New here and newish to welding

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I have been doing some mig welding at work for a year but it was just holding rebar in place inside of molds till the concrete gets poured. I had no real training so some of the stuff was real ugly but it always held together. I just bought a lincoln 180 pro mig this weekend i set it up with 035 flux core wire. I also bought a 30 foot holiday rambler camper frame this weekend with hopes to convert it to a dunebuggy/ fourwheeler trailer/ anything less than 6000lbs since it has 2 3500lb dexter axles with electric brakes. The frame is 2x6 rectangle tubing with crossmembers every 4 feet or so but they are low in the frame so they are no good to hold boards but im going to keep them for support. The entire frame was coverred in foam so i got most of it off. Then i started to add the crossmembers to hold the boards i used 2x4 channel that is 1/4 thick. I spaced them 4 feet apart. When i went to weld them in the welds were pretty poor they had little tiny pin holes and just didnt work well. I read about stick out and techniques over and over but no luck. So untill i figuire it out i have just tacked them in place. I also plan on making  8in triangles on the outside of the frame out of 1x1 tube to make the deck 8ft wide. I dicided to use a pre made frame since i am a new welder and im not going to be modifying the bare bones of the frame. Any thoughts would be great.
Reply:Check that you've got the polarity switched for fluxcore -- the machine might have been delivered set up DCEP, and you'll probably need to change that to DCEN.  Also check that the fluxcore you're using isn't designed to be used with gas -- some wires are; some aren't.Finally, if you're new to welding (or even to this particular machine), then I'd do a bunch of practice welds and tear them apart before you work on something that could leave you in a wheelchair if it breaks while you're using it.  And then I'd post pictures of them here (cleaned up with a brush).  But that's just me.  Jack OlsenMy garage website
Reply:i read the manual and set it up for flux core including polarity and a knurelled drive wheel. Whats funny is that im in a wheelchair right now anyway but it should be temporary. The wire came with the machine and is listed in the manual as the wire to use for gasless welding. Thanks for the tip. When i learn how to post pics i will.
Reply:Without seeing this its a bit tough to get a good feel for exactly just what you are doing. Please take the rest of this the right way.I'd think long and hard about making major mods to this trailer at this point. Since you are just learning, I'd suggest you look into a good night class at a community college or local tech school. Trailers are a poor place to be learning.I understand you plan to keep the existing frame intact, but improper welding procedures and weaken the tube frame if you don't do it right. Those sorts of trailers are designed to use the least amount of steel possible and to keep the weight to a minimum. That means the tube is very thin and unforgiving to things like undercut and excessive heat. More weld does not equal more strength, often its the opposite. Also it sounds like you plan to do a deck over wheels conversion or drive over fenders. Those 1" tube angles are probably way undersized and mounting them to the frame will be critical. Remember that if the tires rest on the widened area, the new structure takes all that weight cantilevered from the frame. It needs to be stronger than the frame to support that weight. Again these are poor areas to be doing design on the fly especially if you've not done this before. Seems simple if you don't know what you are doing. This is probably one of the more critical types of projects most hobbyists will ever attempt. When something on this fails going down the road other lives are at stake. What happens if that cantilevered potion fails with the bouncing of a vehicle on it going down the highway at 55MPH? Bad things will start to happen FAST! You'd be better off building the off road buggy frame than this. If the buggy fails you are most likely the one who's going to get hurt. Vehicles that go on the road, whether a truck or a trailer are the wrong things for you to be welding on at this point.I'd put this project away for at least a year while you get some serious training from a good teacher. You need to burn quite a few pounds of wire to get really good even under the instruction of a good teacher. Learn on your own is even harder and will take much longer and cost you way more money than the cost of a few good classes. You could probably get the teach to help you do the project in class if you ask. If not take this project to a pro and have them do it..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:The widened area would be for walking and loading 4 wheelers sideways. The track with of my dunebuggy and transam are right at 70in the frame rails are also at 70 in so i figured that all the major load would be directly on the frame.Between my work and a buddy that owns a automated hyd. press and machine shop i can get it welded.My plan was to tack everything in place. make my ramps, mount my fenders cut 7 feet of it off and load it on our 30 foot gooseneck with our forklift and take it to my buddys shop to finish welding all supports and crossmembers.I found this to show what my plan is http://www.millerwelds.com/resources...ead.php?t=2038
Reply:I am working on the ramps now i have enough 3in channel to make each ramp 8 feet long. I want to make them long so i can get my Trans Am on it easy. My question is should i use 2in angle for the cross pieces and slide them inside the channel or should flip the channel so the open side faces out and use 3in angle for the cross pieces. thanks
Reply:Yes, I recommend facing the open part out and welding to the flat face. Not knowing what thickness of angle you are using, I'd say stick with the 2" (3/16 or 1/4" thick) for the cross pieces. Those ramps are going to be heavy, plan accordingly.
Reply:the channel is 3/16 and the angle is1/4. I am re thinking my design from the concerns of the angles sticking out. i can haul my dunebuggy and 4 wheelers as it is with out widening it. My other question is how close do the crossmembers need to be that support the boards. i have crossmembers every 2 feet but  the boards are only supported every 4 feet the other crossmembers are the factory ones and sit low in the frame.Also how should i address tie downs? and one more if i drill a small hole in the frame to run wire for marker lights every 4 feet will i need to do any kind of bracing? Just to review the frame is 2x6 tubing the crossmembers i added are 4in channel it is going to be 20 ft long and will be used to carry my vw sandrail and my yamaha kodiak and my girlfriends kawasaki bayou. So i guess the bayou weighs about 500lbs my kodiak weighs 700 max and the sand rail weighs about 1200 i think. so with gear the pay load will weigh around 2600lbs it has 2  3500lb axles with brakes.