I'm about to weld a small hole in my chassis rail and I wasn't sure if I should make the replacement patch exactly the same size as the hole or if it should be slightly oversized, say about 5 mm each side?
I'm about to weld a small hole in my chassis rail and I wasn't sure if I should make the replacement patch exactly the same size as the hole or if it should be slightly oversized, say about 5 mm each side?
Depends on your welding skills and condition of surrounding metal.
I prefer to overlap as im not brilliant at welding and tend to blow holes when butt welding thin metal lol
Yea I'm the same. Not really grand at the ol welding!
But I wasn't sure what the mot man would think about the patch not being flush and I was also concerned that I wouldn't be as rigid?
The MoT guy will only look to see if there is a continuous weld all the way round the patch. Can be a lap joint or a butt joint, whatver you feel more comfortable with doing. A butt joint would more for aesthetics though.
Cool, I think aesthetics are out of the window for me!! Cheers guys
I always cut the plate to fit the hole. To avoid blow through holes you need to keep the temps down. So its small runs at a time.
Id prefer butt joints too so will have to try that cheers snops
Just don't continuously weld, do really short bursts to build a pool then connect them once you've tacked all around the plate. I sucked at welding thin sheet so I did this instead and it seems to do the job (good old hammer test to prove )!
Also better to cut the hole a little bigger till you find really good metal will save a lot of ****ing about fixing blow throughs
If it's in a square bit of chassis rail might be easier to cut a square out of the plate you're replacing i.e (excuse the text pic attempt):
chassis rail: l_l
remove rust: l l
weld in new palte: l_l
that way you can get a nice tight fit and only have straight lines to weld.
Lot better than my second attempt lol
Thanks dude, although Im slightly concerned about how much penetration I'm getting. But that's nothing new
Looks better an my welding! I'm going to start on the short bursts to build a pool method, only found out it was a thing recently.
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What i would like to know is how they go there as that is from inside the rail rotting through to outside
Most cars rot from the inside out, especially nissans as the seam sealer they used from the factory is porous. I'd wager that most 200's have rot hidden under the seam sealer. Also the insides of the rails and sills have basically not rust protection, so as soon as salt and moisture works it's way in there it can cause rust without issue.
Best fix is to remove all the oem sealer, use something like por15 seam sealer, then use a cavity wax for insides.
I hope so, it seems solid and looks okay but my practice stuff just seems to get through the material and no more.
Oh yeah, and it definitely rusts from the inside out!
Steve, I'd be happy to help you in any way if you share some of your rebuild tips!
Last edited by Tanuki; 28-03-2015 at 21:35.