Removing Welding Stains From Looking Glass

It is indeed melted into the glass. I have seen 10's of thousands of dollars worth of glass replaced because the welder from the precast company wouldn't protect the glass while welding the mid connections. Six months later the final cleaning crew discovers it and all the burn marks point straight up to the brackets hidden behind the ceiling tiles. Anyone with a grinder or a gas cutoff saw can and has done equally as much damage. Cutting rebar from the top of a brick balcony wall ruined the entire length of a town house project's sliding glass doors and windows. Taking out a trucks' windshield and paint job has been known to happen too. Some of this is hard to ignore!

Glass polish will remove the black burn mark but it will do nothing to remove the pitting cause by the slag. You may try tooth paste as it has fine abrasives in it as a polishing compound. Polishing compound will notremove any slag that melted in to the glass that is stuck there. You maybe be able to pry the slag out with dental pick or break them up. The little round balls of slag are usually hollow and brittle. Other then that Del answer of replacement is the course to rectify the problem.

Note in US industry standard any defect in window glass that can't be seen from 10 feet distance is okay. Then again customer always right or the wife which ever the case is.

OP wants to know how to remove it not how to prevent it. Even though your solution to prevention is correct as to how most welders protect glass. You changed the scope of the question.

The usual setup is an expendable clear plastic cover lens in front of the shaded glass lens.

Tornado comes with a good solution.

You can also spray an "anti- spatter" solution (comes in spray cans) on everything that you do not want to be affected by the slag. Your glass included.

Cleans very well, especially if you watch close- by and your glass get also "smoked".

The film is very transparent and stays wet.

This product is also good to spray in the guiding hose of the MIG torch and provides more resistance against melting down or burning the tip.

Nothing you can do except change it or live with it. You should not have listened to the expert welder who had come to install safety grills on your windows.

Hi

I use a Stanley blade to " de-spatter " the windows in my workshop, it removes the spatter but does not scratch the glass. Also do the same with my welding helmet, even though I use a sacrificial plastic shield some spatter invariably gets past and sticks to the glass.