Shop ventilation - plasma cutting?

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oldmule

Active member
Joined
Sep 12, 2007
Messages
43
Location
Colorado, East of the Peoples Republic of Boulder
I'm still learning to use my new plasma cutter, so I have been a bit timid to break it out and play. I know, I'm being a bit paranoid....

I'm concerned about the gases coming off the cutting when I'm in the shop and I don't have a good ventilation system. What are you guys using?

I'm working out of an over sized two car garage. I have a furnace blower that I want to use for helping airflow, but, can't seem to figure out if I should be pushing air in from the top or pulling it out from the top. Where are the gases wanting to collect more?

Up to now, I have always used it out side. Tonight it is about 10* out and I have the furnace cranked up in the shop. I ran it for about 15 minutes total and had to open the garage a couple of times to try and get everything out.....

I know this crap isn't healthy to breath and I know I'm not getting good enough ventilation with just the door up a some.

Thanks
 
It is nasty stuff alright. I use a water trap, and an over head vent hood. I built the water trap out of an old wheel. The fins come out or turn over. Water level is just about a 1/4 inch below the fins. When I clean it out I am amazed at the coffee ground looking junk in the bottom. Legs adjust to make it level.
 

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Bone,
I'm outta my league sometimes around here...

Do you put the material to be cut on top of the water trap?

I did say I was outta my league......Right.
 
Yep, it is just a watertank with a grill over it. The air from the plasma blows the material, into the water. The weight of the material keeps it in the water. Plasma is a tungston arc with air pressure driving it through the material. Works great, but the air carries the metal as fine dust that you can breath. I use a respirator, or at least a dust mask, the majority of the time.
 
This thread reminded me of two things. First of all, Dan almost gassed us the other night because he used brake clean to clean the area he was going to weld on his frame. When he did the welding it put off some hellatious fumes. I was clear across the shop and I could smell them, and he got lightheaded and had a headache and nausea afterwards. We hear those fumes are clorine based. Won't be doing that again. :eek:

Secondly, Boneheads water trap reminded me of something I did to our sandblast cabinet to make it work better. We have one of those cheap $200 Harbor Freight ones (gonna save up and buy a good one someday) and it was hard to see inside when you were blasting......dust was like a cloud in there. So I made a water trap and it made a world of difference. What I did was run an old shopvac hose from the back of the cabinet to a 5 gallon plastic bucket I bought at Home Depot, the ones like drywall comes in with a lid that snaps on. I punched two holes in the lid the exact diameter as an old shop vac hose extension and forced one down almost touching the water for the inlet, then I ran another identical shopvac hose to a shopvac.

Now, when I turn on the shopvac the dust is drawn out of the cabinet by the suction and the sand and debris settle in the bottom of the bucket. You want the hoses to stop right above the water level so water isn't sucked out.

I also put one of those spotlights like you have on the outside of your house on the interior of the cabinet. Now it is much brighter than the original flouresant light. I simply hung it up from a wire tie and it shines down on the work I am doing. I also spent some time putting duct tape around every seam in the cabinet and added another layer of weatherstripping on the door. I was getting lots of sand escaping through the seams before I did that.

Finally, I have stopped using that lousy clear plastic film they give you to stick inside the viewing window to protect the glass from sand. It was getting chewed up quickly, and I found out the local hardware store will cut me pieces of glass for like $ 2 each to the size I need. When mine gets sandblasted too bad to see I will just replace the entire window, it's cheaper that way.

Just thought I would pass these tips along. Here is how I made the water trap. Now our sandblaster is much nicer to use.

Don
 

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I own the same cabinet. I caulked all the seams from the start, and put in a bigger light, but now thanks to Don I have to build a water trap shop vac thingy.
 
Hummm, that was a lot better info than I figured I would get.

First off, THANKS!!!

For the smaller stuff, the rim idea would work great... I was cutting perches and brackets off a 14 bolt axle that was under the vehicle the other night. I thought there was a lot more dust than I was expecting. I need to figure out how to cut down on the dust floating around. I have too much other stuff in the shop that I don't want getting plastered with it.

I haven't used my benchtop blast cabinet so I will do the upgraded to it before I start. I have a hood for it that vents to the outside, but the other ideas will make more of a difference.
 
The water trap will also work if you are painting in a garage.If you have a side door that goes to the outside.Put a sheet of plywood on it to match the opening.Cut a good size hole in it and use a piece of HVAC metal 2x2 duct and run it down to a good size tub with a good size fan in it.I usually use antfreeze instead of water.This keeps the overspray down and the neighbors happy.
 
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Does anyone use a swamp cooler type filtration for exhaust? Or do you filter your exhaust?
I was thinking of putting a vent fan w/ hood out the side of my garage, but like 35Mastr said I don't want to make the neighbor unhappy..... i can at least stick a furnace filter into the mix. I need to do some canalized painting in there too, I am hanging plastic sheeting from floor to ceiling and wetting the floor down. Not much, but enough that it needs to be vented (I'm painting a hight power rocket).
Something like this w/ a duct facing down.
http://www.grainger.com/Grainger/items/1HLA1
 
Does anyone use a swamp cooler type filtration for exhaust? Or do you filter your exhaust?
I was thinking of putting a vent fan w/ hood out the side of my garage, but like 35Mastr said I don't want to make the neighbor unhappy..... i can at least stick a furnace filter into the mix. I need to do some canalized painting in there too, I am hanging plastic sheeting from floor to ceiling and wetting the floor down. Not much, but enough that it needs to be vented (I'm painting a hight power rocket).
Something like this w/ a duct facing down.
http://www.grainger.com/Grainger/items/1HLA1


That is the way I do it.With that style fan with a 90 degree hvac duct into straight duct into the liquid.You could also slice the straight duct and slide a filter into it.I mount all that to a piece of plywood that fits into and 30 inch doorway.Then when done I just take it apart and store it.
 
Hey George,
I just got a chance to get back on here.....

That would kill two birds for me. If I duct it out the wall of my shop, I can put a pan of water under it to catch the solids and that would keep the neighbors happy when I cut and paint. I have tarps that I hang down to section off the shop from my other tools and parts, so it would be easy to do this.
Thanks for the idea.
 

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