Welding Tips and Tricks

hello, my name is troy, i work for a wireless internet service. ive been welding since i was 10 years old and now im 24. have had many jobs welding and the job i have i sort of fell into. i was laid off from working in a sawmill, a buddy called and asked if i would like a part time job welding. i did welding for this company off and on for about 2 months, my buddy that got me the part time job left for reasons unknown. the owner asked if i wanted the job being a full time project manager and welder designing towers for wireless access points. so i took the job. so now im a tower builder and i do wireless networking alongside the way. i have not had much experience with pipe welding before, im use to welding heavy industrial projects with flat plate and useing spray transfer and dual shield wirefeeding. i have an airco dip-pak 200 wirefeed machine, a hobart handler 140, and an everlast 200 dx. i have been welding the sections of pipe together with my hobart handler 140 and SS fluxcore, getting it as hot as i can for good penetration and it burns the sch 40 pipe together but im wondering if its cutting the corners off the edge of the pipe when i weld them together is it hot enough? im not butting the pipes together and welding them no, for example i slide say 2 and 1/2 inch pipe inside of 3 inch pipe about 4 feet then i weld them together around the neck and use plug welds. im curious to know if what im doing is correct. im doing this pipe welding out in the field where i cant take my tig machine or the big wirefeed. so im sort of forced to use the 110 volt wirefeeder. please someone let me know what your thoughts are about the way im welding this pipe. thank you all.

Welcome to the forum.

Welcome, Troy,

I think the Hobart 140 is enough machine for the structural work you're doing. The sleeved weld with plug welds is entirely appropriate, and the 140 with fluxcore (Innershield or dual-sheild? Just curious...) will handle sch. 40.

From an engineering standpoint, I must say (though you may already know this, and I apologize if I'm preaching to the choir), the inner sleeve pipe should not be square cut... a 45* with the ends chamfered with a grinder is preferred, as tower legs must flex and a square cut puts all the load on the outer pipe in a straight line.

If you get in the engineering reference book, you can find a SS tube size with a comparable wall thickness, but an OD closer to your sch. pipe's ID for a better fit. This makes alignment/straightness easier to achieve, and reduces welding gap and subsequent "draw", also aiding straightness in the finished product.

I've not built towers, but I've done truss work with pipe and tube, and these are tidbits I picked up along the way.

Steve S

hello, this is troy again or welderkid556 whichever you prefer to call me. the SS i was refering to is the flux core wire im useing, where ive worked we used SS short for self shielding wire. im working outside in field work i cant really be dragging around a argon/co2 tank, its a bit much just for the welding im doing. i have found that the self shielding wire works good for this type rather useing dual shield or hard wire with argon/co2 especially if it is windy outside. im useing the hobart 140 on this job for welding the pipe together. i use my airco 220 mig to run the dual shield inside the shop for welding the base of the pipe (tower) to the 4 ft by 4 ft 3/4 inch thick plate. i had the machine shop cut a hole dead center in the pipe big enough for a 4 ft peice of 3 and 1/2 inch pipe to fit inside of it, i weld the 3 and 1/2 inch peice of pipe into the plate but i have the pipe 2 ft sticking out each way through the plate. i then slide a 10 ft section over 1 end of the pipe i weld the 4" pipe to the 3.5" pipe and also to the plate with about a 1/4 inch gap, with the dualshield in spray transfer pretty much, it makes a high quality weld and looks very good. we then move the tower base to site and i start to slide 1 peice of pipe into another and my co-worker measures and gets everything calculated while i weld everything together. this pipe im welding together is 4 inch sch 40 pipe mild steel, 3 and 1/2, 3 inch and 2 and 1/2 inch peices of pipe. what im building is what the guy at the machine shop called a tapering pole like for a flag pole or so he called it but im just slideing pipe inside of pipe. there are no threads or anything of that sort. the filler metal or wire im useing is .035 diameter, E71t-gs alloy for the outside welding in the hobart 140. the welding im doing inside with my 220 machine is .045 esab dualshield 7100 ultra and its about $120 a roll down here at my welding supplier shop. ive also been having some trouble with the dual shield sometimes, im not sure if my gas is up too high or if not enough and is my nozzle big enough for this type of spray transfer,but sometimes i get porosity in a weld and i have to grind it out, if i crank up the gas to almost max which is about 55-60 cfh the weld turns out beautiful and clean, slap pops right off and no porosity. i now have a 3/4 inch nozzle which i just put on the gun and it seems to be giving excellent shielding gas now. here is a picture of a regular joint i have to weld up. this joint is welded up but this is a typical joint and i dont usually chafer of grind the corner off of the pipe because theres enough room for what would be called a fillet weld i believe is what it would be but i dont quite see a need to grind the edge of the pipe because im filling in a big enough gap as it is. well i tried to upload the picture i took, and it wouldnt upload it because it says file is too big. ill try to post it in an added message.

Ah, I misunderstood in several places.

What I said about sleeved pipe still applies, though. I'd cut both the inner and outer pipes at 45* so nothing sees a straight line. The weld is more critical than the end of the inner pipe, but maximum strength and lowest stress is achieved by having the weld on a 45* bias. This increases the welded area of the pipe by 41%, and spreads the loading along the length of the pipe by a full diameter.

I still feel the Hobart 140 is enough machine for the job. I'd be more comfortable stick-welding it, but that's a personal preference/experience thing.

Welderkid556.

If you get a chance, attach some photos.
Include one view from a distance of the overall pole.
Also include some close-up views of the different type of joints.

I have never seen a flagpole being fabricated so I am curious to learn more how they are constructed.

Tanks.
Alexa

yes, i understand what your saying, ive never had much luck with stick welding, i strike the arc almost instantly sometimes and other times it sticks to the work peice and burns up the rod and i get frustrated and i just finish the job with my industrial 220 mig. i cant use a 220 stick welder out in the field because we dont have a powerful enough generator and i cant take my tig/stick machine out in the field because its my baby and i dont want it to get scratched or anything lol. we have finished our current tower but i will be starting another tower soon. so what your saying is on the outer pipe that the inner pipe slides into, i should grind about a 45 degree angle around the edge of the pipe so it has more surface area a.k.a more penetration? ALEXA, im sorry but the photo files i have taken of the project are to big to send through the sites sttachment option. i can post the pictures on my facebook account if you have facebook or if anyone else has facebook ill give you my full name.

I'll try to come up with a picture, rather than a thousand words.

The pipe on the outside, when pipe size steps down, should not be cut at 90 degrees. This puts the weld in a straight line, and the shortest possible line around the pipe.

Cut the outer pipe on a 45*, like you were going to make a mitre joint.

Then your weld goes up and down the smaller step-down pipe, rather than a tight circle. Two benefits. 41% more welded area, and the load distribution is no longer perpendicular to the weld.

ok, thanks for this information bud, i have posted some pictures of the joint i usually weld on facebook. my name is troy shuler, im sure there are quite a few troy shulers but i am from idaho and my main picture is of me with a background of a bunch of trees and such. if you do happen to find my page click on my photo's and once you get to the photos page click on the tab that just says photo's not photo's of troy because my ex posted a crap load of pix of her on my account for some odd reason, anyway i have been planning on our 3rd tower the one i have to start getting parts on monday, my co-worker wants us to use 5 inch pipe for the base and i told him ok. i go to the welding supplier which is also my steel suplier and had him call to pacific steel company for the sizes of steel they have and their prices. they can get us 5 inch pipe, 4 inch pipe and 3 and 1/2 and the 3 inch pipes. but the problem is between 5 inch and 4 inch there would be a pretty massive gap im thinking. in their steel suppliers book it says that there use to be 4 and 1/2 inch pipe that they kept in stock but apparently now 4 and 1/2 inch pipe doesnt exist anymore, like they dont even make it anymore.

sorry for the type-o in the last message. i posted the pics on facebook i meant.

Hi,

We have a Face book page. Welding tips and tricks forum.

Mivk

weldin mike 27 wrote:Hi,

We have a Face book page. Welding tips and tricks forum.

Mivk

Okay... Was misspelling your own name a typo?

That's irony.

Just extreme in-attention on my part....

MICK

Troy, that li'l problem your having with the absence of 4 1/2" pipe is where my "tube" suggestion comes in.

There are two main differences between pipe and tube. The sizes available, and the spelling.

Select a tube with a similar OD to your missing 4 1/2" pipe, and wall thickness similar to schedule 40.

hello, my steel provider is very picky about what some people call tube and pipe, the steel provider i go through is the only one in this little town and they measure pipe with I.D. and they do the same with tube. but he says there is no such thing as round tube. i think my steel provider is a picky obsessed shmuck to be honest, but he is the only one in town. i will ask them to see if we could get a sleeve or some sort of a pipe adapter otherwise i think i could weld a 2 inch wide strap 1/4 inch thick to the pipe, heat it up and bend it around the peice of pipe to make the gap close then slide the pipe inside of the pipe it has to go into. but i would do this strap welding and bending around the bottom middle and top of where the pipe slides into the other pipe, that way there is no wiggle room and it should be straight up and down. but im curious, does everyone else measure pipe and tube with i.d or do any of you measure with o.d.

A QUICK BREAKDOWN

"...
Based on the NPS and schedule of a pipe, the pipe outside diameter (OD) and wall thickness can be obtained from reference tables such as those below, which are based on ASME standards B36.10M and B36.19M. For example, NPS 14 Sch 40 has an OD of 14 inches and a wall thickness of 0.437 inches. However the NPS and OD values are not always equal, which can create confusion.
(...)
For NPS ⅛ to 12 inches, the NPS and OD values are different. For example, the OD of an NPS 12 pipe is actually 12.75 inches. To find the actual OD for each NPS value, refer to the tables below. (Note that for tubing, the size is always the actual OD.)
For NPS 14 inches and up, the NPS and OD values are equal. In other words, an NPS 14 pipe is actually 14 inches OD.
The reason for the discrepancy for NPS ⅛ to 12 inches is that these NPS values were originally set to give the same inside diameter (ID) based on wall thicknesses standard at the time. However, as the set of available wall thicknesses evolved, the ID changed and NPS became only indirectly related to ID and OD.
(...)
For a given NPS, the OD stays fixed and the wall thickness increases with schedule. For a given schedule, the OD increases with NPS while the wall thickness stays constant or increases. Using equations and rules in ASME B31.3 Process Piping, it can be shown that pressure rating decreases with increasing NPS and constant schedule.[note 1]
(...)
Some specifications use pipe schedules called standard wall (STD), extra strong (XS), and double extra strong (XXS), although these actually belong to an older system called iron pipe size (IPS). The IPS number is the same as the NPS number. STD is identical to SCH 40S, and 40S is identical to 40 for NPS 1/8 to NPS 10, inclusive. XS is identical to SCH 80S, and 80S is identical to 80 for NPS 1/8 to NPS 8, inclusive. XXS wall is thicker than schedule 160 from NPS 1/8" to NPS 6" inclusive, and schedule 160 is thicker than XXS wall for NPS 8" and larger.
..."

source: http://en.wikipedia.org/wiki/Nominal_Pipe_Size

I've messed with some thick tubing or pipe, whatever ya want to call it. it was sch 40 pip, sch 80 pipe but after sch 80 the co-worker i had worked with just called everything after sch 80, shelby tubing. At what point does pipe become tubing and what is the difference between a piece of pipe and tubing. i know pipe has a place where it comes together after being rolled but with shelby tubing is there a spot where it comes together also or is it solid stock that they drill out? thank you for the references Alexa, I'm still young and trying to learn all of these tables and such and work at the same time, i have a lot on my table right now with making these towers, trying to get my Commercial Drivers License to drive truck and trying to learn more about fabrication and welding. I've been to a welding school and passed my test to get my cert, it was for FCAW using the Dual-shield 7100 ultra that i use these days. thank you all for these knowledgeable replies. thank you for the reference tables Alexa.

The main difference between pipe and tube, is that pipe diameters and thicknesses fit in one of the pipe tables, such as those Alexa shared.

Tube sizes and thicknesses are all over the map, and are always designated by actual O.D. and wall thickness.

This is why I suggested looking at tube when you can't find an appropriate pipe size. You may be able to find a tube with an OD that is close to a pipe ID so they telescope neatly for an easy weld with minimum gap, and a wall thickness similar the to sch. 40 you'd normally use so you don't compromise strength.

In a (seamless) tube-only example, 3" X .250 wall tube will have an ID of 2.5 inches, so a piece of 2.5" tube will JUST fit inside. This will be a tight fit so lubrication (Spatter spray works and won't affect the weld like other lubes), or heating of the outer tube may be required. This might not be practical in the field, but should give you an idea of the possibilities.

Depending on tower regulations in your area, a material change may require engineering analysis, though I kind of doubt it if you didn't have to develop a WPS for using self-shielded wire in the field.

Steve S

thank you otto. i talked with my steel provider and he looked up what he thought would work, it would be the correct outside diameter he said but the tube was shelby tubing and it was half inch thick. he quoted a 10 ft section to be around 400 dollars and i told him no no, thats too much, i would much rather go for a more reasonable price with our budget, we have the money but half inch thick steel tubing is way too much overkill. I'd much rather use an idea of welding straps around the 4 inch pipe and bend the straps around then i would have the correct size. i believe 2 inch wide 1/4 inch thick steel straps wrapped around 4 inch pipe should get me closer to being able to fit inside the 5 inch pipe.

Well, it sure sounds like a workable plan. Take some measurements. Maybe 5/16 or 3/8 flat stock will give an even better fit. Get the flat stock hot enough and you won't need a hammer, until you cut off the excess and close the ring, but you will have to clean scale off the "to be welded" areas.

If you do enough of them, you might get a shop to make "half-rings" for you in a press; Just clamp two around the inner pipe where needed and weld. Big time, labor, & gas saver, having a box of those in the truck...

Let us know how it goes!

Steve S

hello, i talked to the steel provider/ welding supplier, and they are a machine shop and welding shop also. i asked the head foreman if he could make the rings for us and he talked with me about it and he said the only way they would do it is they would have to have me make them a template peice exactly how i want it then they could make them but they are going to charge 85.00 shop fee and hour for making however many we need. i think it would just be better to make a dozen of them myself and then be done with it these for awhile. im doing some wireless networking stuff this week but next week we are suppose to get our steel in and i will be starting with it. one thing ive been meaning to ask someone here. the self shielded flux core ive gotten the last couple times is this cheap stuff and 1 roll had a bunch of wire that was twisted and some spots were open and i could see the inner core. didnt weld worth a hoot and the roll im on now isnt twisted but its still running like kaka. i run a straight bead on a flat peice of iron with no mill scale and i get porosity and the slag isnt covering the weld. i pull the wire just like ya do with stick and i have the correct gun angle. im guessing just bad rolls of cheap wire. this is some cheap taiwan stuff im thinking. but i can get a 10 pound spool of lincoln innershield for around 60.00 and ive heard it welds excellent. im guessing my boss should dish out a little more wire for better quality im thinking. please give me some thoughts guys this wires got me sorta confused.

Hey,

Money well spent , I'd say....

My advice... anything that has flux or self shielding of any kind... spend the dough and get the good stuff. Also a note I have learned through experience that drive roll tension is very critical with cored wires. Solid wire you can about get away with anything. Cored wires are soft and susceptible to being crushed or misshaped with too much pressure and misshaped from spin out if to little pressure. I would get the drive roll pressure as close to manufactures spec as possible.

Mick and Nick (sounds like a good name for a sit-com) are both right.

You're doing this job with adequate (rather than "ideal") equipment. Get the good wire, it's worth the money versus the rework for using "cheap".

Nick's quite right about roller tension on cored wire. In fact, there's a knurled roller set available (though perhaps not for your machine), that has tiny "teeth" to feed cored wire reliably with fairly little roller tension to avoid crushing. With this setup, you should definately have a cleaner pad in front of the feeder, as the tiny indentations in the wire will carry dirt into the liner.

Steve S

before i started this tower, the roll i had before was a decently priced roll of lincoln innershield a small roll and it had no problems, i didnt mess with the tensioner or anything, its been stock since i bought it, only top it off to putin new wire or to clean the drive rolls. im pretty sure its just these cheap rolls of wire. i ran that lincoln innershield wire for a good while with no problem. my boss got me these cheap rolls of wire 18 bucks a pop and they are garbage. i have trouble with these cheap rolls constantly. bad welds, porosity, no slag covering the weld, and i opened up the side of my machine to see what was going on and the wire was twisting coming off of the roll then it made a loop then went into the drive rolls. ive never seen wire come off of a roll like that before. and my co-worker was watching it come off the spool as i welded and he could see the inner core of the wire and twists in the wire. cheap isnt always best from my experience. i guess ill have to tell my boss we NEED lincoln innershield or hobart wire. i have been to a welding school and passed with flying colors in flux core welding but they never taught us anything about what happens if ya have bad wire. i know all of the proper gun angles and if there slag ya drag. i know all of that but i just dont understand why this wire is so bad lol.