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Paint blister proposal for Vans resolution

andrew phillips

andrew phillips

Well Known Member
The paint blister thread is one of the most highly viewed (over 9000) and one of the most replied to (over 120). This leads me to believe there are a lot more people out there who haven't taken the time to respond.

I am very disappointed in this situation. I paid Vans their full asking price for the quickbuild option. This makes them the manufacturer of my wing tanks. As a manufacturer they should accept responsibility for this problem and offer some kind of compensation to their clients.

As an individual I have a small voice but as a group we have a large one.

I propose that we start a database of all the individuals that have experienced this problem. I will volunteer to collect the data unless someone else has a better (easier) solution. This will let everyone know how large the scope of the problem really is. My suggestion is that affected individuals answer the following questions and then send a copy of their email to me and to Vans. As this is a proposal at this stage I am open to any and all input.

Questions:
Name and contact info: Andrew Phillips - contact through VAF
Model of plane: RV-7A
Quickbuild tanks (yes/no): yes
Year received: 2007
Blisters elsewhere (other than tanks) on aircraft (yes/no): no
Prep and paint info: epoxy primer + house of color base/clear
 
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Andrew,

How about a link to the original thread. I searched "paint blister" and "blister" with no luck other than this thread. I had a rivet leak on my L wing tank (QB) that was discovered (fortunately) just before painting started. This would have probably resulted in a blister after painting.

greg
 
DanH said:
http://www.vansairforce.com/community/showthread.php?t=10187&referrerid=2320

Let's get behind this effort. Report those blisters!
Click to expand...

Not to turn off the wind in this sail - Van's knows about the issue. They do read this forum now and then.

Van's determination regarding the cause is surface contamination at the rivet head/skin joint. The blisters occur because the contamination creates a gas that has no where to escape except up through the paint because the rivets are pro sealed around the shank. At rivets not sealed with pro seal, the gas escapes down around the rivet shank. That's why the blisters show up only at the tank rivets.

The theory makes sense except guys who are professional painters, like the friend who painted my airplane, disagree. He said he has painted many airplanes and has never had it occur.

So there you are - we have some interesting theories about what is causing this very frustrating event, but no hard scientific proof as to what is causing it.
 
As an aside, I'm opposed to this even if Van's quickbuilds are to blame (I don't think that's the case). Trying to get Van's to pay for repainting the tank is just gonna increase the price of everything Van's sells, which isn't a solution.

I'm all for manufacturers stepping up when a structural issue is discovered. Cosmetic issues... pass.
 
As I mentioned earlier, I have had my last 2 airplanes exhibit this problem. The common theme between both of them is that they were the same vintage quickbuild (circa 2001-2002) AND I painted them. So, now that I am getting ready to paint my 10 QB tanks, I am really suspicious of anything I do. I am wondering if there is some interaction going on between the prep solutions and the pro seal on the tanks, as the blistering only occurs on the tanks. So, last week I did the usual prep--- scotchbrite and clean with acetone, and a week later I noticed weeping of some type of contamination around a good number (60%) of the rivets on the tanks only. No weeping or similar looks around any other rivets on any other parts. So, I now wiped one half of the tank down with Prepsol, and will look at them this week end to see if there is any difference. I usually wipe with enamel reducer prior to primer and paint (all Dupont products).
Clearly there is something going on here, and it might just take some time to show up once paint is on it.

Vic
 
tanks

well i hate to hear that, and i wanted to make a post a long time ago?. I know of two other people that had quick build wings and all four tanks are leaking in less than 100 hours?. I am building a -8 and i was hopeing that vanswas not going to be like all the new places you eat?. good food and service at first, then service down hill from there?.
 
Cleaner

Vic,
I wonder if you're not on to something here. I often here of people using pretty strong solvents to wipe down before painting. And we clearly have pro-seal around the rivets that will be softened by acetone, MEK, lacquer thinner, etc...

I've had REALLY good success with simply using rubbing alcohol. Its clean and cheap and will remove the residue of the prep work, which is all we need.


vic syracuse said:
. I am wondering if there is some interaction going on between the prep solutions and the pro seal on the tanks, as the blistering only occurs on the tanks.
Vic
Click to expand...
 
I propose a test specimen

I propose that we build a test specimen.

It would be a small cubical tank, prosealed together. The top and bottom panels of the tank would have 8 or 10 rows of stiffeners riveted into them, and the perimeter of the top and bottom would be formed similar to the aft tank baffle seam.

On each of the top and bottom panels, every other stiffener would have the rivet tails fully encapsulated, and the stiffeners in between would be well sealed, but the tails wiped clean. On the perimeter rivets, half the upper rivets and half the lower rivets would be encapsulted, the other half not.

Each pair of stiffener rows on the top would be given a different surface prep prior to painting. The bottom would get the same treatments.

One pair would get the full normal treatment of solvent wash and scotchbrite, followed by the acid etch wash, alodine, etc.
One pair would get only mild soap wash and scotchbrite, followed by the normal paint prep
One pair would get no liquid wipe, only dry scotchbrite scrub and dry wipe, followed by paint prep.
One pair could get a loctite drop on each rivet prior to prep and paint.
One pair could get an epoxy drop on each rivet, then sanded flush, then prep and paint.

Finally, the tank would be painted and filled half full with avgas, and left to do what it does. The idea of the identical top and bottom is to see the effect of fuel vapor vs. liquid fuel. For each pair of stiffeners, the various surface preps would have one with encapsulated rivets, one not.

I think this tests all the likely variables and combinations, except perhaps for the coriolis force from rotation of the earth being reversed in the Phillipines, and any other environmental factors that might be present there vs. here.

IF this test specimen shows what variables or combinations are involved in promoting blisters, we all learn. If none of the rivets blister, it focuses attention on something in the process for the QB's that we can not reproduce here, which I think puts it on Vans that they are doing something else wrong. Heck, maybe they are thinning their proseal with solvent during assembly? Just wild speculation, but.....
 
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Steve has the right take I believe - test, test, test! What we have is a lot of anecdotal evidence - real blisters, absolutely - but until you control the variables, it is hard to "prove" a cause. What we need is someone who has just finished their project and is going through withdrawal from not building to set up such an experiment...;)

(I'm having too much fun helping Louise on the -3 right now)

Paul
 
David-aviator said:
Van's knows about the issue.
Click to expand...

Yes, but quoting from a Van's email you posted in the original thread:

.... It references only 6 airplanes out of 4700+ flying, so the
sample is very small...... I don't see that any conclusion can be drawn from what we have here, other than that apparently < 0.2% of RV builders have
problems with paint on tank rivets.

Judging from reports here on VAF, it seems many more than 6 airplanes have shown the problem. How many more? Are they mostly QB's of a certain vintage, or is the blister problem common to all tanks from any source? This is basic information necessary to track down the problem.

As for Van's, I don't think anybody is asking for paid repaints. What I want personally is knowledge; I've not painted them yet. What do I need to do so my new tanks don't blister?
 
Just read Steve's post, and I think it's a marvelous idea. Obvious we need a volunteer.

I nominate Rick Galati. Rick is a fast and experienced sheet metal builder with clear (and high) standards, and he has been thinking about the problem. I imagine he is quite capable of building perfectly sealed rivet lines as well as imperfect lines with the specified variables.

Rick, would you do it? I would be more than happy to contribute to a fund for materials, and I'm sure I'm not alone.
 
DanH said:
Just read Steve's post, and I think it's a marvelous idea. Obvious we need a volunteer.

I nominate Rick Galati. Rick is a fast and experienced sheet metal builder with clear (and high) standards, and he has been thinking about the problem. I imagine he is quite capable of building perfectly sealed rivet lines as well as imperfect lines with the specified variables.

Rick, would you do it? I would be more than happy to contribute to a fund for materials, and I'm sure I'm not alone.
Click to expand...
Dan,

I'm truly flattered you would toss my name into the hat to conduct such a test. I must however defer the project to someone more willing to expend the necessary time and substantial effort required to do this thing right. :)
 
Missed the point

osxuser said:
As an aside, I'm opposed to this even if Van's quickbuilds are to blame (I don't think that's the case). Trying to get Van's to pay for repainting the tank is just gonna increase the price of everything Van's sells, which isn't a solution.

I'm all for manufacturers stepping up when a structural issue is discovered. Cosmetic issues... pass.
Click to expand...

I certainly don't want Van's to pay for a repaint. I don't want them to pay for anything. I want to box up my QB tanks and return them for an exchange for a new tank kit. Is that a lot to ask? Take back a defective part for a good one. If your empennage skins were full of pinholes wouldn't that be cosmetic and not structural, wouldn't you want to exchange for new ones? I've personally borescoped my tanks and assess it would be much easier to build new ones myself properly than try and fix the mess inside them. There is needless globs of proseal randomly throughout them, there are shop heads of rivets exposed throughout them. Stay on that Van's does no wrong bandwagon but if you don't build your own tanks, you will be wandering what yours will do also. I paid premium price for my QB kit so I didn't have to worry about this sort of thing.:mad: Yes I've reported this to Van's, their not interested in helping. Where else is there to turn? Maybe you have an idea?
 
decathlon737 said:
There is needless globs of proseal randomly throughout them, there are shop heads of rivets exposed throughout them. Stay on that Van's does no wrong bandwagon but if you don't build your own tanks, you will be wandering what yours will do also. I paid premium price for my QB kit so I didn't have to worry about this sort of thing.:mad: Yes I've reported this to Van's, their not interested in helping. Where else is there to turn? Maybe you have an idea?
Click to expand...

until Vans thinks there is a real significant problem you might consider contracting someone to build you some tanks. sell the ones you have, probably lose some money. in the end you should be happy with the tanks, and out the extra money. this guy builds tanks: aviacomp, don london.

http://www.mstewart.net/michael/rv/Links/homebuiltyellowpages.htm

there should be other people who will do the job for you. i don't see how this would interfere with the 51% rule, since you can buy complete tanks from vans, so you should be good to go witht he feds.

just think of it as the alternative engine problem, everyone here thinks the best thing to do if you pay for one of those is sell it and start over with a lycoming ..... this is how i feel for you --> :(


edit- have you asked vans if they will exchange your QB tanks for a slobuild tank kit? seems like if you haven't done much work on them they wouldn't think that was to bad of an option for everyone
 
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Danny7 said:
until Vans thinks there is a real significant problem you might consider contracting someone to build you some tanks. sell the ones you have, probably lose some money. in the end you should be happy with the tanks, and out the extra money. this guy builds tanks: aviacomp, don london.

tank kit? seems like if you haven't done much work on them they wouldn't think that was to bad of an option for everyone
Click to expand...

I don't think there's anyone on this planet (except for Dan Horton) that I would trust to build my tanks other than me the next time. I don't mind the work and wish a thousand times I had done it myself. When you pay extra for a QB (only because I wanted to fly sooner) you don't expect to have to redo something out of your control. Does Van's have a good product? I think they have the best product, but need to recognize they have a problem with QB foreign built tanks. There are several thousand slow build tanks in the field without this problem. That in it's self is reason to believe they can be done right. Don't fool yourself into thinking it's not fuel causing this problem. Fact of the matter is the tanks were not properly sealed and vapors are escaping through the rivets. Rick Galati is I believe the only one who positively knows this other than myself. I want to trade these junk tanks to Van's for a tank kit to rebuild them myself. I ask again, is this too much to ask? Once again I will state this: ( This problem was out of my control). Sorry if this was short and to the point, I have almost exhausted all my options with Van's who insist it is the consumers fault.:eek: On another note, I have a QB7 in my paint shop now prepping to paint. It belongs to another member of this site, we have borescoped these tanks and found the same problems as mine. So what to do, paint and hope for the best?
 
Danny7 said:
edit- have you asked vans if they will exchange your QB tanks for a slobuild tank kit? seems like if you haven't done much work on them they wouldn't think that was to bad of an option for everyone
Click to expand...

Their not interested in this solution. I proposed this several emails ago. One of them deals where if we replace yours we would have to replace everyone's.
 
decathlon737 said:
There are several thousand slow build tanks in the field without this problem.
Click to expand...

Just to be fair, there are also slow-builds in the field WITH this problem (according to Kahuna, who said this on another thread), so it is not JUST a problem with the QB's - it is a problem that can hit either side of the pond, and if the cause was 100% known, then it would probably be fixed.

I would be frustrated as well Bill, believe me! I am fortunate that my QB tanks built in 2004 haven't developed the blisters - and I have no idea why not...

Paul
 
Ironflight said:
Just to be fair, there are also slow-builds in the field WITH this problem (according to Kahuna, who said this on another thread), so it is not JUST a problem with the QB's - it is a problem that can hit either side of the pond, and if the cause was 100% known, then it would probably be fixed.

I would be frustrated as well Bill, believe me! I am fortunate that my QB tanks built in 2004 haven't developed the blisters - and I have no idea why not...

Paul
Click to expand...

I realize some slow builds have this problem to Paul. But the fact that even one tank that does not have this problem shows it can be done right. Your right, very, very frustrating.:(
 
David-aviator said:
Not to turn off the wind in this sail - Van's knows about the issue. They do read this forum now and then.

Van's determination regarding the cause is surface contamination at the rivet head/skin joint. The blisters occur because the contamination creates a gas that has no where to escape except up through the paint because the rivets are pro sealed around the shank. At rivets not sealed with pro seal, the gas escapes down around the rivet shank. That's why the blisters show up only at the tank rivets.

The theory makes sense except guys who are professional painters, like the friend who painted my airplane, disagree. He said he has painted many airplanes and has never had it occur.

So there you are - we have some interesting theories about what is causing this very frustrating event, but no hard scientific proof as to what is causing it.
Click to expand...

I had several leaking rivets which has nothing to do with gas. Also the one closeout was leaking badly. Not a paint issue. And also a couple dozen blisters.
 
osxuser said:
As an aside, I'm opposed to this even if Van's quickbuilds are to blame (I don't think that's the case). Trying to get Van's to pay for repainting the tank is just gonna increase the price of everything Van's sells, which isn't a solution.

I'm all for manufacturers stepping up when a structural issue is discovered. Cosmetic issues... pass.
Click to expand...

I dont want compensation from Vans for the same reason you said, I am commited to looking after our "supplier", HOWEVER it is quite depressing when your pride and joy is leaking and blistering and Vans wont take responsibility.
 
What to do...

Like others viewing this thread, I would just like to know what to do as I near the point of painting my QB wings. How about asking Van's to build a test tank as was suggested and have them complete a definitive study? I know the results may not be what they want to hear and then again it may be determined it is, in fact, a builder/painter prep issue.

I would think that they would want to know if they have a quality control issue.
 
preventing this?

For folks like me with pre-built tanks (i have slow-build wings, but bought Vans' pre-built tanks), is there anything we can do to treat the inside of the tanks before painting, to avoid this?
 
Slow build/blisters

I have the problem too, and researched this a long time ago. I slow built my tanks and all rivet shop heads are sealed inside. I have no fuel leaks at all (740+ hrs). I had the plane professionally painted by an aircraft painter. The paint blisters appeared only on the top of my tanks on the rivet heads and took several months after the painting was complete to manifest itself. After much research, I finally concluded it was a reaction of the paint thinner/solvents used in the primer/paint that reacted with the proseal causing trapped solvent gases to eventually cause the blistering. It took the heat of the summer as well to create this condition. Google "trapped solvent", "paint thinner blisters", "solvent popping" or some such. Apparently, some painters may use paints and thinners that aren't compatible or aren't compatible with proseal. Even the thinner in the paint, not the solvent used to clean before painting, can be the culprit. Bear in mind that many production planes don't have this issue because they use fuel bladders or internal tanks, not a wet wing sealed tank like we have. Here is a link to one of the resources, look for "Solvent Popping".

http://www.tat-co.com/tat-co/documents/paintdefectguide.pdf
 
Rusty,
The "Solvent Pop" described in the linked document is nothing like the tank blister problem. It's a fairly common novice painter problem included in my own learning curve; I pushed on too many coats too quickly. The paint does not lift off the surface or form a blister. It's just full of tiny closed bubbles and open pinholes.

That said, your theory about solvent reaction with proseal may be correct; it's certainly on the list of suspects. Did you find anything directly linking proseal and solvent?
 
DanH said:
Rusty,
The "Solvent Pop" described in the linked document is nothing like the tank blister problem. It's a fairly common novice painter problem included in my own learning curve; I pushed on too many coats too quickly. The paint does not lift off the surface or form a blister. It's just full of tiny closed bubbles and open pinholes.

That said, your theory about solvent reaction with proseal may be correct; it's certainly on the list of suspects. Did you find anything directly linking proseal and solvent?
Click to expand...

MEK has to be on the top of the list of solvents that could interact with cured proseal.
 
David-aviator said:
MEK has to be on the top of the list of solvents that could interact with cured proseal.
Click to expand...
Piper Cherokee fuel tanks are very similar in construction to RV fuel tanks. I wonder if the many thousands of Piper Cherokees flying have had problems with paint blistering. I doubt it. The airliners you flew for decades are as you well know, pressurized. Pressurization means all those tens of thousands of exterior rivets are wet-sealed into place using proseal. I suspect MEK is not exactly a rare commodity among aircraft manufacturers and in addition, most airliners end up in a livery of bright and sometimes bold colors. If that paint had an inherent reaction to proseal, I'm sure engineers would long ago have isolated the root cause. Fact is, proseal is highly paintable at least when used with the type of paints associated with the commercial airline industry...and Piper Aircraft.
 
Mooney too, if I recall correctly.

Regarding proseal/solvent reaction, do we yet have a single report of paint blisters anywhere on the airframe other than tanks? Plenty of proseal used elsewhere with the same solvents and paints.
 
Proseal

I prosealed many other places on my plane during construction. No other paint problems anywhere except tanks. Doesn't the yellow streaks coming from my paint blisters indicate mogas leakage? They are very minute, but are there never the less. A lot of maybe's and what if's are flying around this thread. I can tell you with certainty fuel is the cause of my problem.
 
I've done some tank repairs for -6's (slow build) and never had blisters, always die and fuel. Is it possible the problem is the brand of sealant being used?
 
Acknowledgment

OSXUSER

That is very well a possibility. Do you fault the QB builder for this? Too many people have chimed in for a problem not to exist. Acknowledgment is the first step to repair. Remember how many A models had to flip over and destroy before an acknowledgment was admitted?
 
MEK/Pro Seal reaction

here is an excerpt from this site that hints at a reaction. I found a lot of these a couple of years ago.

http://www.coltindustrial.com/Library/sealers/proseal/proseal.html

APPLICATION
Surface preparation: Surface of joints should be free of dust, dirt or loose particles.
Do Not use solvents (MEK, Acetone, Xylol) for cleaning agents on application area.

Application: Use Pro-Seal Pro-Gun™, or a standard caulk gun to apply. Maintain constant, light tip pressure on surface.

Finishing: Use a soap solution for a tooling lubricant. Painting is recommended for high touch areas. Sealant may be painted upon application. for best results wait 24 hours.

Clean Up: for cleaning tools after application is completed use chlorinated solvents: Acetone or Xylol. If product is cured, out of scrape the bulk away and remove residue with solvent.
 
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Another thing that

is different about my particular paint is the painter used filler and sanded to cover all the rivet heads on the top of the airplane. I think it is the filler/solvent/proseal that do not get along, esp. when heated. This would explain why the top of the plane sitting in the sun seems to blister first.
 
Rusty, the material data sheet you referenced does not appear to be aircraft "proseal".

Read carefully: "Pro-Seal 34? is a single component, non-sag, elastoplastic, M34 Polycarbonate sealant material.."

Aircraft fuel tank sealant (our "proseal") is a polysulfide base. The product currently sold by Vans is Flamemaster/ChemSeal CS3204.
 
Wrong "Proseal"

hecilopter said:
here is an excerpt from this site that hints at a reaction. I found a lot of these a couple of years ago.

http://www.coltindustrial.com/Library/sealers/proseal/proseal.html

APPLICATION
Surface preparation: Surface of joints should be free of dust, dirt or loose particles.
Do Not use solvents (MEK, Acetone, Xylol) for cleaning agents on application area.

Application: Use Pro-Seal Pro-Gun™, or a standard caulk gun to apply. Maintain constant, light tip pressure on surface.

Finishing: Use a soap solution for a tooling lubricant. Painting is recommended for high touch areas. Sealant may be painted upon application. for best results wait 24 hours.

Clean Up: for cleaning tools after application is completed use chlorinated solvents: Acetone or Xylol. If product is cured, out of scrape the bulk away and remove residue with solvent.
Click to expand...

WHOA! Stop the presses. Before someone takes the above as gospel, be aware that the above quote applies to a concrete sealant material. The sealant used on our fuel tanks is neither a "single component" nor a "polycarbonate."

The fuel tank sealant used on our fuel tanks is a two-component (part A and part B mixed together prior to application) and is a polysulfide. The sulfur atoms give the compound the offending odor.

There are multiple products on the market under the name "Proseal," "Pro-Seal" etc. While the above precautions MIGHT be applicable to our sealant, be aware that they were not written for our "black goo," which is sold to us from Van's under the name "Flamemaster" (a company name). Aircraft Spruce sells it under the name "Pro-Seal."

Polysulfide sealant has been used for years in the aerospace industry as a sealant, and it has been used on the Space Shuttle Solid Rocket Boosters since the beginning of the Shuttle program.

What made me investigate this source is the mention of chlorinated solvents. Neither Acetone nor Xylol contain chlorine atoms, so they are not chlorinated solvents.

I do admit that I did not stay in a Holiday Inn Express last night! :)

P.S. Looks like Dan was quicker than me...as usual. :)
 
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Another clue

Let's suppose the problem is fuel vapors leaking upward along the rivet shank and out at some breach along the perimeter of the rivet head. Wouldn't we expect to see the blister intitally form at this spot; that is, at a single point on the rivet head perimeter. On the other hand, if Van's theory were correct, we would expect to see the blister form along the entire rivet head perimeter. In the small number of photos I've seen, the blister seems quite round, as if the entire perimeter, and perhaps the rivet head itself, are affected.
 
In my case, ALL my blisters start out as a tiny point and expand around and away from the point. They only engulf the entire rivet after months of sun exposure.

Even today, I have tiny point ones, and fully engulfed rivet ones.
During the cold winter , there are no changes in blisters. In fact just as a data point. If my plane never left the hanger, I would have NO blisters at all.

In the summer, with each flight, I see more and more.
 
szicree said:
Let's suppose the problem is fuel vapors leaking upward along the rivet shank and out at some breach along the perimeter of the rivet head. Wouldn't we expect to see the blister intitally form at this spot; that is, at a single point on the rivet head perimeter. On the other hand, if Van's theory were correct, we would expect to see the blister form along the entire rivet head perimeter. In the small number of photos I've seen, the blister seems quite round, as if the entire perimeter, and perhaps the rivet head itself, are affected.
Click to expand...
Take a good hard look at the series of photos in post #121, particularily the area around the fuel filler flange, and then you tell us what YOU see:
http://www.vansairforce.com/community/showthread.php?t=10187&page=7

Also note the blisters on the rear baffle, an area so many posters seem to have trouble understanding how fuel can be a factor in that area when in fact it can be if a void exists in the fay seal boundary.
 
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decathlon737 said:
OSXUSER

That is very well a possibility. Do you fault the QB builder for this? Too many people have chimed in for a problem not to exist. Acknowledgment is the first step to repair. Remember how many A models had to flip over and destroy before an acknowledgment was admitted?
Click to expand...

Bill & all,

All i'm saying, is I don't think it's and actual fuel leak/tank leak. Obviously a problem exsists. Additionally, I don't think Van's should be held FINANCIALLY responsible, although the problem could be with their supplier.

Myself, the only proseal I use is the pre-ratio'd tubes, as available from ACS or others. The kind that fit into the gun.

Maybe the problem has something to do with mix ratio or non-spec'd sealant? Anyone with a slow-builder's who had blisters want to chime in on what brand/mix type sealant they used?
 
Clean Up: for cleaning tools after application is completed use chlorinated solvents: Acetone or Xylol
Click to expand...

My chemistry education compels me to nit pick: Acetone and Xylene (Xylol) are NON-chlorinated solvents.
 
Pro Seal Data Sheet(s)

I found this link and it is obvious to me that there are SEVERAL different "recipes" of polysulfide used as fuel tank sealant all from one source. I am also under the impression that all of the U.S. produced polysulfide comes from one manufacturing plant. [I have since changed my mind about the number of plants which produce polysulfide fuel tank sealer. See my later post in this same thread- DCH]

Also, I checked with an old NASA engineer who built an RV-6A in the 1994-1996 time frame, and the polysulfide used on Solid Rocket Boosters was called "PR-1422." He said when he built his tanks his first thought was that this stuff is the same stuff he used on the boosters in the late '70s.
I'm not sure that's a good data point but it might be valuable, since there is a "PR-1422" sealant in the linked list. Also, I queried him about any blisters around his fuel tank rivets, and he doesn't have any. Furthermore, he was not aware that RV pilot/builders are having this problem.

My recollection from my few years on the booster program is that the polysulfide sealant was produced at the same plant, but it went through several changes of ownership. It used to be PRC and I believe the same plant is now owned by Flamemaster. I'm not sure of that and would request verification by some of you California folks as I believe the plant was/is located in Pasadena or possible Glendale.

Interesting history and it might hold the key to possible variations in the sealant used on our tanks. Right now, if there does prove to be a deficiency with the proseal, I'm leaning toward improper/inconsistent mixing of the two parts prior to application. But I haven't built my tanks yet, so what do I know...:eek:

P.S. I also just realized there is another thread on this topic which appears to be running parallel to this one.

P.P.S. Googled "prc desoto ppg" and found this, dated Oct 1, 2002: "PRC-DeSoto International and the aircraft transparencies business of PPG Industries have launched a new brand identity called PPG Aerospace. The announcement came at the National Business Aviation Association conference which was held in Orlando, FL in early September."
 
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Rick6a said:
Take a good hard look at the series of photos in post #121, particularily the area around the fuel filler flange, and then you tell us what YOU see:
http://www.vansairforce.com/community/showthread.php?t=10187&page=7

Also note the blisters on the rear baffle, an area so many posters seem to have trouble understanding how fuel can be a factor in that area when in fact it can be if a void exists in the fay seal boundary.
Click to expand...

I stand corrected. Wow, that interior pic is deplorable. I suspect that the first cost saving measure that a manager of a tank building shop would try would be to use as little sealant as necessary.
Regarding testing, how about two jelly jars full of fuel with a couple of rivets in their lids? Prep, paint, leave in sun.
 
Ted Johns said:
My chemistry education compels me to nit pick: Acetone and Xylene (Xylol) are NON-chlorinated solvents.
Click to expand...

Yes, I agree. (See my previous rather long post.) There are several rather obvious typo's/errors on this page which would cause me concern if I were the head honcho of this company. All for naught, tho, as this is obviously a different "proseal" than what we use on our RV's.
 
Sources of Proseal

rv7boy said:
<SNIP> I am also under the impression that all of the U.S. produced polysulfide comes from one manufacturing plant.
<SNIP>
It used to be PRC and I believe the same plant is now owned by Flamemaster. I'm not sure of that and would request verification by some of you California folks as I believe the plant was/is located in Pasadena or possible Glendale. <SNIP>
Click to expand...

I am now under the impression that there are more than one manufacturing plants here in the U.S. than produce polysulfide sealant for the aviation industry.

See this RV10 builder's site which contains some interesting comments about proseal from one John Cox. He has experience with both PR-1826 and PR-1422 proseal.

His opinion is that the FLAMEMASTER brand is not as good as the old proseal he had experience with. Several of his thoughts from 2007 are worth considering in this present discussion.
 
This is interesting

from the Flamemaster spec referenced above:

CURE
Specified application and cure schedules are based on the standard conditions of 77?F and 50% relative humidity.
Increased temperature and relative humidity will reduce the work life and speed up the cure while reduced
temperatures and relative humidity will extend the work life and slow the cure. Cure may be accelerated by heating
up to 120?F. However care must be exercised to avoid the entrapment of solvent when heat is applied.
 
Fuel Tank Sealer Comparison Chart

I found this chart which provides some comparisons of different sealants. Notice it was last updated in March 2009. Ignore the yellow highlights; they are there to emphasize one company's products.

Under Specification AMS-S 8802, Fuel and Fuselage, both PR-1422 (from PRC Desoto/PPG) and CS 3204 (from Chem Seal/Flamemaster) are listed. From this and from a quick review of the corresponding Technical Data Sheets, it appears that both PR-1422 and CS 3204 are interchangeable, at least from a specification standpoint.

I did notice that the mixed color of PR-1422 is BROWN and the mixed color of CS 3204 is GRAY. So there must be some difference(s) between the two.

[Anyone know John Cox in the Portland area? Apparently he is a Tech Counselor in EAA Chapter 105 with RV building experience. From the previous link I found and posted yesterday, he is of the opinion that the current CS 3204 from Flamemaster is not as good as the PR-1422 he has used in the past. I believe his words were "think facial tissue vs. Kleenex."]

And for a lagniappe, here's a product information sheet which contains a link to a technical data sheet on PR-1422.

At this point several may be asking why I am putting up so much info on PR-1422. It's because I'm of the opinion (and I may be wrong) that in the early days of building RV's, PR-1422 was used to seal RV tanks. Does that have any bearing on paint blisters? I don't know, but I think it's worth investigating.

Not sure if this adds anything at all to the discussion of paint blisters. Just hoping that the "cure" (pun intended :D ) can be found before I get ready to make my tanks. I'm gonna find a Holiday Inn Express tonight; maybe that will give me new awareness. :rolleyes:
 
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Blisters

andrew phillips said:
The paint blister thread is one of the most highly viewed (over 9000) and one of the most replied to (over 120). This leads me to believe there are a lot more people out there who haven't taken the time to respond.

I am very disappointed in this situation. I paid Vans their full asking price for the quickbuild option. This makes them the manufacturer of my wing tanks. As a manufacturer they should accept responsibility for this problem and offer some kind of compensation to their clients.

As an individual I have a small voice but as a group we have a large one.

I propose that we start a database of all the individuals that have experienced this problem. I will volunteer to collect the data unless someone else has a better (easier) solution. This will let everyone know how large the scope of the problem really is. My suggestion is that affected individuals answer the following questions and then send a copy of their email to me and to Vans. As this is a proposal at this stage I am open to any and all input.

Questions:
Name and contact info:Tim Bauer/[email protected]
Model of plane:RV-7
Quickbuild tanks (yes/no):Yes
Year received:2004
Blisters elsewhere (other than tanks) on aircraft (yes/no):no
Prep and paint info:
Click to expand...
Didn't build it, but blisters over rivets of right tank.
 
Jump in people!

People don't seem really motivated to collect this data. This thread now contains formatted data for 2 aircraft. Stop sitting on the sidelines and submit the data. It's part of the solution to determining the cause!
 
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