Welding

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Dave Plowman (News)

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Apr 21, 2011, 2:12:26 PM4/21/11
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Since I'm pretty hopeless at MIG welding thin steel - car stuff - I
wondered if a spot welder (from one side) would be easier, since it would
do quite a bit of the stuff I need.

So, am I right in saying it needs to be AC rather than DC? And that they
are usually quite low current?

If so, would the el cheapo one that Lidl are offering this Monday do -
with a spot weld fitting from Ebay? I realise the length of time matters
as well as current, but I'm sure I could knock up a timer.

--
*Men are from Earth, women are from Earth. Deal with it.

Dave Plowman da...@davenoise.co.uk London SW
To e-mail, change noise into sound.

Adrian

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Apr 21, 2011, 2:16:37 PM4/21/11
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"Dave Plowman (News)" <da...@davenoise.co.uk> gurgled happily, sounding
much like they were saying:

> If so, would the el cheapo one that Lidl are offering this Monday do -
> with a spot weld fitting from Ebay?

This is an arc + spot-weld-bolt-on?

Don't waste your money. We tried that on one of the 2cvs a year or two
ago, with the bolt-on that Frost (reputable, compared to fleaBay) sell.
The guy doing the welding was a professional welder. He couldn't get it
to do anything useful.

Dave Plowman (News)

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Apr 21, 2011, 2:22:12 PM4/21/11
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In article <91bak4...@mid.individual.net>,

Adrian <tooma...@gmail.com> wrote:
> "Dave Plowman (News)" <da...@davenoise.co.uk> gurgled happily, sounding
> much like they were saying:

> > If so, would the el cheapo one that Lidl are offering this Monday do -
> > with a spot weld fitting from Ebay?

> This is an arc + spot-weld-bolt-on?

Yes - the welder is a 40-80 amp one. The spot welder thingie uses carbon
rods.

> Don't waste your money. We tried that on one of the 2cvs a year or two
> ago, with the bolt-on that Frost (reputable, compared to fleaBay) sell.
> The guy doing the welding was a professional welder. He couldn't get it
> to do anything useful.

In what way? Not enough power or too much? In theory, it should be a
simple task with less skill needed.

--
*Shin: a device for finding furniture in the dark *

Adrian

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Apr 21, 2011, 4:55:01 PM4/21/11
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"Dave Plowman (News)" <da...@davenoise.co.uk> gurgled happily, sounding
much like they were saying:

>> Don't waste your money. We tried that on one of the 2cvs a year or two


>> ago, with the bolt-on that Frost (reputable, compared to fleaBay) sell.
>> The guy doing the welding was a professional welder. He couldn't get it
>> to do anything useful.

> In what way? Not enough power or too much? In theory, it should be a
> simple task with less skill needed.

<shrug> I can't weld, so - with the aid of a bit of temporal distance -
all I can reliably say is that it wouldn't stick two bits of metal
together in any kind of reliable way. So we went back to drill & mig.
This was on shiny-new-panel to shiny-new-panel, too.

TMC

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Apr 21, 2011, 5:32:40 PM4/21/11
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"Adrian" <tooma...@gmail.com> wrote in message
news:91bjsr...@mid.individual.net...

x2

I am not a welder either but am OK with arc and need more practice with my
mig

The best welder I know and have I known several top ones says the arc to
spot kits are a waste of time.
Something to do with the cleanliness of the surfaces and the need for
pressure at the site of the weld

Drill and mig only way to go unless you can braze with gas

Regards

Andy Dingley

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Apr 21, 2011, 6:20:04 PM4/21/11
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On Apr 21, 7:12 pm, "Dave Plowman (News)" <d...@davenoise.co.uk>
wrote:

> If so, would the el cheapo one that Lidl are offering this Monday do -
> with a spot weld fitting from Ebay?

They'll act as a power source for a DIY spot welder big enough to weld
sheetmetal. However a spotwelder also needs mechanical clamping -
usually with a footpedal and lever arrangement. You can make this
yourself if it's bench-mounted, but not for a take-it-to-the-car model
(you'd be better buying one from Machine Mart).

The hand-pressure spot weld kits are useless, because they don't apply
any clamping pressure.

To be honest, spot welding isn't much use for repair and it's sod-all
use for restoration. It's a great weay to build a car on an assembly
line, when the various bits arrive in the right sequence and you just
have to assemble them, while there's access, with a simple weld as-
designed. For repair, then if you're lucky it'll fit a new wing more
easily than anything else, but otherwise forget it.

If you can't MIG, then get yourself some decent gas (not CO2), get a
decent automatic helmet, ideally a decent welder (not SIP) and then a
wheelbarrow full of scrap to practice on. Learn the theory (5 minutes,
essential), then practice with the dials turned right up, on 3mm
steel. Then practice again, on 20 & 22 gauge.

Dave Plowman (News)

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Apr 21, 2011, 6:36:57 PM4/21/11
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In article
<9bc4c745-0748-4da4...@d12g2000vbz.googlegroups.com>,

Andy Dingley <din...@codesmiths.com> wrote:
> ideally a decent welder (not SIP)

Heh heh - I bought mine as a Practical Classics best buy. I've modified
the drive to PWM control - so at least that speed stays as set now even on
very slow. What else is wrong with them?

--
*I didn't fight my way to the top of the food chain to be a vegetarian.

Dave Plowman (News)

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Apr 21, 2011, 6:33:34 PM4/21/11
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All interesting stuff so it looks like a no-no.

How do pro body shops do spot welds with access to one side only?

--
*If a pig loses its voice, is it disgruntled? *

Andy Dingley

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Apr 21, 2011, 6:56:00 PM4/21/11
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On Apr 21, 11:33 pm, "Dave Plowman (News)" <d...@davenoise.co.uk>
wrote:

> How do pro body shops do spot welds with access to one side only?

They don't - they do plug welds instead.

Andy Dingley

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Apr 21, 2011, 6:57:56 PM4/21/11
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On Apr 21, 11:36 pm, "Dave Plowman (News)" <d...@davenoise.co.uk>
wrote:

> > ideally a decent welder (not SIP)

> What else is wrong with them?

Everything that could be cheap and nasty _is_ cheap and nasty.

The mechanical design of the wirefeed, doesn't.


If you can remember how to open the wire door of your welder without
looking, something is wrong.
If you habitually weld with the wire door off, for easy access, then
you're using a SIP.

Mark

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Apr 21, 2011, 7:01:51 PM4/21/11
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Dave Plowman (News) wrote:

> In article
> <9bc4c745-0748-4da4...@d12g2000vbz.googlegroups.com>,
> Andy Dingley <din...@codesmiths.com> wrote:
>> ideally a decent welder (not SIP)
>
> Heh heh - I bought mine as a Practical Classics best buy. I've modified
> the drive to PWM control - so at least that speed stays as set now even on
> very slow. What else is wrong with them?
>

Think of it as the difference between a Silverline and a Makita jigsaw
you can cut a straight line with a silverline jigsaw but.......


-

tony sayer

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Apr 22, 2011, 3:58:48 AM4/22/11
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In article <fb40ab10-1108-4662...@l6g2000vbn.googlegroups
.com>, Andy Dingley <din...@codesmiths.com> scribeth thus


As someone who's only used Arc can you recommend a MIG/TIG whatever?
welder for say around 1 mm sheet type steel welding and if that machine
could also do Aluminium that would be very useful;))..

Cheers....
--
Tony Sayer

Tabby

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Apr 22, 2011, 4:19:41 AM4/22/11
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On Apr 21, 7:12 pm, "Dave Plowman (News)" <d...@davenoise.co.uk>
wrote:

> Since I'm pretty hopeless at MIG welding thin steel - car stuff - I


> wondered if a spot welder (from one side) would be easier, since it would
> do quite a bit of the stuff I need.
>
> So, am I right in saying it needs to be AC rather than DC? And that they
> are usually quite low current?
>
> If so, would the el cheapo one that Lidl are offering this Monday do -
> with a spot weld fitting from Ebay? I realise the length of time matters
> as well as current, but I'm sure I could knock up a timer.

Spot welders use far more current than mig/arc/etc, and there's no way
you can spot weld from one side only. And of course the metal junction
must be clean. I don't see how you could use one to repair cars.


NT

Andy Dingley

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Apr 22, 2011, 4:21:20 AM4/22/11
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On Apr 22, 8:58 am, tony sayer <t...@bancom.co.uk> wrote:

> As someone who's only used Arc can you recommend a MIG/TIG whatever?

Haven't looked for a couple opf years, and given the way copper prices
have gone, that's a long time.

Murex are about the best UK machines, but not cheap now unless you're
either serious or buying S/H. Second to that, Cebora used to be the
best at a lower price.

> welder for say around 1 mm sheet type steel welding and if that machine
> could also do Aluminium that would be very useful;))..

Any of them (that are robust and reliable) will do steel of that
thickness, or up to 3mm, without any trouble. 6mm and upwards starts
to be more of a test for small machines.

For aluminium, you probably want to (eventually) use a "spool on gun"
torch, so that it's not feeding the tricky aluminium wire up the hose.
You don't need to buy this today, but make sure you get a machine with
a Euro socket removable hose. Spool guns can also be expensive, as you
usually have to buy them new - they're rare S/H.

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