02GF74
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 posted on 12/12/06 at 09:50 AM |
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poor welding...
my stays - 4 mm thick, 20 mm steel.
To strenghtnen them, I doubled up the metal at the lower part, drilled 6.5 mm hole, countersunk, then weled to the other piece (plug welding I think
it is called).
I noticed that the other sdie of the metal did not change colour (showing little heat) and when I bumped into one stay, two fo the welds pinged
apart
Examintaion shoed that harldy any of the lower metal was wsleded so mainly the hole was filled up in the top piece.
My welder is clarke, and is rated at 4 mm max so I presume therein lies my problem. (I am welding 8 mm thickness in total).
Any tips on how to improve this?
For exapling, dirrling the hole all the way trough and then filling up?
I won't be redoing them but will weld up along the edges of the second piece where it lies on top of the first piece.
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Bluemoon
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| posted on 12/12/06 at 09:58 AM |
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Pre-heat the metal, with a blowtorch?
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Wadders
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| posted on 12/12/06 at 10:04 AM |
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You would be better chamfering the edges of both pieces and laying a butt weld along them.
plug welding is hard with a lack of power.
Even better would be to braze them, it withstands the vibes better than weld.
[Edited on 12/12/06 by Wadders]
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oliwb
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| posted on 12/12/06 at 10:04 AM |
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I'd drill right through like you suggest....failing that find someone with a bigger welder (Stick perhaps??) Oli.
If your not living life on the edge you're taking up too much room!
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pewe
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| posted on 12/12/06 at 10:19 AM |
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Suggest, if you haven't already done so, that you check the neg and pos leads coming off the welder as these can fray and reduce power. Also
mine improved 100% by using a meaty power lead from the wall socket (actually came from an industrial vacuum cleaner) - there must have been
significant voltage drop using a thinner lead. Cheers, Pewe 
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NS Dev
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| posted on 12/12/06 at 11:21 AM |
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Also bear in mind that the Clarke claims are well OTT as well.
My 150TE mig was supposed to be good for 6mm if my memory serves me right, I wouldn't use it on anything over 4mm, was at its limit on that.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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macnab
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 posted on 12/12/06 at 11:53 AM |
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Chamfer deep welds and build up on multiple passes. I welded a hydraulic JBC digger back cylinder coupling which was approx 2 1/2 inches in diameter
with a standard car mig welder simply by having a huge chamfer and going round and round and round till I'd built it all up (used a whole real
of wire). The weld has lasted 3 years of abuse and still going strong. The reason your weld failed is that it has cooled down to quickly due to all
the cold metal around it and this has made it brittle, so preheat the job first. I make a habit of cleaning first with a blowtorch and wire brush
before hand, which takes the chill out the metal. You’ll always notice on non preheated jobs that small tackwelds are brittle and that a weld onto
cold metal improves as you work along due to the surrounding metal heating up. So get yourself a good blowtorch…
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02GF74
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| posted on 12/12/06 at 12:10 PM |
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I'll try heating it (may even get the IR thermometer out to see how hot it gets ut doubt it will be much more than 200 C)
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macnab
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| posted on 12/12/06 at 02:32 PM |
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oh yeah reading exactly what your doing it sounds like the hole is to small, the arc from the welder is jumping onto the walls of the hole rather than
striking the metal at the back. Try a 10mm,or larger hole and keep the wire in the centre till that areas molten then move out in a spiral till the
pools flush with the top. Obviously it’s a tad tricky to do that on a small hole so make life easy on yourself.
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zetec7
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| posted on 12/12/06 at 04:20 PM |
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My Clarke 130EN welds beautifully, even on 8mm steel, with great penetration...the trick seems to be to turn down the wire speed a little, and weld
slowly, letting the heat get deep down into the work. I welded some hard 3/8" plate steel this way, and the back side of the plate was purple
once cooled...LOTS of penetration. I went slow, and used a pattern of small, overlapping circles. Ended up looking like a rather smart TIG weld!
If you weld too fast (particularly with lower-power welders), you don't get much penetration, IMHO. Hope this helps...
http://www.freewebs.com/zetec7/
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02GF74
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| posted on 12/12/06 at 04:32 PM |
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re: zetec7hmmm, interesting; I have my wire wound up almost to max; I reckon if I slow it down, all that will happen is that is will melt itself
inside the copper nozzle.:
(amp setting is on max BTW)
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Mark Allanson
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| posted on 12/12/06 at 05:58 PM |
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quote:
Originally posted by 02GF74
re: zetec7hmmm, interesting; I have my wire wound up almost to max; I reckon if I slow it down, all that will happen is that is will melt itself
inside the copper nozzle.:
(amp setting is on max BTW)
zetec7 is right to a certain extent, you can reduce the wire speed a little, but best to set it to the ideal speed and practice the technique (the
welder should sound like frying bacon!). With the plug weld, the two pieces must be sparkling clean (you only get about a second to produce a good
weld at the base so make it good). Wind the power right up, start in the centre, keep close to the work and spiral out to the edge of the uppermost
piece, let the weld pool just lap the edge, and with practice you should be ablt to produce plugs which are just proud of the parent surface.
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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RichardK
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| posted on 12/12/06 at 07:12 PM |
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My welding has improved so much since I replaced the rubbish earth sprung clip with pair of cheap mole grips with an M8 bolt welded to it and the
earth cable bolted onto that.
Really has made a difference.
Regards
Rich
Gallery updated 11/01/2011
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