wings here today

have a couple questions......do I need fuel tank dimple dies.....if so why? also where can I find pro seal that comes in a mixing tube... that you mix in the tube and dispense from the same? know I saw this somewhere awhile back just cant find it again....

Thanks.....Robb....7A

ProSeal that has been "proportioned" is available from Van's and ACS (among others).

When you are ready for the final install of the tank ribs and the tank skins, you will smear a layer of tank sealant (proseal) between the parts as you put the parts in place, hold with clecos, and then flush rivet. The proseal will ooze out of the dimpled holes (this is a good thing). When you jab a flush rivet in the hole, the proseal that ends up remaining in the dimpled hole prevents the rivet from seating completely flush with the skin surface. So, a slightly deeper dimple is desired to get the flush rivet to seat flush with the proseal (desired to prevent a leak).

I have also found that these tank dimple dies work well on the underlying dimpled holes of lap joints in many areas of the skin joints. This aids in the "nesting" of the top and bottom surface sheets.

Thanks noel.......great explanation........so you use the tank dies on the ribs and skins?

Robb....7A

It depends (engineering term)...As an example, I will dimple the skins and ribs with the "standard" 3/32 dimple dies. For what ever reason, sometimes the parts will nest correctly (no gap whatsoever) and sometimes a "slight" gap is present. When I detect a slight gap, I go back and use the tank dimple dies on the underlying rib. This then eliminates the "gap".

Some time ago there was a link to a Walt Disney produced animation that described how and why underlying skins and structures get different amounts of deeper dimples as the rivet joint is composed of more and more layers. This video was produced to help the war effort...back in the '40s...or earlier. But it is still relevant today.

I do not have an answer as to why the layers some times nest without a small gap, and other times a gap is present. It may even have something to do with material thicknesses...and as always, YMMV.

Buy the Quart Kit

Hi Robb,

I sealed my tanks last year. My recommendation is to buy the quart size of Proseal. You are able to use only what you need during that session. If you use the tube, then (I believe) you have to use the entire tube then or throw it away. It took me a little while to finish my tanks, so having the quart size made it much easier for me. I used Sam Buchanan's instructions, as well as Rick Galati's suggestions. Search fuel tanks and you'll find great info. I made some Word docs from the threads and websites. Let me know if you want a copy of anything. I found the process to be just another job to do in getting this beast flying! MEK works wonders in the cleanup. Just treat it with respect!

I did use the tank dies to let the rivets set properly after the Proseal was added to everything.

I added some of my photos detailing my process on my Picasa website, if you are interested.

Good Luck!

rwshooter said:

Thanks noel.......great explanation........so you use the tank dies on the ribs and skins?

Robb....7A

Click to expand...

Yes, because there will be a small amount of proseal under the rivet. Use the tank dies so the rivet doesn't sit proud of the skin.

Sometimes I provide too much info...out of context.

To be specific...use the tank dimple dies on the tank skins and the tank ribs.

Use the normal dimple dies on the other skins, and tank dimple dies on the underlying skin dimples when required.

Thanks

got it thanks guy's....was just makin sure on the tank die thingy.....gonna order those and some other items tomorrow.......still thinking about the proseal....tube=quick, easier, less mess?...should be if you have alot ready to assemble.....right?........right now I have my hands full doing inventory on the wings.........thank God for Pink Floyd

rwshooter said:

still thinking about the proseal....tube=quick, easier, less mess?...should be if you have alot ready to assemble.....right

Click to expand...

I think you'll find that you won't be going fast enough to make the premade proseal tubes economical. I used them on the trailing edges on my empennage. They sure kept things simple and clean.

On the RV-10, most people go through almost 2qts of proseal. That gets really expensive if you buy it in the tubes. McMaster-Carr does sell empty tubes that you can load. I thought that was a great idea, but have yet to use them.

I found on the stiffners, I really didn't need to go to that effort. I just mix the proseal on a paper plate and use a tongue depressor with the end sanded flat. I'll be starting on the ribs this weekend, so I may alter my technique.

Where I think I will loading the tubes and using them is when I come back to filet the edges and cover the shop end of the rivets.

Tube-stuff is fast setting

The "tube-version" from vans (MC-236-B1/2 (3.5 ounces)) is of the fast setting variety (1/2 hour worktime), see:
http://www.vansaircraft.com/cgi-bin/catalog.cgi?ident=1226664830-132-558&browse=misc&product=proseal

I'll use mine on a part of the empennage (elevator-stiffners) because I got a tube of this stuff, for the tanks however it might be a better idea to use the one with a 2-hour worktime.

Kind regards,

Mario

Another good tip

I remember working on the tanks for our -7...it was mid-summer, and man was it HOT! Glad that is over...

Anyway, a good tip that I did when installing the rear tank baffle was to get some large animal syringes (with no needles of course) from the local farm supply store. I then loaded up the mixed proseal into the syringe and applyed it that way. Gave excellent control, and not a single leak anywhere! I used this method on the tank end plates, as well.

derLuigi said:

The "tube-version" from vans (MC-236-B1/2 (3.5 ounces)) is of the fast setting variety (1/2 hour worktime), see:
http://www.vansaircraft.com/cgi-bin/catalog.cgi?ident=1226664830-132-558&browse=misc&product=proseal

I'll use mine on a part of the empennage (elevator-stiffners) because I got a tube of this stuff, for the tanks however it might be a better idea to use the one with a 2-hour worktime.

Kind regards,

Mario

Click to expand...

Ditto. I learned my lesson with the tube stuff. I mixed for 15 minutes, and when it started to kick while I was working, I freaked out. Thankfully, it was only the rudder TE.

For the tank I used the standard quart kit - mix it yourself. Application was done with gloveless fingers and popsicle sticks with the rounded tip cut off so that it was flat. The only time we did something different was when we laid the bead for the rear baffle - we followed the instructions and "piped" it out of a zip-lock bag - worked great and didn't spend a dime on some other contraption.