my first MIG project (too ambitious, I know)

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Hi guys,I am building a steel frame camper for a Isuzu NRR flatbed truck (payload cap. 11,000 lbs).  I have done a prelim. CAD drawing using 1x1 and 1x2  11 and 16 gauge members and calculated the weight to be around 600 lbs.  Once it is skinned in Sikaflex'd 0.090 aluminum and has interior 3./8" marine ply walls, it should be in the range of 1500 lbs or so, which is acceptable.  The skins will add greatly to the strength of the steel frame.I have done some TIG and stick welding using my ThermalArc 185TSW, but I purchased a Miller 211 MIG for this project.  TIG and stick just seemed so slow.  I am amazed at how easy it is to get a good weld with good penetration on the Milller.  I am using 0.023 wire to control burnthrough on the 16 gauge steel members.I am going to do a lot of practice welding 11 gauge to 11 gauge, 16 gauge to 11 gauge, etc. before starting the actual frame.  During this time I would like to get some fixtures on order that will make this job a bit easier.What would you recommend for supporting the base frame, which will be 11 gauge 1x2 A500 steel?  I was considering getting a bunch of regular automotive scissor jacks such that I can support and level the frame while tacking and welding.  This seems like an easy way to get a very level, square frame.  The other option would be what I guess are traditional welding jacks with the vertical center threaded rod.  I think I would want about 10 to 12 of these jacks, which makes the automotive jack attractive.  What do you think?Here is the CAD drawing of my frame to give you an idea of this project.  If I get in trouble, I am not above hiring some professional welding help but I would like to do a lot of the grunt work myself.     I would appreciate any tips or advice, thanks!
Reply:When we rebuilt the flatbed at work, we simply worked off several saw horses and some 2x's and leveled everything up from there. Basically it ended up a giant work table where the top frame was dead level in all directions. Granted the flat bed frame rail members helped us out.If I had to do it again, I'd probably try and do it the same way. In your case, I might look at spending the money on 2 long straight pieces of tall light weight channel and make 2 or maybe 4, long saw horses to support floor/ walls/roof..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Thanks DSW, that is a good idea.I am going to Central Welding again today to pick up some supplies...might see what they have in the way of jack stands also.  I would guess $$$ though.I wonder if there is a model of the adustable camper jack that might work.  Something like these but beefier:http://www.amazon.com/gp/product/B00...pf_rd_i=507846
Reply:If you really want to build something like that, try and find some place that has some used adjustable feet for scaffolding. They have a nice screw thread and turn nut and will fit nicely in 1 1/4" or 1 1/2" pipe ( I'd have to go measure my scaffold again.) If you are near boat yards, the jacks they use to support the hull when they pull the boats work well also.I've got a decent selection of jack stands and home built pipe jacks I've collected over the years as well as a bunch of roller stands and work supports, but 9 times out of 10 I still go back to saw horses for the actual build. The others are usually relegated to cutting operations or when I need to support a single piece..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Got a pic of the truck?  If u want to speed things up, go with .035 or .030.  I found .023 really slow going on 16ga steel.   You will not have a burn through problem if fitup is good and you get your settings dialed inTiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
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Reply:Originally Posted by IGBTHi guys,I am building a steel frame camper for a Isuzu NRR flatbed truck (payload cap. 11,000 lbs).  What would you recommend for supporting the base frame, which will be 11 gauge 1x2 A500 steel?      I would appreciate any tips or advice, thanks!
Reply:Building on the truck is interesting, but not really a good option for two reasons.  1)  I need the truck to get metal supplies, etc.  2)  The finished box on the truck will not fit height wise through my garage door.I had some credit at camping world and so picked up 8 of those jack stands for cheaper than I think I could even buy the steel and make them.  They are not super great quality, but they at least are steel, sturdy, and should get the job done.
Reply:Is this going to be a permanent addition to this truck or one that can be removed and replaced as needed?This may need to be moved over to the projects and pictures catagory pretty soon as it is going to be more than just a general welding question before it's finished.Last edited by Bistineau; 02-13-2013 at 11:05 AM.
Reply:Originally Posted by BistineauIs this going to be a permanent addition to this truck or one that can be removed and replaced as needed?This may need to be moved over to the projects and pictures catagory pretty soon as it is going to be more than just a general welding question before it's finished.
Reply:Building a one off structure, I'd use a space frame based on a system of triangles. You're design minimizes strength while maximizes weight. If you want a stick frame for ease of fabrication, skin it  with an engineered pannel.  Fun project.  Best of luck.Syncrowave 300Maxtron 450, S-52E, 30A
Reply:Originally Posted by wendellBuilding a one off structure, I'd use a space frame based on a system of triangles. You're design minimizes strength while maximizes weight. If you want a stick frame for ease of fabrication, skin it  with an engineered pannel.  Fun project.  Best of luck.
Reply:I have started welding the base of our flatbed cabover camper on an Isuzu NRR, and I am trying to decide what to do about the bottom of the steel frame that will sit on the metal/wood flatbed.Some of the ideas would be easier to do now while I can easily flip the base over.One idea is just to tack weld sheet metal to the underside and caulk it from the inside to prevent moisture somehow seeping up into the floor foam.Or I could try to find some thick tough plastic, maybe 0.25, and screw or sikaflex it to the underside.Or wood, metal or plastic then take it somewhere and get it coated in a truck bed liner material.The plastic would probably be the easiest, but if I attach it now, it will be hard to prevent it melting when I start to weld the upper structure to the base.Ideas?