Okay. Would you recommend pushing or pulling when do the tacks?
- Thread starter Tobymizzi
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I would doubt that your patch is really welded and it would be interesting to see if it would stand a hammering.
The only surface on car bodywork that you can successfully & reliably weld is nice bright shiny steel.
I love the polycarbide wheels as they are great for stripping paint and light rust but don’t remove metal.
I find that wire wheels can burnish rust and make it look like good metal.
A high flashpoint solvent such as Acetone is just the job as it’s cheap, freely available and leaves no traces but do make sure that is stored clear of your work area.
There are good YouTube channels and there are some really awful ones that spread misinformation. I learnt some good lessons from: https://m.youtube.com/@fitzeesfabrications
Look at Fitzy’s butt welds and see how his differ to yours. You will see that there is less random molten weld on the surface and the underside of his weld site looks very similar to the face side.
Fitzy demonstrates how to control heat at the weld site to reduce metal shrinking & distortion.
You may find that the disposable CO2 canisters will limit your work time and probably become expensive. I use a 10Ltr refillable cylinder 5% mix which I pay about £54 per refilled cylinder.
If you pursue welding as a hobby, you’ll find that as you learn your tool kit will increase in size to meet with the challenges surface preparation and manufacturing repair sections or panels.
The distorted metal that you found should be dressed back into shape before and after welding. A good set of panel beating hammers & dolly’s are a great addition to your tool kit and opens up another facet of car body repairs.
It’s well worth getting a good understanding of shrinking & shrinking metal.
It’s a steep learning curve but very satisfying once you are able to see a problem with your weld and understand what the cause is then how to overcome it.
Morrisman
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I generally pull, as I'm right handed and can see the placement a bit easier doing rows of tacks, just watch the red glow fade before you do the next one, to save too much heat buildup. Normal welding I push though.
charlysays
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What's the big issue with over-plating? Just curious because most cars are spot welded together with overlapped seams which isn't much different in terms of creating rust traps. If the seams are clean and well sealed or even regularly rust proofed with cavity waxes then they last decades.
I've seen some nasty rust sandwiches where people plated over rusty metal or even rusty seams and didn't make any effort to seal it. However I have cars which I over-plated 10+ years ago which are in daily use and there's been no rust issues because I kept the overlap to a minimum (5mm or so), made sure both surfaces were clean and coated with weld through primer then painted and sealed the area afterwards.
I can see why you'd want to butt weld everything with a show car or high end restoration but over-plating can last as long as the rest of the car, results in a strong repair and is a damn sight quicker and easier.
Agreed, especially if the "plate" is underneath the original metal, and you are then welding 0.8mm or thinner bodywork onto a 1.0mm or thicker patch.
qwakers
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you are sandwiching rusty metal against uncoated new steel. this will not retard the rust, in fact it will accelerate it. you MUST cut all rusty metal out. most often this is not done.
this sill was done 6 months before this picture was taken by wire wheeling the paint off and plating over the top. 6 months. i don't have a picture of the other side but the rust spread very quickly to the new panel and it fester away unseen. the car was very very rusty in the areas it was over plated, but the other usual rot areas on the car where no worse than expected.
overplating makes it rust faster. end of.
i gave that sill a light kick and it just crumbled.
Popcorn
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Thin metal technique here:
Mig Welding Technique for Thin Metal
Techniques and a video showing how to weld thin metal using a stitching technique.
www.mig-welding.co.uk
Ok so I did a little more today after an hour playing around with the settings practising doing lots of tacks one after the other.
In practise it was going pretty well although not a lot of penetration in any scenario.
I butt welded another patch on the car and was actually pretty happy with it and it definitely looks a lot better than the previous bit!!!
Still not a huge amount of penetration even though I blew a few holes.
I don't know what I need to do to get the penetration. I stripped all the contaminants away, wire brushed and cleaned with acetone.
How can I get more consistent penetration without too many holes?
In practise it was going pretty well although not a lot of penetration in any scenario.
I butt welded another patch on the car and was actually pretty happy with it and it definitely looks a lot better than the previous bit!!!
Still not a huge amount of penetration even though I blew a few holes.
I don't know what I need to do to get the penetration. I stripped all the contaminants away, wire brushed and cleaned with acetone.
How can I get more consistent penetration without too many holes?
practice .... thats all there is to it.
remember welders do a three or four year apprenticeship , dont expect to be an expert in a week ,,,
You're absolutely right. It's something I want to improve upon and get good at!!
Ive been saying exactly that ////
for over forty years now ... but I am getting the hang of it now .
You can hear when your welder settings are right; it’s said to be like sizzling bacon…..mmmmm bacon.
You’ll get there eventually, just enjoy the ride.
Sounds like I need more practice at cooking bacon then as well!!!!You can hear when your welder settings are right; it’s said to be like sizzling bacon…..mmmmm bacon.
You’ll get there eventually, just enjoy the ride.
Shedendman
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Thats down to cost,repairs are cheap,restorations are a bigger bill
One day you’ll hear it and remember this conversation.
charlysays
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I never advocated plating over rust, nor wire wheeling as an adequate form of prep.
The issue with the car in your pic is clearly poor prep, inadequate painting, sealing and rust proofing rather than the singular act of overlapping steel otherwise we would dismantling sound cars and butt welding them back together for fear of a spot welded seam rusting out 30 years in the future or somehow butt welding entire new rear quarters on for example.
If the OP doesn't weld plates over rust then all he needs to do is paint/ seal/ rust proof it properly and it'll likely outlast the rest of the car (seeing as most cars have loads of unsealed or partially sealed seams and still last decades).
Which leads on to this pic below robbed from the dune buggy thread
Why do you get rust like this mainly on mig weld runs like this Suzuki chassis?
Personally I wouldn't include extra water / condensation traps for the sake of a little fitting even if some find the extra filler that over-plating requires beneficial.
Why do you get rust like this mainly on mig weld runs like this Suzuki chassis?
Personally I wouldn't include extra water / condensation traps for the sake of a little fitting even if some find the extra filler that over-plating requires beneficial.
Dozzer
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as someone who has welded things that should not have been welded with all the structural integrity of a doyley.
Power is your friend,
most welders will start at around 20-30 amps, if you are doing a nice long run on clean 0.8/1mm thats fine.
on old body work that can be as thin as 0.4mm where it has been drawn through the stamping process, you want to to get the melt pool to form as quickly as possible, will normally use around 60-80 amps with 0.8mm wire, and a copper backer if you can, a bit of old 22mm water piper flattened works OK.
When you get used to it, you can work along a panel quite quickly, you get a nice rhythm going, you do the next spot weld while there is still a tiny bit of heat left in the last weld. and when you weld, try and put the arc more onto the new material, around 60/40
as others have said, practise is your friend.
