most aero setups for dope is setup towards small clones...wouldn't take much to make the rootspace bigger..but have you priced bigass pvc tubes....expensive
yea well, pvc pipes are not ideal for such a trivial task. sdr26 bell pipes are probably what you are thinking of. beyond those, you get into c900 pipe w/ the joint locks, and they cost even more.
past say 4" pipe, the cost is such that you are better off making your own enclosures...
for small ones, ive postulated that fluted polypropylene sheets are ideal... you can make enclosures by simple folding, and non water tight joints can be made with poly rivits, and possibly solvent welding. water tight joints can be made with with additional pieces of material and sealant such as OSI TeQ bond or perhaps polyurethane adhesives.
alternatively i hypothesis joints can be made with heat welds, drywall corner bead and fasteners,mastic tape... butyl flashing material... HDPE sheeting stock perhaps. etc.
at this small to mid scale, you can reinforce with interior triangular sections of this material, and make fastening in the same manner.
this is good to around 2'x2'x2' ish containers, or 2x2x however long tubes. lengths of tubing can be joined in a similar manner as that noted above.
for larger enclosures,the same material, and even triple layered material can be used. when support is needed, one could reinforce in the same manner one reinforces large negative pressure duct sections, namely with old style snap wire and thin 22 and up gauge galvanized steel or low sch. pvc tubular struts at 18" oc triangles. fastening would require larger washers, larger than the 2x2 duct washer available perhaps.
this would probably be good for like up to 3 or so wide and not much more imo.
any larger, and this thick material becomes too costly to justify, and one must consider a think films with skeletal support structures. a good film would be the thick liners they use create water impermeable areas. one would require a very good heat sealer, and a great deal of time an patience, but i believe this material could be used to build tent like structures, with light weight steel tubular supports, or perhaps wood. in the case of steel, you would make sleeves in a similar manner to that of tents. you would reinforce these sleves with sections of thicker material. lids could be constructed by laying wood purlin like members across the structure. these members could then support panels of extruded PE foam, or perhaps even the fancy aluminum or fiber reinforced XPS panels they use to build walk in freezers.