burgessj
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 posted on 22/9/03 at 06:25 AM |
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Final welding- advice
I have a couple of questions for all those who are building their own chassis..
I'm now in a position to start the final weld of all my tacked joints. Can you give me any advice about the sequence I should follow, to avoid
warping...Should I clamp anything etc..
Also, I have a couple of joints where my angle grinding wasn't perfect. Can I safely fill these gaps with weld or would you recommend replacing
them ?
Thanks in advance..
JohnB
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Mark Allanson
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| posted on 22/9/03 at 06:49 AM |
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Weld all the uprights, starting from the rear, at the back of the tube and then the back of the tube on the other side, then immediately weld the
front of the first upright and then the same on the other side. Work your way forward. Start again at the rear and weld with a mirror image technique.
If you have gaps, these will give you distortion, but this would be minimised if you weld these last.
Mark
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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burgessj
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 posted on 22/9/03 at 07:48 AM |
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Thanks Mark..
Would you also suggest clamping the bottom rails to the board while doing this ?
Also..if I fill gaps with weld, is this likely to cause any structural weakness ?
JohnB
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Mark Allanson
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| posted on 22/9/03 at 06:00 PM |
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I would not clamp it down, the clamps would not stop distortion, only pin it down while you weld, if not pinned down, you can see if any distortion is
coming in. If you fill gaps, it should not be any weaker if your welding is ok, but as you add moulten metal, it contracts as it cools and causes the
distortion.
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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Guams
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| posted on 22/9/03 at 10:15 PM |
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before you start welding make sure you have tack welded the chassis on the corner of every tube using lots of power to really nail them in place.
Then weld the chassis from side to side trying to equally distribute the heat input into the joints. Leave all the fillet welds till last as they
cause the worst distortion , TIG welding the chassis is ideal but MIG/MAG will do niceley with .8 wire , dont use an ARC unless you must (considerably
harder for a novice)
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kiwirex
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| posted on 23/9/03 at 08:09 AM |
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I take it you've trial fitted all of the major components and front suspension??
(If not: do it now).
- Greg H
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burgessj
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| posted on 23/9/03 at 09:34 PM |
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I was planning to final weld all but the transmission tunnel and the front assembly.
I know about the front suspension fitting problems and I'm expecting to have to do some re-work there,but I haven't yet got wishbones,
shocks, uprights etc..
Thanks for your advice
JohnB
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Ben_Copeland
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| posted on 25/9/03 at 07:31 AM |
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Welding opposites helps stop any twist/distortion.
Suggest making any suspension changes before fully welding chassis. Safer that way (might be too late by now, you might of started lol)
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