Rust Repair tips n tricks

[tortron]

Very easy, I just walked in and got it every time. Ordered a 1.2mm sheet once but it was there within the week

[Bling]

I always used sheet that was treated in some form (zinc) as my repairs took months / years. Was mostly new gas fire panels because free. Could sit around in the garage and not deteriorate, unlike my untreated stuff. Can't go too far wrong really, just stay away from galv stuff and remove coatings where you are welding.  

[RXFORD]

I use electro-galv (E.G) at the shop. Its not actually that galv shit like garden sheds are, its just the grey coated stuff. Has a loooong shelf life in Auckland humidity. Ocassionally I'l use raw cold rolled as its its a bit nicer to work with when shaping and its easier on the file, but for what you are doing e.g will be fine. Just match the thickness as best you can. If it measures 0.9, use 1mm. The stamping process of panels can thin it out a little as it gets stretched. 

U-pol Weld-2 copper weld through primer is the nicest stuff I've found to use for flanges/overlaps over the years and one of the few that can tig through without it turning to shit. Can get it from Linkup Paints.

Unless I'm closing off a boxed area, I just d.a repairs to dress it up, prepsol it, then brush on some Epiphos until the job goes off to the blasters or the paint shop takes it and preps for epoxy themselves.

Once I know that area is 100% repaired I'l drench seams in Brunox, either with a spraycan if its accessable or mix it 4:1 with thinners and spray it through the Air-boy gun to get it up pillars/sills/rails etc. Just drench it til it dribbles out over the floor, then ya know its coated plenty until cavity wax time. 

Resene Durepox is my current Epoxy of choice. Its expensive, but is one of the few thats not porous over time. Used to use Protec Epotec alot. No complaints with it.

Sikaflex MS Bond has been a good seam sealer. But best to check with whoever is going to paint it as they may have a preffered sealer.

Linkup Paints sell HB Body 900 cavity wax which does the trick. It comes clear or brown and comes in a can or a cartridge for a Shutz gun.

Only cavity wax once job is 100% painted and buffed otherwise it makes life a pain in the ass.

[RXFORD]

Shit that was a bit of a yarn.

[Dudley]

The aes 2 part epoxy seam sealer is the most amazing seam sealer I’ve used

[sr2]

On 08/09/2022 at 15:20, moparmuppet said:

Is cold rolled steel easy to get hold of?  I have only ever used zintec but it hasn't been a hassle and the offcuts aren't rusty years later.

After decades of body and chassis repairs I'm still a huge Zintec fan. Untreated steel begins to rust the second it's exposed to the atmosphere and has to be ground/linished before you weld it where as Zintec is great to weld.

Re repair panel gauge (i.e. thickness), with anything structural avoid using steel that is thicker than the steel you're replacing. The added rigidity of thicker material will only put more loading on both the welds and the surrounding original metal increasing the likelihood of stress fractures.

[Metalhead96]

With doing small patches, is using steel off another car fine to do? 

Obviously people having been doing rust cuts for yonks would using a more modern vehicle steel be okay on older vehicles? Assuming the thickness is the same that is

[Muncie]

Always found doing big patches easier than trying to do spot repairs and Always blended in better, can be daunting chopping big parts off the car rewarding as though when a big part goes back on.

Try to round your edges where possible you'll end up with more manageable distortion, as in mark your square hole saw out your corners then chop it out with a grinder if your dealing with flat panels.

Dont try hit the whole car at once do the easy bits first then the hard bits won't be as hard by time you get to them. 

Do a side or area finish it before moving on to anything else or you'll end up with with a shell full of half done repairs.

 

[87creepin]

Best/cheapest place to get cold rolled sheet steel? 

[kws]

On 10/09/2022 at 18:32, Muncie said:

Always found doing big patches easier than trying to do spot repairs and Always blended in better, can be daunting chopping big parts off the car rewarding as though when a big part goes back on.

This was one of the biggest things that I changed quickly when welding the Marina. I started doing the smallest areas i could, using multiple small patches. In the end i just cut the whole floor pan out and welded a new one in using only a couple of large patches. It makes for a far cleaner repair and easier to do in the long term.

[VintageSpecial]

On 08/09/2022 at 10:18, JustHarry said:

Edit: buy some keyphos and just keyphos the bare metal till your ready to epoxy all your repairs at the same time and start the paint process . But this also needs to be stripped fully as it's not ideal to paint over 

I used something called Kephos a long time ago. Note the difference in spelling. It was clear and pungent smelling and it was the best stuff I have found to keep bare metal from rusting. Was recommended by a panel beaters to rub onto bare steel until you were ready to paint and it worked very well.

Last time I tried to get some some years later I found it had been renamed to PAINT GRIP 253. And it was really hard to actually find somewhere to buy it from as they only sold huge quantities. This is that stuff: http://www.solvents.net.au/index_htm_files/PAINTGRIP 253 (212997).pdf

Searching though you find other things called Keyphos (although confusingly that is now called Fosgard-109) which looks more like a paint you spray onto things? https://sandwell-uk.com/coatings/fosgard-109-lightweight-coating/

Is that the stuff you mean above?

I have also recently started using cold rolled steel instead of Zintech and found it much easier and nicer to work with and hammer and much better to weld too as long as you really clean it first. I do have a lot of problem with bare steel surfaces rusting in my shed though which is annoying.

Simon

Edited September 11, 2022 by VintageSpecial
Spelling

[JustHarry]

55 minutes ago, VintageSpecial said:

I used something called Kephos a long time ago. Note the difference in spelling. It was clear and pungent smelling and it was the best stuff I have found to keep bare metal from rusting. Was recommended by a panel beaters to rub onto bare steel until you were ready to paint and it worked very well.

 

Yeah kephos is just a general name for the same product. /autocorrect called it keyphos

 

The stuff I buy for work is actually called bonderite 

Rajohnson sell it by 4 litre containers 

[Jusepy82]

Sorry for interrupting thread but how do you guys practice your welds and learn the welder.  Been welding in patches but not that satisfied with end result.

[Jusepy82]

Sorry , I have a cigweld weldskill 185 and I'm using co2 gas. I'm welding panel steel.

[Bling]

100mm or so squares of panel steel for practise. The panel will heat up, so have a few you can cycle through to get the most accurate results. Then i'd just set the welder and hit the panel. So a few "spot welds" and see what the result is. Post them if you like, i'm sure plenty on here with more experience than me. But you can tell a lot from a weld as to what you may need to fine tune.

I have a BOC welder which has a few settings on it, so I can't give you the settings for yours. But I find it pretty forgiving. For example, I was welding some 4mm plate to a 10mm section the other day for an exhaust bracket. Then this last week I plug welded some just shy of 1mm body panels without even changing the welder settings. A lot comes down to how long you pull the trigger for, distance from work etc.

This is with CO2, it's all i've ever used at home, no problems.

[Jusepy82]

Thanks guys. I will stop welding the eskie and start practicing again on some practice steel as u suggest.

I have set the welder to what the information sheet in the welder suggested but thought it was too hot as it was blowing holes.

I have put several patches in but it's when I go to blend or grind my welds down , I get pinholes and cant take the welds back far enough for them too look neat and tidy. I think I'm welding too cold because I'm scared of blowing holes .

Also do you guys use flap discs or backing plates on your grinder with sandpaper discs on it. Thanks in advance.

[Bling]

Post some photos up of practice welds done on bench, or even the patches you have done. 

Here is some I did in my boot, laying upside down. Welder settings are relatively high, for the material thickness, but I do short welds just long enough to fill the 5mm holes I had punch in the bottom sheet. Gave good penetration which showed on the topside with a bit of metal protruding top side too on the plugs. Example included in spoiler.

 

[Bling]

Flap discs for me, and it's only if it's going to be seen really. A lot of my repairs aren't seen so I leave them as they were when welded.

Checked your project fred, yeah looking a bit cold. What I do for patches like that, is do a few decent tacks to hold it in place. Then I weld right next to the tack, aiming the torch at the gap right against the tack already there if that makes sense. What it means is the wire won't go through the gap accidently as it hits the tack that's already there. I'll try get the welder out this week and do some photos of what I mean as it might not make sense. 

[Bling]

So, not a pro welder etc, just showing how i'd do it. On a small patch i'd potentially even have a little break between each set of 4 tacks, to avoid heat build up in the panel. Heat build up will change how it welds, too much heat and apart from the panel potentially warping, the chance of blowing through will increase. So maybe 1,2,3,4, break, 5,6,7,8, break. The smaller you can make the gap between the car and the panel the better too, less chance of blowing through, having the wire go through the gap or even melting the edge away from the panel. If you can have them a tight fit, that will make it easier to weld.

[Jusepy82]

Ok thanks bling !

I do get what you mean but some pics would be grand !

It's mainly the welder setting I think I'm struggling with. I've only had the welder about 4 months using it on and off.