welding cast aluminium & aluminium

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welding cast aluminium & aluminium

Post  littlewilly on Sun Oct 28, 2012 2:31 pm

So a word of warning first gentlemen, All the talk about welding Lambretta casings being straightforward, especially used one's! - is completely untrue. in-fact I cannot think of a
more suspect welding operation (off-hand) For all these reasons :
!. the casing is the main and only suspension arm, everything either runs off it, or is loaded on it.
2. cast aluminium is very porous and the zones of thermal disturbance which any kind of welding
causes around a weld, can easily make several of the small bubbles inerrant in cast aluminium
form into a large bubble and baring in mind that the whole c/case is a load bearing member,
a weakness like that in the metal is just unacceptable.
on used cases the situation becomes considerably worse, as mentioned before cast aluminium
is very porous and there are thousands of small bubbles in the metal, being porous also means
that the used case's metal has absorbed oil,fuel, water etc.
this makes the metal spits back when you attempt to weld it, also it causes what are called
slag-inclusions and it's impossible to completely remove these absorbed foreign inclusions and
slag inclusions are very very bad strength-wise.
If an insurance company know or were to discover this type of repair, they may decline 2
insure or ask for the repair to be x-rayed before offering you cover.
If they were to discover it after an event, they would not pay-up on any claims made.

5. qualified as a radiographer in this field, I can tell you that a competent, time served,
welder would have about a 1 in 5 chance of passing an x-ray test attempting this work.

Just 4 interest I am also an A.P.I. A.S.M.E & Lloyd's coded Welder my company has,
@-times displayed test pieces of my work around the world, as examples of welding.

An alternative method is to use the a relatively new process in welding which is an
odd cross between brazing, bronze welding and soldering. it is 4 times stronger than
aluminium and does not melt the base metal, an so does not have a surrounding
zone of thermal disturbance to worry about. Also the process does not cause
enough heat to turn the absorbed foreign inclusions in the case into slag.
It's much harder than aluminium and so is also ideally suited for repairing damaged
threads, making them stronger than the original ones.
many of you may be amazed to know that no welders services are even required,
as this is very little harder to acquire proficiency @ than soldering and may well
be one of the most useful skills you ever acquire & costs are quite low.
this process is also great for making things like ball-end leavers and inlet-manifolds.
There are many how-2 videos on utube now - please follow the link 4 more info.



Remember to cut a v trench well beyond the limits of your cases fracture with a
suitable rotary file, then heat the casing and steam-out the crack with a domestic
type steamer to remove as much trapped crap as possible n' give it a few hours 2 -
dry-off before you begin your repair.


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