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Wing Tank Repair

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Posted

OK My new Avid is great with one issue. The right wing tank has a slow leak in it. I talk to Brett at Airdale and he recommends the replacement tanks that he sells at wingtanks.com but I have heard there is a treatment that you can do to the tanks (not recommended by Brett). Does anyone know about the treatment and have a link for the product? I will be replacing the tanks at a later date but would like to do this short term if possible. I am going to go to the EAA Fabric Workshop when I get the chance as there is fabric work required for a tank replacement and I have never done it.

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Posted

Google 'phenol novolac epoxy fuel tank sealant'.

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Posted

salut

you can also use this : http://www.kbs-coatings.com/Auto-Fuel-Tank-Sealer-Kit_p_34.html

as there is a cleaning product included in the kit, it can be good for a used tank. but you must care of fuel level sight, car tank sealers are they transparent?

personnaly i plan to use it for prevent my unused fiberglass tank :beerchug:

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Posted

There are several tank sealant formulations available but I firmly believe the phenol novolac epoxy based products are superior for chemical (alcohol) resistance and adherence to polyester resin F/G tanks. The cleaners and rust treatment meant for metal fuel tanks are of little value when doing a F/G tank, IMHO. All you need really is a very thorough AV or MOGAS rinse* (several times). Personally, I would add a few handfuls of nuts or drywall screws during the early cleaning agitations to knock loose any bits of adhesive as Avid tended to 'glop' on way more than necessary. It is common to find chunks in the tanks after being put into service (IMHO, finger strainers are a must!). This also helps give the inside surface more 'tooth' for the sealant to adhere to which will reduce the potential for separation and sheeting (which will most certainly ruin your day as your fuel system plugs with the flaking crap). I also have heard that one final rinse with acetone or M.E.K. to slightly soften the F/G just prior to sealant application may help product adherence as well.

*Some folks do all rinsing with acetone, however, I've attached the recent SB#60 from Kitfox Aircraft regarding wing tank prep when sloshing with sealant. Note they do NOT recommend using acetone rinsing on the earlier F/G tanks constructed with polyester resin (vs. newer tanks constructed with vinyl ester resin). Your Avid tanks were constructed with polyester resin so take that into consideration when sealing.

sb60.pdf

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Posted

There are several tank sealant formulations available but I firmly believe the phenol novolac epoxy based products are superior for chemical (alcohol) resistance and adherence to polyester resin F/G tanks. The cleaners and rust treatment meant for metal fuel tanks are of little value when doing a F/G tank, IMHO. All you need really is a very thorough AV or MOGAS rinse* (several times). Personally, I would add a few handfuls of nuts or drywall screws during the early cleaning agitations to knock loose any bits of adhesive as Avid tended to 'glop' on way more than necessary. It is common to find chunks in the tanks after being put into service (IMHO, finger strainers are a must!). This also helps give the inside surface more 'tooth' for the sealant to adhere to which will reduce the potential for separation and sheeting (which will most certainly ruin your day as your fuel system plugs with the flaking crap). I also have heard that one final rinse with acetone or M.E.K. to slightly soften the F/G just prior to sealant application may help product adherence as well.

*Some folks do all rinsing with acetone, however, I've attached the recent SB#60 from Kitfox Aircraft regarding wing tank prep when sloshing with sealant. Note they do NOT recommend using acetone rinsing on the earlier F/G tanks constructed with polyester resin (vs. newer tanks constructed with vinyl ester resin). Your Avid tanks were constructed with polyester resin so take that into consideration when sealing.

Another product thatbike builders have used is POR 15; kreem tends to dissolve with alcohol the POR 15 HOLDS UP WELL, the trouble would be in making sure you get the tank properly turned so that everything is coated.

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Posted

Thanks everyone for the great info. I assume that since the tank is still in the wing that it is sufficient to have two people tank the wing and rotate it to insure that the tank is sufficiently coated? Also what do you do about stopping the fuel line port? I see from the instructions at Caswell that you should blow air in the fuel line port for about 10 minutes. Any other advice you guys have for getting this done right the first time?

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Posted (edited)

Another product thatbike builders have used is POR 15; kreem tends to dissolve with alcohol the POR 15 HOLDS UP WELL, the trouble would be in making sure you get the tank properly turned so that everything is coated.

I have no experience with either, but the POR 15 MSDS says "Material Incompatibility: Strong Oxidizing Agents, alcohols, halogenated hydrocarbons, acids, alkali, alkali metals, water". The KBS MSDS says similar, plus adds "not to be used in aircraft". Regardless, both are a single component tank sealant formulation.

In our F/G tanks, I would highly recommend using a 2-part phenol novolac epoxy based product. While most one and two-part products are listed as resistant to long term exposure to gasoline, diesel fuel, and additives like methanol and ethanol, phenol novolac appears to be considerably moreso. It is also more thixotropic, which means it 'hangs' on the tank walls during the coating process. This gives a thicker overall coating and is preferable to attempting to apply a single thick, or multiple coatings of the much thinner consistency one part polymer based products (which is exactly what most folks are tempted to do). If a one part polymer sealant pools or puddles at all due to improper, excessive or multiple applications, it can not cure. Oxygen in the air slowly depletes the free radicals in the polymer that are necessary to turn the liquid polymer into a hard permanent surface. Thick material skins over and prevents the deeper material from curing. Not as critical with the catalyst hardener of 2-part phenol novolac epoxy based products. These also retain some resilience to flex, seems like a requirement for use in a wing tank I should think.

Again, I would not use any of the acid strippers or fancy cleaners packaged with metal fuel tank sealant products that are designed to remove oxides from metal gas tanks. Any rust stripper that leaves a zinc phosphate coating as a metal tank preparation for the sealer is unnecessary for F/G tank prep, and may actually hinder rather than help proper adherence to F/G. The reality is, several products have been used and reported successful to some degree. Not a product pusher for any particular brand of sealant however, if I were to slosh my wing tanks (and I won't), because it is such a P.I.T.A. and critical job I would definitely take into consideration the foregoing info.

:2cent:

[edit] You're gonna need all your buddies and a good bit of beer to rotate that wing, lol. I would simply remove the outlet and quick drain fittings from the tank prior to sloshing, tape over the openings, then chase the threads with a tap when dry. I used Permatex Tack & Sealant #9AR on my fuel fittings at reassembly with no problems after several months.

Edited by dholly

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Posted

In our F/G tanks, I would highly recommend using a 2-part phenol novolac epoxy based product.

Doug- I assume that by "2-Part" you mean the mix such as Caswell sells: http://www.caswellplating.com/aids/epoxygas.htm

Would you guys recommend two coats?

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Posted

Doug- I assume that by "2-Part" you mean the mix such as Caswell sells: http://www.caswellpl...ds/epoxygas.htm

Would you guys recommend two coats?

Yes, the Caswell is a 2-part phenol novolac epoxy based sealer.

NO on the two coats (which is exactly what most folks are tempted to do, see above :)).

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Posted

OK My new Avid is great with one issue. The right wing tank has a slow leak in it. I talk to Brett at Airdale and he recommends the replacement tanks that he sells at wingtanks.com but I have heard there is a treatment that you can do to the tanks (not recommended by Brett). Does anyone know about the treatment and have a link for the product? I will be replacing the tanks at a later date but would like to do this short term if possible. I am going to go to the EAA Fabric Workshop when I get the chance as there is fabric work required for a tank replacement and I have never done it.

Hi! I'm brand new to this group and this is my first post. I frequent the Yahoo Avid group and just joined this site too after some lurking :-)

I would not recommend using a slosh sealer for all the obvious reasons (potential flaking, poor adhesion, unknown compatibility with fuel additives etc). The wingtanks.com solution is a lot of work and the second tank on each side fills slowly, although there is a good fix for that. I decided to cut a large hole in each bay of both tanks. Once inside it was easy to use structural adhesive (hysol) to paint all seams and edges in the tanks where leaks are most likely to occurr. I then made covers out of .030 Al and riveted the covers on using access cover proseal and all aluminium sealed pull rivets. This sounds messy, but the repair turned out very nice, like the plane was built that way. I have photos on the Avid yahoo site you can view there, or I might be able to upload them here. Doing the fix this way gives me a high degree of confidence in the repair, and I can always remove the covers if I should need to go inside again. This solution did not add any weight and did not take away any usable tank volume. Yes it was a lot of work, but MUCH less work than the wingtanks.com solution with no loss of fuel capacity. More work than sloshing, but you know you really wouldn't be comfortable with that and would always be worrying about the coating not sticking and causing an engine out.

Hope this helps,

Chris Bolkan

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Posted

Hi! I'm brand new to this group and this is my first post. I frequent the Yahoo Avid group and just joined this site too after some lurking undecided.gif)

I would not recommend using a slosh sealer for all the obvious reasons (potential flaking, poor adhesion, unknown compatibility with fuel additives etc). The wingtanks.com solution is a lot of work and the second tank on each side fills slowly, although there is a good fix for that. I decided to cut a large hole in each bay of both tanks. Once inside it was easy to use structural adhesive (hysol) to paint all seams and edges in the tanks where leaks are most likely to occurr. I then made covers out of .030 Al and riveted the covers on using access cover proseal and all aluminium sealed pull rivets. This sounds messy, but the repair turned out very nice, like the plane was built that way. I have photos on the Avid yahoo site you can view there, or I might be able to upload them here. Doing the fix this way gives me a high degree of confidence in the repair, and I can always remove the covers if I should need to go inside again. This solution did not add any weight and did not take away any usable tank volume. Yes it was a lot of work, but MUCH less work than the wingtanks.com solution with no loss of fuel capacity. More work than sloshing, but you know you really wouldn't be comfortable with that and would always be worrying about the coating not sticking and causing an engine out.

Hope this helps,

Chris Bolkan

Welcome aboard Chris! I have read many of your posts on the yahoo groups and we all welcome your knowledge here! As with all things, the easiest repair may not be the best option you have available. Your repair method seems well thought out and executed. How many hours do you have on the tank now with the aluminum lids? I am just thinking about long term issues such as oil canning working those seams on the top of the tank.

:BC:

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Posted

Welcome aboard Chris! I have read many of your posts on the yahoo groups and we all welcome your knowledge here! As with all things, the easiest repair may not be the best option you have available. Your repair method seems well thought out and executed. How many hours do you have on the tank now with the aluminum lids? I am just thinking about long term issues such as oil canning working those seams on the top of the tank.

:BC:

I have about a year and 100 hours on the repairs so far and I fully expect them to last forever. Both tanks had slow leaks along the rear spar somewhere that leaked out near the rear spar carrythrough. The repair is very strong with no oilcanning. The undercamber of the wing puts some arc in the covers which makes them very strong. A person might have to use a bit thicker AL on the speedwing because the bottom is flat. Proseal is INCREDIBLY strong and flexible and would probably work all by itself not including the rivets, which I chose to space at about an inch and a quarter apart. There is no question in my mind that this is the best way to fix tanks correctly and permenantly. It's just a lot of work. The advantages are 1) you do not have to destroy the paint, covering or replace the tanks, 2) The weight stays the same, 3) You do not lose any fuel capacity, 3) you can go back inside easily (well relatively easily) for further work if need be. Even though this repair method is a lot of work, it cannot be 1/10th the work of replacing the tanks! And those plastic tanks are heavy, have their own potential leak scenarios, and you lose several gallons per side. Plus you have to uncover, re-cover and re-paint a significant portion of the wing. YUCK!

The things to make sure of doing the repair this way is to cut all holes the same size so you can make all the covers the same at one time. Also be sure and cut one hole per bay leaving enough "flange" to seal and rivet to. The holes are cut in the BOTTOM of the wing because the raw fiberglass tank bottom is just under the covering. On top there is usually a sheet of plywood, and depending on the model Avid, may have plumbing running around the inside top of the tank. Then be sure to remove covering and any filler in the flange area before sealing and riveting the covers on to the fiberglass. I painted the covers the same color as the wing and like I said, it turned out better than I imagined it would...like the plane was built with them originally.

ChrisB

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Posted

Chris,

Do you have a link to the photos for the repair you did? I am certainly interested in doing it in that manner.

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Posted

Chris,

Do you have a link to the photos for the repair you did? I am certainly interested in doing it in that manner.

Sure do. Here is the link to them on the Yahoo Groups Avid site:

http://groups.yahoo.com/group/avid_flyer/photos/album/889359366/pic/list

Hopefully you are a member there. If not you should be, because it is similar to this site in that there is a lot of good Avid info there too.

I tried uploading them to this site, but I do not have any place to host photos. I can email them to you if you give me your address.

ChrisB

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Posted

Sure do. Here is the link to them on the Yahoo Groups Avid site:

http://groups.yahoo....359366/pic/list

Hopefully you are a member there. If not you should be, because it is similar to this site in that there is a lot of good Avid info there too.

I tried uploading them to this site, but I do not have any place to host photos. I can email them to you if you give me your address.

ChrisB

I see now how you did it. GREAT idea and I wish I would have seen this over on the yahoo site before I had a buddy order new tanks for his kitfox. This would have been a very easy fix for him. Oh well, whats another grand for new tanks when its not your money :lol:

As far as posting pics, you should not have to host them anywhere, they upload to the server for this site. I have it set to unlimited upload space but a max of 24 mb per pic or attachment. If you are getting some sort of error when you click the "click to attach files button" let me know what it is saying and I will see if I can track down the problem.

:BC:

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Posted

I see now how you did it. GREAT idea and I wish I would have seen this over on the yahoo site before I had a buddy order new tanks for his kitfox. This would have been a very easy fix for him. Oh well, whats another grand for new tanks when its not your money :lol:

As far as posting pics, you should not have to host them anywhere, they upload to the server for this site. I have it set to unlimited upload space but a max of 24 mb per pic or attachment. If you are getting some sort of error when you click the "click to attach files button" let me know what it is saying and I will see if I can track down the problem.

:BC:

I'm trying to upload some pictures. Here goes. Any questions just ask!

Chris

post-258-12992583701483_thumb.jpg

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post-258-12992584129497_thumb.jpg

post-258-12992584211364_thumb.jpg

post-258-12992584298721_thumb.jpg

post-258-12992584419499_thumb.jpg

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Posted (edited)

Chris,

For starters can you tell me what brand you used for the sealant and adhesive?

What are the dimensions of the holes and how much "flange" area did you use?

How long did you let it 'cure' before closing up?

How long did it take you to complete the whole process?

A parts list would be most appreciated.

Looks good!

Edited by OKAvidFlyer

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Posted

Chris,

For starters can you tell me what brand you used for the sealant and adhesive?

What are the dimensions of the holes and how much "flange" area did you use?

How long did you let it 'cure' before closing up?

How long did it take you to complete the whole process?

A parts list would be most appreciated.

Looks good!

I'm at work so I need to keep this short, but we can fill in the blanks later.

Repair/Leak patch: I used Hysol structural adhesive EA-9430 (aircraft spruce) and added a small amount of cotton flox with each small batch. This stuff is easy to work with, tough and strong while not being brittle and is resistant to almost everything anyone can put into fuel. After sanding and cleaning the internal seams and edges with MEK, just paint the stuff on with an acid brush. About a 30 minute working time and fully cures in 24 hours. Most likely your leak is along the rear spar. This can be checked by placing wing on edge and filling with AVgas up almost to the holes and checking for leaks after coating the seams.

Sealant for covers: Chemseal/Flamemaster 3330 Access door sealant. Made for removable access doors. Still sticks like the dickens! Data sheet attached. This stuff is SICK, I mean amazing! Cleanup uncured sealant with MEK soaked rags....Lots of them. It is messy! Two hour working time. Full cure several days.

Dimensions of holes depend on the number of "bays" in your particular tanks. My Magnum has 3 bays. My MKIV had 4 bays. After you tap on the bottom of the empty tank you will easily figure out how many bays and how big you can make the holes. I made 3/4 inch flanges. If you look close you can see my marks on the blue tape for the flange.

It took a long time to do the whole process because I did a TON of research. With what I know now It would take a couple of weeks of evenings after work if I had all the supplies. A lot of how long it takes will depend on how you want the finished repair to look. It will take a lot longer if you really want it to look good. The devil is in the details. It wouldn't take that long at all if you didn't care how it looked and it would still be solid repair.

Hope this helps.

Chris Bolkan

CS3330B05-2008.pdf

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Posted

I'm at work so I need to keep this short, but we can fill in the blanks later.

Repair/Leak patch: I used Hysol structural adhesive EA-9430 (aircraft spruce) and added a small amount of cotton flox with each small batch. This stuff is easy to work with, tough and strong while not being brittle and is resistant to almost everything anyone can put into fuel. After sanding and cleaning the internal seams and edges with MEK, just paint the stuff on with an acid brush. About a 30 minute working time and fully cures in 24 hours. Most likely your leak is along the rear spar. This can be checked by placing wing on edge and filling with AVgas up almost to the holes and checking for leaks after coating the seams.

Sealant for covers: Chemseal/Flamemaster 3330 Access door sealant. Made for removable access doors. Still sticks like the dickens! Data sheet attached. This stuff is SICK, I mean amazing! Cleanup uncured sealant with MEK soaked rags....Lots of them. It is messy! Two hour working time. Full cure several days.

Dimensions of holes depend on the number of "bays" in your particular tanks. My Magnum has 3 bays. My MKIV had 4 bays. After you tap on the bottom of the empty tank you will easily figure out how many bays and how big you can make the holes. I made 3/4 inch flanges. If you look close you can see my marks on the blue tape for the flange.

It took a long time to do the whole process because I did a TON of research. With what I know now It would take a couple of weeks of evenings after work if I had all the supplies. A lot of how long it takes will depend on how you want the finished repair to look. It will take a lot longer if you really want it to look good. The devil is in the details. It wouldn't take that long at all if you didn't care how it looked and it would still be solid repair.

Hope this helps.

Chris Bolkan

Oh I forgot to say you want to by the 6 oz (I think) chemseal 3330 "kit" It comes in a tube (that looks like a small tube of calk) with both the sealant and activator in the tube. Super easy to mix because it is self contained. Just follow the instructions. Then you can put it in a calking gun to apply. You might have to modify a standard calking gun to work, but it is easy. One "kit" which costs about $20.00 will do all the covers on one wing if you are organized with a friend helping and can get all 3 or 4 covers riveted on within the hour and a half or so working life.

You also want to use all aluminium sealed rivets http://www.hansonrivet.com/w22.htm I used aluminium rivets with aluminium mandrels so they could be drilled out easily if I ever had to remove a cover.

Chris Bolkan

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Posted

Hey Chris!

Nice careful job, I followed it on the Yahoo group and think if one intended to stick with Avgas your tank repair solution would be the way to go. It really did come out looking quite professional. Have you considered giving up your day job? :)

For those limited to or wanting to use Mogas, so it seems to me we are still forced to decide between the tank sealant or poly tank alternatives. Since I personally oppose tank sealants but want the Mogas option for float flying, I've just resigned myself to living with the capacity limitations of the poly tanks. My Avid+ wings are pretty much done except for the tank choice and install, was hoping options other than the wingtanks.com or Ridgerunner offerings pop up before I'm ready to cover. Love the capacity but still not comfortable with the so-called "superior" ethanol 'resistance' of the new Kitfox tanks. I want ethanol proof, period. I can't believe we are now looking at E15, buy corn futures!

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Posted

Excellent information Chris; thanks for sharing it. I have not had any leaking in my tanks yet but it is probably just a matter of time. With the push for more alcohol in the fuel, and who knows how much longer avgas will be produced, I think the environazi's would love to have us all restricted to public transportation with travel limited to between a small apartment and a work cube, and no sticking your hand out the window to pretend that your flying. fskepftr.gif

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Excellent information Chris; thanks for sharing it. I have not had any leaking in my tanks yet but it is probably just a matter of time. With the push for more alcohol in the fuel, and who knows how much longer avgas will be produced, I think the environazi's would love to have us all restricted to public transportation with travel limited to between a small apartment and a work cube, and no sticking your hand out the window to pretend that your flying. fskepftr.gif

Have you tried this link? It's a very active link to ethanol free gas stations in the US and Canada.

I've found it most helpful. I learned about several stations in my area that are ethanol free. Still a good idea to test, but this list has proved 100% accurate for me so far!

I've also joined the ethanol free coalition. Just added my name to the voice, they don't ask for anything.

Chris Bolkan

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Have you tried this link? It's a very active link to ethanol free gas stations in the US and Canada.

I've found it most helpful. I learned about several stations in my area that are ethanol free. Still a good idea to test, but this list has proved 100% accurate for me so far!

I've also joined the ethanol free coalition. Just added my name to the voice, they don't ask for anything.

Chris Bolkan

OOPS! forgot the link: http://pure-gas.org/

Chris

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Posted

this Chris's post is old but very interesting ! i do an update to find it more easily ;)

 Sure this is the way i'll move if a leak starts

 

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Posted

salut

 

you can also use this : http://www.kbs-coatings.com/Auto-Fuel-Tank-Sealer-Kit_p_34.html

 

as there is a cleaning product included in the kit, it can be good for a used tank. but you must care of fuel level sight, car tank sealers are they transparent?

 

personnaly i plan to use it for prevent my unused fiberglass tank :beerchug:

is this method  auto fuel tank sealer kit valid for fiberglass tanks. 

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