Laser Welding a aluminium engine head

[doubleboost]

What does the peening do?

It must close the grain of the material.
When you fly cut an un peened weld it seems to be dry inside dull in appearance.
The peened weld has a much brighter finish
Just something i was shown how to do

 

[M sawala]

I didnt end up welding the head but i will post an update anyway. I ended up just cleaning the head and lighting skimming it by hand on a granite surface plate with wet and dry. after only sanding for a short time the crack(or wear mark disappeared and checked for flatness which was under 2 thou. ive now fitted a new gasket and the engine is now working fine (apart from a slight vacuum leak)

In terms of welding aluminium, ive been practicing on scrap, and its alot harder than welding p20 or H13! but im still playing around with the settings.