I couldn't resist. I Clecoed the horizontal stab skins onto the rear spar. I took this apart and then started on the first step - break the edges of the rear spar stiffener. I used the Scotch Brite wheel on my bench grinder to do this.
I then put together the center elevator bearing hinge. I match drilled the holes on the drill press and then primed the bearing. The advice in the construction manual to have a can of self etching primer is good. I went to the trouble Alumiprep, Alodine and prime it all because I didn't have a spray can of primer and I wanted to go through the process to spray it on anyway. When it dried I riveted it together. This was my first real riveting job (other than practicing with scrap).
After more match drilling, I then moved on to the front spar. More match drilling on it and then I shaped the re-enforcing bars. Again I used a not-course-enough file and spent hours getting it to look right.
Next I notched the two inside front ribs to fit around the
re-enforcing bars. The metal shears worked well for this for a rough
cut. First I drilled a hole where I had to make a 90. I then filed
(again, aaargh) them down smooth and then put them under the Scotch
Brite wheel.
I then fluted some of the ribs using fluting pliers. It is amazing how that works. The ribs were all little bent from the manufacturing process and just by bending (fluting) the flange part straightens it out perfectly. I then Clecoed the spras and ribs together and drilled some holes.
I took it all apart, cleaned the holes and put it all back together. This time I Clecoed on the skin on the left side. I match drilled the holes on the inside rib and the inboard part of the spar.
The yoke for the pneumatic squeezer came in today. I put it together and practiced dimpling and riveting some scrap. The scrap is now scrapier.
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I finished drilling the front inside rib and then removed the Clecos in the left stabilizer. I then drilled and did everything I did to the right stabilizer as I did to the left one. The picture above is of the right stabilizer flipped upside down.
It wasn't easy to drill the holes that attach the inside rib flanges to the front spar. I used a long drill it which I bent slightly as it turned to try to get it to be normal to the spar. Riveting these is going to be interesting.
I also didn't notice that the front two holes in the outer spar on the left stabilizer need to be drilled. I need to Cleco most of it together again to do this Aargh! When that is done, it will be time to debur the holes, have one last shot at breaking edges and then Alumiprep, Alodine and prime everything. I still don't have a plan for containing the giant cloud of primer that will surely result.
I put the right stabilizer back together with Clecos because I was worried about the hole lining up between the skin, re-enforcing bar and middle spar. When I was taking out the Clecos last night I noticed that it wasn't lined up by almost a full diameter. When I put the Clecos in tonight, it was within about 1/4 of a diameter and the Cleco went right in. Panic over nothing. I took it apart and Clecos the left stabilizer back together. I needed to do this to drill the two holes I missed last night.
I removed the plastic on the inside of the skins, broke the edges and deburred the holes. Everything is ready for Alumiprep and Alodine.
The first picture below is of the front web of the middle right spar inside of the innermost rib. Hopeful it shows how little clearance there is for drilling and riveting.. The second picture is of the same but from the side.
The third picture shows the outside of the outside right rib. The
fourth one is of the inside of the right stabilizer as viewed from the
inside rib. The multiple reflections really make it confusing to look
at. There are two Clecos on the top - the rest are reflections. The
dotted lines going up and down are flutes in the middle rib.
After I finished with this, I practiced dimpling and squeezing rivets with my pneumatic squeezer.
At lunch I went to Harbor Freight on a recon mission. I bought a HVLP mini spray gun. HVLP means high volume low pressure. It is supposed to put more paint on the surface and less generating a friendly neighborhood cumulonimbus. It is supposed to do a better job too. I'll soon find out.
One problem I had was the front middle rivets. My C-Frame bumps up against the skin where it can barely get to the second rivet but certainly not the first. There are probably several ways to do this but I chose to drill a hole on one of the rough sides of my bucking bar so that the die could fit into it. It worked just fine.
The C-Frame scratches the aluminum. I put it on top of a towel but that didn't help a whole lot.
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On the third to last dimple on the right spar, I manager to poke a hole in the flange part of the rib with the pneumatic dimpler. It went through it like butter. I started to try to "fix" it but I decided against it. This was a real bummer. I turned in for the night.
I think part of the problem is that I was tired after working a full work day and then almost 6 hours on this.
I thought my idea about the bucking bar was original but I found it in the Van's manual. I had read it before but apparently it was retained by only 1 or 2 of my neurons.
Tonight I Alodined the skin again and this time put it on thicker and made sure it was on for the full amount of time. It turned out a lot better (see below). I finished dimpling and then I etched and Alodined the rest of the stabilizer parts.
I plan to continue with the stabilizer with the spar with 1 extra hole up until it is time to rivet it in. The new spar should be in way before then and after preparation, I'll make the substitution.
I am ready to prime.
I primed all of the stabilizer parts. I used 600mL of Akzo to cover everything with a fairly light coat. I know it's and eye sore so please excuse the picture of me. I will someday need to prove to the FAA that I did all of this.
Lessons:
- The paint boot isn't necessary with the HVLP spray gun. There is very little paint mist.
- The fumes are strong. I wore all of the protective garb with a mask with filters and I still breathed in some of that stuff. Since there is very little mist with the HVLP gun, next time I'll paint out in the open.
- Before the 30 minute "induction" period, some acetone needs to be shot through the gun to keep it from getting clogged.
- Having the parts hanging from wires is OK since the gun doesn't really blow them around. I had them laying down on coat hangers (our chicken wire substitute) which lead to inevitable touch marks when I had to turn them over.
I don't think it is the greatest paint job in the world (due to the touch marks) but I think it is good enough.
I didn't rivet in one of the rear spar halves, which I have decided to
replace.
I went flying (to show the Warrior to a prospective buyer) and then came back and resumed assembly of the left stabilizer. I riveted the front middle rib onto the skin on both the front and back sides. I couldn't get my hand in to buck the rivets but Christine came to the rescue. All except one turned out great. I didn't push down on the rivet gun enough so the rivet was not flush. I drilled it out and we did it again. This time it turned out perfect.
I am getting to be pretty good at drilling out rivets Unfortunately it highlights my my lack of skill in other areas.
I
then blind riveted the front and back middle ribs to the middle spar
with blind rivets. The occasional gray in these pictures is of self
etching primer. Whenever I manage to ding the original primer, I give it a little
shot of this stuff to keep it protected.
Lessons Learned Today:
- A 1 lb bucking bar is not enough for AD4 rivets. My arm is still shaking.
- Think before riveting or else you might have to drill it out (like I did).
Out of all of these rivets, I only had to drill one out. This one was because I riveted one place with the plastic still over the hole. Aaargh. Since I am no expert, I checked ALL rivets with my handy rivet gauge. I had to pound some more on about a half a dozen of them.
I am finding that very little pressure to the rivet gun is working out best for me. About 25 PSI seems right for these AN426AD3-3.5 rivets.
The primer is tenacious. I managed not to scratch the inside skins even though I accidentally let the bucking bar bump against it several times while riveting.
I don't think there's anything else to do on the horizontal stab until the replacement rear spar comes in.. I am going to work on the Vertical stab. for now.
I made and primed an aluminum strip to back up the rivets. I then countersunk the skins and popped the rivets into place. Yes, I de-burred and primed the metal parts.
