Well basicly my dirt bike casing snapped were the kick starter went threw so a friend of mine tried to tig it but did not last long. So i got a new housing on the way I wanted to add a small 1/8" brace to were the housing cracked last time.

Whats some tips for welding a small alum brace to the cast alum housing?

Ill post a pic tomorrow when i get home.

josh

 

what were your settings on the welder???

 

1) Clean it really well. Cast aluminum is very porous and collects all kinds of dirt and oil. Any contamination makes welding a hassle. I have seen it pop and hiss like crazy when it is not clean.

2) Pre-heat the cast part if you can.

Best of luck with your project.

 

I don't weld much but from my experience cleaning the cast doesn't do much. Shitty cast is shitty cast, good cast is good cast...You can clean the outside all you want, as soon as it puddles it starts pulling all the **** up.

Pre-heating isnt' a bad idea...

99% of the time i just put some heat into it and weld it how it is and hope it turns out good. Alot of the cast from Asia/india is junk, i would really like to know what goes in the cast lol

 

I weld a lot of cast aluminum, intake manifolds, transmissions etc. What I do is go over the area to be welded with either an AL specific cutting disk or grinding wheel to get the surface of the material off. Than I go at it with a wire brush and some alcohol, than I pre heat the area with a butane/propane torch and than weld her up.

 

Thats what i was thinking. Im gonna post some pics tonight when im home. Im not sure what the settings were.

I think what im gonna do to start off with is clean the whole object realy good. Ie degreaser then alchol and then acetone. Ill post pics just cause this piece is hard to get and this motor has alot of Compression now and i can only kick start it.

 

i grind the area to be welded out a bit with a carbide burr. it helps a little, but always seems to get contaminated anyway.

 

Toss the new part in an oven first and cook out any crap. Then clean the area with acetone and a carbide burr. Then scrub it with a stainless brush. Then preheat in oven again and weld with a clean tungsten. You may have to clean it some more and weld it again.

 

The problem is that its not only cast but it die cast.And nobody can weld die-cast and make it strong.Its going to get dirty every time you hit it with the torch.Its impossible to get it clean.Its made with bubbles in it on purpose.

 

are you 100% sure its aluminum?? what model and year of dirtbike is it?

 

I have always been told when welding al. that after you sharpen your toungston get some copper and put a ball of copper on the end of it. But i do agree heating it does help because we had a guy at school that broke a cast piece on his banshee and i remember one of my instructors telling him to heat it with a torch.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Sol Rosenberg &raquo;</TD></TR><TR><TD CLASS="quote">The problem is that its not only cast but it die cast.And nobody can weld die-cast and make it strong.Its going to get dirty every time you hit it with the torch.Its impossible to get it clean.Its made with bubbles in it on purpose.</TD></TR></TABLE>

 

Die casting is not that big a deal as long as it is aluminum. I have welded aircooled VW heads before that are cast in a similar method and after cleaning and grinding and cleaning and grinding they weld pretty decent. I have had to preheat and weld , then come back and grind some more and build up onto of the new weld to get the problem fixed.

As long as it is aluminum you can weld it, it will just take more work depending on the type of aluminum.

 

A type 4 VW head is nothing close to a new motorcycle case trust me

 

as they said above clean it really well and sometimes youll find that it easier to JBweld it rather than tig it. I had to do it once on a hydraulic reserve cause it was just so dirty

 

If your motorcycle casting is japanese, then it is typically cast from a much cleaner aluminum than the old German stuff. Plus the old German stuff is just that old, used, dirty castings. I have welded Honda heads and intakes and they are significantly cleaner castings than the german stuff I have welded.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by turboteener &raquo;</TD></TR><TR><TD CLASS="quote">If your motorcycle casting is japanese, then it is typically cast from a much cleaner aluminum than the old German stuff. Plus the old German stuff is just that old, used, dirty castings. I have welded Honda heads and intakes and they are significantly cleaner castings than the german stuff I have welded.</TD></TR></TABLE>

damn dirty germans...

 

You guys are not listening. The bike cases are DIE CAST totally different than just cast aluminum.

 

Are they aluminum or Zinc?

 

its probably cast Mg

 

Its a 1990 DT 200 yamaha. Same as your yamaha blaster motor. Ill be home tonight ill take some pics. The case i have now is non broken. I just wanted to weld a gusit on it to strenghtin it to prevent this problem.

\**** guys thanks for all the advice ill post pics soon lol