Prior to getting to this point, in the week since my last post, I have been very busy reviewing my fiberglass materials and instructions from the practice kit as well as my old information from the Composite Sport Air work shop I attended a few years ago. I found myself deeply immersed in the details of the original reason I started on this LE mod a long time ago - to be able to select and change out different leading edge platforms - one of those being a formed leading edge with LE light simulated machine ports that I can connect to the electrical system and mount to my leading edge to have a little simulated gun fun.
There is a lot of fiberglass work involved that will utilize a number of different materials. the real challenging part (yes I haven't even got to that point yet), is creating the removable leading edge that will attach to the subskin that I have been working on for so long now. I will either be making this detachable LE from metal or from fiberglass, and I will be making a separate mock up to test out which method may be best.Anyway, lots of research and reviewing previous posts and information have taken place over the past week.
As it turns out, I also needed to do some review and research and relearning of how to prime. I had to review and relearn everything from the setup, prep, execution and cleanup. The main focus was on the two small 90 degree rear flange extensions that need to be riveted to the modified 408 rib. The rib itself also needed to be primed before I could rivet the extensions on. Since this seemed like a small amount of metal to prime, even for my 7 ounce touch up gun, I decided to prep the normal 408 rib as well, and also the original W423 joiner strap for the left wing.
The other part of this adventure was trying to determine if my Akzo Nobel 2 part epoxy primer was still any good or not, since I first obtained this stuff from Aircraft Spruce back in 2012 at about this same time (May). This stuff is supposed to have a very specific shelf life that has long since expired, so this was to be an experiment to see if the primer is still good or not.
So all I needed was my smaller touch up spray gun from Harbor Freight. It has a 7 ounce cup but normally holds 5.25 ounces of fluid. Akzo Nobel epoxy primer is mixed at a one-to-one ration and then must set for .5 hours before it is ready to use. These next couple of shots show everything that needed to be set up to prime.The list includes:
Card Table
Newspaper
rubber gloves
wood paint mixer
mixing cup
paper filter
spray gun
method to hold the gun steady on the table (I used the tea pot from my trailer)
Both parts of the primer (each part comes in a 1 gallon can)
paint shaker
Plastic Turkey Basters (one for each part of the primer)
Post It Easle for testing spray patterns and flow
Acetone
microfiber cloth
paper towels
respirator
Safety goggles
Small sized priming fixture with chicken wire for supporting the parts
Turkey Basters? What on earth are those for? Well that became another experiment. In the past I had a hard time getting the material in the one gallon cans into the small mixing containers that I use from NAPA auto parts, and this led to very big messy, smelly mess during one session. SO I wanted to find a way to be able to extract smaller amounts of material from each one gallon can without having to pour it out of the can. All these plastic paint can doodads just don't seem to work well for me, and I wanted a better, safer, cleaner solution. SO I went looking for a metal turkey baster - never found one. But I did find some plastic ones. I knew that they would allow me to cleanly take the amount of material from each can and place it in the mixing cup, but I was not sure if the plastic would met away when dipped into each can, or if it would contaminate the primer somehow. Decided to give it a try and see what happens.
Here is the result after using each one. Prior to dipping them in the can, they were both clear. In the next pic you can see how the plastic has in fact crazed just a bit, but for the short time that I needed them to get the right amount into the cup, they seemed to do the job that I needed. Made for a much cleaner mixing session:
For smaller sessions not requiring very much primer, I love using the 1/2 pint mixing cups from NAPA auto parts in this next picture. After mixing all this volatile carsenigenistic stuff, the basters and the cups all go into the trash.
And here is the primer. Pigment comes in one can and the hardener comes in the other one:
Notice the mix date going all the way back to 2011. This stuff was made in 2011, was sold to me in 2012, I believe a month before the date in which it was to expire if I recall correctly. Then it has sat on my garage floor in hot summers and extremely cold winters, and has not been used in well over 2 years. SO yes, this was going to be a grand experiment indeed. I figured that if it did not perform as expected I could remove it from the metal and order some new stuff. At 200.00 a pop, it was worth a try to see if this stuff was still any good.
Next up is my jury-rigged solution for keeping the spray gun upright after everything was mixed and poured into the cup for the gun. the instructions say to keep the gun level after the cup is attached to avoid getting material in place in the gun where it should not flow. I don't any sort of hangar for this gun, and when I also added a Harbor Freight air regulator to the gun, it made it even more unstable. So I decided to try the tea pot from my trailer, which I had removed while it is being serviced in preparation for the upcoming 2017 Airventure in Oshkosh. While not perfect, it did the job:
And finally, here is the Post it easel sheet that I use to test the pattern and flow before I use it on each part. I have to open the flow valve on this gun all the way to get the flow that I need, and I try to keep the pattern to about 4-6 inches per pass.
And here are the parts after priming. Best I can tell, the primer seemed to mix and lay down exactly as I remember it from before. The parts all look OK, but they are still drying due to increased humidity and rain storms that hit the area right at the same time I was ready to prime (figures). I will check them tomorrow to see if the primer looks OK. If it does then I will be smashing some rivets on the modified rib tomorrow night. Haven't done that in a while either.
All total, it took me about 2 hours to review instructions and get familiar with the spray gun again, an hour to set everything up, .5 hours to spray the parts, and .5 hours to clean everything up. I was glad that I was able to keep everything clean, and that the primer and the mixing all seemed to work as expected.
KPR....
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