to weld or not to....

Welding Techniques, Theory, Machines and Questions.

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golfpin

to weld or not to....

Post by golfpin »

Not sure if this is the right place to post if not, I apologise and ask the moderators to redirect.... my car is showing signs of rust and all the "officianados" say cut out and weld ... I agree but ....... to me welding in what ever form, is the perfect breeding ground for more rust!! My thinking is cut, and epoxy in a repair patch then continue with the normal filler and paint procedure. Would appreciate any thoughts on this. Obviously the areas are not structural cosmetic only.
Golfpin
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Dave_C
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Location: Springfield. MO.

Re: to weld or not to....

Post by Dave_C »

Golfpin,

How you choose to fix rust on an automobile has to do with both the current value and the preservation value of the car. If the car is not one worth preserving or has no historic value or even sentimental value, then Bondo or epoxy can be a suitable fix. Some of this is even used in the new car manufacturing process to cover spot welds.

Welding, when done properly, is not a source of rust! In fact it is the preferred method of "off frame" auto restoration by those who can do it well. I've seen it done so well that even before paint, it was hard to tell where the original metal joined the patch. That takes some skill and experience (of which I have neither)

I've seen guys who knew what they were doing with the welding process and their cars were awesome!

Dave C.
I learn something new every day! Problem is I forget two.
golfpin

Re: to weld or not to....

Post by golfpin »

Morning all, Thanks for the reply DrDave, must agree with you on all points except perhaps the rust.I agree that welding in a replacement piece of metal is an agreed way to go, however what so often happens that the weld area that is closed by the patch cannot be got to for adequate anti rust/pirmer or any other treatment....hence my perhaps inane query.
However in defense of myself and idea my thinking is that an underlay patch of perhaps correct thickness S/Steel epoxied in on an overlap basis then the outer area finished with filler might have a better chance in the longer term.
I was a certified welder but age arthritis and eye sight!! [71] are taking huge toll. I could still weld in with gas or wire and end up with a reasonable job I just thought this might provoke some of those outstanding brains out there to perhaps add another technique.
I might add that I live in very tiny rural area that is notorius for rust, humidity, proximity to the sea and wind and a largish river, the Kowie hence the term "Kowie Cancer" and the chance of getting a good job done is ZERO. There is no such thing as qualified capable artisans so perhaps truth beknown I am contemplating the repair myself and using the glue method.
All criticisms welcome Thnks Golfpin
redneckalbertan
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Re: to weld or not to....

Post by redneckalbertan »

golfpin wrote:However in defense of myself and idea my thinking is that an underlay patch of perhaps correct thickness S/Steel epoxied in on an overlap basis then the outer area finished with filler might have a better chance in the longer term.
I would not try this. If there is an incomplete seal on either the ss or patch moisture will get between the two pieces and rust out quicker than just the patch without ss backer.
WJH
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Location: Florida

Re: to weld or not to....

Post by WJH »

You cut away the bad metal, and butt weld in new metal. The weld properly done with no porosity leaves no avenue's for moisture to hide and cause rust. Epoxying a patch of metal over bad metal? Like a band aid? Why not slap on some speed tape while your at it.
golfpin

Re: to weld or not to....

Post by golfpin »

Thanks for the input guys, glad I asked.
Golfpin
Magicniner
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Re: to weld or not to....

Post by Magicniner »

golfpin wrote:to me welding in what ever form, is the perfect breeding ground for more rust!!
But only where bare metal is exposed to oxygen and moisture ;-)

For external surfaces use paint, for internal surfaces use a good quality body cavity injection wax, you can use a high solids cold galvanising paint prior to welding, which will only burn off very close to the weld and will not leave residue which will prevent the wax working correctly.
A good quality body cavity injection wax will have a low viscosity to enable it to fill very small spaces by capiliary action, Waxoyl is fine for painting on but not runny enough for closed sections, Roberlo Cavitex with a suitable air/spray application system with a tube for closed sections is ideal.

- Nick
aribert
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Joined: Wed Mar 03, 2010 11:55 am
Location: Metro Detroit

Re: to weld or not to....

Post by aribert »

I'll pile in on this older thread.

If you cut away the rusted metal and your adhesive covers the entire overlap joint and flows around the cut edge of the original metal (to encapsulate the bare edge), your joint should be good for years (mine are going on about 5 or 6 years at this time on my winter car). Automotive structural adhesive is expen$ive at $40 or more for a smaller tube. You will also need the applicator gun since these adhesives are two part. Typically each package of adhesive comes with 2 mixing nozzles. Cure time to green strength varies greatly by product. Some will begin to cure in a matter of a few minutes, other types may take 45 min or more. Green strength is when the material has set up (and you no longer need to hold the part if gravity is not working in your direction) but before the adhesive has reached full strength. This adhesive typically is structural - many brands of semi tractor cabs, Corvette bodies, Some farm tractor cabs, fiberglass boats, auto door skins, etc. are all bonded with this type of adhesive.

I own torches, MIG and a stick welder so I am not anti-welding. Sometimes the welding heat will burn away more of the existing rust protection and for difficult to access, closed cavities, bonding is a better solution.
golfpin

Re: to weld or not to....

Post by golfpin »

Many thanks for your input Aribet glad to see that someone gets my angle of attack, yes one of the major points is the bare cut edge. Unless this is covered rust will start again, My statement stands, in my opinion if you weld it creates the perfect enviroment for rust to start again, any way am too old and riddled with arthritis to even think about tackling a job such as this.
Thnks again Golfpin
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