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Welding, bugeye parts

To: british-cars@autox.team.net
Subject: Welding, bugeye parts
From: "W. Ray Gibbons" <gibbons@northpole.med.uvm.edu>
Date: Tue, 23 Nov 1993 11:18:45 -0500 (EST)
Alex Levinson wrote regarding welding and parts for his bugeye.

On welding:  Are those who say MIG welding is easy being disingenuous? 
Maybe a little.  It is easy in comparison with other ways of welding I've
tried, but not as easy as drawing a line with a magic marker, as one
restoration text said.  I agree, it is easy to burn through when butt
welding 20 gauge sheet metal.  If you teach yourself MIG welding by trial
and error, there will be a lot of errors.  If somebody who knows how
stands beside you and tells you how to do it, it will get easier.  I have
sold a couple of welders (at no personal profit) to friends by proving
they can weld a good bead the first time if I set up and show them how to
do it.  I suspect A.L. used the same trial and error, weld, grind, weld
again method that I did. 

Jump on now, if you are sick and tired of hints from an amateur welder.

Hints:

Metal must be CLEAN.  MIG does not work well on rusty or painted metal.

The two pieces to be joined should be in contact, to equalize heating. 
The books say to leave a slight gap.  That's ok with 1/8 in steel, but it
only causes problems (IMHO) when welding sheet metal.

Butt welding light sheet metal is challenging, I agree.  To minimize burn
through, have the best contact of the edges possible and--this is
important--weld in short bursts so the puddle gels between trigger pulls. 
High buck welders have a stitch mode that does this automatically, those
affordable by hobbiests will do the same thing if you just keep pulling
the trigger.  If you try to butt weld a continuous seam on 20 ga without
letting the puddle cool, the heat keeps increasing.  You either have to be
skillful enough to adjust arc length and travel speed (hard) or keep
pausing (easier) to avoid burn through.  You will want to do this for
other reasons, too.  If you try a continuous weld, or even stitch welding
without cooling periods, the panel will heat up and may warp.  Not much
problem on floor pans.  On exterior panels that must not warp, weld 1/2
inch here, 1/2 inch far away, 1/2 inch in the middle, etc, with air or
damp rag cooling between welds, until all those 1/2 inch segments are a
continuous weld. 

When you can, use a flanger (brit. Joddler) to make an offset on one
panel, lay other panel on top, and avoid the hassles of butt welding. 
That gets MUCH easier.  Other hints above still apply.

Heat and wire feed are only the most obvious adjustments.  If the torch
moves closer to the work, the heat increases.  Ditto if the travel speed
decreases.  Strive to keep these constant, or change them only
deliberately. 

If welding dissimilar thicknesses (e.g. floor pans to inner rocker), point
the torch toward the thicker piece as necessary to heat both evenly, or
zig-zag torch across the join dwelling on the thicker piece.  (If you do
not have intimate contact between the parts, it will be exquisitely
difficult to weld parts that are substantially different in thickness.) In
general, think about heating of two pieces--for example, when welding a
small patch into a panel, the patch will heat fast and the panel more
slowly.  Adjust torch angle and movement to compensate. 

Big, huge, most important hint of all.  You can't do a good job of welding
when you can't see what you're doing.  Once in a blue moon you may want
the hand held eye screen that comes with some cheap welders, but you
should also buy a decent hinged helmet.  Then save the glass (intended to
protect 8 hr/day production welders) that comes in it for solar eclipses. 
Replace it with a gold coated glass (not sure of exact term, but welding
store will know).  You can adjust the hinges on the helmet so you can
place the torch, using both hands if necessary, and nod your head to
lower the shield (looks real professional).  Trouble is, your eyes take
a few seconds for the iris to adjust, so you cannot see the beginning
of the arc.  For really critical stuff, I beam a 600 watt bulb on the work so
I can set up through the lens with the faceplate down; it also helps me to
see things.  If you cannot see the edges to be joined as well as you would
like, draw a line along the intended weld with a soapstone marker.

I also wonder at those pictures of guys free-handing a torch.  You see
them waving the torch around, but I bet that's not how they got the welds
that are shown in close-up examples.  I invested in a couple of machinists
magnets and a piece of angle iron.  When possible, I attach the magnets to
the car, lay the angle iron across the magnets, and rest my hand on that. 
One can also rest the edge of the torch on the work at a slight angle, and
the arc is about right.  Or use the sign-painters method with a wooden
stick and a rubber ball (a picture would be worth 1k words). 

Re welders.  I have a Lincoln SP-100.  It is pricier than the imports, but
has continuous adjustment on both the wire feed and heat, a 3 yr warranty,
and parts available at the corner welding store.  Butt welds in 1/8 steel
push this machine, but it can do anything on a Spridget.  It is a good
quality machine.

Parts for Sprites:  I think the A frame trunion (a trunion in British
terms is anything that does not have another better name) kit may be
available from Ron Hopkinson Ltd, which took over Spridgebits.  They
probably advertise in Practical Classics, or I will dig up the number if
you want.  FAXing them is pretty cheap.

I got new windshield glass for 60 bugeye in USA for about $160; I would
not fiddle with used.  It is not worth the considerable effort of
installation.

Ray Gibbons















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