large scale advise - materials, mounting and cost

[itamarj]

Hey guys,
I working on a proposal for a temporary large scale art piece. I've attached a very rough simulation of what I would like to do, and now is the time I need to think about how to make it practical.
The dimensions are about 19' width and 30' tall.


The piece is supposed to stand outside for about 8 months - most likely it will be taken down before any major snow storm will hit, but it should be durable for elements.
I was planning not to mill the whole piece - only the front part since this is the only part that is seen from the street.

I need to keep cost as low as possible - I was thinking to mill it out from either Styrofoam or bluefoam and then coat it with Epoxy probably (as Bill suggested in one of the posts) - MAS epoxy, for boatbuilders.

I was also considering to use a browncoating, but I'm a bit concerned of weight issues.

Since I have never worked on this scale before, it would be great if i could get some advice on the following:

1. what is the ideal material/coat to use for this project?
2. What kind of stucture should support the piece and what kind of mounting technique would be the cost/effective to mount it between the building?
3. If you can roughly calculate the cost of material that would be great. I'm not taking into account fabrication cost and labor, but do need to consider materials and special equipment for the installation.

[shoeshine]

Sorry David,

I have very little input on your questions, as I am usualy working on the exact opposite of scale (my problem is usualy how fine a bit and cut I can pull off)

But I gotta say...

Rock and Roll. I have long thought the bot is incredibly well suited to artist's work. Relatively low cost/ high adaptability. I've actually run a couple of seminars here localy to introduce the art community to CNC machining. (had the privilege of working on the Temple of Transition at this past year's burning man festival)

Love to see that these kind of projects are coming to the boards, and I hope your questions are answered.

Best of luck,
Chris

[billp]

David,
You have left out the most important dimension, the depth. THAT is what will decide how much material you are going to really need.
It's a pretty ambitious project to be sure, so you're going to have to spend a lot of time in the planning stages.
If low cost is imperative your options are probably limited to styrofoam, or maybe EPS ( "popcorn") foam. EPS is what is used in larger, commercial projects such as entrances to gated communities, etc. I never work with it, so you'll have to get pricing from those that do.
As far as calculating the volume you'll need, that's where your CAD program comes in. Create your shapes, and then measure /extrapolate the size 'block' of material you're going to need to carve it out of. That should give you the info you'd need to calculate the cost of whichever material you wind up using.(In the example you show you could probably consider the torso as your main project, and then cut the head/feet from separate pieces).
Good software (Aspire, Artcam, etc.) will let you "panel and slice" a shape in this size range so you can machine it in manageable sections. Obviously this will take a lot of slices to fit under your gantry, so your material thickness will be limited by that dimension.Once you have figured out the size of your "block"you can figure out the cost of the materials.
Mounting it will again come down to depth as well as overall height/weight. In the past people have used everything from PVC pipe,electrical conduit, to steel armatures. There should be numerous examples on this Forum if you check through the search engine, but installing projects in this size range MAY be the biggest challenge of all. Do you need any permits? Are you planning to attach it to someone else's property?
Coating it is another animal altogether. Projects in this size range are usually sprayed with coatings such as Styrospray, etc. You might also find similar products at either smoothon.com, or polytek.com but you'll need good spray eqiuipment, etc. Primer/epoxy might be cheaper, but much more labor intensive, you'll have to do your home work to crunch numbers.
This is one where I would spend a LOT of time going through the ALL of the "what if?" questions well in advance of buying anything, because "BIG boo boos" take a lot of time to repair, or live down....Best of luck with it, and please keep us posted on your progress...