Distortion for long welds

Pony · 2025-07-24T01:51:10.000Z

I have to extend the rear of my cattle crate down 2 inches as its a bit to high for most cattle loading ramps and i also have now got a trailer to pull and its also to high for that as well. The crate is not permanently attached to the truck tray and only clamped on. The existing "bumper" is 125mm x 75mm RHS (rectangular hollow section) mild steel (don't know what thickness) which has been fully welded to a piece of 75x75 (6 or 7mm) angle. My extension is a piece of 100x50 RHS fully welded to a piece of 30x30 RHS (both 3mm wall) I made the extension this shape as i wanted to bumper to butt against the crate when backing against the ramp, so the tray takes the force rather than the clamped on crate. My question is around the distortion which is going to be caused by fully welding the extension on. I believe fully welding the entire join is necessary because it will be living its entire life is cattle feces and urine and every crate ive ever seen with stitch welds and either no caulking or even with caulking it soon fails and allows liquids in which rusts out. I fully welded my extension and got a bend as expected but was also able to press it out also as planned. However welding the extension in, if it warps i wont be able to press it out. I have stick and mig available (both gas and gasless), but am entirely self taught so probably by professional standards pretty ordinary, but things usually stayed glued together when im finished. Don't really want to hire it out to be tig'd, but if its the only way well so be it. I fabricated the other crate you can see in the background in one of the photos and every join in that was fully welded and apart from surface rust due to my crappy paint job it is rust free after 15yrs. However none of the rhs was off the same size im going to use now, i don't know if having the welds further apart will cause more or less distortion? My extension will be welded along the long side, so 130mm apart, both ends welded and 2470mm (8ft) of weld. Previously kept my welds to about an inch and skipped along keeping both sides even and keeping the voltage down to reduce heat input. Was using gas mig. In the photos, white steel is tray, maroon is crate and unpainted is my extension. I know it will distort to some extent, a few mm i can live with, looking like a banana, probably not. Any better way? Or other advice? Thanks

Started by PonyJul 24, 202528 replies

PonyJunior MemberAug 18, 2025#21
Bloody hell, I really am a hack. As I was going to be welding this out in the open, decided to bring my little Kempi welder down, save trying to push the big welder and trolley around in the dirt. The Kempi is only used fencing and yard building with galvanised steel, so only runs gassless wire. Get set up, swap the cored wire spool for some solid wire hook the gas bottle up and start to tack everything together. Couldn't get any penetration and bead was really high. Checking my settings, was trying to keep the heat down, but turned it up as it just wasn't any good, checking earth connection, nothing was working, couldn't figure it out. Then remembered what i didn't do, DOH, didn't swap the polarity. After that it all went swimmingly. Cause I had to grind my initial tacks down, i decided to keep the weld thin and grind the join seam visible. I also figured that it would make it a bit easier for the.needle scaler to beat on the weld. Decided to go with the needle scaler despite the divided opinions, I figured that if it didn't help, at least it wouldn't hurt. No visible distortion, happy camper. Thanks all
eastroadNew MemberSep 4, 2025#22
Pony said: Bloody hell, I really am a hack. As I was going to be welding this out in the open, decided to bring my little Kempi welder down, save trying to push the big welder and trolley around in the dirt. The Kempi is only used fencing and yard building with galvanised steel, so only runs gassless wire. Get set up, swap the cored wire spool for some solid wire hook the gas bottle up and start to tack everything together. Couldn't get any penetration and bead was really high. Checking my settings, was trying to keep the heat down, but turned it up as it just wasn't any good, checking earth connection, nothing was working, couldn't figure it out. Then remembered what i didn't do, DOH, didn't swap the polarity. After that it all went swimmingly. Cause I had to grind my initial tacks down, i decided to keep the weld thin and grind the join seam visible. I also figured that it would make it a bit easier for the.needle scaler to beat on the weld. Decided to go with the needle scaler despite the divided opinions, I figured that if it didn't help, at least it wouldn't hurt. No visible distortion, happy camper. Thanks all Click to expand... Thanks for the reminder to fit the polarity to the wire. I almost never switch from flux core, so I’d likely not remember to adapt. Could you put up some pictures of the Kempi welder and how you power it up in the field ? I use a Lincoln 140 and power it off my Miller Bluestar for the rare occasions I use wire feed in the field and use the flux core wire for obvious reasons of gas and wind don’t play well together. Thanks. Odie
PonyJunior MemberSep 4, 2025#23
Don't have current photos of gear as they're back out bush and I'm home atm seeing the family. I went with dedicated generator rather than a portable welder as i really only need the smaller mig as portable and have other uses for the generator. Kemppi Minarcmig Evo 200 Genelite 15KVA generator i put on dodgy little trailer
LegdocJunior MemberSep 5, 2025#24
Nige said: If you have an offsider to run the needle gun while you weld it would make the process really easy. Click to expand... While I'm an educated man I never have claimed to be smart. Although I do claim to be good looking! That being said I must ask what is a "offsider"?
eastroadNew MemberSep 5, 2025#25
Legdoc said: While I'm an educated man I never have claimed to be smart. Although I do claim to be good looking! That being said I must ask what is a "offsider"? Click to expand... I take it as a helper;someone to do the small and necessary tasks to enable the main event to proceed without interruption.
PonyJunior MemberSep 5, 2025#26
Spot on Legdoc. Sidekick might be more American? Lacky? Either way, i don't have one, I'm Chief and all the Indians rolled into one.
PonyJunior MemberSep 5, 2025#27
Oops, sorry eastroad was right, Legdoc asked the question.
John ShippJunior MemberSep 5, 2025#28
Surely (don't call me surely) and offsider is someone who gets near the goal ready for the big "hoof" down the field...
LegdocJunior MemberSep 6, 2025#29
John Shipp said: Surely (don't call me surely) and offsider is someone who gets near the goal ready for the big "hoof" down the field... Click to expand... "I don't do impressions" Great movie!

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