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Topic Review (Newest First)
04-25-2013 03:47 PM
oldred
Quote:
Originally Posted by Serkan View Post
What about running a 50' hose and roll some of it inside a large garbage bin filled with cold water and put a water separator after that ?


That works like a charm, a barrel filled with water with a coil of Copper pipe in it is the usual way to do this and it's probably the best way short of a refrigerated drier to accomplish the condensation process. I think that while a length of rubber hose would not work quite as well as Copper pipe I seriously doubt you would be able to see the difference. If the air is cold and dry you might want to just try running the hose off the tank first because there might not be enough moisture in the air to be a problem.
04-25-2013 02:58 PM
Serkan It is still not warm in Canada and I can definitely pick a low humid day to do the job.

What about running a 50' hose and roll some of it inside a large garbage bin filled with cold water and put a water separator after that ?





Quote:
Originally Posted by oldred View Post
That compressor is going to have a 100% duty cycle and it's meant to pretty much run continuously however it will get hot enough to keep the water in vapor form with very little condensing in those small tanks. The solution is something that should be utilized anyway regardless of the compressor and that means cooling the air so the water can condense and be removed before reaching the spray gun. There are several methods for doing this but the most popular is not going to be practical for a temporary setup, that would be 50' or more of metal piping with collection drops and a water separator. In your case you are going to have to improvise by doing things such as choosing a day to spray with relatively low humidity and maybe running the air through a cooler of some type before passing through a water separator as near as possible to the gun. What you need to do is cool the air as much as you can by whatever means you might have available so that the water will be in liquid form rather than a vapor as it enters the moisture separator, a desiccant filter may be all you would need depending on the amount of moisture in the air, obviously a cool dry day would be far less of a problem than a hot muggy day. Even with a big high volume compressor there is no safe way of just connecting a hose to the compressor and connecting the gun to the other end, it's successfully done all the time but it depends on several factors and it's always risky. The only safe way of avoiding water is to have proper cooling and separation methods in addition to whichever air supply you have.

BTW, I don't think I would attempt to do this with that big diesel jack hammer compressor!
04-25-2013 02:12 PM
oldred That compressor is going to have a 100% duty cycle and it's meant to pretty much run continuously however it will get hot enough to keep the water in vapor form with very little condensing in those small tanks. The solution is something that should be utilized anyway regardless of the compressor and that means cooling the air so the water can condense and be removed before reaching the spray gun. There are several methods for doing this but the most popular is not going to be practical for a temporary setup, that would be 50' or more of metal piping with collection drops and a water separator. In your case you are going to have to improvise by doing things such as choosing a day to spray with relatively low humidity and maybe running the air through a cooler of some type before passing through a water separator as near as possible to the gun. What you need to do is cool the air as much as you can by whatever means you might have available so that the water will be in liquid form rather than a vapor as it enters the moisture separator, a desiccant filter may be all you would need depending on the amount of moisture in the air, obviously a cool dry day would be far less of a problem than a hot muggy day. Even with a big high volume compressor there is no safe way of just connecting a hose to the compressor and connecting the gun to the other end, it's successfully done all the time but it depends on several factors and it's always risky. The only safe way of avoiding water is to have proper cooling and separation methods in addition to whichever air supply you have.

BTW, I don't think I would attempt to do this with that big diesel jack hammer compressor!
04-25-2013 11:34 AM
Serkan I understand that it will supply enough air for the gun to spray continuously but doesn't it have to run all the time and cause a lot of condensation in the line ?

Is there an easy way to check if the air compressor is letting oil in the line ?
04-25-2013 11:30 AM
oldred Should work ok, 18 CFM should keep up and in any case the recharge time for that outfit would be seconds anyway. Make sure the exhaust is outside the building however for safety reasons (carbon monoxide) and the fact that the gasoline engine could be expelling soot and possibly even oil that could play havoc with your paint.
04-25-2013 11:22 AM
Serkan Anyone ...?
04-24-2013 07:29 PM
Serkan OK so I went to a tool rental place and I have 2 options :

-18 cfm at 90 psi , 10 gallon air compressor (gas powered)

-125 cfm, big tank (diesel powered)

Big compressor is more expensive and not convenient for me.

How would a compressor with high cfm, low capacity tank do for painting car ?

The compressor is smtg like this :


03-30-2013 10:52 PM
69 widetrack
Quote:
Originally Posted by Larry123 View Post
When I was a kid I watched my dad paint a tractor with a undersized air compressor. He would spray a few passes, then drink a beer while waiting for the compressor to pump up, paint job didn’t come out too good….
LOL...I bet your Dad came our real good...I remember back in the day when I used to indulge in a few pops while painting in my hobby shop...on cool days my flash times where measured by 2 beer...instead of 1. I hated those transparent colors that took 6 ot 7 coats...I'd run out of beer before clearing the car and had to resort to the old fashioned way to check to see if it was ready for another coat by touching the masking paper to see if it was flashed...LOL

Ray
03-30-2013 10:47 PM
69 widetrack Another thought would be hook the two compressors up in tandem, that way you would be getting the value of the CFM output from both compressors and the added 25 gallons won't hurt. I don't know the CFM output from the compressor that has the 25 gallon capacity but often a larger tank means they put a bigger compressor head on it. Your still in the over use mode but, if they where working together your recovery time would be much better.

Make sure you rough up the metal on the new pieces you put in with something like 80 grit paper on a DA...that way you'l get much better mechanical adhesion.

The installation of the new parts looks quite well done...good job.

Now if I had know it wasn't an American muscle car well...it wouldn't have mattered...LOL

Ray
03-30-2013 10:36 PM
Larry123 When I was a kid I watched my dad paint a tractor with a undersized air compressor. He would spray a few passes, then drink a beer while waiting for the compressor to pump up, paint job didn’t come out too good….
03-30-2013 09:49 PM
Serkan Wow thanks for all the replies. You guys are a great bunch in this forum.

I don't know how you guys treat outsiders but the car I am working on is actually an import

I will be calling the rental places after the holiday. Meanwhile I asked a friend and he has a 25 gallon compressor same brand as mine with inflated numbers

What if I were to use both compressor at the same time, switch the hose right away when pressure drops on one .

Here is a pic of the engine bay. I still have to sand down the frame rails and strut tower skirts to bare metal. I am not touching the firewall, it is scuffed up.

So there are only 2 sides and inner wells which aren't completely stripped.

This is a 2004 subaru impreza engine bay.

03-29-2013 07:41 PM
Northern Chevy I was laughing at the comment about using a large tank to pre fill before starting a painting project as thats actually what I did a number of years ago. Mind you it wasn't a vehicle but was pouring through gallon after gallon of tremclad rust paint onto grain bin hopper bottoms. I used a 500 gallon propane tank on wheels and pressured it up to 175 psi with a true 5 horse two stage compressor. That took an hour from empty to full to fill that tank size but the compressor is made to run fairly continuously and I've done that a lot in filling the tank for other air needs and the compressor never has missed a beat all these years. I was using a one gallon if not more canister type painter that would have used fairly low air volume and a long set of hoses off of that to the gun.
03-29-2013 06:24 AM
Lizer I had hooked up a 30 gallon tank to my 20 gallon compressor a few years back and I think it literally bought me an extra 10 seconds of spray time because once the pressure decreases the compressor kicks back on again. And it didn't take any time at all for the pressure to decrease. However, it took it forever to build the pressure back up.
03-29-2013 06:11 AM
oldred The little 15 gallon compressor should be capable of doing something like an engine compartment but of course it depends a lot on his other equipment. If using a conventional paint gun and the lowest air pressure that will still do a good job plus working in sections then it should work just fine, people have even painted whole cars with little compressors. However if the spray gun is a HVLP type and/or the whole compartment is sprayed in one operation then this is going to be a very frustrating endeavor! The trick to using a small compressor is to accept it for what it is and properly MANAGING what air is available because nothing can be done to make the compressor put out more air than it does already. Instead of trying to squeeze more air out of a too-small compressor concentrate on spraying the most paint practical with as little air as possible while still maintaining good results.


widetrack, I see your point and I understand that if 15 gallons gave 30 seconds of spray time (it wouldn't even be that long with only 15 gallons!) that an additional 45 gallons would add more time (another 90 seconds theoretically) but that's only 2 minutes of spray time, which is probably too optimistic, and then the problems would begin. While in theory it would take 4 times as long to fill a tank 4 times as big in reality it would not work that way because as the compressor heats up efficiency falls off rapidly. On a setup such as this by the time the tank was half filled the pump would probably only be able to manage 50% or maybe even less of it's original CFM rating, this problem will only compound itself the longer the compressor runs. If this is one of the little oil-less type compressors then filling that tank a couple of times or so without long cooling periods will most likely result in destruction of the pump. I have seen it tried many, many times and adding significant extra tank capacity will almost always result in more frustration rather than solving the problem.
03-28-2013 09:32 PM
Lizer I'm not going to speak in hypotheticals and theoreticals here, but I'll speak from practical experience with what I've actually done. I have a 60 gallon 3.7 hp 13 CFM compressor now, but before that I had a Crapsman 5 impossible HP from 110V 20 gallon. I ran a whip from it to a water filter/regulator on my wall, and that's where my main line tied in. I could easily spray an engine bay with my 20 gallon. In fact, when I moved out here to Michigan, before I got the 220 ran in my shop for my big compressor, I was spraying with my little 20 gallon and it does just fine for small things like an engine bay. I know yours has 5 gallon less capacity, but take this for what you will.

Something else to chew on. I took my engine bay down to bare metal, primed with Sikkens 1K wash primer (etching primer in a rattle can) and sprayed two coats of Bill Hirsch chassis black (also in a can). The cans have the tip that sprays the pattern so it lays on nice. This I did in 2009. It looked great then. And still looks as good today as it did then. There's only one part of my car that I haven't had to continually sand down and respray because of rust popping through throughout the course of my restoration, and it's been the engine bay.
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