Welding help and advice needed please.

[pfillery]

Ok, so I want to weld some flanges onto the ends of a round steel pipe. The flat flanges will butt onto the pipe ends and be welded around the 90 degree join between the pipe and the flange and probably on the inside as well for extra strength (trailer axle is what I'm making so think the end parts of a diff housing welded onto a tube instead of a diff housing). I have an arc welder (a basic one) with a heap of GP6012 welding rods in 2.5mm thickness, the pipe is 4.6mm thich wall and the flange about 6-8mm thick.

Are the 2.5mm rods going to be ok for this assuming the amps are going to be up a bit or should I be going with bigger rods? My welder is a cheapie, standard arc only so what sort of amps should i be running to weld that thickness? I did a test weld on some scrap bits of the same tube and on max amps it lays a nice neat weld and doesn't burn through but that was just surface welding, not joining 2 different bits together. Are there any rods that are better ie going to help a mediocre welder get better welds? Both are only steel although the diff tube end flange seems a little harder than the mild steel tube it is welding to.

Any experienced welders who can offer some advice would be greatly appreciated. I did price getting it done for me but at $88+ an hour and no indication of how long it would take I'd like to try myself first.

[tomalophicon]

If I were you I'd be practicing LOTS of welding things together that may resemble your project. Then I'd be using a sledge hammer to test my welds for strength.
They say 6010 or 6011 is a good rod as it penetrates deeply and the slag freezes quickly.
If you're using 4.6mm tube I don't think there would be a problem going for a 3.2mm rod, if your welder has the capability.

Remember, a poor weld in this situation could mean someone dies.

Tom.

[pfillery]

I luckilly have a 3m piece of pipe to practice with (only need 1.2m) and figured it was worth having a go at in the first instance and if not will get it done. I've seen some pretty weak home welding used on some very dodgy homemade trailers that still takes a fair bit of strain but I want this to be strong. I will be doing a lot of practice first.

Thankfully (or could be said to be unfortunately depending on how you look at it) the onus is on the builder/repairer/restorer to ensure it is safe as there is not currently a need for any engineering, safety inspections or certification in Qld for a homemade trailer. You can even register it and obtain a VIN without anyone from transport even seeing it once (self assessment) which is a bit dodgy - theoretically if you knew your measurements you could register it before it is even built! But that is going off topic a bit.

I did even consider a high tensile threaded rod up the centre of the axle, effectively bolting the flanges to the tube as well, to provice some additional safety and strength, this will only be a 750kg GVM trailer so only light duty, not offroad or anything like that, so as long as the axle can handle that weight it will be fine.

[spudboy]

Definitely worth checking the penetration on some test pieces first.

I have done some beautiful looking welds that had low penetration and later came apart..... Luckily nothing critical, but I was surprised because from 'the outside' they looked very nice :eek:

[Killer]

Also note that if you want to bolt anything onto the flange, (and I am presuming you will bolt on stub axles) you will need to machine the faces to ensure that they are flat and parallel to each other. If you need help with either welding or machining give me a yell.

Cheers, Mick.

[pfillery]

Also note that if you want to bolt anything onto the flange, (and I am presuming you will bolt on stub axles) you will need to machine the faces to ensure that they are flat and parallel to each other. If you need help with either welding or machining give me a yell.

Cheers, Mick.

The flanges I'm using are ex diff flanges and so the surfaces are flat already, assuming I cut my pipe straight which is the plan, they should be parallel and level prior to welding, hopefully since the welds will be on the inner side of the flange I shouldn't need to machine it down. The plan is to tack it and check it, make any level adjustments so it is right then weld it. I may yet take you up on the offer of help if I can't work it out. The closest I've come to machining is using my drill in the vice as a mini lathe. Works well for small stuff but not great for an axle!

How do you ensure good penetration? Is it more the speed and technique, the quality of the welder and rods or how hard you push? Any tips?

[mick88]

Set it up and get it all square then tack weld it.
Then take it to an Engineering Business and get them to run over it with the Mig. Then you just have to machine the faces to get them perpendicular to the axle and parrallel to each other.
It will give you peace of mind!

Cheers, Mick.

[pfillery]

Sorry, excuse my lack of knowledge, but if the pipe is cut square with ends perpendicular, and the flanges are welded on after being squared and are set in the correct position, wouldn't it be square enough at that point? Is there a reason why it would need to be machined? It would be too thick to warp from the heat of welding.

[incisor]

nothing is too thick to not warp or move when welded.. if welded properly

you want to do it properly, get them machined afterwards...

[isuzurover]

nothing is too thick to not warp or move when welded.. if welded properly

you want to do it properly, get them machined afterwards...

What Dave said. If you are putting enough amps into it to get sufficient weld penetration then it will warp to some extent.

There are ways to avoid it, like using a MIG, welding both sides and letting the weld cool between short runs, and of course pre-stressing the section to be welded.

At the end of the day though it is a light box trailer. You can check the flanges for warpage after welding and if it is only minor you can file them flat.

But as mentioned, the proper way to do it is to face them after welding.

[Tank]

If your not an experienced welder then you should either get some experience on something other than someones life could depend on or get a professional welder to do it, Regards Frank.

[celtic4x4]

Mate i'm a boilermaker and trust me mate even if it is justa light trailer.dont muck about with trying to weld it yourself will take a welder no longer than 15-20 minutes to weld it up so $44 dollars is better to wear than 15-20 years in jail for killing some poor sucker minding their own business ,keep the welding to your benches for your shed until you get alot more practice regards celtic4x4

[PhilipA]

Before seeing the above posts I came to the same conclusion.

I fitted a towbar to the front of my RRC by cutting it short and rewelding the flanges. To get the weld done , I tacked it how I wanted it and took it to the local trailer manufacturer that I bought the towbar from.

It took about 15 minutes and $20 , and I have good welds and a reduced chance or hurting someone in a recovery as they have the correct equipment and experience.
Regards Philip A

[RufRangie]

What PhillipA said mate, get someone that knows what its about to do it. There is a lot to welding something together other than whacking a bead of weld on it, like they say. Ya don't want it coming off and sconning some poor bugger with a wayward wheel and maybe killing them ;). Wouldn't want that one on my conscience, take old mate up on his offer to help out, i'm sure he loves beers :D.

Get stuck into a heap of practice with your welder and make sure you are ready for the next project!

Cheers........................Pete!

[Jonno007]

Yeah good advice guys, I'm a pretty decent welder on the stick and the mig but if it's structural where failure could hurt someone, I ain't doing it!

[justinc]

all good advice, take it to a machinist/ engineering shop, they will do it quickly and cleanly but above all safely!

jc

[Flaps]

But if u are going to do any more welding i would use Kobe LB-52U Low Hydrogen E7016 (http://www.westozwelding.com/node/85)welding rods they get good penetration at low amps and are high tensile. And if u dont want it to warp clamp it down

[POD]

Totally agree with the above advice, it will not take more than half an hour for an experienced welder to do this job once you have tacked it up. Also the flanges will need to be machined true once welded in place.
I think a better way of achieving your end result is to machine the axle shaft to fit inside the spindles then weld the spindles in place. I used this method to fit RR hubs and brakes to my camper. The weld in the setup you are planning will be under enormous stress.