Supplied Air Alternative???

[Anonymous-0]

There is no question about the necessity of using a supplied air or fresh air system when doing hazardous operations like sandblasting or painting with toxic materials. I know that I need to buy one but I would like to see if there is another way around this before doing so. What I would like to kick around is the alternatives of purchasing something like a hobbyair system and maybe save a few bucks.

Basically the hobbyair and others similar to it are nothing more than a high volume low pressure turbine probably no more than a two or three stage system where the output is somewhere around a few psi and maybe 5-8 cfm, I think. If so, has anyone ever tried to modify a low cost turbine air pump from let's say a H.F. HVLP paint system for this application? The only downside is that the air is quite warm out of one of these compressors.

Another option which would work quite well is using a old cpap machine which is used for folks who suffer from sleep apnea. This would work quite well if one could find a used one at a reasonable cost.

Other options are to use air from the main compressor but that requires a lot of filtering and I think that it maybe the least desired approach. I just don't like the idea of using air out of a tank where a bunch of nasty things may be lurking, but let's talk about that also.

Lastly, we have the option of using a vacuum cleaner blower. It too is a low pressure high volume system. Has anyone played with this approach?

While we are on the subject can we also discuss your experiences with face masks and hoods.

As you can see, I am a beginner and am trying to get some ideas and approaches to this very important subject.

 

[Anonymous-0]

Why not wear a full face cartridge type respirator with a full hood over it that is plumbed to a vacuum cleaner or source of your choice?? All you really need from a supplied air system is the positive pressure it supplies around your head. The respirator would filter out any dust or critters from the supplied air source. Maybe a little clumsey for everyday use but you would get double the protection and low price???? Make sure the air supply is in an uncontaminated area.

 

[Anonymous-0]

I have used the Hobby Air hood with a cartridge mask under it, with the idea of having some protection to refill my gun, etc without dragging the hose all over the building. Don't do that any more because the hood is too hard to get on and off due to the mask. Now I just take off the hood, use the mask for as short a time as possible and evacuate the area. I have heard of people using vacuum cleaners. Best to start with a new one and don't use it for anything else. But, I prefer a product made for the purpose rather than trying to modify something to make it work. Just lazy, I guess.

 

[Anonymous-0]

Hi Mike,

I'll respond since I've been successful in "cobbling" together a workable supplied-air system. I also understand the desire to "make do", if possible. When I put mine together years ago, supplied air was not that common and commercial systems were all very expensive. I first purchased a commercial full facepiece for a mask. I tried using it supplied with air from my regular compressor. Two big problems with that - one, my compressor was not large enough to supply enough air continuously to both the facepiece and the spray gun at the same time. You should have 4 cfm for a facepiece and 6 cfm for a hood to have an adequate breathing air supply. Second, I did not have any filtration devices for breathing air and I noted a distinct taste of oil in my mouth. This was totally unacceptable to me. I then purchased an oiless, tankless compressor to be dedicated to supply air to the facepiece. It wasn't an "official" breathing air compressor. I used (and still do) a 1hp Campbell Hausfeld portable air compressor. I backed the built-in pressure regulator off such that it had no effect and pressure would build up only as needed to overcome hose resistance and supply the maximum amount of air that the compressor could produce under those conditions. I left the pressure relief valve in place for safety. I used 100 feet of standard 3/8" ID compressed air hose between the compressor and the facepiece. I verified that I had enough air at the mask by holding my palm close to the exhaust port on the mask while breathing in at the same time. By feel, I confirmed that I always had an outflow of air which also confirmed that there was a positive pressure in the mask, relative to the ambient air, even when breathing in. It's very important that a postive pressure be maintained in the mask at all times to prevent any infiltration around an imperfect face seal. This is a system that has served me very well for a lot of years.

That said, I don't think you will save any money going this way unless you can utilize something you already have available. The rise of relatively inexpensive turbine systems such as the Hobby-Air and the other one on Ebay in recent years has made cobbling together some kind of decent system of questionable economics. If you have to buy the parts, I don't think you can do so for the price of those turbine systems. I prefer a compressor-supplied system because the air never gets hot and the hose is much smaller and easier to drag around. It also can be extended significantly in length, as needed, w/o adversely affecting the airflow.

I have no use whatsoever for the systems you can buy that process the air from a regular compressor. For one thing, they are expensive to buy and to maintain, especially if you have the recommended CO monitor/alarm equipment. For another, I am opposed in principle to filtering out bad stuff when an alterative is readily available. I think it is far safer (and cheaper) to use fresh air in the first place than to rely on filtration of questionable/bad air. There just is no need for that, even if the shop compressor is big enough to supply everything simultaneously.

The only issue I have with my system is the compressor is very noisy, as most of the portable, non-lubricated ones are. But it's a relatively short duration and acceptable to me for the great benefit it provides. You can get a commercial system that operates on the same principle and that is quiet but you are looking at a minimum of about $800 or $900 for that. The things that I think are most important are 1) a good fitting full facepiece or hood, 2) a supply of air that is sufficient in quantity to provide a positive pressure in the mask or hood at all times, 3) a source of air that doesn't add any nasties to the air itself, 4) the ability of the source to supply the needed quantity of air through whatever connects the hood to the air source over the longest distance needed for the job and 5) a location of the source where there is always fresh, breathable air available and there is no possiblity of ambient contamination. If you need to wear glasses when spraying, then you should look at a hood and not a full facepiece.

If you go the route I did by assembling purchased parts yourself, it is likely to cost at least as much and probably more than the Hobby-Air or the <a href="http://cgi.ebay.com/Supplied-fresh-Air-Respirator-breathing-full-facemask_W0QQitemZ290078671475QQihZ019QQcategoryZ11905QQrdZ1QQssPageNameZWD1VQQcmdZViewItem">"Breathe Cool"</a> Ebay commercial units.

I don't think there is a cheap, quick fix here that I'd want to use. $400 is not a high price to pay for a ready-to-use safe breathing air system. You can spend more than that just for paint on one job. If you are only thinking one job anyway, think about re-selling the system on Ebay after you are through with it. There is plenty of demand for something like that and you'd likely get at least half your investment back. That's what I'd do for a one shot deal. If you are going to be painting into the indefinite future, then the investment is well worth the full cost, IMO.

Rod

 

[Anonymous-0]

Hello Rod:

Thanks for the very informative reply, you guys are great. I have no problem buying a fresh air system and yes, I probably would sell it on E-Bay when I no longer needed it. After many years of absence, from the days of lead,lacquer, and siphon guns, I want to refurbish and paint a bunch of JD garden tractors that I have collected and needed your inputs on this important subject which we never worried about years ago. I have much to learn anew now and seek your advice and thank you accordingly for it.

I now need to look at face masks and hoods, what are some good sites for this information?

Mike

 

[Anonymous-0]

i have put some thought into a homemade supplied air system . i had given some thought to the vacum cleaner and decided against it because the air goes through the motor for cooling . vacum ceaner motors are brush motors and you would be breathing the fumes from the motor . what i came up wth is to use the blower from clothes dryers . i have 2 that i have removed and modified for use but haven't tested them yet . my plans are to remotely locate the blower and use the 4" corrigated flexible drain tile hose (very cheap ) to get to my work area then reduce to smaller flexible hose and connect to a hood or mask . any fed back on this idea good or bad will be apprciated . if it will work it should be inexpensive .

 

[Anonymous-0]

Hi Rod:

Another quick question. I am planning to do both sandblasting and painting. What are your thoughts on getting two different hoods or would one for both applications suffice? Also, if one were to use a good quality positive air flow hood would you also need a face mask? Are latex gloves acceptable for handling paints or do you need different types. Sorry for the learning curve questions, hopefully, someday I will be able to impart knowledge to another learner.

Thanks,

Mike

 

[Anonymous-0]

CNKS: Your reply got me chuckling, as I've been accused on many occasions of spending twice the time and three times the money to build something from scratch as it would have cost to just buy it off-the-shelf! Guess it's the curse of being an engineer. I've also toyed with the idea of building my own supplied-air system, and would be interested in any ideas on where to purchase the hood setup, as that's the part that would give me the most difficulty. I'm sure I could come up with a way, but if I can buy that part off the shelf I have enough other components around to make the air supply and piping.

 

[Anonymous-0]

Mike,

My full facepiece was made by Pulmosan Safety, which is no longer in business. <a href="http://www.sassafety.com/shop/shopdisplaycategories.asp?id=35&cat=Respiratory+Protection">SAS</a> is a major supplier of hoods, masks and systems. <a href="https://secure.foxvalley.net/axispro_com/OCCS/Default.asp?Func=Menu&Name=Category&Value=HobbyAir%2DRespirators">Hobby-Air</a> also sells the individual masks and hoods as well as the complete systems. I don't know if the Breathe-Cool products are sold individually. <a href="http://autobodystore.net/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=NA">Neoterik</a> is another one. There are others also but those are the ones that I'm more aware off.

I have no experience with SA hoods so hopefully CNKS will respond concerning the hood and sandblasting. I wouldn't expect you'd [b:654c4848f0][i:654c4848f0]need[/i:654c4848f0][/b:654c4848f0] two supplied air hoods. The issue I see with using one for both painting and blasting is protecting the faceplate from the blast grit. I don't know if the acrylic peel-off paint protectors are suitable protection when used for blasting. CN would know. If you use a supplied-air hood for blasting, I see no need for a facemask in addition to it. The blast "hood" that I have has no supplied air. It's only covers your head and protects your eyes, face and hair from grit. It has no respiratory protection.

Regarding gloves, my experience with latex has been poor. <a href="http://www.epa.gov/opptintr/dfe/pubs/auto/gloves/index.htm#4">Nitrile</a> is much better and is generally recommended instead of latex. Latex goes to pieces very rapidly when exposed to reducer solvents. Nitrile will too but it lasts longer. You can get a box of 100 nitrile gloves for about $15.

Rod

 

[Anonymous-0]

Hoods used for the Hobby Air can be purchased from www.autobodystore.com. They are tyvec, and have presented no problem for me. When it wears out, you keep the frame and purchase a new cover.

 

[Anonymous-0]

I keep two identical hoods, use the older one for sandblasting, the newer for painting. As noted in the post below, once you are set up you simply replace the tyvec cover when it gets worn out. For my small sandblaster, I don't need the canvas or cloth hood, surprisingly the tyvec works fine. But, I used an extension between the sandblasting tip and the on-off valve at the end of the hose. That way I don't have to have my head/hood close to all the sand particles bouncing around, I can stand out of the line of fire. It works fine.

 

[Anonymous-0]

I have question about supplied air systems that I have always wondered about. How can you be sure that the paint fumes aren't getting to your supplied air system's pump? Where do you place the air source to make sure it doesn't get any fumes?

 

[Anonymous-0]

Hi,

That's a great question. It's also one of the most important when dealing with a fresh air system. Here's how I do mine: I always paint outside. I place my supplied-air compressor outside about 60-70 feet away from where I am spraying and around a 90 degree corner of the house. That location is also generally upwind from the spray area. The arrangement works fine for me. Which brings up another argument for exercising care in determining how much hose is needed between the air supply and the mask/hood. Some of the turbine systems have limited capability in that area so anyone should plan out an expected suitable air supply location before deciding on equipment purchase. The "official" turbine hose can also be quite expensive, which is another reason why I prefer the non-lub, tankless compressor. I run 100ft of standard, inexpensive, 3/8" pvc airline hose and believe my system would work just as well if I decided, for whatever reason, to add more.

Rod

 

[Anonymous-0]

here's another method - used SCBA systems from firefighting. i.e. Scott pac's. There has been a change to a higher pressure/ lighter weight system that has made many towns/city's upgrade.

What I've done is to gang 4 of theses old steel tanks together in the corner of my painting area and run them through about 50 ft of line in the face mask. I was able to get ahold of the pac's for free. I ended up buying the line and 4 way valving on ebay for about $80. Tanks need to be hydro'd every 5 years. Last time I had it done it was like $30. I get the tanks filled at my local dive shop for $5. I get about 25 min of air from a single tank. I run two tanks at a time. When those go dry I switch to the other two in the gang. That has been plenty of air for any of my projects so far. I think I have about 10 tanks in all with about 8 or so I keep in service.