- Thread starter heinz57
- Start date
inchpincher
2-stroke terror
- Messages
- 471
- Location
- Tring, UK
The problem with 'pot' metal (zamak etc) is the impurities, zink reacts badly to tig welding. The pulse feature is really just to control the heat input to the weld for thin metal or alloy and to get a very consistent bead form.
Like langy said, depending on what you're trying to mend, lumiweld or durafix rods might get you out of trouble
Like langy said, depending on what you're trying to mend, lumiweld or durafix rods might get you out of trouble
Is this the same problem I've had recently?
Yesterday infact, I had a Corsa engine mount to plate for a rally car. Kept cracking in the same place so just as I'd done for this guy on another mount, just plated the flat sections on the new replacement and welded round them and a slightly more detailed job on the ribbed sections, joining up each section individually to turn open sections into small boxes...
Anyway, my suspicion is / was that the 'crap' Aluminium GM had used must have had some Zinc content because as soon as it got a little too warm it decided to become an ever enlarging pulsing mass of oxidized scum! Another annoying aspect of it was that it didn't want to 'wet' like the 6000 ish Aluminium plate I was trying to attach to it.
Am I right? And is there a technique or rod more suited to less than ideal material combinations?
The best behaved I found it was when it was cold, creeping along with barely enough current, weaving around and adding tiny doses of filler at a time - Laborious to say the least!
Yesterday infact, I had a Corsa engine mount to plate for a rally car. Kept cracking in the same place so just as I'd done for this guy on another mount, just plated the flat sections on the new replacement and welded round them and a slightly more detailed job on the ribbed sections, joining up each section individually to turn open sections into small boxes...
Anyway, my suspicion is / was that the 'crap' Aluminium GM had used must have had some Zinc content because as soon as it got a little too warm it decided to become an ever enlarging pulsing mass of oxidized scum! Another annoying aspect of it was that it didn't want to 'wet' like the 6000 ish Aluminium plate I was trying to attach to it.
Am I right? And is there a technique or rod more suited to less than ideal material combinations?
The best behaved I found it was when it was cold, creeping along with barely enough current, weaving around and adding tiny doses of filler at a time - Laborious to say the least!
Try boiling the zinc out the material, then welding with 12% silicone rod. After you have got rid of most of the zinc it will be a lot easier to weld, but ultimately breakage may occur anyway as zinc/alloy die castings are pretty weak, even if you reinforce them.
You typically get lots of white soot/smoke when zinc content is high. The majority of Al based castings usually top out at around 3% Zn. Magnesium castings (and filler wire) often contain more zinc and while they can be quite sooty doesn't trash the weldability
Dirty, porous, scummy weldpool... can get that with castings that contain < 1% Zn. As said boiling the crap out can help, for example with a really dirty casting can might the torch over the joint just melting the surface (rather than trying to weld) to get the crap to the surface. Remove crap with a die grinder and then go for the weld. If it's really bad (bleeding oil as it's a porous mess cast from old cat food tins) might take a few attempts to get a cleanish weldpool, buttering each side of the joint can help/be faster. 4047 has a lower melting temp and can make life easier- the 12% Si wire mentioned
For true Zn castings those Durafix/Lumniweld rods are the ticket as they are a Zn alloy. Not hyped up but cheaper if bought as aluminium solder from welding suppliers- SIF 555 Al solder for example, available as a 6 rod pack or by the kg
Dirty, porous, scummy weldpool... can get that with castings that contain < 1% Zn. As said boiling the crap out can help, for example with a really dirty casting can might the torch over the joint just melting the surface (rather than trying to weld) to get the crap to the surface. Remove crap with a die grinder and then go for the weld. If it's really bad (bleeding oil as it's a porous mess cast from old cat food tins) might take a few attempts to get a cleanish weldpool, buttering each side of the joint can help/be faster. 4047 has a lower melting temp and can make life easier- the 12% Si wire mentioned
For true Zn castings those Durafix/Lumniweld rods are the ticket as they are a Zn alloy. Not hyped up but cheaper if bought as aluminium solder from welding suppliers- SIF 555 Al solder for example, available as a 6 rod pack or by the kg
stealthbob
Member
- Messages
- 11
I have played with MuggyWeld with success, mostly for filling in pot metal pits but it should be good for repairs as well.
http://www.muggyweld.com/super1.html
http://www.muggyweld.com/1clip6.html
http://www.muggyweld.com/super1.html
http://www.muggyweld.com/1clip6.html
