Nothing like the day after a big airplane EAA/Fly-in to peak your motivation.
I laid into finishing riveting Rib #2 (the final rib to have bucked rivets). Rib #2 went in fairly well, again same as every rib, I had the odd rivet slightly 'cant' to the side on my while riveting. Here is what it typically looks like. (look at the second rivet in from the left)
Now a closeup.
The same rivet cleaned up
Well this simply won't do for me. So these I have been drilling out and re-bucking. I cannot nail down for 100% certainty what is causing the rivets to cant. I figure its a bit of combination of a few factors;
1 - I have dimpled the holes with tank dies. This results in a slightly deeper dimple and a slightly larger rivet hole. Which in my opinion aids to increase the chance of the rivet moving around a bit in the dimple.
2- Proseal. It acts as both a lubricant and a sticky medium. No question that it lets the gun/bar slip more easily when things are gooey, but it also has a stickiness to it. I suspect that when there is proseal on the bar/rivet tail. There is enough there to just pull the tail to one side when you are setting up to buck that particular rivet.
So basically on average I have been drilling out and re-bucking about 4 rivets per rib. Perhaps this may be more than the average builder...but in the end I am pleased with the end product. Its about on par with my leading edge riveting were no proseal is used.
In the end what personally worked for me (or greatly improve my chances of success) was to always clean the bucking bar and gun between each rivet set. I really think that this helped in reducing the change of a tail being pulled on initial setup. The disadvantage is that this adds lots of work and time to the session. But...Time is one thing I have and I sleep much better when I feel I have done the job right.
So...While I am talking about what worked and what didn't. I should probably summarize my thoughts and processes so far for the tanks. First off....the big debate of does a person proseal and cleco 24 hours prior to riveting? or do you wet set the rib (i.e. rivet right away). Well personally I intended to celco 24-hours prior to setting rivets after reading about it all on the forums.
But after discussion with some local builders....I switched over to the wet set method. Primary due to the reasoning that it greatly reduced the chance of pillowing the skin when bucking the rivets the next day. Although I am curious if bucking would have been easier with the 24 hour method. (no question that it is the cleaner method)
The biggest issue at first was to figure out method of applying proseal. Darin had lent me his Semco gun and I was fully intent on using it. I chose to use Popsicle sticks for the first rib just to get a feel for what I am up against, no sense in dirtying up the Semco gun straight out of the gate. My first rib set was a huge eye opener. More in the time it takes me personally to set/rivet a rib in. I was surprised how quickly the proseal was setting up (I was using the 2 hour stuff) . Coupled with the fact that I needed to drill out and re buck the rivets that were canted, I just could not see myself doing more than one rib an evening. Well that started to rule out the use of the Semco gun. I dunno...Maybe I should just have used it anyway and bought a bunch of the syringes??? Oh well. Popsicle sticks worked despite it being messy. In the end I found that about 40 grams of proseal per rib did the trick.
I know this....I will be glad when I am done with proseal. It's not the worse thing, but I can't say I love it.
Well in any case. I set up to put the fuel markers on the inside of the right rib #7.
Almost to the end of the quart of proseal...I mixed up what was left and put a dollop of sealant on each rivet head of the right tank. A tedious process. No question the Semco gun would be a perfect fit for this task.
1 quart of proseal....gone. Need to order another.
