THE PAINT BOOTH

 

I decided right from the start that most if not all of the parts for this plane would be primed for a couple of reasons. 

 

First is that all aluminum corrodes.  Priming slows this process down.  Most of the parts in this kit are made of alclad aluminum.  Alclad is very corrosion resistant in itself but I live close to saltwater.  I have seen the atmosphere in Florida break alclad down in a relatively short period.  Are you worried about weight?  I am worried about beauty and believe me corrosion is ugly.

 

Second is my belief that we are not building these planes to fly but rather we are building them to sell.  Do you have any other vehicle that has been in you possession for as much as 5 years?  When I sell this plane I believe the fact that it has been primed will make it easier to sell.

 

I will etch and alodine all of the parts with DuPont 225 and 226.  This product is available through most automotive and marine paint suppliers.  I will also use Alodine 1201 instead of the 226S occasionally because we stock it and sometimes I work on Saturday or at night and the auto paint store is not open.  1201 is available from Aircraft Spruce.  Both the 226S and the 1201 need to be stored in a relatively dark place.  Direct sunlight eventually will make them go bad.  Alumiprep No. 33 can be used instead of the 225S.  It is also available through Aircraft Spruce (read, "Delivered to your front door.").

 

I am going through this process to clean the metal in preparation for primer instead of as a needed treatment that aluminum that is bare (no Alclad) has to have for corrosion protection.  Aluminum has to be very clean for primer adhesion, whether or not it is alclad.  Bare aluminum has to be etched, alodined and primed or it will corrode very quickly.

 

I intend to use a commercially available primer that has Boeing Spec "BAC 377" made by DeSoto division of PRC Sealants, Inc.  I also will try Sherwin Williams CMO724400 primer to test it out.  It is available to anyone at most automotive retail outlets that sell paint.  Some marine retailers also carry the Sherwin Williams products.

 

“Door” side wall 2 sides clamped together. Door side on floor

I have been looking at lots of Internet sites and got some good ideas about building an in-garage paint booth.  I decided to build one of my own.  I was half done before I remembered to take a few pictures.  The photo at the left shows the “door side” under construction.  The photo at the right shows the two equal sides standing up.  I made the booth out of 1 by 2’s.  I assembled it with screws instead of nails and I applied wood glue to all the joints during assembly.

“Flow Through” door Filter box on top of fan box

 

The left picture shows the door side complete.  Note door is designed to allow air to flow thru. The right picture shows the filter box nearly done.  The metal box is to house the exhaust fan.

 

Fan box on wheels Fan box attached to filter box

 

I put wheels on the fan housing so that I could move it around easily (LH photo above).  The fan housing rolls right up to and into the filter box on the booth (RH photo above). 

 

Paint booth clamped together Explosion proof fan

 

The left photo above shows the booth clamped together temporarily.  The right photo shows the fan and the fan housing.  This is a 24” 1700 RPM fan driven by a sealed explosion proof motor.  It is very powerful.  When I first turned it on the housing rolled across the floor.  Quite impressive.  It is available from W. W. Grainger and it is not cheap.  Paint fumes are highly volatile, much less poisonous.  The fumes must be evacuated quickly and safely.  The act of applying paint with air pressure puts paint particles into the air.  These particles must be filtered in the exhaust system.  This is what the filter housing was built for.  If you don’t remove these particles from the air, they will attach themselves to the walls of your garage, your car, your neighbor’s car and anything else they can get to.   This is not a good idea.  You may even meet your angry neighbor’s attorney.  If you get cheap on the fan make sure that your life insurance is paid up.  Your loved ones may need the money to bury what is left of you if you manage to ignite paint fumes.

 

Fan in housing Carpet tape to hold plastic to sides

 

The left shot above is of the fan inside its housing.  The right photo shows the installation of carpet tape (two sided tape) on one of the paint booth sides.  This is to help hold the plastic in place.  By the way, the dimensions of the booth are 8’ wide, 8’ long and 7’ high. 

 

Paint booth assembled minus top, inside photo Paint booth assembled, outside photo

 

The left photo is the inside of the booth with a paint filter installed on the fan side of the filter box.  I put one more sheet of filter material on the booth side.  The filter material comes on a roll and is specifically designed for paint particles. I doubled it up to try to maximize the filtering process. RH photo shows the completed booth.  This booth was made to be easily disassembled.  To hold it together, I fabricated 16 each 5½ by 3½ wood blocks ¾ inch thick.  I attached two of these to each side of the booth with 3 wood screws.  I then used 2 machine screws with large washers and furniture nuts to attach any two sides of the booth together.

 

Paint booth assembly brackets Screen assembly to hold parts

 

Photo on left shows a close up of one of the attach brackets.  The 2 machine screws are easily removable allowing the booth to be disassembled.  The photo on the right shows a simple paint screen for holding parts during priming.  This photo also shows the filter box with additional filter material added from inside the booth (notice the masking tape.

 

O.K.  We have work space.  We have work benches.  We have lots of tools and we have a place to paint.  Let’s get started.  The first major assembly is the empennage.

Different filter material Installed in the booth

 

UPDATE: September 2002, I moved the paint booth with the rest of the kit to Tennessee.  We obtained an FBO in Gallatin (identifier M33) and I have been spending a lot of time there.  The RV 7 has been ignored since July and I believe I will have more time to work on it at our "new" place.  The two photos above were taken in Tennessee after the paint booth was moved to there.  I also switched to a different filter material at that time.  These pink filter elements, available at WW Granger, do a better job of keeping paint particles from getting into the atmosphere.  For details on the move click the link below.