Thick & Thin - can they play together?

[Murray61]

Hi guys - can anybody give me some tips on this little job I'm doing for a friend? (besides to not tell anybody you have a mig welder!)

Exhaust flange stubs for a '66 Mustang 289. The flanges are 'home made' - no originals available in NZ, it seems. They are cut from 10mm plate and the pipes are 51mm (2") x 1.75mm (approx. .065") wall thickness. See PHOTOS.

So the problem is ... sticking thin stuff to thick stuff???

I have a Lincoln SP170T (brand new), with 0.8mm solid wire and Argoshield gas (argon/CO2).

I also have about 7 minutes and 35 sec. of experience with mig welding. Somewhat more with stick.

There is not much clearance for the bolt heads, so I want to keep the weld as small and neat as possible. Would it be better to weld around the inside of the flange at the face? At least it is all new and clean! Any advice much appreciated - thanks.

 

[Bigjoe]

Welcome! christ they are some flanges!,welding thick to thin can be trickey with a mig,the best way (i think) is to focus the majority of the heat on the 10mm but allow the pool to run into the tubing,if you have any offcuts etc i would have a play before hand with techniques and settings.

Good luck

Bigjoe

 

[Wozzaaah]

No problems at all with that. The best way to do it is to sit the tube lower than the flange as you've got it in the first pic and weld it from the inside as you suggested. Use a high power setting and maybe a slightly slower wire speed but concentrate the weld onto the flange rather than the tube allowing the weld to just lap onto the tube to avoid blowing through it. If you do decide to weld it from the outside, keeping the wire speed low, the power high and travelling slowly will give you a smaller weld bead. Again, concentrate on the flange rather than the tube. Have a practice with some scrap first to get a feel for it rather than ruin your nice flanges.

 

[Murray61]

Thanks Bigjoe - you're right about the flanges - 10mm?? Glad I didn't have to make them with a hacksaw and a drill! - looks like someone who knows one end of a plasma cutter from the other made them.

Good idea - I'll rustle up some scrap (from my last attempt at making something useful) and have a few goes.

 

[Murray61]

It's too late to get started on it tonight (my garage is a freezer), so I'll post some photos for you to laugh at tomorrow - thanks.

 

[rtbcomp]

I'd be inclined to weld all round the inside as stated above, but also add some weld beads on the outside to increase the mechanical strength. Keep the beads away from the stud holes to allow room for the nuts.

 

[malcolm]

I welded my last set from the outside and used an angle grinder to remove weld in the way of the bolt heads. Ended up looking almost like it was intended to be that way.

Whichever way you do it it's going to be angle the torch towards the thick stuff, start the arc on that, then once you have a weld pool just flick into the thin tube for a short time - enough to melt it in but not blow holes, then back into the thick stuff and and so on as you go around the pipe.

 

[Murray61]

Thanks everybody - here are pics of the welds for your enjoyment. He didn't want the inside welded as there is some sort of ring which locates inside the flange.

The first two show parts I had to go back over coz no penetration to the pipe. The second two show the heat line on inside of the pipe - is it sufficient, or should it have melted through more? There seems to be a little spatter, is this normal (Argon/Co2 mix)?

Next project - a 'lazy suzy' turntable for my welding table - the biggest problem I had was stopping and starting, trying to keep the weld uniform. Thinking of using an old axle with the wheel flange as the turntable. It will already have the roller bearing, but earthing through this may weld the balls/rollers to the cage? Any suggestions?

 

[irondarren]

look good to me, quick buzz over with a flap disk, to knock off any splatter and what not and they will be great

 

[Wozzaaah]

Nice work!

 

[Murray61]

What I'm looking for is "you should have held your tongue a touch to the left" or "don't give up your day job, sparky". I appreciate kind remarks, but would value constructive criticism more. Honestly, the welding doesn't look that good to me - serviceable, sure, but how can it be better? Is it just more practice I need?

 

[Wozzaaah]

No criticism needed Murray, they look absolutely fine! You can see that you did as suggested and concentrated the weld more into the flange than the tube, the welds are nice and tidy, the little bit of spatter will come off easily and I think most of us would be proud to show the pics if we'd done them .
Woz

 

[malcolm]

I'd have gone for slightly more penetration into the pipe to leave a tiny amount to grind off with the air grinder (prob slightly more heat so you get more into the flange too.

Pipe welding is a pain though. The pros have powered rotary tables but for the DIY types some way of turning the pipe quickly is handy or elde the weld gets cold and you get a load of build up when starting the next run. I've been known to clamp a V block in the vice, lightly jubilee clip the pipe in so it can be turned around with one hand.

I don't really manage better results though unless I've been practicing a lot.

 

[Murray61]

Cheers guys - boosted my confidence no end. I'm off to apply for a job at the cryogenics vessel plant up the road, using you lot as referees on my CV, okay?

I'll get started on the turntable, which will be fine for these 'vertical cylinder' welds, but, yeah, have to do something else for horizontal pipe welds. So, Malcolm, you say you can weld with one hand and turn the pipe with the other? Way to complicated for me - you must be one of those freaks who can rub your tummy in circular motion with one hand and pat the top of your head with the other!

I've got a 150:1 reduction gearbox I use for spit roasting (via vee belt from my concrete mixer motor). Maybe I could rig it with a four-jaw chuck and support the pipe at t'other end with a vee-block. Or just practice my tummy-rubbing and head-patting.

 

[steve202]

Get an apprentice to do the turning, Murray. Great looking welds there. Mine would be like that except sh1te.

 

[williamz]

Nice work!

 

[Haze]

pipe fitters would weld the inside also, the outside welds look good enough but i'd still run a bead on the inside edge too.

 

[virago125@hotmail.co.uk]

HI. TO BE BRUTAL.

IT LOOKS LIKE YOUR GUIDE DOGS DONE THE WELDING

NOW THAT YOU HAVE THE FLANGE/TUBE TOGETHER. YOU CAN PUT IN OVEN. OR PLACE IN A PAN. ADD WATER ABOUT 5mm ABOVE FLANGE. BRING TO BOIL. ADD SALT TO TASTE. THIS WILL ALLOW THE FLANGE TO PREHEAT TO HELP PENATRATION.
FULLY WELD INSIDE TO MAKE GAS/LIQUID TIGHT. THEN WELD OUTSIDE PIPE/FLANGE STOPPING TO ALLOW PLACEMENT OF WASHER/BOLT. YOU NEED LOT OF PRACTISE TO MIG WELD AROUD SMALL DIA PIPE. BETTER TO TIG WELD OR BRONZE WELD WITH GAS.
ALSO HELPS IF YOU BEVEL INSIDE FLANGE TO ALLOW MORE WELD IN. ALOWING SMALLER CONVEXITY OF WELD. MY FIRST WELD LEFT THE WELDER ROLLING AROUND THE FLOOR IN UNCONTROLABLE LAUGHTER! IT USED TO HAUNT ME LIKE THE SILENCE OF THE LAMBS. SINCE MY VISIT TO THRESHERS THE LAUGHTER HAS STOPPED.
CHRIS. LONDON

 

[Haze]

what