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Fay sealing?. did it work?

wfinnell

Well Known Member
I read Rick6A?s 05-08-2006 post Tip: Proseal....The Facts and the Fiction where he explains how to porseal the tanks with less mess by letting the proseal partially cure before setting the rivets?

So my question for Rick, Dave, Chad and others that have used this method is have you had any leaks? Did the partially set proseal cause any difficulties riveting (bulges or dents)? I am ready to start on my tanks and I will probably use this method.

Also has anyone talked to Van?s about this?

Thanks,

Bill Finnell
RV-8 wings
Tucson AZ
 
I used this method building my tanks and finishing them up last week. I can honestly say it made the job pretty easy,,,,,, enjoyable in fact. There is no way I would build my tanks any other way. I still have to install the vent lines and close up the backs so I can not say weather or not I will have any leaks, but using this method allows you to take your time working, setting the rivets, carefully inspecting all the sealing areas and covering them up when set. I found that if I used a heat gun on low power, or a hair drier, the pro-seal would flow a lot easier. I did mine in stages. First I sealed and clecoed the short stiffiners and the "J" stiffener. After cure I cleaned up the holes, dabbed them with fresh pro-seal, back-riveted, covered up the rivet shop heads and filleted both sides of the stiffiners, removed my electrical tape I put down as a guide, cleaned up the pro-seal where it wasn't supposed to be and let cure again. After cure I again cleaned with MEK and inspected carefully, dabbing pro-seal where needed, then installed the ribs. I found that it was easiest to start outside the jig. Starting in the middle, I buttered up a rib and started at the most forward hole on the top side and clecoed the first three holes. I did this one rib at a time only clecoing the first three holes on the top side of the skin. This held the ribs straight and the spring of the skin kept the unclecoed holes away from the skin so pro-seal was not getting all over. When all the ribs were installed with the first three holes on the top, I flipped it over on the bench and did the bottom three holes. I found doing it this way your not fighting trying to push down on the ribs to get the holes lined up, you are pretty much just wrapping the skin around the ribs starting at the forward holes. The tank was now taking shape, the ribs were lined up where they were supposed to go, and I did three more holes up on each side. I then slipped the tank into the jig and finished up the clecoing, doing a few holes at a time on each side working my way up (aft). I buttered up the ribs heavier on the bend side,,,,this gave a nice squeeze out that I ran a Popsicle stick over to give a nice fillet seal. Its cold here so I keep the shop at 55* when I am not in it so I fashioned up a temporary heat box to put the tanks in to cure for a few days.. Again, after cure I unclecoed, cleaned up the rivet holes, set the rivets in a dab of pro-seal, and with the help of a friend bucked all the rib rivets and covered up the shop heads. One other thing,,,,after I placed the rivets in the holes with Pro-seal, I pushed them in flush, wiped off the squeeze out and ran a strip of rivet tape over the rivets. This minimized the squeeze out mess on the tools, ect. I was generous with the Pro-seal and am confident I will not have any leaks,,,,,,at least I am hoping I won't!:eek:
 
The fay sealing method worked EXCEEDINGLY well for me! I'd mix a batch of sealant, seal & cleco two ribs, then walk away. The following day I'd set the rivets, take a break, go back, and repeat. I used clecos in every rivet hole and did not bother to clean them after. (I pulled the sealant off the clecos as necessary.) I focused on only two ribs at a time to limit the number of clecos sacrificed to the procedure. No leaks at any of the rib junctures. (Two small leaks at the rear baffle of one tank due to insufficient application of sealant.)

It cost me ONE t-shirt from absent mindedly wiping a finger across it!

Without a doubt, I would use the same procedure again and recommend it to others.
 
I will be putting fuel in my tanks within the next couple of months, and I'm confident that I won't be leaking. If I do, it won't be because of the fay seals...;)
 
I will be putting fuel in my tanks within the next couple of months, and I'm confident that I won't be leaking. If I do, it won't be because of the fay seals...;)

Chad,
I'm not worried about your tanks, but should I send you a box of "Depends" just in case you start leaking during the fill? :D
 
I'm right in the middle of building my tanks and have been using the fay sealing method. The hardest part is the "just walk away". :D So far so good. It is still messy setting the rivets, but very manageable. Dab a bit of sealant in the rivet hole with a toothpick. Insert the rivet - I press it in with the tip of an old icepick and get some good squeeze out. Then put some rivet tape on and buck the rivet. Then repeat ad infinitum... Took about 4-5 hours to set all of the interior ribs on one tank doing this solo. Mix small batches of sealant, so it won't go too stiff on you during this time. I used about 30 grams on a pair of ribs covering the shop heads and fillets. I'm using a veterinary syringe as an applicator, which works fabulous to lay down a consistent bead on the ribs. Change gloves often! I still have the baffles to go and hope to get there in the next week. There are some photos at the link in my sig.
 
First tank done - Second in progress

On the first tank, I buttered up the inner 5 ribs, clecoed them in every hole and let it sit for 8-10 hours before riveting. Not bad, but still got messy when I inserted the rivets "wet".. no leaks though ! ! ..... but I am going to do the second tank differently.

On the second tank, I am going to butter up the ribs, cleco every other hole, "wet" the rivet holes and start shooting. Doing it this way I will use 1/2 the clecoes (pain in the butt to clean), also get it done faster, also since the wet rivets are a bit messy anyway, it seems it will be no different.

Looking forward to the second tank. Actually, looking forward to getting past the second tank.. ;-)
 
Please do on not make it more difficult than it is!!

I don?t understand this hype about Pro-seal. Just apply the pro-seal where you need and don?t overdo it. Wipe off excess as you go along. No problem at all !

A few tips: use 10 cc syringes to apply it, works really well. Wipe off excess with paper towel and throw away (use lots of clean bits of paper towel)

Regards, Tonny.
 
Just 'cause I'm funny that way, I Fay sealed one tank and did the other the traditional way.

Neither tank has leaked in 140 flight hours over the last year, but I believe I got a better riveted joint on the tank I did NOT fay seal. Basically, I could tell that there was a thicker layer of ProSeal between the rib and skin on the Fay sealed version. It showed up in length of rivet required, and the fit of the skin vs. the dry fit.

I didn't find it to save any time or effort either, which is the main reason I just followed the instructions on the second tank.

Basically, do whatever makes you happy. It's a messy job no matter what, but will soon be forgotten. The 10cc syringe advice is good advice--I did the same on both tanks.

Guy
 
Well, I've done it both ways. I did it the traditional way on the first tank, and used the faye method on the second tank. I found the fay sealing method to work EXCEPTIONALLY well and if I had to do it again, I would do it this way exclusively. It's so much easier and far less messy, IF you let the stuff cure enough before riveting. That's the key here. It works especially well this time of year, when many of us have a shop that's cool or cold. The proseal may take as long as a week, or more, to fully cure. It gives you a lot of working time, which takes the stress and pressure off.

I mixed up small batches of proseal, roughly 25 to 30 grams, and did two ribs at a time, using a cleco in every hole. A small cheap 1" wide paint brush with the bristles cut down to 1/2" long is stiff enough to use to apply the proseal to the rib flange. I had the other ribs clecoed in as well, cleco in every hole, to keep the shape of the tank intact. I found I could let it sit for 24 to 36 hours, depending on temperatures in the shop, before riveting, and it was still pliable enough. I used a toothpick to wet each rivet hole with fresh proseal before inserting the rivet. A piece of rivet tape over the rivet gun is much easier than putting tape over each rivet. It's good for 5 to 10 rivets before it needs to be replaced.

For the fillets, I used some syringes that a pharmacist gave me for free (now THAT was an interesting conversation!). It's easy to apply, like a mini caulking gun, right after clecoing the rib in place. Then wait for 24 to 36 hours. If you time it right, the proseal is pliable enough to be pushed around like silly putty but stiff enough to not stick to your bare finger. So you can easily go in there and push the stuff down into the gaps and make sure it's sealed and smooth. No gloves, no mess. It's amazing how your fingerprints disappear after a while and it glosses over. Nice!

Cleanup is so easy. After a few days, any blobs of proseal on the clecos just pull off easily. For sealing the rivet tails, same thing. Put a small blob on each one and wait 24 hours. You can easily go in there and push the stuff down around each rivet tail to make sure you've got no gaps anywhere.

I haven't added fuel to my tanks yet, but they held an inflated balloon full for 3 days, so I'm very confident I don't have any leaks. I have lots more detail, and lots of pictures on my web log pages.
 
Tanya and I have built them both ways. We concluded that we prefer to build them wet.
 
I too used Rick's method, and was very happy with the results. If I were to do it again, I would squeeze a clamp between every cleco on the end ribs (in addition to the rear baffle), thereby squeezing excess sealant out. This may have prevented the fit issues I had between the leading edge and the tank. Some shimming of the L. E. was required.

Overall though, a great method...
 
I've built quite a few and always used the "wet" method.
Personally, I never saw a problem or a reason to change.
 
In reference to the thread title....both methods describe fay sealing.

Descriptions:

Fay seal ? Sealant trapped between mating parts during assembly. When the mating components are riveted within the sealant?s specified application time, the sealant extrudes from between components. The remaining fay seal is very thin, typically only 0.001? to 0.003? in the vicinity of fasteners.

Fastener seal ? Sealant applied to the fastener before insertion in its prepared hole. All properly installed fasteners fit their prepared holes with small tolerances in order to limit relative movement of the fastened components. A rivet is (or should be) the ultimate extension of this principle. Following rivet expansion to completely fill a properly prepared hole, the fastener seal is much like a fay seal; most sealant is extruded, leaving a very thin 0.001? to 0.003? film.

Filet seal ? Sealant applied to the mated and fastened components after assembly. Unlike fay and fastener seals, a filet seal is quite thick. The minimum typical filet is found at the junction of a skin and a rib flange edge. It equals or exceeds the thickness of the rib material (for example 0.032") and is thus 10 to 30 times the thickness of a fay seal. A properly tooled filet is expected to have a slightly concave surface contour blending smoothly into the sealed surfaces.


Installation convenience aside, is there a results difference between the "wet" method and the "cleco, cure, then rivet" method? Does one method seal better than the other? Moot question; none of the industry literature considers a fay seal to be more than an accessory to a filet, which is the primary seal.
 
Fay Sealing

I did it this way and just completed my second tank. It went very well and was actually not a chore at all. No leaks, Not much mess. I highly recommend it.
 
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