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Tip: Proseal ...The fact and the fiction

This is one thing (setting wet rivets) where a helper can make a HUGE difference: two hands holding/stabilizing the rivet gun and two hands holding/stabilizing the bucking bar. I also second the comment about the air pressure. Too low and you work-harden the rivet, but too high and you have control problems (esp. if solo).

I remember the tanks being very messy work, and making liberal use of shop towels, lint-free rags, and MEK to keep the tools (and everything else!) clean.
 
Proseal Solutions

Scott,
If you put a generous coat of proseal on the ribs before you cleco them to the fuel tank skin, there should be no reason to put proseal on each individual rivet. After all my ribs were finally in, I added an additional layer of proseal on the buck tails. I agree that a tungsten bucking bar works best. I prefer old cotton t-shirts though as shop rags tend to leave too much lint behind.
 
...I remember the tanks being very messy work, and making liberal use of shop towels, lint-free rags, and MEK to keep the tools (and everything else!) clean.
One thing, and this is very important, DO NOT clean up the tanks or rivets with MEK!

It is best to let the tanks dry and then sand the excess MEK off the tank.

I flew for two years before having my plane painted. Before going to the painters, I cleaned the excess proseal off the top of the left tank with MEK. A year after it was painted I had the dreaded paint blisters but only on the top of the left tank, where I had used MEK to clean it up.

Do use MEK to clean up the tools and clecos, that won't be a problem.
 
Scott,
If you put a generous coat of proseal on the ribs before you cleco them to the fuel tank skin, there should be no reason to put proseal on each individual rivet. After all my ribs were finally in, I added an additional layer of proseal on the buck tails. I agree that a tungsten bucking bar works best. I prefer old cotton t-shirts though as shop rags tend to leave too much lint behind.

There seem to be conflicting opinions on this. I agree that if you have a perfect coating there should be no path from the edge of the rib to coming out the dimple, in a perfect world. I guess it is a belt and braces thing. I have talked to professionals at AC mfgs and they put sealant on the rivets in the hole before shooting them according to their published milspec type processes. I think my biggest problem is that I am not very good at riveting in general, having bought an almost structurally complete project. But I am learning. Thanks for your input.
 
I am trying to remove sealant from the tails of some rivets because i don't think I inspected them carefully enough. I bought poly-gone 310 gel, thinking it would just dissolve it away but I found it not to be that effective. I had to reapply it so often I used up a $40 jar and still didn't get everything done. It seems to only dissolve the top few thou of material. Is there a trick to using that stuff? Also, do the urethane sealant cutters work well? Are they a better bet to clean things off quickly? Any wisdom appreciated.
 
One thing, and this is very important, DO NOT clean up the tanks or rivets with MEK! QUOTE]


MEK is one of the best cleaners to use for pro seal. If you read whats in proseal, some of the Mil spec sealants have MEK in them! I work on aircraft for a living and use only MEK to clean metal before proseal application and for clean up and I have never had paint issues with the use of MEK. We actually add MEK to proseal in some instances because it will help thin out the sealant to flow a lot better and it will extend the working time if need be. In over 10 years of resealing windshields, Mooney fuel tanks, and numerous other pro seal adventures, I have never had MEK bubble paint.

SBlack - In my experience Poly-gone does not work the best on certain sealants. The only sealant I have seen it actually work as advertised on was the pink color sealant Piper uses on some models to seal the fuel panels onto the lower wings. The sealant urethane cutters that you can buy that look like they thread onto a 90 degree drill are AMAZING! They cut through sealant like you wouldn't believe. You still have to do some scraping with a plastic scraper (especially around rivet tails) but it will get rid of most of the sealant. I have used these a lot on Citation fuel bays where I was unable to bend my arm to reach with a plastic scraper. If you do purchase these, please beware, they are ment to be used with a slower RPM motor. I believe if you buy the kit that comes with what looks like a 90 degree drill, the motor only spins around 900RPM. If you use them with a regular 90 degree drill it will melt the cutters before cutting through the sealant (ask me how I figured that one out :) ).
 
Bill R,
Just wondering, do you have quick build wings?

Sorry missed your question. No it is a 4 and I don't think they exist for that model. On the other hand, I bought the project almost all built, holes have been drilled. So I suppose it could be considered QB, except that the previous owner spent 25 yrs getting it there:eek:
 
What is the "easy" way to remove dry Pro Seal? I had to remove the wedge from my rudder and need to clean it now for a second prosealing attempt.
 
Quantity of pro seal to mix??

Ready to seal my first tank and wondering if there is a general quantity of sealant to mix for the stiffeners, etc. Having a number in mind would make the first mixing go easier.
 
Proseal

Ready to seal my first tank and wondering if there is a general quantity of sealant to mix for the stiffeners, etc. Having a number in mind would make the first mixing go easier.

Vans sells the quart kits. Buy one to start then if needed order a second later. That way your second will be fresh. My 7a tanks took about one and a half.
 
I found that about 1 gram per inch of surface I was sealing was a good amount to mix up. Always had some extra. So if your in the waste no Proseal camp you could probably back that down to .8 grams an inch.
 
Misunderstood

I found that about 1 gram per inch of surface I was sealing was a good amount to mix up. Always had some extra. So if your in the waste no Proseal camp you could probably back that down to .8 grams an inch.

Thanks. I misunderstood the question. That sounds about right.
 
prime components?

Hi Guys,
So I've read through this thread and I'm not exactly sure the extent of priming I should perform before assembly. I'm not priming any alclad or internal components, but my concern is around T-712 z brackets and the T-405 angle. I would normally prime these non alclad components but I'm concerned about interaction with the ProSeal/MEK. I'm thinking the best approach to fully Fay seal the T-712 and T-405 followed by wet riveting, then priming these components after the tank is complete. Let me know if I'm off base with this one.
Tom.
 
I found that about 1 gram per inch of surface I was sealing was a good amount to mix up. Always had some extra. So if your in the waste no Proseal camp you could probably back that down to .8 grams an inch.

Thanks! Very helpful!! My scale doesn't do tenths of grams so I mixed up 1 ounce to see how it would go. Had enough to get the stiffeners on, but needed more to do a nice fillet seal around them. Then got the fuel cap flange and drain on. Unfortunately had to drill out 3 rivets on the cap. Not fun.
 
Hi Guys,
So I've read through this thread and I'm not exactly sure the extent of priming I should perform before assembly. I'm not priming any alclad or internal components, but my concern is around T-712 z brackets and the T-405 angle. I would normally prime these non alclad components but I'm concerned about interaction with the ProSeal/MEK. I'm thinking the best approach to fully Fay seal the T-712 and T-405 followed by wet riveting, then priming these components after the tank is complete. Let me know if I'm off base with this one.
Tom.

I primed the z-brackets except for the mating face on the tank baffle side.

I left the rest of the parts unprimed for now. Once I have the forward angle fit and drilled to the fuselage I'll paint the rest of the tank.
 
Just finished my first ProSeal session, and I can vouch for the one gram per inch methodology. It worked out almost perfectly. I can see how this could get cut back to 0.8g/inch or so once you get better technique with regard to laying on a constant bead.
Tom.
 
Shop heads

Thanks! Very helpful!! My scale doesn't do tenths of grams so I mixed up 1 ounce to see how it would go. Had enough to get the stiffeners on, but needed more to do a nice fillet seal around them. Then got the fuel cap flange and drain on. Unfortunately had to drill out 3 rivets on the cap. Not fun.

Remember to put a dollop on the shop heads before moving on. They're easy to access before the ribs get installed.
 
I did about 1 gram per linear inch, BUT the stiffeners with a filet around them or the ribs when they are installed and the baffle all work out to about an inch wide strip of sealant. So 1 gram per Sq in. would be a good standard as well. This also leaves enough to put a dollop on each shop head. I used a pneumatic seal gun(worth it's weight in gold) laid down a bead about 3/16 in. diameter.
 
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Thanks. I bought the pneumatic sealant gun and a mixer that appears to go on the end of a drill. The mixer is a round disc with 2 protruding screw heads. Can someone walk me through exactly how to use this mixer?
 
I mixed smallish batches, no bigger than 40 grams each, and Popsicle sticks were all the tools I needed. In fact I've got one of those pneumatic tools setting on a shelf; never once thought it would be needed.

However I did use 3 types of sealant:

1. Van's type B sealant.

2. Access panel sealant for the hatches.

3. The thinner, lower-viscosity type A sealant to overlay the rivet heads and edges.

Skygeek had the last two.

Dave
 
Hi Guys,
So I've read through this thread and I'm not exactly sure the extent of priming I should perform before assembly. I'm not priming any alclad or internal components, but my concern is around T-712 z brackets and the T-405 angle. I would normally prime these non alclad components but I'm concerned about interaction with the ProSeal/MEK. I'm thinking the best approach to fully Fay seal the T-712 and T-405 followed by wet riveting, then priming these components after the tank is complete. Let me know if I'm off base with this one.
Tom.

I primed my z-brackets, then used scotchbrite to remove the primer (duplicolor) from the faying surface before final installation. You could also mask the faying surface before priming. I think it would be difficult to get good coverage on the forward-facing surface of the aft flange after installation.
 
proseal

Not exactly on topic but dip your hands in water with dishwashing liquid mixture during application and you can wipe the proseal off your hands with a paper towel. Its a great way to make a smooth filet I am not so sure of spelling, but try it next time you proseal.
 
Proud rivets

So I finished my first session of stiffener attachment last night, and the second session this morning. The ones I did last night, I dabbed a little extra proseal in the skin dimples before I inserted the rivets. My thinking was that most would work out, giving me a smooth finish, however I was mistaken. Some did, and those rivets came out fine, but others didn't, leaving the rivet approximately 3-4 thou proud. During the session today, I didn't add any extra proseal to the rivet holes, just smeared the sealant that had come through the holes when I applied it to the inside skin surface. I just pushed the end of a popsicle stick in the dimple, give it a 360degree rotation and called it good. In addition, I made sure when I put the stiffeners on, I pressed down a little harder against the back rivet plate than I did the first time, to push the rivets up hard before I began driving them. These rivets came out perfectly. I'm just going to hit the proud ones on the other wing with my heavy duty cage, die grinder and avery shaver bit combination. Anyway, just thought I'd throw this one up for others attempting their tanks. Just don't go overboard putting too much sealant in the dimples.
Cheers,
Tom.
 
Good call on priming the Z brackets now, given access to the back of the bracket will be difficult later. I think what I'll do is just tape off the surface to be fay sealed, hit up the rest of it, then peel off the tape afterwards. I think I'll leave the T-405 angle until I paint the exterior of the tank once it's complete.
Cheers,
Tom.
 
Good call on the tank dies also. Unfortunately that would be two weeks shipping to get here, so I'm going to drill out and reseal tomorrow the couple of proudest ones, and plough on with the the remainder as I hope to have these tanks wrapped up by the weekend. I think the next set of wings will be quick build, blisters or no blisters, as these tanks are a mountain of work. T.
 
Can someone explain the process of using a pneumatic sealer to apply the sealant? Do you have some sort of disposable cartridges you fill with proseal? How do you clean the gun? Do you shoot a uniform bead on the skin and ribs or just one side?

I still do not like the idea of using popsicle sticks to spread the sealant and am considering buying a pneumatic gun.

Thanks
 
The "sealant gun" is similar in operation to a "calk" gun, except that the sealant gun is attached to an air hose. You fill the disposable cartridges with the sealant of your choice, load the cartridge into the gun, attach the air hose, and pull the triger.

The cartridges are available in two basic sizes, the screw on tips are separate as are the end cap plugs. These plugs are what push against the sealant to eject it out the tip.
 
The "sealant gun" is similar in operation to a "calk" gun, except that the sealant gun is attached to an air hose. You fill the disposable cartridges with the sealant of your choice, load the cartridge into the gun, attach the air hose, and pull the triger.

The cartridges are available in two basic sizes, the screw on tips are separate as are the end cap plugs. These plugs are what push against the sealant to eject it out the tip.

Or buy a full cartridge in this form from AC spruce and it will fit right into the sealant gun.

09-38510.jpg


I found the 3.5 oz size correct for the rear baffle on a single tank.
 
Proseal gun

Sorry, I can't resist.
Here's mine. Cheap. Yes, I actually used it and it worked. Syringes were modified by cutting off the ears and thumb loop. Once done, just toss them.
33xep8y.jpg
 
MEK Alternative

Such a great thread, thanks to everyone for their thoughts and experiences.

I'm getting ready to start the tanks. I live in California, if the name sounds environmentally hazardous, they have stopped selling it.

What are some good alternatives to clean the tank before prosealing and cleaning wet proseal off areas I don't want it on?

MEK, Toluene (I think anything ...ene have been banned, including xylene and naptha) are all not for sale in CA to the general public.
 
Automotive wax and grease remover.

At the end of the day what you are trying to achieve is an impecably clean, mechanically etched surface to bond to. Thus, what you hope to do is remove all wax and grease deposits. So long as you let what ever solvent you are using fully evaporate after the cleaning stage, from my perspective there should be no risk of it impacting your bond. I found out that builders in Europe were using automotive wax and grease remover as they couldn't source MEK, so I gave it a try. My tanks came up great and passed the manometer pressure test with flying colors. The only reservation is that I am still a few months away from flying, so I can't give you the long term test results. Perhaps the European builders can chime in here.
Tom.
 
From my query on this subject:

> Hi Vans Aircraft,
>
> I'm nearing my tank sealing and am acquiring the materials to do it.
> In the construction manual, naptha or MEK are suggested as cleaning
> agents to cleanse the parts before sealing. I also checked the website
> for the sealant and they suggest methylene chloride (http://flamemaster.com/wp-content/uploads/2014/07/CS3204-rev-01-07.pdf).
>
> I'm in California and MEK is not for sale here. I cannot find naptha and
> cannot find anything labeled methylene chloride -- at least not by those
> names. In my internet research, it is suggested Coleman camping fuel is
> naptha -- I can get this but I don't necessarily trust the internet. I can
> also find a number of other solvents (acetone, denatured alcohol, etc.).
> Do you have suggestions for alternatives that might be available in
> California which would be acceptable for cleaning parts?
>
> Thank you,

And the reply:
The coleman camp fuel is most likely the best product you will find in your
state and is what most of us here would use on our own projects.
 
From my query on this subject:

And the reply:
The coleman camp fuel is most likely the best product you will find in your
state and is what most of us here would use on our own projects.

Thanks, I've seen camp fuel mentioned a few times as well. Does it clean up the wet proseal from the areas that need it too?
 
> Thanks, I've seen camp fuel mentioned a few times as well. Does it clean up the wet proseal from the areas that need it too?

Yes, I used it for that too. Acetone worked also. I felt both of those were superior to denatured alcohol for cleanup.
 
> Thanks, I've seen camp fuel mentioned a few times as well. Does it clean up the wet proseal from the areas that need it too?

Yes, I used it for that too. Acetone worked also. I felt both of those were superior to denatured alcohol for cleanup.

Thanks, I'll pick up a can and give it a try!
 
Thanks, I've seen camp fuel mentioned a few times as well. Does it clean up the wet proseal from the areas that need it too?

It works but may require a little more effort than MEK. I always have a quart of MEK available when sealing but will only use it when I am not making fast enough progress cleaning up the mess with "Camp Fuel". IF in the Peoples Socialist Republic of Kalifonia where MEK is not available, the MEK substitute will work but not quite a well are real MEK.
 
One thing I did was use the tubes of pro seal and took an ordinary caulk gun and ground down the plunger on a grinder until it would fit in the pro seal tube
Put a large washer on the nozzle that would fit in the retaining collar on the caulk gun and presto you have saved your self a hundred dollar bill from having to buy the professional Proseal gun
 
It works but may require a little more effort than MEK. I always have a quart of MEK available when sealing but will only use it when I am not making fast enough progress cleaning up the mess with "Camp Fuel". IF in the Peoples Socialist Republic of Kalifonia where MEK is not available, the MEK substitute will work but not quite a well are real MEK.

MEK is available in California. I bought a quart of it recently at Aircraft Spruce in Corona.
 
8A Fuel Tank Sealant Question

Got a question for all you guys with strong magic. I'm about ready to do the ribs on the fuel tanks this week and have read Rick6A's and everyone else's fantastic posts on pro-seal. Great words/pics. The plan is to do all five ribs at once. What I can't quite figure out is should all the required sealant be mixed up at once or in batches? Also, is it better to apply the sealant to the upper portion of all the ribs/skin (after the nose area is sealed/clecoed) and then cleco them all at one time and then seal the lower portion of the ribs/skin and cleco all of them? I live in Co Springs so the garage will be in the high 50s / low 60s this week when all this takes place so the working time will be around 1+30-ish. Hopefully this makes sense as I still get a bit of a helmet fire on this stuff. Thanks for your support!
 
Got a question for all you guys with strong magic. I'm about ready to do the ribs on the fuel tanks this week and have read Rick6A's and everyone else's fantastic posts on pro-seal. Great words/pics. The plan is to do all five ribs at once. What I can't quite figure out is should all the required sealant be mixed up at once or in batches? Also, is it better to apply the sealant to the upper portion of all the ribs/skin (after the nose area is sealed/clecoed) and then cleco them all at one time and then seal the lower portion of the ribs/skin and cleco all of them? I live in Co Springs so the garage will be in the high 50s / low 60s this week when all this takes place so the working time will be around 1+30-ish. Hopefully this makes sense as I still get a bit of a helmet fire on this stuff. Thanks for your support!

I ended up doing it in 2 batches, just to be safe because I wasn't fully sure how much proseal to mix up for each. I put proseal on the entire rib, fit it, and clecoed a few on the nose, did the same for the rest of the ribs, mixed batch 2, finished up the last ribs, repeating the same process. Then I clecoed my way up one or two holes, then across the tank, then back up until I got to the top. When I did tank 2 I mixed it all at once as I got a lot more comfortable with the exact quantity needed.

Good luck, it's not as bad as it seems. On tank 2 I don't think I got any proseal on my clothes. You'll learn quickly.
 
Got a question for all you guys with strong magic. I'm about ready to do the ribs on the fuel tanks this week and have read Rick6A's and everyone else's fantastic posts on pro-seal. Great words/pics. The plan is to do all five ribs at once. What I can't quite figure out is should all the required sealant be mixed up at once or in batches? Also, is it better to apply the sealant to the upper portion of all the ribs/skin (after the nose area is sealed/clecoed) and then cleco them all at one time and then seal the lower portion of the ribs/skin and cleco all of them? I live in Co Springs so the garage will be in the high 50s / low 60s this week when all this takes place so the working time will be around 1+30-ish. Hopefully this makes sense as I still get a bit of a helmet fire on this stuff. Thanks for your support!

I did all the ribs at once and didn't seem to have a problem with working time. I left the end ribs off just for better access and did them after the others were all riveted but it's probably not necessary. The sealant Van's sells has a 2hr working time IIRC so you should have plenty of time to do all the ribs.

I used the Semco sealant gun which was a big help but you can probably do the same thing with a Ziploc bag. Just butter up the flanges with a thin coat of sealant.

I buttered up the flanges of each rib one at a time and clecoed each rib to the top of the skin with about three clecos while the skin was open. Once they were all clecoed to the top I slipped the skin with the ribs into the cradle and put clecoes in every hole. I let it cure for several days then riveted when the proseal was basically cured. I didn't bother putting sealant in each hole when I riveted the skin to the ribs. Others recommend it but I found it to be more of a pain and the bucking bar kept getting sealant on it which made it hard to rivet because the bucking bar kept slipping. Then I encapsulated the shop heads and finished up the rest of the tank. No leaks.
 
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