My understanding is that conventional squeegee channels and handles have been made out of brass because brass doesn’t scratch glass.
I’ve used 0000 Steel wool for many years.
Tried Bronze wool and loved it but it’s 6 times the price!
Why is it that there isn’t Brass wool being used by window cleaners? I’ve heard of it but can’t find any info. Anyone?
Search “Bronze Wool”.
There are two different scales of hardness to consider, Rockwell and Mohs. Rockwell measures how resistant a material is to indentation. Mohs measures resistance to scratching. The two are not mutually inclusive, that is to say, even a “soft” metal like brass can scratch a harder, less flexible material like glass under certain conditions. So there is nothing magical about brass itself that will save glass from scratches.
As for why brass wool doesn’t exist, I could only guess that it has to do with cost. Bronze wool is already 6x the price of steel wool, likely as not due to lower demand and production, besides material cost. Brass wool wouldn’t necessarily be any more effective than bronze, and perhaps even MORE costly to produce.
I don’t know why the original squeegees were brass. Probably had to do with production since stainless is a pain to use and cast iron would be too heavy.
And probably not due to fear of scratches. Old glass is darn near impervious to scratching, even with steel razors.
The good ol days 
I focus on making money. My costs incurred are passed on to the clients. I don’t care that bronze wool is 6x the price, it’s passed on.
Just like I don’t care if my choice of rubber costs more, that too is passed on.
Whatever makes life easier for me, I’ll be using.
Brass also contains lead. So if you were handling brass wool all day barehanded, you would need to worry about lead poisoning.
Got a lot of old glass up north. Seen some scratching here and there. Still always cautious.
Great stuff guys!
The Wikipedia says, “Bronze is an alloy consisting primarily of copper, commonly with about 12% tin and often with the addition of other metals and sometimes non-metals or metalloids such as arsenic, phosphorus or silicon. Brass is a metal alloy made of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties.”. To simplify Bronze is made of copper and tin, whereas Brass is made of copper and zinc. Think bronze/tin and brass/zinc. They are two different alloys of copper.
Regarding whether bronze wool will scratch glass;…well I have scratched glass with a home made plastic (acrylic) scraper. It is the quality of the glass surface that is responsible. That is what the Glass Committee is working on with Penn State.
One more thing. I live up here in the NH woods. Old glass is very common. It is very resistant to scratching. Sometimes I will come across what I call “ice glass”. It is really old super smooth glass. Even causes the soapy water to break away leaving dry spots. The razor just guides like ice on ice. Totally fascinating!
Henry
