Spot Welding Issue

I would recommend preventing the contamination that is causing the black spots in your weld. I'm unsure of how you are spotwelding this chassis but the aluminum you are welding and the electrode holder/filler material must be very clean to prevent this. Also, the shielding gas must be flowing correctly and be of good quality. A good chemical washdown prior to welding should fix this problem. I have used acetone in the past, but it is very flammable so use extreme caution. There may be a more appropriate cleaner for industrial use that may be safer. Good luck!

Hi, Thank you very kindly for your input. I am quite sure that there is no filler agent

in the process should one be ?

Regards

Liron

Hi,

Can you please recommend on the welding firm you have experience with, I wish to offer future needs in low volumes of enclosures, (10s to 100s).

Regards

Liron

I used to do some aluminum welding making solar glazings, and in additon to the welding, we had to cleanse the aluminum of all oxides before we could use double sided adhesives to bond the glazing films (tedlar and teflon)

We used a product called MEK. or Methyl Ethyl Ketone. but also used wire brushes on the welds.

Hi Criss,
MEK is a powerful cleaning and diluent/solvent chemical for sure .
I once supervised maint.-team where MEK used to drain and cleanse industrial inkjets (Image FR) that uses polarized inks else, wire brushes are the perdominent tool in the welding industry which I try to avoid on hitech chassis. I would greatly appreciate any additional information in the future.

Best Regards

Liron
myemail@netvision.net.il

When using wire brushes, what are the risks (if any) of brush metal left behind?

We used to use a cup shaped wire brush about 3" dia. for our tasks, there were no bristles left residually in the welded joints, although the brushes did shed bristles... eye protection is critical for this reason. I even recommmend glasses and face shield. A flying piece of wire in the eye is not pleasant.

Muriatic acid also works well. But like MEK there are the health issues. You would need rubber gloves, safety goggles, face shield and apron. Also very good ventilation and/or appropriate respirator

The most common cleaner(etchant) for aluminum is a dilute Phosphoric Acid. Rinse with de-Ionized water, a quick wipe with MEK then assures a very clean surface

You never did mention what welding method you are using. I would recommend a totally fluxless welding method such as TIG or very good MIG( Tig preferred).

If you cannot change welding methods I would recommend blasting with glass as the grit which is lighter on metals than most acids and it can be done robotically.