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Welding

Posted: Sat Jul 22, 2017 2:44 pm
by Shederic
Hi Gang,
Bought myself a rusty 2.8i bare shell to save. Going to experiment with Soda blasting when I buy some kit and I will take loads of pics of the results.
I want to first have a go at the inner wings and suspension turrets as its the easiest to get to where the cars dumped!

Two questions for you;
1) Any ideas on what metal thickness I should use for tops of inner wings
2) what everyones thoughts on Zintec steel?

Thanks everyone

Re: Welding

Posted: Sun Jul 23, 2017 9:51 am
by brooky
Not sure about thickness you need but i have used zintec before and it welded easily and is then well protected against future rusting so i am a fan of it

Re: Welding

Posted: Sun Jul 23, 2017 3:55 pm
by Paul G
I believe the metal on a capri is 1.1mm thick.

The zintec does help with rust prevention and i've been using it myself on my Laser but I would advise that you grind the edges to be welded down to the base steel. Make sure you use a mask both when grinding and welding with it as the zintec coating gives off noxious fumes.

Re: Welding

Posted: Mon Jul 24, 2017 1:52 pm
by Shederic
Paul G wrote:I believe the metal on a capri is 1.1mm thick.

The zintec does help with rust prevention and i've been using it myself on my Laser but I would advise that you grind the edges to be welded down to the base steel. Make sure you use a mask both when grinding and welding with it as the zintec coating gives off noxious fumes.

This will sound dumb :sorry: but is the thickness of the metal the same throughout the structure of the car (sills, floors, inner wings etc)?

Varying points of view on the net about whether to grind down or let it burn off as the weld forms but I agree that fumes are not to be ignored and masks etc. vital

Thanks for your reply

Re: Welding

Posted: Mon Jul 24, 2017 3:30 pm
by Paul G
I believe the chassis rails are 1.5mm and certainly at the rear where the springs attach they are double skinned as well. I think all the rest was 1.1mm.

As far a welding with zinc coated steel I found that my welder welded much better with the zinc coating ground off and of course it reduces the noxious smoke and gasses given off. I still coated the back of eack repair patch with weld through primer to try to help with rust prevention.

Re: Welding

Posted: Wed Aug 09, 2017 3:58 am
by mjcapri
If you need to check how thick the metal is measure it using a vernier or micrometer. You'll probably need to cut a piece out (not a rusty bit!) and clean the paint off but it's a good way to confirm for sure. Zintec is fine, personally I'd clean the edges off for MIG welding but it will weld through. You already know about the fumes etc. but just take precautions.

Re: Welding

Posted: Wed Aug 09, 2017 7:54 am
by pbar
I have been wondering what is common practice to do with the reverse side of welded metal/patches. Do most people just give it a spray with Zinc 182 or similar?

Re: Welding

Posted: Wed Aug 09, 2017 8:13 am
by Paul G
That is good practise to help stop the grot coming back. I use the zinc rich weld through primer and spray a bit inside the area which the plate will be covering too. The more the merrier I say and if you can get some waxoyl or similar in behind a plate even better.

I swear by zinc 182 over small patches of rust, it really does hold it back.

Re: Welding

Posted: Wed Aug 09, 2017 8:59 am
by mjcapri
pbar wrote:I have been wondering what is common practice to do with the reverse side of welded metal/patches. Do most people just give it a spray with Zinc 182 or similar?
If it's accessible I wipe it down with a rust killer/converter (welded metal will flash rust very quickly) and paint with zinc primer. Once that's cured I then top coat it with something non-porous; you can use a topcoat or just waxoyl depending on location.

Re: Welding

Posted: Wed Aug 09, 2017 9:15 am
by pbar
Excellent, thanks for the advice. Obviously when welding in a patch there needs to be a small gap all around for the weld, what do you usually aim for? Like less than a millimeter kind of thing. Which is then spotted all over (to prevent warping) until all gaps are gone and then ground flush. Is that pretty much the procedure?

Re: Welding

Posted: Wed Aug 09, 2017 4:32 pm
by mjcapri
I usually keep the gap just less than the diameter of the wire I'm using for the simple reason that it stops it going straight through!

Re: Welding

Posted: Wed Aug 09, 2017 8:23 pm
by Dreamachine
What the best type of welder to use. ..mig or arc

Re: Welding

Posted: Wed Aug 09, 2017 8:24 pm
by Paul G
On a car a mig is. Too easy to burn through with arc, it's better for welding thick material.

Re: Welding

Posted: Thu Aug 10, 2017 2:08 am
by Dreamachine
Ok thanks :cool:

Re: Welding

Posted: Thu Aug 10, 2017 2:09 am
by Dreamachine
Ok thanks :cool:

Re: Welding

Posted: Thu Aug 10, 2017 6:14 am
by pbar
mjcapri wrote:I usually keep the gap just less than the diameter of the wire I'm using for the simple reason that it stops it going straight through!
Great, that makes sense! Thanks.

Re: Welding

Posted: Thu Aug 10, 2017 6:15 am
by pbar
Dreamachine wrote:What the best type of welder to use. ..mig or arc
As Paul said, Mig. You have most likely already seen, but these Clarke ones get great reviews and work from a standard mains plug -

https://www.machinemart.co.uk/p/010110125/

Re: Welding

Posted: Thu Aug 10, 2017 7:43 am
by mjcapri
Dreamachine wrote:What the best type of welder to use. ..mig or arc
MIG with gas, not gasless.

Re: Welding

Posted: Thu Aug 10, 2017 7:48 am
by mjcapri
For bodywork you're better off with:

https://www.machinemart.co.uk/p/pro-90-mig-welder/

It goes down to 25amps which is very low for a £200ish machine. OK it's a bit lacking at the top end but you can't have it all unless you pay! You can easily fit a cooling fan too. ;)

Re: Welding

Posted: Thu Aug 10, 2017 8:55 am
by pbar
Thanks :) What is the advantage with that one over the Clarke?