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New fuel tank SB (13-12-19 released and effective December 19, 2013)

My s/b package arrived yesterday. A little depressing considering I had ordered the finish kit with a new tank built option and it arrived only a few months ago. Now I will end up spending more time and money completing the s/b, and I might as well do the vent as well while I have it apart.

So now I have to call and order that kit, plus all the extra items to remove the sealant and new sealant of course as well.

Definitely like throwing a wrench into the works I think.
 
I am waiting for a report on how well the sealant removal stuff works. In having my tank apart a few times already, I have become proficient at removing the pro-seal stuff without it.

cactuspilot said:
My s/b package arrived yesterday. A little depressing considering I had ordered the finish kit with a new tank built option and it arrived only a few months ago. Now I will end up spending more time and money completing the s/b, and I might as well do the vent as well while I have it apart.

So now I have to call and order that kit, plus all the extra items to remove the sealant and new sealant of course as well.

Definitely like throwing a wrench into the works I think.
Click to expand...
 
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Mel said:
If I thought that my airplane had anything close to the reliability of a computer, I'd be walking!
Click to expand...

Tough luck Mel! As soon as you rely on a glass cockpit as we do with the RV-12, your plane becomes, if not a computer, highly dependent on a computer with all the weakness it has but also all the strengths. The reliability of the bundle (Al + Si) is the sum of the reliability of each component. On the plus side, as Dynon already demonstrated many times, SBs are much easier on the Silicon side than on the Aluminum side. I wish I could do the Fuel Tank SB by uploading the new version!
 
Tips on Proseal Removal

I am struggling mightily in my attempts to remove the T-1209 sender plate from the tank bulkhead. The screws are out and the small fillet of Proseal around the perimeter has been removed/dissolved. I cannot get anything plastic in between the tank bulkhead and the sender plate to work on prying them apart. I am unwilling to use anything metallic for fear of scratching the aluminum....but I am at my wit's end (all 2 of them). I used some methylene chloride based stripper to soften/dissolve the Proseal, but it is too thick for any capillary action to wick it into the joint.

Any ideas?

Thanks,
Tom
 
Having done it twice Tom, what I did was just get a putty knife and push it between the two surfaces, when wide enough, use a screwdriver and twist it as you break more seal with the putty knife or razor blade. Once you have a start, it comes apart pretty easy.
Once apart, I found a wire brush on a dremel tool cleaned up the remaining pro seal.
 
Scratches?

I'm with Don...I imagine a good ole putty knife and a small ball peen hammer (to drive it with) might be called for. Why worry about scratches? The new pro seal will seal then up fine, so I dont understand what you're concerned about. Am I missing something?
 
Just redid mine - -

I used a fairly thin blade putty knife and small hammer. Just get it started, and work your way around. Wish I had made a video. Once you see it done, it really only takes a few minutes.
 
CTT_4712-L.jpg
 
Excellent picture Tony - -

Once you get it started, turn it to the side and keep driving it around. Work a little deeper if needed to get it completely loose. After you have done it once, it is fairly easy. A flexible blade helps a bunch.
 
I feel a lot better now...

Thanks gentlemen...I'm breathing a lot easier now. I'll proceed to locate a thin bladed knife as pictured. Tony - great picture, thank you.

Tom
 
In case the cover should ever have to removed again (hopefully not), make sure you follow the steps described in the KAI and do not fully tighten the screws that hold the cover (or the fuel level sender) in place, when re-installing it.
This will leave a .030 - .040 " gap filled with sealant that will make tapping the putty knife around, much easier.
 
Guilty as Charged...

...did not follow the directions and tightened both sets of screws too tight. I had to remove two of them by cutting a grove into the heads with the Dremel tool to use a bigger flat bladed screwdriver.

Even with the thin knife, I suspect it is going to be a fight.

Thanks all,
Tom
 
During the previous SB I removed the cured tank sealant with 3M Roloc 2" abrasive wheel (didn't need any MEK), will take about 20 minutes to clean the mating surfaces.

FP14052012A0000V.jpg
 
Yes and after all the scraping and cleaning and re doing all the metal work and goo you still have your airplane down for a couple three days while you thorougly test the tank for leaks, then test the fuel system when it's all back together. That's why it's not a 5.5 hr job. (Sorry, I am just not crazy about messing with the tank).
Dick Seiders
 
tboyett said:
...did not follow the directions and tightened both sets of screws too tight. I had to remove two of them by cutting a grove into the heads with the Dremel tool to use a bigger flat bladed screwdriver.

Even with the thin knife, I suspect it is going to be a fight.

Thanks all,
Tom
Click to expand...
You aren't alone. I bought my tank pre-assembled and it too was locked up as tight as a drum.
 
That may be a GOOD thing, less proseal to stick it together!

tboyett said:
...did not follow the directions and tightened both sets of screws too tight. I had to remove two of them by cutting a grove into the heads with the Dremel tool to use a bigger flat bladed screwdriver.

Even with the thin knife, I suspect it is going to be a fight.

Thanks all,
Tom
Click to expand...
 
DonFromTX said:
That may be a GOOD thing, less proseal to stick it together!
Click to expand...

It's not a good thing.
If all of the contact area between the tank and the cover plate is fully coated with sealant, the thickness of the coating has no baring on how much it sticks.
But, if that coating thickness is only a few thousandths thick (what you get if you fully tighten the screws) it leaves very little space to tap the putty knife into and removal of the cover is much more difficult
 
TANK TEST

Can't seem to fine the direction for the tank test.
I believe that it is 1 psi...but for how long?
This is the third time I have opened the tank. Have had no problems with the first two..but can't seem to get it to seal with this latest mod.
I added the fuel vent and the mechanical fuel gauge on this trip into the tank.
Any ideas?

Gary Krause
 
Fuel tank leak testing shouldn't be thought of as a time period. It is a check for evidence of leaks.
A good method is add pressure to the tank.
Put tank in shower or bath tub.
Spray liberally with a soap/water mixture (approx 30:1, water to liquid soap)
Look for evidence of soap bubbles forming.
 
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Leak testing

Make yourself a good testing apparatus:
i-pPHJd9h-L.jpg

The gauge shown is calibrated in inches water column and the pressure shown is 15" w.c. or about 1/2 psi. Use a bicycle pump and don't use a higher pressure gauge. You could damage the tank. Van's recommends a balloon, but I didn't have much luck with that, and balloons can be porous, so if it leaks down how do you know it's not the balloon? The pressure will go up and down with temperature in your shop, but if it goes to zero, you have a L E A K. And you gotta find and fix 'em.
The same apparatus can be used to test the fuel lines but with a higher pressure gauge so 5 or 10 psi can be used, makes it a bit easier to find the leaks.
CTT_2995-L.jpg

A proprietary leak detection fluid works best. This stuff is not expensive and can be found on the internet or even maybe in a local store but who wants to drive around looking for obscure stuff?
i-2bwFgzp-L.gif

BTW, the Leak-Tec website says that soap is not approved by ASTM, ASME, or USAF. I know, I know, we are not going into space here but just saying...
 
Tony_T said:
BTW, the Leak-Tec website says that soap is not approved by ASTM, ASME, or USAF. I know, I know, we are not going into space here but just saying...
Click to expand...

Since they wouldn't sell much of their detection liquid, what would we expect them to say?:p

Seriously, regular soap doesn't produce the big easy to see bubbles, but since we have the luxury of being able to rotate and position the object (fuel tank) we are checking. you can just re-position and flood the soap solution on to the upper surface. Even a very small leak is generally easily detectable.
I am sure the purpose made leak detection fluid is a better choice, but personally I have no interest in applying a little bit at a time to every single rivet, skin seam, cover plate, etc., on an RV fuel tank (especially something the size of an RV-10 tank).
 
Poor man's option to a gage is to attach a Tygon tube in a "U" forming two water columns. One vented to atmosphere and the other with tank pressure on it. An added benefit is it provides over pressure protection.
 
Why not use Balloons

So, what's the problem with the simple balloon, as described in Van's builders manual???

Tom
 
I'm not saying there is anything wrong with the balloon. I just prefer the control the manometer tube gives. There's more than one way to skin this cat.
 
For testing the tank in our second RV-12, I took it to a radiator shop that knew fuel tanks! They precisely dialed in 1/2 psi and submerged the tank. First time, there was a leak in a corner. The next time in, it tested clean. None of this waiting for a balloon to go down, or having a leak in the test fitting. They had plugs for the neck and all the fittings needed. I will never do it any other way again. Ten minutes and you know.

Bob
 
Bob, sounds like a good process. I wish I could have completely submerged the tank. Fortunately I didn't find any leaks and two years of flying have confirmed the results.

Rich
 
RFSchaller said:
I know we've talked about it before, but this latest mod seems like an opportunity for Vans to consider a wing tank option for those of us who don't care about the wing removal issue.
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Amen! After flying with a cockpit tank in my old Ercoupe for a few hundred hours I agree..
 
A Suggestion For Earlier Builders

I am well into doing the bulletin on the tank along with the top mounted gauge and the vent mod. This morning I installed the rivets, bolts, vent fitting and top mounted gauge. Still need to reinstall the main sender plate and test.

I was amazed at how helpful it was to have the hole for the top mounted gauge to look through when doing the work for the doubler plates. That "window" made it easy to see where I needed to remove old pro seal and much easier to be sure the tank was thoroughly clean, position the new doublers, assemble the hardware and do the final pro seal touch-ups. So much better than with mirrors or by feeling around.

I like the sight glass and was not a fan of the top gauge. But having that extra visibility for this exercise was really nice.

If you are on the fence about the top gauge maybe this is a reason to do it.
 
Fuel Tank Mount Issue

I'm planning on doing the "last" fuel tank mod in May. The last time the tank was out was for the gear leg mod one year ago. I had the original builder to the mod. Yesterday, I was looking more closely at the fuel tank and it's attachment to the forward tank bracket and found the outboard frangible bolt sitting on the outside of the forward tank bracket. There's a gap of about 1/4 - 7/16" between the tank nut plate bracket and the forward tank bracket -- is that normal? Should there be a spacer for that gap? It looks like the longeron prevents the fuel tank from fitting flush against the forward tank bracket in the outboard corner.

I've been unable to get the frangible bolt started into the nut plate. The inboard bolt and the rear bolt are OK.
 
Try removing all 3 bolts. Then install the hardest one first, then the other front one, then the rear one last. Do not fully tighten until all 3 are started. Good luck.
Joe Gores
 
Leak test

Thought I would put my 2 cents in here, I used to work with proseal extensively and we pressure tested a lot and had to trouble shoot leaks on old models of the tanks. The tanks are used on currant day fighter systems. I also have built several RV tanks and fixed leaks on a few. I use shampoo for the soapy water and the results are just like the Leak-Check fluid. No conditioner type. And it smells good too, liquid soap doesn't work as well. I would say I use about a 1/4 cup of shampoo to a quart of water in a hand pump sprayer. I am currently helping a friend with a 12 that has a pre-sealed tank and luckily hasn't had fuel in it yet. I will let you know how it goes.

Cheers RT
 
On this most recent SB I changed my sealant to 3M 350-B1/2 instead of the 236 or 240 that most vendors sell. This stuff has a 1/2 work time (make what you need) and cures in 3 hours. I put fuel in it after 4 hours...all 18 gallons. Works great...same price.
 
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