This is debate, and it might seem harsh in general, I feel no offense to a sorry but you are wrong nor I expect does ricc0luke in my response. Such debates are of much value in getting to the
point of an issue.
Well done in response and in my own respecting your views as very much important for debate on me being right or wrong or the concept of foam faced scenery in it’s proper use. Please expand upon the specific type of foam in scenery you use which is safe in use over such a large area of the
stage in not giving off poisonous fumes should it even smoulder. This above combustibility, breakage, sets falling apart sooner than later, structure of a hard
flat relying upon the surface material as a part of it’s structure, much less a actor putting their
hand thru it during a fight scene short of say 9" on center supports for it which I would consider sufficient as a wall at 3/4" thick.
My exceptions are that lumber when it burns does not have the problems of plastic/extruded polystyrene when it burns in giving off a poisonous gas which if I remember right is heavier than air in lying low but might be wrong, that will kill before the
smoke in general from a fire does. I would hope I'm corrected on the thoughts of gasses given off by foam lying low instead of near the ceiling because this could be a serious reason not to use foam, but one I don't remember well enough in detail beyond concept of concern.
While I have not done a flame test on the effects of a 4x8 much less a 20x40 wall of foam, I do know that foam tends to not resist heat well in not giving off those gasses. My opinion is that when following the rules of what you can and cannot use, if you can’t use
Visqueen and are limited in the use of foam overall such as on a staircase when coated in gesso or some other flame retardant method, entire flown walls of something that all it takes is a mis-directed
Q-Lite to start it giving off gasses would be a bad thing for use on
stage because the heat would tend to melt
thru a layer of three of paint. Paper covering, foil or any other covering short of lumber which would absorb the heat, in my opinion I would avoid foam for
flat facing. Now there might just be some merit to the use of some plywood based laminated flats in that they don't need further support of a frame and are reversible, but such materials are not the
point here. In addition to this, they can be of use for platforms. Given such materials are cost prohivitive.
The question also is how well flame treating much less paint itself attaches itself to the foam short of a primer which adds to the cost of the
flat. This 100% flame treating of the foam would normally be required on all surfaces of the foam used as non flown scenery and get to be very expensive on such a wide area as a flown
flat 40 some odd feet wide. This not that I’m concerned about fire primarially, it’s the lights focused on the
flat melting the foam in giving off gasses. On another part of the forum we are discussing the proper distance of drape to a
Fresnel, I would assume in being an ass for thinking foam covered hard
flat are not very safe to use, that a
Fresnel too close to a foam hard
flat would be even more dangerous not because of the temperature it requires to combust but because of the smoldering
smoke given off.
Non-porus, very brittle, I would assume this is primarily the difference between extruded and expanded polystyrene of which expanded would be more brittle in assuming my thoughts wrong on what'e most brittle - not the extruded type. Given of the extruded types, there is different forms of it as a yellow more industrial foam I believe though I don’t remember the type will react better than a pink Corning or Blue Dow normally used for houses in these situations for
insulation and limited in use for scenery.
Now don’t get me wrong, I had a fairly large part in constructing Six Flags New York’s Yukon villiage’s construction which has an entire foam mountain range. The difference is that this is outside and not in a building, much less near people. It was also completely encased in Sculptural Coat which is a flame resistant coating which would be counter productive to use on a hard
flat which by nature needs a
flat surface. Similar to this, I have often used in designs both expanded and extruded foam of varying types and once it’s coated with a plaster
base, and as long as it’s extent of use is of scenery and limited to extent I felt safe in using it. We are talking about what a 16' high by 40' wall of foam however that has lights focused on it from close by or if in a mis-focus during flying, that foam could have serious problems with the heat. This is the core of my concerns about the facing materials.
Easier and safer to hang is dependant upon one’s opinion. Even a 3/16" facing of a hard
flat adds some structure and sway much less sag bracing to the on-edge structure of the
flat when flown, the foam by it’s nature adds a very limited amount to it’s structure. The frame in being equally as strong as a traditional hard
flat needs to be beefed up in it’s structure to support such a covering since it's not self sufficient in bracing itself which might add up to extra weight on the 2-3 weights necessary on the cart/
arbor above the weight of the foam potentially being lighter than
Luan coverings. Is of even 1/2" 4x8 size rally lighter than a sheet of 3/16" thick
Luan? In any case, it can't be two to three weights worth of effort.
Adding 2-3 weights as opposed to one is all the same in my
book, adding one weight takes the same effort in doing so because someone with the experience of adding one weight should be sufficient for adding a second or third one. Such a concept is outside of the
point thus in the necessity of someone with less experience verses one with more experience. For the most part, hard flats are not really designed to be flown without added support anyway due to the structure if not hard covering over a soft
flat structure.
Thru bolting a foam covered
flat as required for hanging items is added in difficulty in foam covered flats even if on
flat to the material as opposed to the frame on
edge in that short of pre-rigging the
flat for a hang, a T-Nut or
Carriage bolt won’t have much
effect with even a ½" piece of foam between the
thru bolt and the frame you
bolt to. You do
thru bolt your hanging flats do you not? This would also be the norm in flown flats from my experience.
As for construction and coming loose from the
flat’s frame, that’s outside of my general concerns about this material. If the material is on
edge to the foam than there is little surface area for a proper contact cement much less Liquid Nails gluing foam to frame. Given Liquid Nails is very dependant upon the lot number of it as to which will and will not burn
thru the foam. Gluing foam would be much superior in strength to fasteners designed to hold it in place while the glue sets up. Once the foam pops from the surface, nails and screws won't add to it's structural strength as a sway brace when flown.
See a semester in college on plastics and metals for the theater with much of it specifically about using foam, much less about five years as a sales rep for building materials in the construction industry, much less having worked in some fairly large professional scene shops, and having read some very good books such as Scenery for the Theater amongst many others does even if a few years in the past in study have value at least in my concerns about using foam as a flown hard
flat material. There are other types of screws or nails that could help but in my opinion as only one of the un-initialed into newer acceptable techniques as it would seem I am out of step with what the next generation of tech people are using and is considered acceptable to be using much less the local fire inspector would not have conniptions about if he is doing his or her job properly. In the end I would say this should be taken to Stagecraft for a ruling on the use of foam for a hard
flat covering material. Since I don’t actively
build scenery anymore as a
Master Carpenter, perhaps the industry has changed in the last five years and there is some new foam material that does not kill people when it smolders especially as a wall that’s near lights.
Happy days, and this is a response based upon saying that foam as a hard
flat covering is acceptable and I’m wrong in my opinion of it’s use. But I do admit that I have not studied recently the other types of foam introduced to the market in the last five years, perhaps there is one that does not give off poisonous gasses if it gets hot, one that has sufficient structural integrity so it can support a hard
flat frame when flown as a large
unit much less as a
flat in general can be
thru bolted as I expect and hope is still required, and that given the paper facing on foam I’m yet to know about but would greatly appreciate knowing about since it would be nice to use, that this foam than is easier to flame treat much less paint without a treatment to the foam to accept the paint. In any case it seems I am out of step with what’s acceptable in methods today, please enighten me more into these new techniques.
Just a realization on paper covered foam products into one I used to
build scenery models out of. Are you talking about the black or at times white foam with paper facings used for artistic exhibitions? This foam while very ridgid for model making and strong in general is still foam and as a hard
flat covering should such things be flown not add much to the strength of the
flat assembly especially if constructed in a hard
flat board on
edge way. Good stuff but the paper ripping apart from the foam is not really that strong in comparison to a piece of
Luan laminated to a frame. Perhaps if the flats were faced with the material but to flats constructed in a soft
flat way they might have more strength in not relying upon them structurally but this method is not described. Such foam I used to use for model building also while it might be more flame/melting proof than normal foam board in only melting but at a lower temperature as I remember my use of a
hot glue gun in using it, still I have no doubts about it's lack of temperature
rating. Interesting idea but I'm against it's use.