What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Supplied Air Respirator

ShawnAM

ShawnAM

Member
Was not what section to post this in but seemed appropriate for safety.

So I am trying to create a "cost effective" fresh air supplied respirator for spraying epoxy primer with a HLVP gun.

I am looking at something like this and hooking it up to an oil-less compressor. I will be spraying outside in open area too.

Any thoughts or comments as to if this will provide adequate protection.
 
Wonder if "FDA" and "CE" means the same thing in Chengdu as we think it does here in the USA.

For spraying epoxy (not polyurethane) with an HVLP gun in an open area, I'd think a decent cartridge type industrial respirator would be more than sufficient. You can get one for under $30 at Harbor Freight.

The odour threshold for isocyanates, i.e. the level at which an individual can smell
an isocyanate, is typically higher than the allowed exposure limits. In other words, if
a painter smells the sweet, fruity, pungent odour of an isocyanate, they are probably
already overexposed. That is why the recommended respiratory protection for
employees spraying isocyanates is a supplied air respirator and not an air purifying
respirator (i.e. filter cartridge style).
Click to expand...


https://multimedia.3m.com/mws/media/777847O/isocyanates-3m-techupdate.pdf
 
Last edited:
Lol I did not catch that about the “certification” being Chinese FDA but hilarious!

I posted this same question on garage journal forum and got a ton of responses. Consensus was that there is not an oil free compressor able to supply enough air, plus they too are not made for creating breathing air.

I searched the SDS for Azko Nobel primer and cross checked each chemical with 3m filter selector. From what I found, the 3m OV filter (p100) should do the job on a full face mask respirator.
 
Solution:

Hood from Amazon:

https://www.amazon.com/Atoplee-Proo...s=gateway&sprefix=splash+mask,aps,167&sr=8-37

Corrugated vacuum hose:

https://www.amazon.com/Poolmaster-3...m+hose&qid=1551149146&s=gateway&sr=8-16:cool:

Bathroom fan as blower:

https://www.amazon.com/Delta-Breez-...=bathroom+fan&qid=1551149219&s=gateway&sr=8-5

Make an adapter (15 minute fiberglass project) to connect the blower and the hose. Use duct tape or zip ties to hold the other end of the hose under the hood. It is good to secure the hose to your waist and leave slack in the hose between your waist and the hood.

Stick the fan in an area with clean, fresh air, turn it on, and voila, a blanket of fresh air inside your spray hood.
 
Last edited:
If you're doing small/medium pieces outside, IMHO don't mess with a fresh air respirator. It's more trouble than it's worth. Even in an enclosed space they're a giant pain since you add an additional hose to drag around and catch on things. The one I used (hobbyaire) also whistled constantly and loudly.

A proper organic respirator will do fine outdoors as long as you have even a soft breeze. Get a full faced one if you're worried about your eyes.

It is nice in an enclosed space doing large sections. I've sprayed for 30+ minutes with it on and the fresh air was welcome. The whistling not so much.

The hobbyaire supplies around 1 psi (basically just positive pressure) through a clear pvc garden hose (it even uses garden hose connectors). When you breathe in the rubber check valves close and all the other times the air is wasted out. I haven't looked inside it but something like a bilge fan with an adapter cone may do what you want.
 
I use standard standard filters that will capture iso's, though have considered a fresh air system. The problem with the linked device is that it uses air from your compressor. Unless you move the compressor to somewhere outside of the spray area or develop an intake system with clean air, this approach will be much worse than using a standard filter mask. This is all less of an issue for light priming, it is a major issue for large spray jobs.

Also suggest that you smell the air coming from your compressor. Mine smells pretty bad and I expect a fair amount of mold/mildew due to the condensed water that lives in sealed tank. Most large compressors use oil and that leaves the air with an unpleasant odor. I would not want that air pumped into my mask for breathing.

Larry
 
Last edited:
From other's opinions, it sounds like compressor air, even an oil-free, is not safe for breathing. So the system in my first post is no longer being considered.

Primer that I am spraying is the azko nobel 463-128 with the CA116 curing solution. Neither of the SDS sheets list isocyanate or any diisocyanates.

Of the chemicals that are listed on the SDS, each are able to be filtered by p100 filters on a full face mask. The only real unknown is for long the filter will work. As I understand, you can't really smell the problem chemicals so if you wait until you start smelling chemicals in your mask you have already been breathing in "bad stuff" for a while.
 
Shawn

Part of the work we are involved with is the manufacture of agricultural spray tanks for helicopters, typically AS350 or similar types. These are of carbon fibre and vinyl ester construction consisting of upper and lower halves which are bonded together. At some point through the process a worker has to literally climb into the tank to complete the interior laminate. Think confined space combined with resin fumes and limited oxygen supply.

We use a unit very similar to your example and this makes a huge difference to the quality of breathing air. The unit is mounted outside the tank and supplies air from the compressor through a long flexible tube to the operator. Admittedly we are set up for gel coat/paint spraying and use good quality air filtration from our compressors for this very purpose.

In your case perhaps a unit like this using air supplied from a blower of some sort located in a clean air environment would do the trick?? I would be cautious about using a face mask only unless you have a reasonable source of flowing air and can position yourself ‘upwind’ of the piece you are working on.

Clive Whittfield
Auckland
New Zealand
 
I use a Hobbyair remote fresh air system and a full helmet. Not super cheap($500) but isocyanates are something I want in or on my body. I made a paint booth and many others have. It has has furnace filters as the input filters with a negative air pressure exit fans. Your really need to move the air to get rid of the overspray in a confined space The exit fans are just 20" cheap box fans with 20X20" paint arrestor pads(cheap) in front of them. The arrestor pads are incredible effective at preventing any paint from getting out of the booth(but not the fumes) and into the hanger. Also tyvek paint suites are very cheap($7) and keep the paint off your body.
 
ShawnAM said:
From other's opinions, it sounds like compressor air, even an oil-free, is not safe for breathing. So the system in my first post is no longer being considered.

Primer that I am spraying is the azko nobel 463-128 with the CA116 curing solution. Neither of the SDS sheets list isocyanate or any diisocyanates.

Of the chemicals that are listed on the SDS, each are able to be filtered by p100 filters on a full face mask. The only real unknown is for long the filter will work. As I understand, you can't really smell the problem chemicals so if you wait until you start smelling chemicals in your mask you have already been breathing in "bad stuff" for a while.
Click to expand...

Not unkown at all. Typicall, unopened 3m cartridge filters are good for 5 years from the date stamped on the unopened package. Once opened/installed, if I recall, we used the cartridges for a maximum of 6 months, and 90 day for heavy use. If your filter cartridge becomes coated/clogged with paint, you will find it harder to breath.
 
Instead of the bathroom blower, go with a small bounce-house blower. Select a model that does not have the motor in the primary air path. These go new on e-bay for <$50. The outlet is already round, just take it from 2-3" to 3/4" and you are done.



Kyle Boatright said:
Solution:

Hood from Amazon:

https://www.amazon.com/Atoplee-Proo...s=gateway&sprefix=splash+mask,aps,167&sr=8-37

Corrugated vacuum hose:

https://www.amazon.com/Poolmaster-3...m+hose&qid=1551149146&s=gateway&sr=8-16:cool:

Bathroom fan as blower:

https://www.amazon.com/Delta-Breez-...=bathroom+fan&qid=1551149219&s=gateway&sr=8-5

Make an adapter (15 minute fiberglass project) to connect the blower and the hose. Use duct tape or zip ties to hold the other end of the hose under the hood. It is good to secure the hose to your waist and leave slack in the hose between your waist and the hood.

Stick the fan in an area with clean, fresh air, turn it on, and voila, a blanket of fresh air inside your spray hood.
Click to expand...
 
N804RV said:
Not unkown at all. Typicall, unopened 3m cartridge filters are good for 5 years from the date stamped on the unopened package. Once opened/installed, if I recall, we used the cartridges for a maximum of 6 months, and 90 day for heavy use. If your filter cartridge becomes coated/clogged with paint, you will find it harder to breath.
Click to expand...

3M has a table of exposure time for their filters. I think under heavy exposure (like an amateur-built paint booth painting large parts), they are good for around 2-3 hours.
 
ShawnAM said:
From other's opinions, it sounds like compressor air, even an oil-free, is not safe for breathing. So the system in my first post is no longer being considered.

Primer that I am spraying is the azko nobel 463-128 with the CA116 curing solution. Neither of the SDS sheets list isocyanate or any diisocyanates.

Of the chemicals that are listed on the SDS, each are able to be filtered by p100 filters on a full face mask. The only real unknown is for long the filter will work. As I understand, you can't really smell the problem chemicals so if you wait until you start smelling chemicals in your mask you have already been breathing in "bad stuff" for a while.
Click to expand...

p95/p100 is not enough. You need OV rating as well. Something like the 3m 60921

3m has a service life calculator at 3M.com/ServiceLifeSoftware but good luck figuring out what your ppm exposure is going to be in free air.

For example, using the 78-93-3 (MEK/butanone) from the curing solution at 250ppm the 60921 has a 16 hour service life. That's a lot of spraying.

I generally just change them about once a year.
 
60926

I like the 60926. Date and store in a heavy zip lock with desiccant bag. Document hours of use on the bag. Replace after 6 hours of spraying.
That said, I plan to spray more and purchased a Hobby Air.
 
You must log in or register to reply here.
Back
Top