before i started the design i did some basic calculations assuming simply supported boundary conditions. i don't recall any red flags, but i'll double check with Solidworks/Cosmos or ANSYS FEA before i push on the gas...
there are two bottom beams (12x26 I-beams) and two top beams (10x26). the bottom beams are 95" long and the top are 105" long. vertical supports and cross members are cut from 2x6, 0.25" to 0.5" thick channel, with the exception of the two lower inside cross members which are made from 2x4, 0.375" thick channel. i purchased the steel from a metal yard and there's a nice thin layer of rust from being exposed to the elements. i cleaned the rust off one beam (top beam shown in the photo), but it cost me a brand new harbor freight hand-grinder ($17.99 + tax) -- the bearings disintegrated with no warning. now i own a dewalt grinder valued over four times the HF, which should last to clean the remaining three beams and the channels. the frame is temporarily bolted together. i don't know how to weld, but i plan to have it welded before it's painted. i'm taking advantage of the fact that it's assembled to build the bottom and top mold, cattrack, test the bladder, etc., before i dissemble it to paint. oh, i have the parts for the base and casters -- inching it around the garage gets old as i'm not much of a leaf cutter...
overall dimensions: width: 22"; height: 51.12"; max length: 105"
cavity dimensions: width: 18"; height: 13"; length: 95" (lower beams)
current weight (just beams and channel): ~1000 lbs.
with the molds, bladder, etc., it'll probably be around 1200 lbs.
i went with the open-throat design because i wanted room for the bladder to freely extend.
if Kublai fails as a press, one friend suggested: bunk bed
![Wink ;)](./images/smilies/icon_wink.gif)