I know you said you're just a hobbyist, but a positive air pressure respirator is just the way to go when you're a welder. It's basically an over the head setup that works like those old hazmat suits you'd see in movies. It's got a fan or something blowing in slightly higher pressure air, so none of the air outside can get in as the air is always moving out due to the difference in pressure. What it means is that ALL particulates, gasses, and whatever else you don't want to breathe have no way to get to you unless it somehow gets into whatever is supplying your air.

They make fanny pack sized units with batteries that are mobile, which works for me as I've had to go down in ships and up on scissor lifts to do welding before. I believe they also make slightly bulkier stationary setups that are significantly cheaper but often require other equipment (eg. Specialized compressor) to function. The all in one setup i got is quite expensive (about $2k new) but I managed to find it for quite a bit cheaper used on ebay. I'm comfortable doing this as I've been a welder for 15 years and have experience with quite a few different PAPR systems and am confident in my ability to troubleshoot any problems. If you're completely relying on something like this for safety without really knowing how it works, I'd recommend definitely getting something that comes with a warranty. The parts can be finicky, delicate, and expensive.