My son's 1980 repaint begins.
10-06-2010, 10:39 PM
#166
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I don't mean to be a *****. You've done way more than I could have. But perhaps postive pressure would be better. Everything is forced OUT by pressure rather than using your 'whiteroom' fan as a vaccuum , sucking dust in from the spaces and cracks and filtering it to the outside.
You have done a Masterful job, don't get me wrong
You have done a Masterful job, don't get me wrong
However, I'm sure it's going to work pretty well!
Don't forget to mask off the 4 wheel arches, as they are a major source of dirt that gets stirred up when you spray.
10-06-2010, 11:14 PM
#167
Drifting
Thread Starter
If I went with positive pressure then do I just turn the fan and add filters on the intake side??? I really don't know whats best at this point. There is soooo much crap on the net...for very "do it this way" there is as many " no thats wrong" statements. I could use some feedback from those that know. My main concern is the positive pressure will cause the airborne paint to settle back on the car causing a ruff surface???
10-07-2010, 12:13 AM
#169
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[QUOTE=Mark SF;7954825]Like he said - positive pressure is best, as you won't suck dirty air in through the tiny leaks.
I didn't read that.
Anyway NASA for all their satellites and shuttle assemblies always used positive pressure.
Must be for a darn good reason.
Look once your inside structure is clean with pos. pressure it'll stay that way.
With suction of course you open up some plastic to enter and outside dust and **** will come in with you.
I didn't read that.
Anyway NASA for all their satellites and shuttle assemblies always used positive pressure.
Must be for a darn good reason.
Look once your inside structure is clean with pos. pressure it'll stay that way.
With suction of course you open up some plastic to enter and outside dust and **** will come in with you.
10-07-2010, 02:31 AM
#170
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If I went with positive pressure then do I just turn the fan and add filters on the intake side??? I really don't know whats best at this point. There is soooo much crap on the net...for very "do it this way" there is as many " no thats wrong" statements. I could use some feedback from those that know. My main concern is the positive pressure will cause the airborne paint to settle back on the car causing a ruff surface???
Clean rooms all use positive pressure, so do chemical suits, biological suits, you name it - because you can have small leaks and the escaping air just keeps the nasties out.
10-07-2010, 08:05 AM
#171
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I've done 4 cars now with a negative pressure system as shown in the above link. Yes, dirt can come in through the "door" you need to get in and out. It is just more elegant to rig the downdraft with a perimeter system if you use an exhaust style system. The disadvantages are as noted - a home system will have compromises. Pro paint booths are downdraft, this is the main point, regardless of whether the downdraft is from a fan blowing down or a vacuum (not technically a 'vacuum') on the floor. Since I'm 'single-stage-to-color' there is no clear, making the job less dust sensitive. Each shop, skill, gun and paint is unique, but your set-up looks good. Using lacquer with a sparking fan is a no-no, however. A negative home system should have an old style belt driven furnace fan with the motor isolated from the vapor stream. If you rig a positive system a row of tubes can be used as a flow straightener - I've done this for scale wind tunnels in the physics class I taught. In any case, the area of 2 typical furnace filters is enough volume for hobby work. The filters themselves will soften the flow. The airflow is mostly for you - breathable air; the overspray benefits are not quite so important, but still considerable. The proof of my method is my floor - the amount of paint on my floor after a job is minimal and most sweeps up - the suction pipes are full of paint dust.
10-07-2010, 06:58 PM
#172
Man of many SIGs
Rennlist Member
Rennlist Member
More filters and airflow would probably be better but what you have there will work fine. Be sure to clean EVERYTHING. Once you are sure you have cleaned everything, CLEAN IT AGAIN. 
Keep in mind that no matter how clean you get the booth and car, you will still get some dirt in the clear. When we painted my car, the roof was done first. Then, once dry, it was papered over and the rest of the car was cleaned again. Then the sides were shot. The loose parts such as hood, headlight buckets, mirrors, valance, fenders etc. can all be done later. That way you will have room to spread them out so you don't brush up against them with your cloths or the air hose. If I were you, I would contact Sonnett over on Pelican and explain what you are doing. He might have some pointers. Our booth is homemade as well so he might have some tips to save you some grief. In the end, you will be able to sand out the dust from the clear if the clear is laid down thick enough. You will see flaws but most other people will never see them. It will look great and you will be able to be proud of it.
Go get 'em
Keep in mind that no matter how clean you get the booth and car, you will still get some dirt in the clear. When we painted my car, the roof was done first. Then, once dry, it was papered over and the rest of the car was cleaned again. Then the sides were shot. The loose parts such as hood, headlight buckets, mirrors, valance, fenders etc. can all be done later. That way you will have room to spread them out so you don't brush up against them with your cloths or the air hose. If I were you, I would contact Sonnett over on Pelican and explain what you are doing. He might have some pointers. Our booth is homemade as well so he might have some tips to save you some grief. In the end, you will be able to sand out the dust from the clear if the clear is laid down thick enough. You will see flaws but most other people will never see them. It will look great and you will be able to be proud of it. Go get 'em
10-07-2010, 07:46 PM
#173
Rennlist Member
Sucking is always better than blowing! Sucking only allows for ambient air pressure to push anything into the paint booth, while blowing allows all kinds of stuff to be blown in forcefully and perhaps at much greater force than ambient air pressure will allow. Stay with the set-up you have. It is consistent with all the how-to-paint books I have.
10-07-2010, 08:56 PM
#175
Rennlist Member
I don't mean to be a *****. You've done way more than I could have. But perhaps postive pressure would be better. Everything is forced OUT by pressure rather than using your 'whiteroom' fan as a vaccuum , sucking dust in from the spaces and cracks and filtering it to the outside.
You have done a Masterful job, don't get me wrong
You have done a Masterful job, don't get me wrong
10-07-2010, 09:30 PM
#176
Rennlist Member
Look at it this way: Would you rather have ambient air flowing gracefully across your freshly painted car after coming naturally through the furnace filters, assuming you have the other leaks sealed up, or would you like to have air being forced into the paint chamber by your big fan directly onto your freshly painted car bringing with it everything it can suck or blow through whatever filters you have at that end of the booth?
10-07-2010, 09:59 PM
#177
Rennlist Member
In fact, Dean, if you were to give any merit to this bad advise about blowing the air in rather that out of your paint booth, all you would really need to do would be to rig your big fan up with some kind of large filter chamber on the inlet side and some kind of difuser on the outlet side and then simply blow filtered air over your car while you are painting it and for a short time after. You would not even need a paint booth.
10-07-2010, 11:35 PM
#178
Drifting
Thread Starter
I am staying with the negative pressure. Thanks for the ideas guys. There are good ideas both for and against...I just am making a call.
The LAST thing I want is to let the airborne spray dry and then fall on the car. Getting airborne spray OUT fast makes the best sense to me.
I shot the rock guard on the rockers today and finalized masking the car. I start jambing in the morning!!!!
I will have updated pics tomorrow showing some COLOR!
The LAST thing I want is to let the airborne spray dry and then fall on the car. Getting airborne spray OUT fast makes the best sense to me.
I shot the rock guard on the rockers today and finalized masking the car. I start jambing in the morning!!!!
I will have updated pics tomorrow showing some COLOR!
10-07-2010, 11:41 PM
#179
Drifting
Thread Starter
More filters and airflow would probably be better but what you have there will work fine. Be sure to clean EVERYTHING. Once you are sure you have cleaned everything, CLEAN IT AGAIN. Keep in mind that no matter how clean you get the booth and car, you will still get some dirt in the clear. When we painted my car, the roof was done first. Then, once dry, it was papered over and the rest of the car was cleaned again. Then the sides were shot. The loose parts such as hood, headlight buckets, mirrors, valance, fenders etc. can all be done later. That way you will have room to spread them out so you don't brush up against them with your cloths or the air hose. If I were you, I would contact Sonnett over on Pelican and explain what you are doing. He might have some pointers. Our booth is homemade as well so he might have some tips to save you some grief. In the end, you will be able to sand out the dust from the clear if the clear is laid down thick enough. You will see flaws but most other people will never see them. It will look great and you will be able to be proud of it.
Go get 'em
Keep in mind that no matter how clean you get the booth and car, you will still get some dirt in the clear. When we painted my car, the roof was done first. Then, once dry, it was papered over and the rest of the car was cleaned again. Then the sides were shot. The loose parts such as hood, headlight buckets, mirrors, valance, fenders etc. can all be done later. That way you will have room to spread them out so you don't brush up against them with your cloths or the air hose. If I were you, I would contact Sonnett over on Pelican and explain what you are doing. He might have some pointers. Our booth is homemade as well so he might have some tips to save you some grief. In the end, you will be able to sand out the dust from the clear if the clear is laid down thick enough. You will see flaws but most other people will never see them. It will look great and you will be able to be proud of it. Go get 'em
It sounds like that is the best way to minimize the "airborne dry fall" I have been concerned with. MANY thanks for the idea and guidance.
10-08-2010, 05:10 PM
#180
Rennlist Member
He seems to do nice work:
http://forums.pelicanparts.com/porsc...s-painted.html