[jroark]

Hey guys. I have a little aluminum job coming up and its cast. Its not a critical part but it will be visible so I'd like to get it right. Its on an inboard motor but its just cosmetic. Can you braze it or would a spool gun work? My machine will tig but its only DC. Any advice is appreciated. Thanks.

[Superiorwelding]

jroark,
I would recommend the spool gun as I have no experience with brazing alum. It will be difficult to get set just right and I recommend pre-heat depending on how big the actual piece is. Also, clean, clean, clean. I do quite a lot of cast alum repairs but always use TIG and 4043 works best as a universal filler. Let us know how it goes and post up some pics!
-Jonathan

[jroark]

Will do. Wasn't sure about the spool gun but I'm gonna give it a shot. Thanks.

[AKweldshop]

Will do. Wasn't sure about the spool gun but I'm gonna give it a shot. Thanks.

If all else fails, die grinder it out and try again....

Good luck.

[castweldsolutions]

Well its a little late, but if you haven't done it yet here's some info.

I welded a lot of cast aluminum with a spool gun before I was able to afford a tig welder. It won't be as pretty as tig welding and there will be porosity, but it does work. Here are the parameters that I used:

- 375 IPM (sorry I don't remember the voltage but you definitely want to be in spray transfer)
- 3/4" stick out (I cannot tell you how many friggin contact tips I went through struggling with this. Aluminum will burn back and braze to the tip and it CANNOT be fixed.)
- 100% straight argon (I actually use a Helium/Argon mix now, and in my opinion it is the way to go. Helium REALLY smoothes things out in terms of welding aluminum and cuts down on the porosity, but straight argon will work.)
- use a push angle
- use intermittent welds or the piece will get too hot and you'll punch through the piece.
- Use acetone and a stainless brush for cleaning.
- In my opinion I only saw a need for preheat to avoid cold start. Cast aluminum isn't as prone to cracking as cast iron. I preheat my castings to 150-200 degrees max.
- Most cast repairs I do are cracks in transmission cases. If you weld over a crack without grinding it out, you will have problems. I use a straight angle air die grinder with a bit that allows me to make "U" grooves in the crack. This enables 100% penetration.

I hope this helps. Good luck bud.

[jroark]

Thanks for the advice and settings. That will be a huge help. The intermittent welds also is a good suggestion. I may have tried to just blast through to keep it hot but I'll try that instead. Thanks again.