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Discussion Starter #1 (Edited)
A recent thread about homemade fresh air respirators and the fact that I am about to start the painting process got me interested in making one rather than spent that 350-400 bucks for the low end models I have seen advertised.
So anyway I built one today and it seems like its probably going to work pretty good.
Here is the cost breakdown...

Shop vac 30.02
Respirator 19.99
Sprinkler connector 2.99
Sump hose 6.99
8’ Shop vac hose 14.94
Goggles 2.99
Brass ferrule 1.49
¾ Ball valve 5.49
misc plumbing/clamps 10.00
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$100.00 (apx)


And here are some pics (please excuse the 'model')

http://pg.photos.yahoo.com/ph/bikeopellidave/album?.dir=1c73&.src=ph

I used actual 1 1/4 shop vac hose on both ends with the cheaper (24 foot) sump hose in the middle. The sump hose (Craftsman 42 27909) is not nearly as flexible as the actual shop vac hose. Tried to get away with running the sump hose to the respirator but it was too stiff so I purchased an 8' length of vac hose (Cost 1/2 what the shop vac did!)
I was surprised how much excess air there was when I first tested it (whistled like crazy) so I put a 'T' right after the shop vac outlet to bleed off the excess air followed by a ball valve to tweak the airflow to the respirator. Works just about right.
The respirator is an 'AOSAFETY" unit, part nbr 95190. Came with a standard filter which I tossed. Fitted the grey 'T' into it. Got lucky, is a perfect fit.
I also wanted to have a little positive airflow to the goggles so I plumbed the sprinkler line from the grey 'T' to the middle of the top of the goggles. Used a 1/2 inch long brass ferrule and a small clamp to secure it to the goggles. This line was too stiff and did not want orient very well so I stumbled on the idea of heating it with my heat shrink gun and coaxed it into the shape I wanted. Again, the airflow to the goggles seems just about right.
I purchased all the parts at a local hardware store. Did not glue or fill anything. Most connections were a nice tight fit, where they were not, I used clamps. Took me about 8 hours to do it with three or four trips to the store.
 

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That is awesome. Think I'll try making one of those.

One question.... how do you get your head into that red thermos?:D
 

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nice way to do it....but extra hoses around make me nervous...:thumbup:
 

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Looks nice :thumbup:

I'm working on homebuilt system right now with a couple of major differences. On my setup I'm using a bathroom exhaust fan to supply the air, and I'm using a full hood rather than a mask and goggles. I can't get a mask to seal good with my beard and my wife has threatened to leave me if I shave it off so a hood is my only choice :) I like your shop vac idea, if I hadn't already gone to the trouble of building an enclosure for my fan I might have changed my plans.

One quick tip for testing your system that a buddy of mine showed me. Pick up several smoke bombs from a fireworks store and light them in an enclosed area while wearing your respirator then if you smell anything you'll know you still aren't protected. That's what convinced me to build my system. I was using a regular canister mask and fresh filters each time I painted thinking that I was probably OK because I wasn't smelling the paint (or at least not much if any). When I tried his trick I was smelling the smoke and sulfur odor within a few minutes. Definitely not long enough to paint a car. With my homebuilt setup I am only getting a very faint smoke smell, and then only after several minutes. I've got a few bugs to work out that should (hopefully!) eliminate the smell completely. I haven't been in any rush because my 36 is still quite a ways from being ready to paint so I have plenty of time to tinker with my respirator before I need it.

EDIT>>>
My bad, I saw the link to this post on another forum and replied to it before I realized it was nearly a year old. Sorry about that!
 

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BackwoodsBum said:
EDIT>>>
My bad, I saw the link to this post on another forum and replied to it before I realized it was nearly a year old. Sorry about that!
Not a problem. It was interesting and pertinent stuff you had to offer. Old threads get revived around here all the time with new and updated info - often very helpful.
 

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i have experimented with a setup of my own... but i use the air from the compressor, with a small pressure regulator with a flow screw on it... got for 28 bucks at a discount auto warehouse store... the mask is a hudson mask (you know those greenish pvc masks in hospitals, with tape half over the holes, so it doesnt dry out my eyes) and a home made canister for the water and oil filter from the expensive sata systems.. (had to buy that one new) but other than that its only 1/4 inch pvc hose and used stuff (its duct-tape "installed" in an old el-cheapo tool-belt) the excess air simply blows past my mouth and out the holes in the hudson mask

cost me about an evening in the shop to mcgyver together (plus the sata filter).. and its one of those things i mean to redo in a less homebrew style... but if it aint broke.
 

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the things that come to mind are
1 static electric created off the vac hose please make sure its grounded some how preferably more than once and

2 where is the vac motor ? a gain i am concerned about a spark that will ignite your paint fumes let me know about these things please ive toyed with these ideas my self but my problem @ the present is getting a shop to work out of

it looks to me as if you've done a fine job
like ive always said necessity is a mother :nono: :D of invention

sr66 :thumbup:
 

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I built my own also. I started with a bathroom fan but it felt like I was doing as much of the work as the fan was on drawing the air in. I was going to try a little pump for airing up air mattresses, but it runs on DC and with the paint booth set up in the garage I wasn't able to get to my charger. A friend had lent me the pump for his HVLP gun. It has a hose coming out of it about the size of a big garden hose. It put out way too much air. I may have to look into getting one of those valves or look for a way to feed some air off.

But I am really happy with my mask that I got for $19 plus shipping (although a hair bigger size would have been nice.. I have trouble getting my glasses in it). The sump pump hose slips right over the spot where the filter normally attaches, and then I just block off the standard air hose inlet.
 

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I doubt that anyone will pay much attention but you guys are playing with fire here. Do what you will but that vac set-up is potently lethal. Don't believe me? check with a respiratory professional and you will see that pressure you could be exposed to here can cause serious lung damage if not properly regulated. There are other problems also such as tiny particles from the motor and other parts that will normally wear and these will be induced into your "clean" air. Breathing compressed air from a compressor is especially dangerous because you will again expose your self to dangerous air pressures and even greater contamination from oil and even dangerous levels of carbon monoxide but the biggest problem is that your very life will be hanging on a regulator that is set to a level it was not designed to operate any where near, if that regulator fails(and it happens)it can kill you. Guys I have worked with compressed air systems for well over 30 years and I know what I am talking about, What you are doing here is very dangerous and your life and health is not something to experiment with. If you are not willing to believe what I am telling you talk to a professional in breathing air systems and he will tell you the same thing that I am and probably a lot more. Most people would be surprised at how low a psi setting it takes to cause lung damage, remember your lungs are very sensitive and even one small mistake could be the biggest one of your life.
 

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i hate to tell you this... but being a med student i actually considdered this whan i built the system.. the mash i am using is a hudson mask used to guve oxygen to patients from..... a compressed oxygen outlet in the wall!! it has two 3/4 inch holes over the nose region which allows excess air (like expired air) to escape... the overpressure your lungs will tolerate is in the order of 6-7 psi (pressure generated when you sneeze is about 6 psi, and im not dead yet having sneezed many a times)

and with regards to the oil... that is fintered out using the sata activated carbon filter to which i fabricaded a crure canister...

all good pionts though
 

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Deuce-since you are a med student then you should be able to see the problem here and you are doing a disservice to everyone involved in this by trying to say this is ok. You also make my point about the compressor set-up, you have high pressure on one side of that regulator and a setting on the other side it was never designed to drop down to, now as a med student you should know what will happen if that thing allows a surge of high pressure(and it CAN happen!). Also do really believe you can filter carbon monoxide with activated carbon? Any kind of obstruction on the vent on that shop vac set-up would send pressure levels dangerously high, far above the 6-7 psi level and how many of these guys have a way to measure that kind of pressure in the first place? Are you willing to bet your life on a shop regulator that is running grossly out of designed range? If you go above this by only a few pounds and are exposed to it for slightly longer periods of time than a short surge at high pressure? There is no doubt that these things can work but if you make even a small miscalculation you can do serious harm. Your comparison between a compressor or shop vac to a dedicated breathing O/2 system just does not make sense and is the old saying of comparing apples and oranges. Pointing pressurized air at your lungs is like pointing a loaded gun at your head if something goes wrong you could be in trouble. As I said these things can work IF you do everything right but the ways to err are many and the potential cost is too great. If you want to take the chance your self than that's you business but please don't tell someone else that it's ok when it is clearly not.
 

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Ok, lets take it from the top: first of...
I do not assume to remove carbon monoxide from my airsupply using activated carbon... i am using a Sata carbon filter to remove oil and solvents from the air, not wanting oil in my lungs (the sata filter is what the professionals use in the 500$ Sata fresh air systems)

i am however curious as to where the carbon monoxide should come from?? i am sucking fresh air into my compressor from an intake on the far side of the shop... away from the shop vent..

the compressed air now passes through the refrigrated drier and through the watertrap and large pressure regulator...

on my toolbelt i have a tee that allows me to tap onto the pressure hose from my compressor, onto this i have fitted a pressure regulator WITH a flow valve (not unlike what you propably have on your MIG welder)..

from this i am running a hose through the Sata carbon oil and solvent filter to a medical "HUDSON RCI® ADULT NON-REBREATHING MASK with SAFETY VENT"

now there is no way i can overpressurise my lungs with this $1.98 baby... its FDA aproved for chrizt sake! even if everything malfunctioned, and i got 140 psi to the mask, it would simply blow past my mouth and vent through the safetyvent.... its not like im intubated!!! :drunk:

but that doesnt mean that i dont agree with you that breathing through a shopvac, without thinking safety is about the dumbest thing ever...

happy hotrodding
 

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Ok, as I said it can work if engineered properly and it looks as if you have done that from a pressure standpoint however it is dangerous to assume every one will take the precautions you did. But again my point is one mistake may be too many and this should not be encouraged because it is dangerous and the fact that you did not know about the carbon monoxide just proves my point. While significant amounts of carbon monoxide are not always present it most certainly can and does form during the compression process with the amount depending on the oil and other impurity's in the air being compressed. I guess I harp about safety too much but as I said in another thread a few days ago I have seen far too many preventable accidents in my Field of work and since I work with compressed air it just plain scares me to think of someone with only the basic understanding trying to build something as serious as a breathing air supply. The only one described that appeared safe was the vent fan, as about the only problem I see with it is if it simply did not supply enough air. You have a major advantage in that in your chosen profession(very impressive by the way) you have a good understanding of how much pressure your lungs can tolerate and apparently how to control it but honestly do you really believe it is something everyone understands enough to build something as critical as this? I think that instead of everyone jumping in and applauding what seems like a good idea we need to take a good look at the negative side and this idea certainly has one. There are a lot of people that might hook up a shop vac with an improperly designed vent and expose themselves to many times the safe psi levels if we all just say "yeah great idea, go for it" this is simply too dangerous for a home experiment. And to anyone thinking about doing it I ask, are you willing to bet your life that I am wrong?
 
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