Originally Posted by
Cubrath
Chuck,
I see the pictures of that GT40! I'm sure you know more about painting than I do!!
The one area that I have struggled with the most over the years is to dial in the paint booth. I wish I could justify a 75k downdraft paint booth but I just can't get the numbers to work. I also think that if I had 20" exhaust coming out of my garage roof my wife would divorce me and my neighborhood association would evict me! I will explain my poor mans paint booth and what I have found to get the best results.
There are four parts to the paint boot:
1) Clean work area
2) Contain/exhaust overspray
3) Lighting
4) Temperature control
The first one is obvious. You are not going to get good results painting outside in the wind. I took my third stall garage and framed it off with simple 2x4 construction. I then went to the local hardware store and bought 4 mil vapor barrier plastic sheeting. I comes in all sizes so get the right size so you can go from floor to ceiling all the way around the room without cutting the plastic. I just staple mine up and don't have any seams all the way around the room. I find this plastic last for about half the project so when it gets dirty I just staple up another new layer over the old. After three layers its time to tear it all down and start over. It is also easy to cut in filters and exhaust fans. I have moved the location of the filters and fans several times trying to get the best results.
You will also have to clean the booth between each coat of paint. I started out covering the floor and it just became a hassle. I now just sweep out and wash the floor between coats. Polyfiber sprays very dry so you will have a lot of dust between coats. Some paints you can wet the floor to keep the dust down and others (like polyfiber) won't tolerate the humidity in the booth. I found it best to just keep the floor as clean as possible.
The second one is the tough one. It is easy to contain the overspray and exhaust the overspray. However, I have found it is very difficult to do without introducing dust into the paint when using slower drying polyurethane paints. The problem is that when using poor man box fans (I know, more on that in a second) you can't move enough moving air to keep the dust suspended and it ends up in your paint. If you look at a 75K professional paint booth they use an enormous amount of air volume that they move through the booth and thats what makes them so good. The dust and overspray is moved out before it has a chance to end up in the paint. I have come to the realization that to get to that level is too difficult and expensive for me and for what I am trying to accomplish. I do use Walmart style box fans. I know they are not an explosion proof fan and there is risk in using them. I accept the risks with the box fans and after aprox 300 hours of spraying in the booth I have not had any problems. This is something you will have to decide for yourself. If you have the ability to use or find a paint booth fan by all means go for it. I am always on the look out for one that I can afford!
If you look at the pictures below you can see my setup. From my experience I have found that it is better to pull fresh air into the booth through the filters and exhaust the contaminated air out with a fan to get the best results. Over the years I have tried to force air into the booth and then use an exhaust fan to move more air but I had more dust contamination with that method.
My goal with my setup is to use enough air to clear the paint booth of overspray and introduce as little dust as possible. I have found the best results by using two high flow furnace filters at about the five foot level which allow air into the booth. I have used more expensive paint booth filters and couldn't tell a difference. I then use a box fan at the other end of the booth and simple cardboard boxes to duct the contaminated air out of my adjacent garage door. Its not fancy but I think it provides the best bang for the buck. Another side note, do not just pop your garage door and slide a box fan under it. It will wreck the top of your garage door with overspray. Ask me how I know!!
If you are going to use polyfiber polybrush/spray/tone or other fast drying paints you will have very few problems with this set up and dust contamination. If the paint dries quick it does not have time to pick up dust.
Third is the lighting. This is an important one for good results. You have to have enough light to see what you are doing but you also need to have enough light to see where the paint is going onto the surface you are spraying. This is what they call looking at the glare from reflected light. This can be accomplished by using light angled at 45 degrees from the surface you are painting. The lights can be mounted on the wall or you can use portable lights to accomplish this. I do a little of both. This also takes a little experimenting but when try it you will pick it up quick and be able to position your lights to the optimum position. Another side note is try and use LED lights or lower draw lights. If you try to run five halogen lights plus an Axis paint sprayer on one circuit you won't be painting for long! I have switched over to almost all LED lights and I am very happy with them.
Last but not least is temperature control. Even though my garage is heated I have found I can bump my temperature up in the booth 10 degrees with a small portable heater before I am ready to paint if I need to. I find that 70-80 degrees works best for me.
Next installment will be on a few of the tricks and tools I have found helpful while painting.
First picture is the outside of the booth, notice the small boxes at the bottom right of the picture to exhaust the fumes out the other garage door. Extend it out far enough so you don't get overspray on the house, you will be surprised at how much paint comes out. Also, move the cars out of the driveway!!
Second picture is inside the booth and you can see the small exhaust fan.
Third picture is inside the booth looking forward. You can see the two filters. The upper fan/filter is not used, just a failed experiment that has not been removed! I am also using two of the new BIG ASS LED lights on the ceiling and they are amazing.
Third picture is of the boot cowl that I painted yesterday. I'm very happy with the results. Notice my Carbon Cub tee shirt in the reflection!!
MR