j4cko
Part of things
Posts: 100
|
|
|
|
|
Hi, after some tips, I have a Porsche 944 S2 that has some rust on one front wing at the bottom, the very back of of one sill and some surface rust aft of the rear wheels where the stones have knocked the protection off. Most of the work required is below the stonechip layer.
Plan is, before I attack my car with a grinder is to practice on a spare wing and improve my technique, but basically I was thinking, grind the stonechip back where its bubbled, cut out the old rotten metal and then make a patch which I will then weld in place, carefully, slowly so it doesn't distort the panel, then fill, prime, re stonechip and, then a coat of India red and a clearcoat.
I will disconnect the cars battery whilst I do the welding, concerned that I don't screw the electrics up, did some work on our Fiat 500 but that is less complex electrics wise, is there any other precautions I need to take, any general tips on putting patches in ?
The sills on the car are actually great, had a look inside with an endoscope and they are great so its just these bits but I want to do it myself and do a good job, hence the need to practice, need to get a couple of old panels to chop about, already have some steel.
I have a Clarke Mig which seems ok, what else will I need, I have one of those bristly disks for removing the stonechip etc, guess I will need some cutting disks, my angle grinder is the 115mm variety, I have the magnets so I can hold the patch in place whilst I tack it, I guess it doesnt need to be seam welded for a patch, on a panel which will be covered in stone chip and paint but do people tpically welld all the way around, just thinkign of not trying to builld up too much heat but guess that will come with practice, it isnt a big patch anyway.
So, any tips gratefully received, also if you are in the South Manchester area and have any old panels you want to bin I will remove them to practice on.
Regards
Mark
|
| |
|
|
|
|
chrisdcapri
Part of things
Avid collector of rust
Posts: 205
|
|
|
|
|
When welding in patches like this it's probably best to spot it in all the way round the patch and then fill in between the spots a bit at a time so you don't overheat and distort it
|
| |
|
|
j4cko
Part of things
Posts: 100
|
|
|
|
|
Cheers Chris, was sort of thinking along those lines, it isn't structural so its probably best to err on the side of caution in terms of how much heat I put into the panel, will practice until I am not distorting or blowing though, appreciate this is quite specialized work butI cant really afford to pay someone to it, well I could I suppose but I don't want to !
|
| |
|
|
|
|
|
|
|
|
|
|
The way you are saying is right. The only thing is are you patching over or actually lettng in. Patching over asks for trouble as rot can come back letting in less so. Expect the repair to need to be bigger than you think. Use 1mm cutting discs in the grinder, they produce less heat and give a neater cut. Always wear goggles/gloves especially with twist knot wheels and 1mm discs, they can be nasty. Thats pretty much it
|
| |
|
|
|
|
|
|
|
I'd want to weld all the way around for a patch like that, using the method that Chris said above. One tack on each side or corner of the patch, allow to cool and then lay a tack onto the last tack to create a seam with minimal distortion. The hardest bit is being patient enough to let it cool between tacks  The only other thing to emphasise is that you need to cut out all the grotty metal, and will probably end up having to cut out more than you expect. There's a recent discussion on this section of the forum about the best cutting discs to use. |
| |
...proper medallion man chest wig motoring. |
|
j4cko
Part of things
Posts: 100
|
|
|
|
|
Not patching over, cut out the grot, make a piece the same size, have already ordered the 1mm disks and am very cautious around angle grinders, bits of hot metal in your eyes is not fun, not fun at all !
Expect it to be bigger than anticipated, may have to remove the wing to get at it fully but hopefully not.
|
| |
|
|
scruff
Part of things
Posts: 621
|
|
|
|
|
Remember that the 944 wings are galvanised - burning zinc fumes are VERY bad for you.
Make sure you have plenty of ventilation.
|
| |
1994 Lotus Esprit - Fragile red turbo with pop up lights.
1980 Porsche 924 - Fragile red turbo with pop up lights.
I spy a trend...
|
|
|
|
|
|
|
Taking time is the key, as others pointed out allready. Take twice the time you think is neccesary between every spot And make use of the 'pilgrim step' or 'step back' technique; one spot after the other, as far away from each other as possible. This should bring distortion down to a minimum. I've also done it another way; I cut out the damaged part, joggled the edges and put in an overlapping patch with only a couple of plug welds. Then ground down, flooded the gap with primer, sealed from the backside and hid everything with filler. But joggling only realy works on a flat panel... |
| |
|
|
|
|
|
|
|
For galv, worth wearing a mask. They say drinking milk stops the queasiness but breathing zinc can't be great... Patch will need continuous seam weld, for MOT apart from anything else. Gradually hot-spotting all the way round, skipping from place to place should do it, takes time as said - impatience is the enemy  Re sparks, I like the full-face visor jobs, you can position them so the visor is touching your chest kind of thing, stop sparks sneaking up there. And you can always wear safety glasses under them too. And if poss align the grinder to one side so yr not in the firing line. Can sometimes help with thin stuff to use a lashed-up heatsink behind the panel, I use bits of ally sheet, ally blocks, or copper tube beaten flat etc, anything like that. |
| |
'66 Amazon <-> '94 LS400 <-> '86 Suzuki 1135 EFE
|
|
|
|
j4cko
Part of things
Posts: 100
|
|
|
|
|
I will be working outside on this as my garage is 1/2 a single, the other half being full of toilet and domestic appliances so should be ok ventilation wise, hadnt thought about the Zinc fumes though.
Will have a practice on a panel and see what happens when I go hell for leather running a weld round the patch, you know, to get that experience, then on the real deal make sure I introduce as little heat as possible and cool it inbetween, will try to get a feel on the practice pieces for what I can/cant get away with, then err on the side of caution on the car itself.
I tend to end up dressed up fairly well covered, not keen on blobs of red hot metal about my person.
My thinking is with this, and a lot of things, do a bit, leave it and come back rather than blundering through, do the reading, listen to what people say, practice, buy the correct tools and do the best job I can.
Watching TonyBMW's work in that thread is jaw dropping, seeing him fashion what looked like a factory replacement of that battery panel from flat steel was incredible, some people just get the way metal works.
|
| |
|
|
scruff
Part of things
Posts: 621
|
|
|
|
Use a wet cloth to cool the panel after each burst. Check out www.mig-welding.co.uk/ for some videos and techniques. |
| |
1994 Lotus Esprit - Fragile red turbo with pop up lights.
1980 Porsche 924 - Fragile red turbo with pop up lights.
I spy a trend...
|
|
j4cko
Part of things
Posts: 100
|
|
|
|
|
My nice new angle grinder arrive today, just waiting for the cutting disks and I realised I have an old Fiat 500 door lurking in the shed so will sacrifice that (it isnt that great) in the name of practice.
Any suggestions as to what else I need in terms of tools/consumbles ?
My mig is on 0.8 wire so will try that and perhaps drop down to 0.6 if its too heavy duty.
|
| |
|
|
scruff
Part of things
Posts: 621
|
|
|
|
|
play, practice, practice, play, run out of gas, play, practice, etc.
BTW: Disposable bottles will last no time at all
|
| |
1994 Lotus Esprit - Fragile red turbo with pop up lights.
1980 Porsche 924 - Fragile red turbo with pop up lights.
I spy a trend...
|
|
j4cko
Part of things
Posts: 100
|
|
|
|
|
So I need a big bottle ?
|
| |
|
|
scruff
Part of things
Posts: 621
|
|
|
|
|
Or lots of little ones...
|
| |
1994 Lotus Esprit - Fragile red turbo with pop up lights.
1980 Porsche 924 - Fragile red turbo with pop up lights.
I spy a trend...
|
|
j4cko
Part of things
Posts: 100
|
|
Mar 10, 2012 19:27:05 GMT
|
|
Got some time today and gave it a go, managed ok apart formt he spring in the earth clamp on my mig snapping, very poor, email to Clarke next week !
I cut out a 4 inch long by about 1 inch wide strip and welded it back in, managed to warp the panel a bit but that was part of the plan, to see what happens, did cool a bit with a wet cloth but got to busy with the welder and subsequently the grinder to grind back my frankly terrible welding. Part of the problem was that I welded back in what i cut out and I had over a millimetre all the way round to bridge with weld, so in future will make a new piece.
Will have a go at posting the photos but cant be bothered at the moment.
|
| |
|
|
johnna
Part of things
Posts: 46
|
|
Mar 10, 2012 23:22:39 GMT
|
|
Diesel Weasel mentioned joggling.
Jogglers or joggling pliers will allow you to create a recess in which to sit the new section of steel.
|
| |
|
|
scruff
Part of things
Posts: 621
|
|
|
|
|
Yes, a recess means you are not welding into fresh air which makes things much easier!
|
| |
1994 Lotus Esprit - Fragile red turbo with pop up lights.
1980 Porsche 924 - Fragile red turbo with pop up lights.
I spy a trend...
|
|
RobinJI
Posted a lot
"Driven by the irony that only being shackled to the road could ever I be free"
Posts: 2,995
|
|
Mar 12, 2012 11:28:21 GMT
|
|
The other option if you are faced with a gap is to clamp a piece of copper (or other non-ferrous metal) behind the hole, so you can arc to it, but it wont get welded on there. That way you can build up the pool on something, but you don't end up with excess metal on the back of the panel.
|
| |
|
|
|
|
