fresh air, venting, etc

[slackdaddy1]

My garage is well insulated and really tight, it will hold its temp for days when we have a temp swing. (it is also a heated slab).
I had to install a direct drain de-humidifier because things where rusting in there: if we had a temp swing from 60 to 80, the cool interior of the garage and contents would allow condensation from the "new" warmer, moist air.

That all said,, when welding or even using a rattle can of paint,, it is health hazard of fog/smoke in there for hours in less I throw up the garage doors.

AND,, I really need a fresh air supply paint mask AND welding hood.

Not sure how to approach these 3 things, that they will work together?
(De-humidification, venting fumes, fresh air supply)

I would prefer to have the fresh air supply permanently installed with a coiled up hose on a hanger, like a whole house vac?

I do have a used whole house vac I pulled from a house,, could I use that for a "spot" exhaust system, like lay the house near where I am welding?

Anyone have pics of their permanent fresh air setup,, and what they are doing for exhaust, especially when welding ?

 

[matt_i]

A couple of thoughts.

If you tig weld, then the smoke is reduced to whatever coating on the steel (oil, paint, etc) is burning, but if you grind or clean that off first there's very minimal smoke.

It does sound like there's some air infiltration though, if outside swings are getting inside. Or it could be thru the slab depending on vapor barrier and stone base issues. I think a ceiling fan 24x7 is a good start, low speed is fine, but keep air moving. The dehumidifier is a good idea.

You can use exhaust just like a bathroom fan but incoming is then the makeup air which has to come from outside. That can be humid/radically different temp than you are trying to keep the shop. The high end solutions seems to be heat-recovery-ventilators (HRV) which attempt to preserve the internal temp as much as possible.

 

[Showkey]

Measure and monitor relative humidity...........suspect if your getting rust and condensation your up around 60-80%. Bad things start happening at prolonged humidity levels of 70%.
Dehumidifier is the solution.

Welding.........open a door or window, fan in the door or window and getting a cross flow of air. Vacuum system would NOT be a good choice........it’s high vacuum ( pressure) , small volume......... ventilation is high volume low pressure. Vacuum could also **** up a welding spark or ember, real fire danger hours after a welding session.

How often are you welding? Venting will temporarily screw with the humidity and HVAC. Welding vented hood and dedicated welding area would be another solution.

You did not mention location.........if your in the south AC would be a solution.

I have a permanent mounted fan in the window, open the door across the room. Estimate air exchange rate is 6-8 times per hour when running. Air flow can be adjusted by meting the make up air at the door.
I run a dehumidifier in summer months with humidity levels at 50%. When the heat is on in the winter humidity levels are 30-40% with no dehumidifier. Summer humidity are at + 75% and mold mildew will form on organic materials like paper, leather, rubber etc. The shop is stand alone in the woods and acts like basement. The door and windows are normally closed. In the summer on the hottest days in August the shop will still be 70*.

 

[slackdaddy1]

Thanks guys,
I am in MD,, if you don't like the weather here,, wait an hour, it will be completely different.

Shop is tight, vapor barrier and 1" foam under slab (slab sits on 6-20" of gravel)
If the weather is cool 50-60 deg, then swings to 80deg, the shop will stay cool for days, and always seams to stay cooler than the outside air temp in the summer, and I think that IS the problem, as warm moist air comes in from opening doors, etc (or slowly seeps in over time)
I did just put a direct drain dehumidifier in there, it's helping greatly.

Perhaps an ERV would be the ventilation solution, only turning it on when welding or spray painting?

The 2nd half of my question was fresh air supply for my welding hood. I have found I NEED to have a "back cover" on my welding hood, or I am blinded from the glare getting into the helmet and reflecting on the INSIDE of the lens. (Shop has all new bright 4' LED lighting.)
Any examples of permanently mounting the "hobby" units and ducting 2 ports,, kinda like a whole house vac??

 

[zoomzoomjeff]

Any examples of permanently mounting the "hobby" units and ducting 2 ports,, kinda like a whole house vac??

Maybe a cheap dust collector with 2 holes cut in the wall?



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[slackdaddy1]

I was asking about the Hobby fresh air supply for breathing (Hoods)

Maybe a cheap dust collector with 2 holes cut in the wall?



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