sealing fuel tanks on RV-14

I just finished my RV14 fuel tanks.
I basically followed the plans and procedures set out by Vans which I have also used on four previous sets of tanks.
Usually I use about 1 1/2 quarts of the sealant this time I used 7 tubes of sealant that are applied with a caulking gun. This is a much easier way to go and is actually cheaper then purchasing the 2 quart cans.http://www.aircraftspruce.com/pages/cs/fueltanksealants/prosealant.php

I divided the sealing into 7 , four to five hour sessions. I work alone

1. stiffeners bottom of both tanks (all sessions take one tube of sealant)
fuel fittings on both inboard ribs

2. five outboard ribs on right tank

3. five outboard ribs on left tank

4. inboard two ribs, J channel, and the tank support bracket on right tank

5. inboard two ribs, J channel, and the tank support bracket on left tank

6. back baffle on right tank

7. back baffle on left tank

Thus I have a total of 28 to 30 hours of sealing and riveting on the fuel tanks. This was spread out over two or three weeks.

Note that although the plans call for you to start on the left side I always start on the right side of the airplane. People ALWAYS look at the left side of the airplane. If I make any little mistakes I want them to be on the right side!

RV-7 tank sealing times

I realize this is the RV-14 forum, but since you have experience on other RV models, would you say that the seven sessions would be about the same for RV-7 tanks as what you are describing for the RV-14 tanks?
Also, would the tank parts for each session be grouped in the same manner?

Great information Tom! Coincidentally I was planning to assemble my tanks in four sessions. I was planning on riveting the lower stiffeners on the first, then the five outboard ribs, then the inboard two ribs, stringer and tank support bracket, then finally the back baffles. I ordered six tubes of sealant....I guess I better order two more to be safe. Got all of the parts done and ready to assemble over the weekend but cannot get to the assembly until the end of the week.

Thank you for sharing you're assembly technique

rv7boy said:

I realize this is the RV-14 forum, but since you have experience on other RV models, would you say that the seven sessions would be about the same for RV-7 tanks as what you are describing for the RV-14 tanks?
Also, would the tank parts for each session be grouped in the same manner?

Click to expand...

It has been a few years since I helped rivet some -7 tanks together but I think you could do them in one less session since the -7 does not use the inboard tank attach brackets that tie into the first rib.

Thanks, Mike.
I hate to admit it but "other priorities" have kept me away from my RV project too long. IIRC, getting ready to do the tanks is where I left off. I have given serious thought to doing the ailerons or flaps first, but I guess it really doesn't matter. I just need to get back in the shop.

Would you post a few pictures showing some of the more difficult areas?

Tom,
I've been ready to start my tanks now for about 6 weeks, but reading some of the horror stories, I just about decided to hire it out. After seeing your post, I'm now thinking there maybe hope for me yet in completing this section personally and, dare I say, competently? If you've got some, I would love to see how the build on this section progressed for you -- I'm a cheater that way, I like to read others posts about a section and it's issues, usually before I start the section, that way I can learn, hopefully, to avoid others pitfalls --- I just make my own mistakes instead

Sorry, no pictures. Start with the stiffeners on the bottom of the tank skins. These are not difficult and it will give you the confidence to do the rest of the tanks.

Here are a few pointers:
I do not like using popsicle sticks. All they do is stick to things. Make a couple of spreader sticks using .032, half to 5/8" wide and 4" long. Make one with a rounded tip, this is good for making fillets and dabbing the ends of rivets with pro seal. The other little stick has a straight end and is good for spreading pro seal on ribs and skins.

As a solvent I use spray gun cleaner, it comes in 5 gallon pails and is good for all sorts of clean up on your project. It is good for cleaning up proseal that has not yet cured.

1. Give the skins, and stiffeners a good bath using the above solvent. This is not the final cleaning but will works as a pre cleaner. You want to remove all oils and such before you start to scuff the seams.

2. Clecoe the stiffeners in place, two is enough for now. Using a cheap electrical tape mask around all the stiffeners and over the rib holes. Do not stretch the tape or it can pull away from the metal. Leave a small cap, less then an eighth of an inch around the stiffeners. This gap will be the "fillet' gap.

3. Remove the stiffeners and scuff the mating surface with red scotch pads. Scuff all things that you want to stick.

4. Use an air gun and blow off all residue from skins and parts.

5. Using a proper pre paint wax and grease remover carefully clean all mating surfaces, using clean cloths.

6. Lay a bead of proseal on a stiffener. Spread it out with the little stick until it covers the stiffener in a thin film. How thin? a bit more then the thickness of the part. After you do a couple you will know the right amount. Two much and it goes everywhere, not enough and you do not get that nice little bit that squeezes out around the edges.

7. Cleco it in place with two clecoes, and insert rivets in other holes. Remove other clecoes and place rivet in holes. Now back rivet the stiffener in. You will be left with some residue on the external skin and this is ok, it will clean off nicely after you are all done. Residue on the outside means that pro seal made its way around the rivet head. Admire your work and do remaining stiffeners.

8. When you are done, go around and use the round head stick to wipe off any excess material. No need to be fancy. Save this excess on a bit of cardboard, you can use it to lay a little dab on all shop heads of the rivets.

9. Carefully remove all the electrical tape, voila, no mess and perfect fillets around the parts!

10. Wipe down any other wayward proseal with the gun cleaner solvent.

11. Throw all the clocoes, spreader sticks, etc in a plastic container with some of the solvent. Then next day you can just wipe them down. Leave the clocoes for a few weeks and they can be used again with no further cleaning. They will never be pretty but they will still work.

12. NO ONE will ever see inside your tanks. I am not telling you to be messy but more pro seal, within reason, is better then not enough.

13. Have a beer, or two.

If you like, you can call me at 519-281-1369 and I will be pleased to coach you through the process.

Vent tube fitting?

Should I put sealing under nut before tighten or is there a o ring under nut?
Where the fitting attaches to rib

If this is the flared tube fitting you are talking about you do not need a sealant. But you might choose to apply proseal on the threads as a threadlocker to prevent the nut from backing off as it's at a place that is very hard to get to later and you do not want it backing off. It will only take a small dab.