Lost technology

Growing up in the house of an artist/inventor is great. I remember when I was a kid, I would enter his workplace and watch him paint, sometimes welding stuff, sometimes pounding on something. It was amazing to watch him working with tools that he himself made to make a specific task much easier. I remember one contraption of his that simply amazed me. It was a gasoline welder. That's right! A gasoline fueled welder. I didn't get to see much of the details of the thing, but what i do remember is that most of its parts are made of bronze. Its nozzle was actually from an old machine gun bullet casing. A .50 calibre shell casing from the 2nd world war. it had a rubber hose connected to a metal container that is made out of a spent bomb shell casing. it was rather large and heavy. This is where the gasoline was poured. The gas tank is then connected to an air compressor. A regulator is used to control the air pressure. When the uses the welder, he lights up the nozzle just like you would on an acetylene welder. he carefully controls the airflow with two air valved on the welder. In no time, a blue beam of flame would appear on the nozzle. Although it couldn't be as hot as an acetylene welder, you could make it hot enough to melt bronze. And if you think about it, its fuel is just a pint of regular gasoline as compared to an expensive acetylene welder with 2 high pressure tanks of acetylene and oxygen. Pretty much inexpensive to operate and downright cheap to make as most of its parts are from recycled bronze tubes and WW2 shell casings.
I came home one time to find out that a certain family member took the welder. And knowing who took it, got me really worried. By now the welder would have been destroyed and or sold or given away to someone. The one who took it had no respect for those kind of stuff. Things he borrows and takes literally get destroyed due to utter carelessness. This actually led me to believe that he had no respect toward the owner/maker. I could go on and on about this person, but that wont bring back what is lost.
The artist died 2 years ago and the technology died with him. I didn't get the chance to study his invention to have it patented and replicated so that his legacy will live on through me. I know the basics of how his invention worked, but the details of it have eluded me. How i wish the artist was still alive. I have so many questions to ask him. I want his legacy to live on, and i want to take that responsibility. I am but his grandson, but i believe he would have wanted me to take care of his inventions.