Trying to fix splits in my 1963 Morris Traveller Bonnet.

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Bubblemechanic
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Trying to fix splits in my 1963 Morris Traveller Bonnet.

Post by Bubblemechanic »

Hi Guy's after spending an eternity on getting my bonnet paintwork right the first time I put the bonnet down the next day noticed 2 crack lines in the paint.
These were either side of the Bonnet catch where the bonnet return fold is slightly narrower than the rest of the front of the bonnet. I bit the bullet and stripped back the paintwork to reveal that there were 2 splits, so after a bit of tooing and froing I tried to weld up the splits with the lowest settings on my mig welder but it just kept blowing the metal away.
I kept trying even trying to use a piece of plate to put behind, Anyway my question is would using Fibre glass matting behind and folding around the return fold be strong enough to make a nice strong joint and fix my problem.
Could really use some advice I have even considered having them Brazed or Gas Welded but am worried about distortion and being the bonnet will always be on show.
philthehill
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Re: Trying to fix splits in my 1963 Morris Traveller Bonnet.

Post by philthehill »

In my opinion fibre glass matting is not going to be strong enough.
You could get the cracks brazed which uses a lot less heat than welding. When brazing use a flattened piece of copper pipe clamped to the bonnet near the splits which can be used as a heat sink. With care distortion can be avoided.

mogbob
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Re: Trying to fix splits in my 1963 Morris Traveller Bonnet.

Post by mogbob »

Fibreglass repairs have their place ,providing the area concerned does not compromise structural integrity or as in this case is not in an area subject
to continuous stress.
I would continue with "pulse " welding , with your piece of brass / copper behind. It's the same technique as plug welding ( when replicating
factory spot welds ) but this time " in a straight line " as opposed to a concentrated spot.

Lowest setting on the MIG , angle the torch ( even more than for normal welding ) aiming to " hit " clean metal / fresh weld... side on.
Light finger action on the trigger..squeeze /blip the power on for a fraction of a second. As soon as you hear the sound of contact / see the
bright light , release the trigger. You shouldn't have time to say " one second " , it's that quick !

Top tip... observe the bright heat glow of the weld ,move the torch a millimetre or two along the line to be filled. The heat will dissipate and in a second or two , with your welding helmet on , you will no longer be able to see it. So the trick is to blip the torch again , just as the heat source
is fading and you can still see it. Aim for the new edge. Release quickly , repeat , repeat.

A few other pointers. Practice on some scrap first of all, you might like to experiment with the wire speed on your MIG. A little higher than normal for
every day welding. Remember you're trying to fill the hole..just small blobs of weld all around the perimeter , adjust your direction of the torch
accordingly. Hold the trigger too long and you will get big blobs of welds = more to grind down. ( protect paintwork and glass when using an angle grinder in anger ).Watch the potential for heat distortion. Stop the welding and allow the work to cool. Always start with really clean metal.
School boy error ... the gas supply isn't low / running out / has run out has it ? That produces rubbish welds .
I leave you to guess how I know that one. That and the wire running out, stopping the machine. Had a lot of welding to do in the early days and I was dead keen to crack on. Forgot the basic machine checks, Stupid boy.
Good luck with it Bob
don58van
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Re: Trying to fix splits in my 1963 Morris Traveller Bonnet.

Post by don58van »

Hi. Here in Australia, with our bumpy roads, those splits in the bonnet edge are very common. :evil:
The standard fix is to weld a length of steel rod (several mil thick) behind the front edge. The rod will make it much less likely that you will blow through when welding and also make it much less likely for cracks to reappear.

Don
alanworland
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Re: Trying to fix splits in my 1963 Morris Traveller Bonnet.

Post by alanworland »

From the many photos I've seen it would appear the bonnet catch is adjusted too tightly causing the cracks in the first place!
This can be confirmed by looking at the gap between the bonnet edge and the grill chrome, it should be parallel but is often much tighter in the centre.

Alan
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taupe
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Re: Trying to fix splits in my 1963 Morris Traveller Bonnet.

Post by taupe »

I agree with Don a bar welded in or brazed is the answer...

Taupe
Bubblemechanic
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Re: Trying to fix splits in my 1963 Morris Traveller Bonnet.

Post by Bubblemechanic »

Well Thank you very much much appreciated and I use no gas and flux cored .08 wire and all your information will be put to good use over the next few day's
I wish I had seen this coming while the bonnet was stripped to bare metal would have been a lot easier because it was off the car as well anyway I will follow all your advice and try and fix the problem
Wish Me Luck and I wil let you all know how I got on
Cheers Paul.
don58van
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Re: Trying to fix splits in my 1963 Morris Traveller Bonnet.

Post by don58van »

Just to be clear about the reinforcement with a steel rod method...
The idea is to use one piece of rod that will extend across the area affected by splits and a few centimetres beyond. This will disperse the stresses across a considerable area.
Don
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