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Fuel tank repair kit - which saw for hole

fl9500

Active Member
Hi,

I will try to seal all five chambers of one of my RV6 tanks, which has many leaking rivets. with original VAN's "Fuel tank repair kit".

Which is the best saw-type to cut the big holes in the back of the fuel tank ?

What is the best method to reach all seams of the tank with the sealer ?

Thank you for all tips,
Achim
 
Low speed, high torque drill, ordinary fly cutter. Go slow.
.
 

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+1, I built a wooden stand for the tank and positioned it under a pillar drill. Chain drilling takes ages and leads to lots of clean up.
 

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I use a Craftsman fly cutter in my drill press. I hold the fuel tank in the assembly fixture used when I built the tanks. Clamp everything firmly. Verify the tool is square to the workpiece. Drill a #40 pilot hole. Set the drill press speed to the lowest rpm. Feed slowly.
 
With either the hole saw or fly cutter, be sure that the center hole is riding on the smooth shank of the center drill bit when the cutter is actually working on the big hole.

If needed you can usually re-position the center/pilot drill bit out of the body a bit so the smooth shank is what the unit guides from when making the big hole.
 
You are Lucky! Harbor Freight does do one thing better than anyone else: They make great paper weights!

-Marc
To the contrary, if it wasn’t for HF many of us would not be able to afford building a plane. They make less quality product but at great value. Some of those product do not need the precision or longevity that a home user needs.

But for a professional use, I agree a higher quality product would make sense.
 
To the contrary, if it wasn’t for HF many of us would not be able to afford building a plane. They make less quality product but at great value. Some of those product do not need the precision or longevity that a home user needs.

But for a professional use, I agree a higher quality product would make sense.

You Tube the comparison between the ICON 1/2" torque wrench vs Snap-on. You can buy cheap Chinese tools or expensive Chinese tools. Some people have unlimited funds to purchase the most expensive tools out there, when the reality is most are made in China. For a specialized tool I may seldom use, I'll choose the lowest cost one out there that gets the job done. I would much rather have a cheap paperweight as apposed to an expensive one. :p
 
I used a HF hole saw. First in a drill press, I used the hole saw to cut a 5" hole in a piece of 1/2" plywood that fit snugly between the tank skins. The plywood kept the hole saw solidly in position while cutting the tank holes. I cut 6 or 7 holes in two tanks, prosealed and riveted all back together in less than 3 hours. Did not leak afterward. Not my tanks.
 
I would much rather have a cheap paperweight as apposed to an expensive one. :p

The problem I found was that if I bought a cheap HF paperweight I would need to replace it so soon that now I have two (or more) cheap paperweights. After a short time you realize that the old adage of "Buy cheap buy twice" doesn't really save any $$$.

The last HF failure that hit me was for my Automotive Creeper. Just last week I put my knee on it and the Blow-molded plastic just split open. I only used it for working on the plane in the hangar. Mostly just washing the belly with a spray bottle and rag. No more HF for me, I have enough paper weights. :eek: Sorry for the thread drift.

-Marc
 
You are Lucky! Harbor Freight does do one thing better than anyone else: They make great paper weights!

-Marc

Every HF store I've been in is jammed with folks buying 'paperweights'.....and I suspect most of them are repeat customers like me...... ;)

P.S. If you haven't treated yourself to a set of HF wobble-drive rachet extensions put them on your stocking list.....most useful items I've bought in a long time.
 
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Thank you for the tips.

What is the best way to get the sealer into all corners ? I am not the builder but a good friend of mine has build a quickbuild RV8. But also no experience with sealing a Tank. :(

Achim
 
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Thank you for the tips.

What is the best way to get the sealer into all corners ? I am not the builder but a good friend of mine has build a quickbuild RV8. But also no experience with sealing a Tank. :(

Achim

I used wooden ice pop sticks, the flat type that you get in an icecream from tbe corner store. About 3 inches by half inch by one sixteenth with rounded ends. Available at craft stores. Good for working the goop into the corners and disposable afterwards.
 
Be sure to clean the interior sealing area with alcohol and scuff it with Scotch-Brite.
 
Looking at your pictures, you definitely must remove the paint around the cut holes, and roughen the aluminum. Then clean contact surfaces very well with MEK or similar before applying proseal. Also, are those closed-end pull rivets? Even so, a good dab of proseal on the inside ends of the pull rivets would be a good idea. Stand the tank on the long edges when done, so the proseal can settle into the (closed) end of the rivets. The next day you can put a dab of proseal on the outside of the pull rivets. Oh, and clean the rivets with MEK too first.

I'm sure you also get other good advice, like do not touch the cleaned aluminum to avoid contaminating it with oils from your fingers.

Finn
 
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Rectangular hole

I ended up cutting rectangular holes instead of the round holes. I started with the corners first using a stepbit to 3/4” and then cut rest with dremel wheel or use a cutoff wheel. Buy the 3.5 oz Chemseal B2 (a little cheaper than proseal). With the 3.5 oz you don’t have to rush and can take your time using a mirror to make sure you got everything. It will take just under 3.5 tubes per tank including the panel cover. It’s well worth buying the mixer or make your own instead of mixing by hand. Use tight fitting gloves. It’s not that bad to apply it. The worst part is removing the old stuff. If I had to do it again I would use the polygone to remove the old stuff. Professional strength Goofoff removes slosh pretty easy. It softens proseal but you still need a plastic putty knife to remove the old stuff
 
The big problem with cutting large holes into existing tanks is that, regardless of what cutting technique you use, you are going to end up with aluminium swarf inside the tank. Making sure you get every single little bit of that swarf out of the tank is critical. And it’s no easy job.
 
The original Builder used far to little sealer.
Left the Original, in the middle new sealed rivets and on the right the sealed edges.
tankreparatur5.jpg
 
should I seal the rivets and the plate from outside ?

not necessary for the plate if you are sure you applied enough sealant on the mating surfaces before joining, but certainly on each rivet head.
 
How many covers in the kit?

Did the Vans kit have all of those covers and rivets for one side/wing, or just one cover? I think I'm starting this same process in a week...:(
 
Did the Vans kit have all of those covers and rivets for one side/wing, or just one cover? I think I'm starting this same process in a week...:(

The covers are sold singly, the rivets by the bag. I recommend you buy asw many covers as there are cells in the fuel tank. You cam alwasys sell what you don't use, or keep them on hand for the next repair.

-Marc
 
The big problem with cutting large holes into existing tanks is that, regardless of what cutting technique you use, you are going to end up with aluminium swarf inside the tank. Making sure you get every single little bit of that swarf out of the tank is critical. And it’s no easy job.

Place the tank on a bench with a bay hanging over the edge, leading edge up. Have someone hold onto it. Use the hole saw in a hand drill, come up from the bottom. No chips in the tank!
 
How did you clean the tank of gasoline to prevent having an explosive atmosphere when cutting?
 
nice holes

Hi Achim, Just saw this thread for the first time. How did you end up cutting those beautiful holes? Looks like it turned out really nice.
 
How did you clean the tank of gasoline to prevent having an explosive atmosphere when cutting?

Let it air out.. but you are cutting aluminum..no sparks! If you want to get fancy, you could purge the tank with Co2 or even Argon, but again, it’s not necessary. Maybe be careful of sparks from the drill motor though..
 
Thanks Dan
 

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Cover plate thickness?

Getting ready to do this but may go for square or rectangular holes for improved access (I need to clean off and reseal everything inside because the original sealant has turned to goo).

Question: can anyone please confirm how thick is the aluminum for the Vans-supplied T-412 cover plates?
 
Nominal 1/16”
Edit
I copied the vans access plate. Don’t know what the repair kit thickness is
 
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Buy a few syringes and cut off the tips so you have about a 1/8 inch diameter hole and do the initial “squeeze in” with that. Then spread with a popsicle stick. Much neater and more precise.
 
Hi,
Unfortunately, after the repair, 10% of the rivets were still leaking.
We applied aluminum strips (0.2x20mm) from the outside to the rivets with 2-component glue and leveled it with filler. Now no more leaking.
Achim
 

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Hi,
Unfortunately, after the repair, 10% of the rivets were still leaking.
We applied aluminum strips (0.2x20mm) from the outside to the rivets with 2-component glue and leveled it with filler. Now no more leaking.
Achim

Quite the unique fix...very interesting...like it.
I could see using an even thinner aluminum strip.

It must have been very frustrating having leaks after going into the tanks....
 
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.063 is a little overkill in my opinion. IIRC I think I used .040. And I think even .032 would work fine. I did mine several years before Van's offered a "repair kit". The use of closed end rivets is not required. You're using pro-seal to seal everything anyway.
 
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