"Mirrors"

[jwl868]

I need to make three mirror props for a recital. They would be nominally 6 feet tall and 3 feet wide. And they will be flown in and out.

I searched through previous posts on the subject, found some useful information, and I have come to the conclusion that “standard” reflective silver mylar is the material of choice. (The Rosco heat-shrinkable mylar is too expensive.) I’ve located rolls of 2 mil mylar on the internet. (Again price is an issue, so I don’t think I’ll get thicker material.)

For a frame/support, I plan to use 2-inch rigid pink insulation board (rather than make flats.)

Before I start this, a few questions:

How durable is the 2 mil mylar? I have to make the mirrors at the studio and then transport them to the venue. (It’s been a while since those last posts, so if anyone has any experience it would be approcaited.)

To attach the mylar to the insulation board, I plan to run a bead of glue (Elmers glue) along the edge of the board. (Then, I’ll attach a narrow border – cardboard, ribbon [it’s a detail for now] – to cover the bead.) Will the elmer’s glue bond the mylar to the insulation? Is there a better glue to consider? I also thought about a spray adhesive over the entire board so that the mylar will stay flat. I tested 3M “77” and Duro Spray Adhesive on an old piece of insulation and both attack the board (the Duro more so that the 3M). Are there any other spray adhesives?

Joe

[Van]

3M makes a "Foam Adhesive" which is a spray on just like '77 and would be an excellent choice for this application as it will stick to both the Mylar < plastic > and the foam. Make sure you "Frame" is at least 2 1/2" wide , if it's 1" thick foam, to provide enough strength to resist the lateral stresses that are going to be inflicted on it by the tension-ing of the Mylar. You may also want to consider adhering the Mylar to a piece of 1/8" or 1/4" foam-core, that may help with the transportation, and reduce wobble.

[SweetBennyFenton]

Also, if you are not getting the heat shrink kind of mylar, be prepared for some nasty wrinkles. Without the heat shrink you will have to be very careful.

Van's advice is good. Adhere the whole thing down. It will be tricky and take a few people to keep out wrinkles as you lay it down.

I hope you don't get the fun house mirror effect I got the last time I tried to use Non-heat shrink mylar on stage. "Music and the Mirrors" turned into a horror show.

[Van]

Originally Posted by SweetBennyFenton

Also, if you are not getting the heat shrink kind of mylar, be prepared for some nasty wrinkles. Without the heat shrink you will have to be very careful.

Van's advice is good. Adhere the whole thing down. It will be tricky and take a few people to keep out wrinkles as you lay it down.

I hope you don't get the fun house mirror effect I got the last time I tried to use Non-heat shrink mylar on stage. "Music and the Mirrors" turned into a horror show.

Then there is the wonder that was "Vanya"

[jwl868]

Originally Posted by Van

3M makes a "Foam Adhesive" which is a spray on just like '77 and would be an excellent choice for this application as it will stick to both the Mylar < plastic > and the foam.

Van

Is the "Foam Adhesive" 3M Foam Fast 74? I located it on their website, but can't find it in any stores. Just want to check before I order it.


Joe

[Van]

I think 74 might work but I believe spray 78 would be a better choice. 74 is a better choice for flexible foams like Polyurethane and Latex foams that you might use when constructing puppets like Audrey II from Little Shop.

78 is designed for more static applications, and more specifically for EPS and PS foams. It should be availible at a good hobby or art supply store. Here in Portland I find it at Winks Hardware, one of my favorite places in town.

[jwl868]

Thanks, Van.

(The MSDS for #78 doesn't appear to be very different compared to the MSDS for #77 - I'm surprised that the #78 doesn't "melt" the polystrene, too.)

Joe

[Van]

You're welcome. You know my motto, " Better living through <proper> chemistry."
Just as a side note. Whilst the MSDS is the same the formulation is slightly different. The chemicals used have the same basic safety hazzards and handling issues, it's thier chemical properties that really differ. < Besides I think 78 is cheaper.>

[jwl868]

I found another 3M product - No. 6070 Spray Adhesive for Styrofoam. I tested it on the polystyrene and the propellants do not affect the finish - no softening or collapse of the foam.

Joe

[jwl868]

The “mirrors” turned out as well as was to be expected. I ended up using 2 mil mylar on 2” Foamular expanded polystyrene and used the 3M Adhesive for Styrofoam to attach the mylar to the foam. (The mirrors were 6’ x 3’ 8.5”.) Had a few ripples in the mylar – We rolled the mylar on, but it still puckered a little. The nozzle on the adhesive can allowed for a wide spray pattern so I covered the board easily. However, because the adhesive was still an uneven coating, the mylar gave a “frosty” appearance rather than a smooth flat finish. The foam did not warp, so I didn’t get a funhouse effect. However, this was for a dance recital, and the effect worked well.

[The recital generally went well, though the dress rehearsal was tedious. In addition to the mirrors, we had a “London roof top” set for a Mary Poppins number that included a four chimneys that the dancers danced on; a couple of 8’ tall flat Oscars made from industrial-grade Styrofoam; and 14’ x 10’ back drop painted with movie or movie poster scenes. All this done by a handful volunteer parents in our spare time.]



Joe