Found a small crack

[toten]

Anodizing aluminum isn't too easy, and since most forms don't corrode enough to cause problems when raw it's not common to do on custom pieces or after repairs.

[grayracer513]

 

If you do have the crack welded up, start by drilling both ends (maybe a little farther out than they appear to go) and then V the whole thing so you get full penetration. If you just lay a bead over the top it's extremely likely that the crack will expand through the new weld.

 

Drilling the ends of the crack ("stop drilling") isn't a bad idea, but grinding out the crack is unnecessary unless you suspect it's full of some contaminant.  As thin as that material is, if it's actually welded instead of having a bead "laid on top", there will be a "bead" on both sides, as the metal will have melted through.  

[thomas liles]

Well the crack migrated slightly so I decided to have it welded. I should get the swing arm back in the next few days. The welder said its not the prettiest

[thomas liles]

definitely not pretty but guess it's going to work

[MidlifeCrisisGuy]

📎ImageUploadedByThumper Talk1437016314.088703.jpg definitely not pretty but guess it's going to work

 

If you leave the bead like that, its stronger than the surrounding material.  If the part flexes, the interface from the bead to the parent material will be highly stressed.  This effect would be minimized if you ground the weld flat with the parent material.   And you'll also find out if the weld is porous !

[toten]

That's one ugly weld. I'm going to guess the anodizing is part of why it's ugly.

[Crf250boss]

absolutely no problem to a welder. Once he's got a good ground, the heat will burn off the anodizing no problem

Had my arm welded due to the chain slider wearing a hole in it, with no problems caused by the anodizing

went from this

To this, after welding and dressing

had the same thing happen to me,the chain slider wore through and started eating away at the swing arm bearings ,sent it to get welded and job is done but waiting to get a dew other parts before