Try to put the melted metal in the weld joint, not on you. And I've learned to stand a little aside of where gravity and wind direct what little sparks do fall.
New clothes do burn up more than old well worn slick shirts and jeans. The new cloth has a lot of fuzz that likes to burn. 'Bout 10 or 20 washing and dryings helps out. Starching too but to much trouble for me. You don't expect my wife to do it do you? She doesn't even iron her clothes.
Once was on a job up in Kansas and was there long enough that we had to send our clothes out for laundry. I had new jeans and shirts but my clothes (and me) were really getting burned up. I guess I had not yet fully learned what my first sentence boast.
Found out the laundry was DRY Cleaning my clothes. We got that stopped and things cooled off a bit, if you know what I mean. Was doing quit a bit of air arcing in a tight spot, downwind, up hill, against the grain, etc.
Speaking of motorcycle clothing, maybe we should get this company to make welding gear. Their suits, jackets, and pants are suppose to protect you from road rash sliding down the road at 70mph.
A few sparks and drops of red hot metal should not be a problem.
http://www.aerostich.com/Floyd