Mid tube welding

[Scottowner]

Having just acquired a MIG welder and therefor still learning,I am not about to embark on a task that I cannot achieve,but I am looking for opinions on the practicalities of welding a baffle plate mid way down a thin walled tube.I am restoring a 1921 motor scooter and it has a petrol/oil tank mounted over the front wheel. The tank is 300mm long x 450mm circumference ,and has a baffle separating the oil from the petrol at 100mm. 450mm c thin wall (1.5mm) tube is easy to obtain,as is 1.5/2mm sheet for the baffle. Your opinions will be appreciated. Thankyou.

 

[Pete.]

I would get the tube, make the divider and braze it in. Make a bung for the end or braze the end on furthest from the divider and pressure-test it at a few psi to check for leaks.

 

[Mr shiney]

I would braze as well, however the question is how you are going to get at it. How big is the tube? Getting 100mm down on a small tube would be an interesting challenge. It could actually be better to do it out of two pieces of tube and join them.

 

[Wendelspanswick]

Make the tube, put a small 90deg flange on the baffle plate and soft solder it into position, you can apply the heat from outside the tube and feed the solder/flux internally.

 

[Robotstar5]

I'd make it in 2 pieces and weld together.

 

[Scottowner]

Thankyou gentlemen, The tube is 125mm diameter. Some interesting solutions there, braze or silver solder in situ,or two parts (like a tin can !). Are there likely to be distortion issues with either solution ?

 

[Paul G]

I hesitate to say this but… er… you could just... weld it.

A disc 100mm down a 125 pipe, 1.5mm to 2mm thick, not exactly like sticking yer arm up a cows rear is it ?


As for distortion it's apparently already shrunk from 450 circumference to 125 diameter.


HNY
Paul G

 

[Gareth0123]

I hesitate to say this but… er… you could just... weld it.

A disc 100mm down a 125 pipe, 1.5mm to 2mm thick, not exactly like sticking yer arm up a cows rear is it ?


As for distortion it's apparently already shrunk from 450 circumference to 125 diameter.


HNY
Paul G

But that is only by about 19mm off the original diameter

 

[Bill Edwards]

It sounds like the pipe is wide enough and the baffle won't be all that far down to just reach it with a MIG torch without any trouble.

If not making it in two pieces would work but I think it also the most likely to cause distortion - but then how accurate does it need to be, you've never said.

If it isn't practical to reach straight in with a MIG then I think I would favor soldering it. And that isn't going to cause any distortion issues if that is a concern.