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Grahame
02-11-2007, 03:32 AM
I am trying to to tig weld the cover panel of a Makita belt sander.

I have not got access the the low temp solder alloys that may work. The weld shops do not sell them in my area of Australia .Occassionaly they appear at the machinery shows but its only intermittent appearances.

Anyway back to the problem .When arced over with the tig the metal agitates as it goes molten and white smoke is given off in a violent explosive action. The remaining metal has the sponge like porous appearance.

As this is exactly what happens when the zinc flashes off from over heated silver solder I am assuming that this unknown (to me) alloy has a high zinc content.
The question oI have for you talented gents ,is the alloy identifiable and
secondly is it weldable.

I have tried to fuse some 5356 into the molten metal an instant before it flashes but invariably end up with porosity.

The same set up on pure aluminium and appropriate filler yields a good clean bead.

Your opinions please

thanks

Grahame

MicroZone
02-11-2007, 05:56 AM
It sounds as if the piece is either galvanized or if it's aluminum, it's probably anodized. Can you take a pic of it and post?

Grahame
02-11-2007, 07:05 AM
The sander cover has a painted surface which I filed off with a new file as a weld prep.
It is definitely paint as it is flaking.

As soon as the arc gets the metal to where one would expect fluidity to start, boom! it erupts in white smoke and an audible hiss.

The eroded crater is the result.

I am fairly sure it is die cast crap, but I have been wrong before.

Grahame

ZTFab
02-11-2007, 09:54 AM
Sounds like good ol' crappy Pot Metal to me.

That stuff is junk.

I have never had any luck repairing it with TIG....brazing is probably the only wat to fix it.


- Paul

gnm109
02-11-2007, 10:26 AM
Sounds like good ol' crappy Pot Metal to me.

That stuff is junk.
I have never had any luck repairing it with TIG....brazing is probably the only wat to fix it.


- Paul


I agree. It's probably pot metal with a high content of zinc. Do you have JB weld Down Under in Oz? That will fix it, although it won't be as satisfying as a weld job.

There are some metals that were devised for ease of manufacturing and low cost. Ease of repair or welding were not a consideration. This is common to many manufacturers.

Good luck!

MicroZone
02-11-2007, 10:59 AM
I agree with ZT - was going to say cast, low end "pot metal". If you have an O/A torch or MAPP gas, trying brazing it. Clean it, gouge it out or file it and heat it really good, apply filler.

Thanks for the pic, it really helps.

Grahame
02-12-2007, 02:29 AM
Thanks fellas for your input. I have only just found some of this JB weld with a local net retailer.
It does run against the grain as I am often asked to deal with the end result of similar 2 pack products that do little but make the work more difficult to weld.
I will check the net to see what this product can do.
Thanks
Grahame