this post was submitted on 30 Sep 2024
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[–] [email protected] 5 points 1 month ago* (last edited 1 month ago) (1 children)

Just looked it up and N95-P100 masks/respirators cover most exposure that welding should create. I’m a hobbyist welder, but wear a P100 respirator 95% if the time (100% indoors).

From NIOSH:

RESPIRATOR RECOMMENDATIONS

NIOSH

Up to 10 mg/m3
(APF = 10) Any particulate respirator equipped with an N95, R95, or P95 filter (including N95, R95, and P95 filtering facepieces) except quarter-mask respirators. The following filters may also be used: N99, R99, P99, N100, R100, P100. 
Click here for information on selection of N, R, or P filters.
(APF = 10) Any supplied-air respirator

Up to 25 mg/m3
(APF = 25) Any supplied-air respirator operated in a continuous-flow mode
(APF = 25) Any powered, air-purifying respirator with a high-efficiency particulate filter.

Up to 50 mg/m3
(APF = 50) Any air-purifying, full-facepiece respirator with an N100, R100, or P100 filter. 
Click here for information on selection of N, R, or P filters. 

(APF = 50) Any supplied-air respirator that has a tight-fitting facepiece and is operated in a continuous-flow mode
(APF = 50) Any powered, air-purifying respirator with a tight-fitting facepiece and a high-efficiency particulate filter
(APF = 50) Any self-contained breathing apparatus with a full facepiece
(APF = 50) Any supplied-air respirator with a full facepiece

Up to 500 mg/m3
(APF = 1000) Any supplied-air respirator operated in a pressure-demand or other positive-pressure mode

Emergency or planned entry into unknown concentrations or IDLH conditions:
(APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode
(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus

Escape:
(APF = 50) Any air-purifying, full-facepiece respirator with an N100, R100, or P100 filter. 
Click here for information on selection of N, R, or P filters. 

Any appropriate escape-type, self-contained breathing apparatus\

Important additional information about respirator selection

[–] [email protected] 2 points 1 month ago (1 children)

Up to 500 mg/m3

I kinda want to know how thick that smoke looks

[–] [email protected] 2 points 1 month ago (1 children)

I think it splits hydrogen off of water molecules too, so if it’s at all humid in there, it might be explosive too.

[–] [email protected] 2 points 1 month ago (1 children)

Manganese does not split hydrogen from water molecules. I think you might have it mixed up with magnesium, which does but not at a high enough rate to release an explosive amount even if it's liquid water and solid magnesium.

Sodium and lithium do release enough hydrogen to be explosive and enough heat to ignite it when they are solid in liquid water, but I suspect the gases wouldn't do that. The density is way lower, and if it does prefer stripping hydrogen from water molecules to just pairing up with the the O2 ones (some reading suggests that this is the case for solid sodium exposed to air), I bet the recently freed hydrogen will take that heat and just join up with the free O2 itself before it has a chance to build up. And the source would also be more spread out, so there wouldn't be any reason for a high concentration to form even if the hydrogen doesn't react immediately with O2 in the vicinity.

Not that welding isn't an explosive risk, but it's usually due to the tanks used directly by the welding and/or explosive/accelerant materials in the vicinity of the weld.

If someone offers you $80k to weld their fertilizer tank because it's too full and they want to add an extension, politely decline and consider avoiding the general area until after it explodes.

[–] [email protected] 2 points 1 month ago

There is no vessel in the known universe I would weld for any amount.

(Mostly because I’m self taught and know that every mm of weld counts on those things).