Tank dimple dies

[Steve]

Lets hear from the tank building veterans on this. Are tank dimple dies worth the $40 bucks or not?

Almost there myself,
Steve

[LettersFromFlyoverCountry]

I bought 'em, I can't say I was terribly impressed after building two tanks. I suppose they couldn't hurt but, you know, I was really more interested in having tanks that didn't leak more than I was having the world's perfect RV. I used a LOT of ProSeal and there's a few rivets that are less than impressive.


Now maybe they'd be even less impressive with regular dies, but I don't know.

I know if I had it to do over again, I don't think I'd spend $40 for something I'm not going to use for, like, two weeks.

Maybe I'll sell you mine for $20.

[Davepar]

I checked out my buddy's tanks that he built without the special tank dimple dies. It's a very slight difference. I'm with Bob. I would have paid $40 for a special your-tanks-are-guaranteed-not-to-leak tool. Don't think it was worth it for the dimple dies.

[FrankK90989]

For the people who have a small lathe they (dimple dies) are not hard to make. I have made most of mine and they work great.
Frank k. N. Mn
waiting for fuse.

[BJohnson]

For those of you that have used the tank dimple dies, did you use them on both the skin and the rib, or just on the rib.

It seems like if the tank die were used on the skin, the rivet head would not contact the skin during bucking. However if the tank die were used only on the rib, that would leave a small gap between the skin dimple and the rib dimple to form a seal around the rivet.

Any tips? I'll be dimpling this weekend

[Captain_John]

Now THAT is a GREAT QUESTION!

I am DYING to hear the answer!


It seems to me that the whole idea is to create a pocket for which the sealant to fill during compression of the rivet.

This makes the dimpling of the rib with tank die argument sound logical.

(I am assuming skin with normal die in this scenario.)

How far off am I from the truth?

I too, will be dimpling soon. I, however have a set of tank dies made available to me from a fellow builder. I plan on using them... correctly!

HELP!!!

CJ

[kellyp]

To answer the previous post: I used the tank dies on the understructure everywhere (not just the tanks), and on all the tank ribs and skin. Why? The tank die makes a larger pocket to fit the normal dimple into. Two normal dimples don't fit together all that great, but the normal dimple into the tank dimple fits fine. The tank dimples give room for Proseal and allow the rivet to be flush. FWIW - My tanks passed the leak test first shot.

[Steve]

I bought Bob's dimple dies (see top 2 posts). While I haven't yet done the official Vans soapy water leak test, I'll pass on a few tid bits on the topic. I dimpled the skin AND ribs with those dies. It's the proseal that you spread on the rib flange and over the rivet shop heads that does the sealing, not the dimple die joint. The deeper dimple serves to provide extra space so the rivet sits flush on a bed of proseal. In my opinion, it's theoretically possible to assemble the tanks (except baffle plate) without proseal then apply the stuff to all the rib/skin/fuel fitting joints later.

Left tank LOOKING good,
Steve

[BJohnson]

Putting a dry rivet in a dimple formed with the tank dies results in the rivet sitting below the surface. To buck it in that position, the rivet will back out until the head is flush, leaving a slight gap between the rivet head and the dimple. The previous posts says the rivet sits on a bed of preseal. Does that mean that proseal flows and fills the gap between the head and the skin dimple?

Is this what causes the heads to protrude when using standard dimple dies on the tanks?

[Steve]

Some proseal does flow through the holes in the skin when you cleco the ribs in place. The plans say to apply a thin 1/16" layer of proseal around the rib flange.
Steve