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acotrel
Advanced Member
Victoria
2147 Posts |
 Posted - 27 Nov 2002 : 8:21:45 PM
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I have recently been involved with scrutineering a few four wheeled tin cans at Winton. I noticed the roll cages sometimes have cocky sh*t welds, they look as though they have been hit with the MIG.
I've often wondered what we would find if we went over all the welds on historic bikes and cars with dye penetrant.
A few years ago a friend was killed at Bathurst. A relative had arranged for some discs to be made out of fork lift discs, to replace those on his RG500 Suzuki, which were chromed aluminium, and had spalled. As this rider reached the braking point on Conrod Straight, the discs disintegrated. He passed Mick Hone, climbing off the back of the bike and ended up in the car park.
If you are building a steel structure in Australia, you should weld to Australian Standard AS1554.1 . This says your welding procedure should be qualified, by tests involving tensile and macro on the material you are going to use, to show you have achieved the strength and penetration. This standard applies to staircases, what do we use when welding racing motorcycles?
If you are using cast iron, greycast iron such as in forklift discs has a strength of about 15 tons/square inch (less than mild steel). When calcium silicide is precipitated in cast iron, it becomes known as meehanite, and is much stronger.
The point I'm making is that I believe a lot of racing bikes are built by people with little knowledge of materials and welding processes. For anyone becoming involved in a death on the circuit, through building a racing machine, the consequences can be quite costly, and traumatic.
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Is your machine authentic or merely eligible? |
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john
Forum Moderator
Victoria
3130 Posts |
Posted - 28 Nov 2002 : 4:31:18 PM
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| I was at Bathurst hen Ross B. was killed, I was experimenting with disc we had made on a sidecar at the same meeting.I have often wondered about some of the things we do produce in the quest for speed and fame. Is there any process in the system that encourages riders to bounce ideas around before they have the mistake that RB had fitted to his bike. |
John Daley Sidecar #68
' there are those who do, those who dont do and those who undo. We must lampoon the latter." |
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acotrel
Advanced Member
Victoria
2147 Posts |
Posted - 28 Nov 2002 : 8:37:37 PM
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| I don't know how good the technical committees are in MA, however last year I was involved with CAMS scrutineer training. I mentioned this business about the welding of roll cages. The CAMS instructor said that the CAMS technical Committees were just becoming aware of the new approach to safety involving risk management, and its technical implications. We've probably got a way to go in this area. Eventually licence testing will probably include (riding ?) competence requirements, and things like welding will have to be done 'properly'. |
Is your machine authentic or merely eligible? |
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john
Forum Moderator
Victoria
3130 Posts |
Posted - 28 Nov 2002 : 9:37:39 PM
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| Luckily we dont have to have roll cages fitted to bikes, but I reckon sidecar teams should be excempted from wearing seat belts in cars, they seem superfluous after racing an outfit and it would enable the passenger to practise some moves on the way to the track! |
John Daley Sidecar #68
' there are those who do, those who dont do and those who undo. We must lampoon the latter." |
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acotrel
Advanced Member
Victoria
2147 Posts |
Posted - 01 Dec 2002 : 10:12:37 AM
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| How often have you used the MIG to weld your sidecar frame? Would you consider it to be a highly stressed component? |
Is your machine authentic or merely eligible? |
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john
Forum Moderator
Victoria
3130 Posts |
Posted - 01 Dec 2002 : 10:41:48 AM
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| In 1972 I broke my neck with a faulty weld in the frame. Since thaT DATE I have only used recognised frame builders, Phil Barlow and Bob Martin with the odd tack by others. I think they use MIG, is that ok? |
John Daley Sidecar #68
' there are those who do, those who dont do and those who undo. We must lampoon the latter." |
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acotrel
Advanced Member
Victoria
2147 Posts |
Posted - 01 Dec 2002 : 4:59:00 PM
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John, MIG is OK if you qualify the weld procedure. Some MIG welds look really good however there may be poor penetration which is not obvious. When you qualify the procedure you weld up some of the material and get a lab to do a tensile test and a macro etch test. This shows whether the procedure will give good strength and penetration. The procedure can then be used in all situations where 'fit-up' is the same. Qualification of a procedure only needs to be done once. After that you simply use the same consumables and welder settings and materials in all situations.
I think you will find that both Bob Martin and Phil Barlow are self-taught frame builders, and probably never qualified their welding procedures. Doesn't really matter, because they would have learnt from their failures. What they are doing is probably OK, but if someone gets killed on one of their bikes, they will probably find out all about welding in court.
If you are doing work for other people these days, you've got to be a bit careful. A mate of mine was going to do some welding on an ultralight. I told him to send the owner away with it. Two weeks later that plane crashed and the owner was killed. I think I saved my mate a visit to the coroner's court. At least motorbikes don't fall out of the sky. |
Is your machine authentic or merely eligible? |
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