Re: Welding, upside down....

Wow, learning to weld on a truck frame is not the correct place to learn welding. Seriously, consider taking a Vo-tec welding course before you hurt someone.

Welding overhead is just like welding in the flat position, no difference. Why your having problems is caused by several problems. Use a 1/8" electrode and the correct amperage and more important the use the correct arc length.

Using the 5/16" electrode is causing you to turn down the amps to keep from buring a hole. That in turn makes you use a very long arc length thus apply more heat to the Haz thus why all the dingle berries keep falling on you.

In all my writings on the tool forum about welding, you'll notice I always harp on using the correct arc length, ie; being very tight to the base metal. This allows you to control the molten puddle using the correct welding amps without having dingle berries (large ones) fall on you.

You might want to spend some time reading the tool forum archives as there's been many threads written on welding.

T_Bone

I think I've made myself appear more of a novice than not, trust me, I've got some skill and ability, but within limitations, that I would not exceed. The work that I am doing is in no way going to get anyone hurt, the frame will be stronger than it was, and I don't agree with the methods used by whoever did this work originally, but it has held with no stress or fatigue, even after the bottom plates popped from expansion of rust.

The main vertical welds are the strength on this extension piece in the middle of the frame, and with the bottom flange plates re-done, ( 3 of 4 were heaved from corrosion, the old poorly done welds failed, the frame did not rust here except on the surface) the vertical welds in-tact, top flange joint fillet welded, and plated over and welded, same joint also gets a 3/8" x 3" angle through bolted spanning over the existing vertical joint, for the dump body mid mount, I'd have to think it will be very strong. If one were to grossly overload the truck and abuse it off road, yes I'd expect a failure, but not with careful or normal use. Ironically the dealer who sold me the truck made no mention of this, I'd have not bought it, loaded my car on it and made the journey home, as is, it would have failed long ago, I think it's been caught in plenty of time and the remedial work will eliminate any worry about it.

I won't ramble on about my experience and skill level, but I do have an extensive background in the building construction industry on some very large projects, and considerable experience with the associated field welding common to the industry, that has been very helpful outside of work, but also agree the vocational welding course would be highly beneficial to anyone needing to learn, including myself, I will keep an eye out for a course locally, even if I breeze through it, there is always something to learn and I'm no expert. It will however expose any bad habits and other practices that may be incorrect, will be well worhwhile.

I have spent considerable time while building mock-ups at various testing labs, doing quite a bit of welding, with experienced and certified welders giving advice, was a real good opportunity to take advantage of, glad I did, was very helpful. I was also senior project manager and a field superintendent for a curtainwall contractor, I used to have a lot of trades to keep track of, and all kinds of structural welds to place, have inspected etc., the experience has been helpful aside from work.

I was thinking that the arc length was the key to this, I know what happens when you get too close, ove too slow, use too much heat, or too far away, either burn through or it starts popping, and you lose the arc, then it sticks on the re-strike. Your work gets covered with slag and the weld becomes porous, you can make a mess quickly, I've done that as I think most people have when first starting out, it is part of the learning curve. I will use the same amperage as what gives me a good weld on the flat and 1/8" 7018 electrode, keeping tight to the base metal. I can test this on scrap and dial in from there mocking the position I need to do it in. I agree, the arc distance is very important, it is obvious when you observe your work, how things are affected, it takes some time to be able to maintain that distance correctly and continously, otherwise snap, pop, crack and you are stuck. The 7018 likes the heat, turn it down too low and this happens I've noticed. I use a dark, shade 11 lense, so it can be hard to see sometimes, which also plays a role here too, but I like to protect my eyes with as dark a lense as I can get away with. I don't need the 5/32" electrode for the underside of the flange, the flange is 1/4" thick, and the top came out very nice, I just need to run a neat, well formed weld to fill in the 2 1/2" joint from underneath, it will look good aesthetically to an inspector, but more importantly will also provide more strength.

These 2 top flange joints were open all these years, not sure why they stopped the weld there, on just these 2 joints, the other side of the piece added, the weld was completed from top to bottom including both flanges. Once done, this frame will be stronger than it was, if I had any doubt I'd have a shop do it. I had the truck looked over for commercial inspection by a reputable truck/diesel engine repair shop I've known for years, we went over the repairs needed in detail, agreeing that the work I'm doing will be fine, and he's strictly by the book. I could add diagonal fish plates to the web, but see no need to do so. I will take a look into the previous threads, I've read many of them over the years, one of the great things about this site is the archives and access to them. Do appreciate everyones advice, thanks again !

You need not take eveything I say in my post as being personally directed at you. I try to respond to threads for everyone's benefit, to which the Vo-Tech comment is more directed to very inexperienced weldors. I figure the more experienced weldors will just ignore my comments that doesn't apply to them.

Something to consider with beams in tandum is both beams would need the same repair treatment so the design flex stays in balance. By beefing up one side of a tandum beam then this becomes less flexable and will cause the opposite beam to stress more than it's design spec thus will also split after a short time.

Once a beam fatiques to the point that it cracks, a gusset 12" on either side of the crack center line is usually what is required to make the repair. I have also seen where 6" works well depending on the location. A person needs to be careful not to tie welds or plating together from horizontal flange to the vertical web.

If your sticking your electrode while trying to keep a short arc length then your most likely about 20amps to cold. With 1/8 7018 rod you should be about 130amps or so for the average weldor. I like 150amps on 1/4" plus material. Travel speed will control small amperage speads, 10 to 15 amps. Yes there are a few joints that I drop to the 120amp range only because of the joint position in relationship to other materials.

If you post this on the tool forum then maybe BFO or Fred O. will respond as they have commented on this type of repair alot over the years. I believe both still have active shops going.

T_Bone

Good point, this repair is mirrored on both sides, and terminates before the bend on the c-shaped frame members. I think I'm going to plate the underside of the top flange, I'll practice up on the overhead welding, like you said, same as welding flat, except a little more dangerous with slag falling from above, have to be careful there. If for some reason I cannot achieve the correct results, I'll have someone do these 4 plates, I've got everything set up here to do it. The top flange plates would in theory be in compression, so as it was, there were no signs of over deflecting evident, so I think the upper flange plates may not be needed, but still good measure, at least they'll keep the integrity of the bend with as much continuity as was there before and then some, without over stiffening it. The bottom ones would seem to be in tension and are probably more intregal to maintaining the strength of the member. I have a hard time visualising rotational forces that wouold apply here and any other similar forces at work, but thinking once it is done, I'll monitor the section and see if any problems arise anyways.

I have not had much trouble with the electrode sticking lately, but did through trial and error figure out how the heat range affects the weld, I take scrap plate, make a 1" to 2" pass, from cold to hot on the amperage, until I like what I see. The 7018 seems to like the heat, does not do well under 100 amps on this machine. I was at 140 amps with 5/32" electrodes and it really did form a nice weld. I have been around that range with 1/8" electrodes as well. Polarity is set with electrode positive and I assume DC as I look at the switch. AC is in the middle and stick negative is on the bottom, which I assume to be DC but with the current flowing the opposite way.

One of the areas I need to learn more about is using this NT 251 trailblazer for thin materials, I would not attempt it at this point, a Votech course would be a great help here I'll bet. I do have a Lincoln 225, "buzzbox" as well, from the 80's, which I need to pull the cover and make sure no mouse nests are in there, looks new, but it sat for years, which I have not used yet, but have used others at the labs with 6013 1/8" electrodes with good success. Next I'll want to add the wirefeed to the NT 251, gettin way ahead of myself here though !

I'll post over in the tool talk board next time, it's a great skill to have and be able to use, especially in a crunch, had a stud break off for a shock on my truck once, had to be out of town for work the next day, sure was nice to be able to complete that repair on a sunday and be at work on time the next day.