebbard (Jan 30, 2018)

Amiers said:


> 4x8 sheets of 1/8” cheap clear plexi/acrylic/lexan plastic. ( Its not cheap ) Then take the orbital sander to it with a 60 grit. Don’t push hard you want to try to get it as even as possible.
> 
> Then push it through a saw with 120 teeth blade or more. If you feel like it will chip you can tape your line but an even push of the saw or sheet will get a perfect cut.
> 
> Personally I prefer a table saw for plastic vs a panel saw but that’s me. Use whatever you are best at.


 @Amiers @DannyDepac Amiers is definitely correct when he advises _Lexan is not cheap_. Lexan is what we used for the front faces of the large automated pinball machines we built three of for three productions of The Who's Rock Musical Tommy in Toronto, Ontario, Offenbach / Frankfurt, Germany and their inaugural production in London, England. Several charges of Pyro-Pak's best were fired every performance less then 1' behind the 1/4" Lexan 'glass' and less than 3' in front of the various productions' leads whilst they were playing and riding the wildly gesticulating machine purportedly winning and causing the machine to short-circuit and erupt in a combination of blinding percussive / concussive charges and showers of flying sparks. The pyro certainly caught the attention of Germany's TUV, their government inspectors for everything from explosives through welds, mechanical safety and structural integrity, electricity and off-gassing. 
*Bottom Line:* Two layers of Lexan were employed for redundancy. The inner panel required frequent cleaning but neither Lexan panel ever showed a hint of cracking in spite of the shock-waves and searing heat thrust upon them nightly and twice on matinee days.
*Lexan.* It's a trade-marked product. Optically pretty darned good. Definitely durable. Most definitely NOT cheap in most person's opinions.
Toodleoo!
Ron Hebbard.


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## DannyDepac (Jan 30, 2018)

RonHebbard said:


> @DannyDepac Perhaps add a few approximate dimensions regarding Circumference, bend radius, uninterrupted length required / desired between joints (Basically how long a continuous length are you hoping to find without having to piece it together where sections end?) This will allow folks to appreciate how tightly you're hoping to curve your translucent material. To be clear [Pardon my inadvertent pun] this is for illumination purposes only, correct? You're not hoping for this material to be structural in the sense of supporting any walking surfaces and live loads, right?
> *EDIT:* The first thing coming to my mind is the pebble-ized translucent panels Home Depot used to sell for laying in T-Bar ceiling grids below incandescent and / fluorescent ceiling lights. These used to be readily available in nominal 1' x 4' and 2' x 4' sizes and were often stocked in pebble-ized clear and milky white colors. If you're hoping to wrap around 20' or 30' feet in a continuous, uninterrupted, length with no light-leaking cracks or ugly, shadowy, seams, obviously 4' lengths aren't going to be to your liking. If what I'm describing sounds like a possibility and you're on an extremely tight budget, you may be able to find some of these panels in a second-hand building material store for very little cost.
> Toodleoo!
> Ron Hebbard.




Thanks so much for getting back to me so quickly and offering to help! 

I am attaching pictures to help - the larger stage platform is 92 inches across at its widest point and I only need to light the front edges. The smaller platform is about 30 inches across and 50 inches long ( sorry I forgot to measure it when I took the pictures).

It doesn't need be structural at all, just an opaque surface that will wash colored light through it.

Thanks again


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## DannyDepac (Jan 30, 2018)

Amiers said:


> 4x8 sheets of 1/8” cheap clear plexi/acrylic/lexan plastic. ( Its not cheap ) Then take the orbital sander to it with a 60 grit. Don’t push hard you want to try to get it as even as possible.
> 
> Then push it through a saw with 120 teeth blade or more. If you feel like it will chip you can tape your line but an even push of the saw or sheet will get a perfect cut.
> 
> Personally I prefer a table saw for plastic vs a panel saw but that’s me. Use whatever you are best at.




Thank you - I am going to look into it. Not that budget isn't a factor but I have some room for the material if its feasible.


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## Amiers (Jan 30, 2018)

Here is another option if real sheets are a price issue.

https://www.marinevinylfabric.com/p...xd0T-H3Ef7OMaAkAGEALw_wcB&variant=26970937862

The idea would be to stretch the vinyl around the front and blast it with some heat to give it a hard edge. Then spray paint some frost on it to give desired effect. The main problem with this is breakage factor. The higher the gauge you go the more it can take.

If you feel it’s gonna get kicked a lot for go the heat treat and just stretch the piss outta it to get that hard look.


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## kicknargel (Jan 30, 2018)

For a low-cost solution, I love Coroplast for this purpose. It will take the bend if you do it WITH the grain. About $15/sheet from a plastic supplier. You want 4mil, natural.


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## dbaxter (Jan 30, 2018)

I used flooring underlayment for a curved structure I had to build. It's translucent (we painted it because we didn't want that) and tough. We stapled it to the substructure. It's the tan dome in the middle. More details here:


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## DannyDepac (Jan 30, 2018)

dbaxter said:


> I used flooring underlayment for a curved structure I had to build. It's translucent (we painted it because we didn't want that) and tough. We stapled it to the substructure. It's the tan dome in the middle. More details here:


Thats a really clever idea! Thank you I might try this!


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## DannyDepac (Jan 30, 2018)

kicknargel said:


> For a low-cost solution, I love Coroplast for this purpose. It will take the bend if you do it WITH the grain. About $15/sheet from a plastic supplier. You want 4mil, natural.


ACTUALLY I THINK HAVE A SHEET OF THIS AT WORK!! I'm going to try it


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## Crisp image (Jan 31, 2018)

if you want acrylic sheet then ebay might be good for you too. I got a sheet here for about $65 aud where as the plexiglass (perspex) was over $400aud I used a light spray paint on the backside to make it opaque.
Regards
Geoff


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## bobgaggle (Feb 1, 2018)

I didn't see this in the previous comments, but you can buy frosted polycarbonate (Lexan). I've done a lot of plastic facings. Some things I've learned:

-The material must be supported on all sides, especially if you go with acrylic. Its tempting to place your platforms then just screw the facing on at the top. But I guarantee an actor will kick it at some point a crack it. So you've got to repeat the curve at the bottom of the platform and screw it in there too..

- If you need to scab two pieces together, using a piece of clear plastic along the back of the seam will look ok, but still project a light distortion. It looks better if you can incorporate seam catch on the outside of the box to give you a sharp shadow.

- It should go without saying, but predrill your plastic. If using acrylic, predrill larger than your screw diameter, not the same size. 

- Leave the protective film on the material until the last minute. Static charge in the plastic will attract airborne dust and leave scratches on it when you wipe it off with a rag. I don't know your load in schedule, but if you can leave the film on until tech week even better...

- When you cut the material on a table saw, set the depth of the blade high. It keeps the fewest amount of teeth in the work piece, and helps if you're ripping really thin stock by pushing the material down onto the table.


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## kendal69 (Feb 7, 2018)

*Flexible Translucent PE Plastic Sheet, or look up sheets of fiberglass both very cheap and can be cut with a box cutter.http://www.eplastics.com/Plastic/5-oz-Translucent-White-48-x-50ft-Roll*


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## wingnut (Feb 7, 2018)

I've used 4x8 acrylic panels to construct light boxes. These are reasonably flexible and I've been able to curve them about 8" across 4' without any problem. Got them at a local plastics supplier (Piedmont Plastics) for about $75 per sheet. They can be cut with a table saw and are translucent, so they glow nicely. Used your basic LED RGB light strips and had great results. Another slightly lower cost option is LDPE, which is not as rigid so it curves easily. The problem is that it can be like trying to nail wet noodles to a wall, so only use this if it's in narrower strips.


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## JTMcQuay (Feb 7, 2018)

One possible solution is to just use whatever clear plastic material you choose and then apply translucent vinyl film over it. This is how many modern "etched glass" signs and windows are made for less than actually etching the glass. 
http://www.uscutter.com/ORACAL-8510-Translucent-Etched-Glass-Cal

The product can even be cut on a computer controlled cutter/plotter to make designs. Similar to how shops make cut vinyl signage and Tshirt appliqués.


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## cadcoke5 (Feb 7, 2018)

How about white cloth? It needs a curved frame top and bottom. This could be cut wood, or perhaps bent pipe. 

or the lighting, perhaps use Christmas twinkle lights. These lights could fit between the vertical supports and the cloth so that there are no shadows from the internal lights. Perhaps a few strands, each with a different color, so that you can plug them into existing dimmer packs,and choose what color you want. It won't be an even illumination, but that may actually give it more punch if there are points of light. Otherwise the white material (or even plastic if you go that route) would tend to show illumination from the front more than from inside. This can be reduced a bit by covering the outside with a sheer black material.

-Joe


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## DIYLED (Feb 7, 2018)

I've found that very fine Scotch Brite pads are the fastest way to sand acrylic for diffusion purposes. It's about surface area rather than material removal, unless you're also going for a texture. I've heard they can be spray-mounted to orbital sander pads. They can also be stapled to wood pieces to make sanding blocks.


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## DIYLED (Feb 7, 2018)

kendal69 said:


> Flexible Translucent PE Plastic Sheet, or look up sheets of fiberglass both very cheap and can be cut with a box cutter.http://www.eplastics.com/Plastic/5-oz-Translucent-White-48-x-50ft-Roll


Is there a good place to get that in small quantities?


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## bobgaggle (Feb 8, 2018)

Also there's this. If you've got a steady hand you can get a really consistent coating on your material...


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