A Few Tank Questions...

[RV7A]

Is it possible to have too much knowledge? Sometimes, I think so.

I'm at the point where I need to dimple the holes in my wing tanks (skins, stiffners, and ribs).

Something as simple as this is turning into a nightmare for someone like me-building my first RV without a PHD in structural engineering.

Apparently, I can use regular dimple dies, tank dimple dies, or "sub-structure" dies!

The problem with a certain very large RV forum, is that there are 100 different opinions and each one is backed up what the person 'thinks' is hard science. Usually, that hard science it seems is another word for "his own damn opinion"

A year ago, I bought the tank dimple dies. Now I'm reading about how they shouldn't be used because the rivet doesn't sit correctly, blah, blah, blah...

I didn't even know there was now something called "sub-structure dies".

The RB forum seems to be a lot more down to Earth or 'reasonable'. That's why I like to hang out here and ask questions here.

It's been my experience to notice that if I dimple two pieces of aluminum, and then place them on top of each other, the dimples don't seem to fit perfectly in one another.

So, having said that, the following seems like a logical way for me to build my tanks-dimple the skins with regular dimple dies; then dimple the ribs with the tank dies.

Dare I ask: can I get some guidance on that method? Does anyone think that it would be wrong in any way to use that method?

Please help...the one thing I don't like about the RV is that there are 10 different ways to do the same thing! And then I stress over which way to pick!

(kinda like how I stress over if I should go with the tip-up or slider...HAHA)

[painless]

I will preface my response by saying that I tend to follow the KISS philosophy.

In a nutshell, you're thinking too much. I know, because I have, and continue to be accused of the same thing.

Don't use a tank dimple die cuz the rivet doesn't sit right in it??? Huh???! Blah blah blah for sure!

You can use whatever type of die you want. The concern about the dimpled parts not mating well with each other is really not a factor in the long run. Personally, I used tank dies with no problem, and no leaks either. As I recall, the idea behind this type of die is that it compensates for the slight thicknes of proseal under the rivets. I also ran a deburring tool a couple of revolutions in each dimple to flatten the walls of the dimple a tad to let the rivet settle in a bit better. I did this with all my rivets, tank or otherwise.

One thing you can do, with any riveting, is to "preset" the parts being riveted, which will seat the parts together prior to driving the rivet. Place your bucking bar and rivet gun set just off the rivet to be set. Very lightly run your rivet gun, just barely. Don't blast away full bore, just a few very light taps. Then set the rivet.

I agree with you that there are tons of opinions out there, but some of the "experts" go way over the top. The old adage that you are building an airplane, not a watch holds true. My advice is don't get hung up on minute details that really don't affect the safety and quality of your airplane.

Take all the above FWIW.

[bullojm1]

As a data point, I dimpled my ribs and skin with the tank dimple dies. The rivets set flush, and I have had 3 years and 140+ hours of trouble free service from the tanks.

I don't think there is any harm in combining two different dimple types on the skin and ribs, however, this combination is probably the least used in RV construction.


IMHO, tank dies all around. Worked awesome for me.

[BSwayze]

Plus one, for what both Jeff and Mike said. I do believe you're overthinking things here. Those "armchair experts" over there on the other forum can drive you crazy if you listen to them too much. Nothing better to do than sit around and critique endless details, ad nauseum. The guys at Vans will also tell you not to spend too much time on the internet. Just build the plane.

Having said that, I bought and used the tank dies, too. My tanks came out leak free, and the rivets look awesome. I see no harm in using the regular dies for the rest of the skins, and the tank dies for the underlying ribs or structure, but it's not necessary. Truth is, like Jeff was pointing out with his method, slight imperfections in the way things nest together are quickly hammered into place when you pull the trigger on your rivet gun. Aluminum is flexible and malleable. The armchair experts don't mention that. Build on, and enjoy the process.

[Scott]

some of the building process. I really have to be in a bad way to post on other forums. Too many folks with too much time to give advice or flame you for asking in the first place.

I have found a couple of photos sent in an email to Vans gets me quick, clear advice; usually with build on. I won't add to the good advice you have already gotten here.

[RV7A]

Thanks all...I'm moving on.

I ordered the new tank sealant from Van's today!!

I forgot about when I was ordering, but I guess I'll need to order TWO rivets! The manual says to put a rivet in the tooling hole in the outboard tank rib, but didn't give me any rivets large enough for the hole

[BSwayze]

If I'm not too late, I'd be happy to mail you a few of those large rivets for that tooling hole. I'm not sure where you can buy just 2 of them. But I have a small jar full of them. Send me a PM with your address and I'll mail you a few.

Cheers

[RV7A]

Thank you Bruce!! PM sent...