Huge angle

[Steve]

Ok now this is just for our enjoyment. I have 20 feet of 8 in angle 3/4 thick coming Monday. I need to cut two pieces 10 foot long, form a box with the two and weld so as not to come apart to make a tow bar for 27 cubic yards of dirt with the machine weighing 72000 lbs. How would you make the 2 10 foot welds?

[Laiky]

It's simple really, just go to Home Depot and get a Lincoln weld pack. If your looking to save few bucks get the 110 machine. You'll just have to make a lot of passes! If penetration is an issue, i would leave the angle in the hot sun for a few hours, that will help, but keep in mind your travel speed will need to be increased! Your going to need a bunch of 1 lb rolls of flux cored, at least .035...................

Before the hobbiest thrashing starts, just kidding! I would love to see how you do this.Please post pics of the process, not just the results.

[diamondback]

when someone starts asking questions such as this I think there is a collective shudder than goes through the site. When there is a real world job alot of us are doing real word applications with real world consequences and are careful of how we word things.

SO...In my opinion from the information provided......I HAVE NO IDEA

It is early sunday so I am in a funny mood, please laugh.

For process I would use a flux cored wire for a good penetration pattern. The skip weld idea is a good one, I would do it because if one weld cracks it won't go through the others right away, there are other reasons as well but I tend to get wordy trying to cover everything. Also watch how the load will be carried. If the angle runs parallel to each other and the load is longitudinal to them then the welds along the axial members won't have a huge tension load but more of a sheer load so watch the starts ans stops for overlap, cracks etc.

If the the load is transverse to the weld or crossing it the stress is now in tension and the size of the weld will matter more, being careful of where the weld starts and stops will help with cracking from overlap, or other fusion problems. Most of you welds like everyone else will probably be fillet welds so consider them to be probably 30% as strong as what is required. This doesnt' mean a 1/4" weld should then be 3/4". Calculate the area of the triangle to see the difference.


Now that this has takes 5 minutes to write maybe I would use 6010 and a 9018 cover.......

[Sberry]

A fully welded box is going to be way stronger than one with intermittent welds.

[Sberry]

Put 2 samples side by side on blocks and center load it like a girder and see which one fails the first. It will buckle under compression between the welds. Say we weld every foot and one of the welds fail now we have 2 feet without weld. Its one of the reasons we see square tube used on many trailer tongues, boat stuff comes to mind. It would tend to kink, pushing the top in allowing the side to bow out between welds.
Force comes down on A, pushing in B and pushing out C causing split seam. Obviously only a concern if it is severely loaded or undersized or under welded. The continuous weld would stabilize the side. Not likely to affect the bottom under this type of load, only the top corner.

[fabricator]

If I understand this right you are putting them side by side? If so,in addition to welding them together adding reinforcement plates would be my suggestion.

[enlpck]

Ok now this is just for our enjoyment. I have 20 feet of 8 in angle 3/4 thick coming Monday. I need to cut two pieces 10 foot long, form a box with the two and weld so as not to come apart to make a tow bar for 27 cubic yards of dirt with the machine weighing 72000 lbs. How would you make the 2 10 foot welds?

So much is missing to be able to answer the question.

What is the end attachment being primary, as that determines whether there will be bending moment applied, or if only tension and buckling are relevent. Also, the max compression load the bar will take is pretty important.

If fully welded out, it will crush before buckling, even with a moderately eccentric loading.

If stitched, less distortion risk, faster, cheaper, but under some loadings, buckling may occur between the welds, especially if it is helped along with a few hard hits in service.

[Sberry]

If stitched, less distortion risk, faster, cheaper, but under some loadings, buckling may occur between the welds, especially if it is helped along with a few hard hits in service.

I can round up a couple pics of farm equipment that was built exactly this way and suffer the abuse you mention from repetitive hits. They were factory welds, continuous, gang beams on a disk. I do like your explanation, real simple.

[Steve]

It will be a straight pull hooked to a D9 cat. A big project for sure. I have already made the cross frame 44 inches. Pictures to follow as the project proceeds. You have all the info I have to make the welds, no further info is required. I need to make a box frame with 8x8 3/4 angle 10 feet long. Skip welds are not an option. Welds will be full pen and continuous. As a teaser I will tell you I plan to make only 4 passes for a total of 4 10 foot welds. I will use an MP65E with .045 wire and stop only to change wet leathers(should be hot next week).
I want honest opinions as feedback and critique. What do we want in way of pictures? This is supposed to be a fun project, remember so lets have some fun.

[admweld]

I,d run NR-212.068 innersheild wire and have that done in no time.