Crack in trailer frame: weldable?

tomasrojo

Just a quick appeal to collective wisdom.

Is the crack in this upright bike trailer weldable? If so, to whom can I go to get it welded?

(There is an identical crack on the other "arm" too -- I guess it's the point of greatest flexing when the trailer is in use).

72hundred

AFAIK. Steel yes, fairly doable. Aluminium no goer.

dave2pvd

It's probably aluminium. Break out a magnet to test for steel.

If aluminium, find a fabrication/weld shop that can do TIG welding. You might look for somewhere that makes custom radiators for cars?

Edit: go on a jobs website and see who is trying to hire TIG welders. Good chance they'll be able to TIG your trailer

thebouldwhacker

Depending on your level of DIY skills there is no reason why you cant bolt a support bar onto it, above and below the crack. This should absorb the pressure and keep you wheeling.
I reckon its alu so welding may not be worth your while.
Tbh if there are two separate cracks perhaps the frame has become fatigued, maybe time for an up grade, there have been a few trailers for sale in the for sale sub forum.

tomasrojo

Thanks everyone. It's tubular steel, so I guess welding should be possible. I'll have a think about the support brace as well.

dave2pvd, thanks for the tip about the jobs website! Nice lateral thinking.

dave2pvd

tomasrojo wrote: »

Thanks everyone. It's tubular steel, so I guess welding should be possible. I'll have a think about the support brace as well.

dave2pvd, thanks for the tip about the jobs website! Nice lateral thinking.

No problem.

So, tubular steel: job search for MIG welding. I'd suggest cut & sleeve that section. Although a good welder/shop will know that.

tomasrojo

Someone mentioned on here that rothar.ie do welding, so I might drop them an email to see what they say.

Again, thanks for the tip on cutting and sleeving, dave2pvd!

cdaly_

dave2pvd wrote: »

No problem.

So, tubular steel: job search for MIG welding. I'd suggest cut & sleeve that section. Although a good welder/shop will know that.

TIG is the better option for tubular steel like that. I have a set but it's down in Athlone. Might be down that way around Mid-Term...

You might be hard pressed to sleeve the outside of that but, if the end caps come off, you might get a narrower tube down the inside of the existing. How thick is the wall of the tube?

macnab

Get a short length of round bar to go inside the tubing, that should strengthen the area. I would not TiG weld it as that will build up stress areas due to high temperature associated with TiG welding. I would braze it if it was mine, brass is a much better option for areas where there is stress movement.

tomasrojo

More thanks!

I got one of the endcaps off with a little difficulty, as they seem to be glued in. The internal diameter of the tubing seems to be about 7mm. A 6mm allen key fits in comfortably anyway.



The towarm is removable, and is held in place by a bolt. You can see that there is a small tubular section welded onto the frame to house the bolt. This means that I probably can't get a sleeve onto it, as the cracks are below this small tubular section.

But I think I should be able to get two pieces of metal down the inside and that should stop the crack spreading any more. Great idea, I think. Thanks macnab and cdaly!

I guess a hardware store might have an array of metal tubes of appropriate diameter that they'll cut to length for me.

(Not sure why I called the image brompton_end_of_tubes.jpg. Should be bikehod_end_of_tubes.jpg)

cdaly_

You could consider pouring a load of epoxy in alongside a close-fitting bit of tube/rod. A rod by itself probably won't prevent the flexing that spreads the crack but epoxyed in place it might...

tomasrojo

cdaly_ wrote: »

You could consider pouring a load of epoxy in alongside a close-fitting bit of tube/rod. A rod by itself probably won't prevent the flexing that spreads the crack but epoxyed in place it might...

I did this last night. I ended up using 10mm masonry drill bits, as the shaft of those are about 9mm, which fitted into the 10mm outer-diameter tubular steel very well. The smooth, non-helical part of the bit is inside the tube straddling the crack and is held firmly in place with Araldite now.

I'm going to the shops now, and hopefully it's all ok. It seems to be very stiff now and the crack certainly isn't making any noise when I lever it with the tow arm.

Thanks everyone!