Anyone have any tips on cleaning cast aluminum for welding (specifically b-series Honda valve cover), Every time I try to weld it, it is like it has to much trash in it. I can weld pipes or sheet maetal with no problems, just cast stuff gives me fits. When I weld the valve cover (or anything cast), it just looks bad. I usually end up welding it, then grinding it out, then welding it again. I usually have to do this several times before I can get the trash out. Is there anyway to prep it to where I can weld it one time and it look good? When I prep it, it strip off the paint with aircraft remover, scrub it with a clean stainless brush and then whipe it very thoroughly with denatured alchohol.



Modified by turbotypeR at 10:24 PM 7/8/2006

 

anybody?

 

welding cast aluminum like that is never fun. i've welded coolant ports on a head before and that wasn't fun, i dremeled out material to clean it up before i welded the area and it seemed to work ok. i've also done valve covers before without too much trouble but it was off the engine for over a year. the problem is the casting becomes contaminated with oil and coolant and such and soaks it in like a sponge and you can't do much about it. i wouldn't bother with the chemicals, i'd just sandblast it then ss wire brush it. good luck.

here is the head i did for a bmw:

before grinding:

prep'd by grinding:

after welding:


all done:

 

You can try sticking it in an oven for a while.

 

Yeah I would preheat it. You can also make a couple passes without filler to bring the trash to the top of the material and then grind it off. It's really hit or miss welding that cast trash. It never looks very good compared to welding clean stock.

 

I think what your problem might be is that you are using a stainless brush. You could be impregnating the aluminum with stainless from the brush. I personally use acetone to clean all my work, but denatures should work just fine.

What rod are you using and what are you running for amps?