Liam
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| posted on 16/3/06 at 04:55 PM |
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Does engine oil attack carbon fibre/polyester resin??
Hi there
I've got a big hole in my steel sump where my starter motor has to intrude slightly. I was gonna patch it up with steel sheet but a) I
haven't got any thin steel and b) I am concerned the welding may distort the sump so it doesn't seal properly and leaks.
My plan is to use a bit of ally sheet which will be easy to cut and bend, and to hold it in place with a layer or two of carbon fibre mat inside and
out with polyester resin. All of this i've got.
I'm sure the strength will be more than adequate, but my question is will the engine oil attack the carbon/resin and fall out one day?? Any
advice appreciated...
Cheers
Liam
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RazMan
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| posted on 16/3/06 at 05:18 PM |
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I wouldn't risk it Liam - polyester resin will degrade very quickly considering it will be immersed in oil and at a very hight temperature. Get
it Mig welded - the distortion shouldn't be a problem if it is done carefully.
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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nitram38
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| posted on 16/3/06 at 07:07 PM |
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Liam, I know it is a pain, but you will find welding a permenant job.
I recommend that you take the sump off if you can and make sure it is very clean. It is murder to try and get a good seal if the oil is present in
the weld and impossible if you do it with oil in still in the sump (plus dangerous  )
[Edited on 16/3/06 by nitram38]
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David Jenkins
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| posted on 16/3/06 at 07:51 PM |
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When I did my sump I screwed it to a nice thick flat piece of plywood, like so:
this keeps everything stable, and stops you having to chase the thing around while you're welding.
David
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Marcus
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| posted on 16/3/06 at 07:54 PM |
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David,
That's exactly what I was going to say!
I'd use a gasket too, so the flange doesn't distort.
Marcus
Marcus
Because kits are for girls!!
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Liam
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| posted on 17/3/06 at 12:06 AM |
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Yeah you're all right - steel is real. I found a non-porked jigsaw blade though and was inspired to have a go at the thinnest stuff I've
got - some 2mm steel.
Turned out fine and I welded carefully having to tweak out some minor distortion from time to time. Thought it would distort much worse than it
did.
Anyone got any good ideas for leak testing? Or what about smearing some epoxy on the outside of the welds just in case, although i'm pretty
happy with the welds and would be surprised if there are any holes.
Cheers
liam
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David Jenkins
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| posted on 17/3/06 at 08:13 AM |
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I put mine on a sheet of clean paper and filled it with water. Came back an hour or two later, identified the leaks, ground back & re-welded.
In the past I got a friend to braze over some really bad leaks - the last time I did it with just a MIG welder.
David
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