Tank repair Q.
 

After 18 hrs I have the start of the "dreaded blue stains" from the right tank upper baffle. :(

I have Vans repair kit and now have 5 large holes in the rear baffle. I have started scraping away the somewhat marginal proseal fillet along the rear baffle, fiddly work but quite doable.

My real question is "what tool do I use to add a new fillet?" Since it's essentially in a blind location and mirrors are needed my usual popsicle tool or SEM air powered dispenser won't work.

How have others got their goop into place?

I intend to remove as much of the existing skin/baffle proseal and hen use adhesion promoter under the new proseal. Since it will be 85 F plus in the afternoon in the hangar the proseal should flow fairly well. :)

Some things I found out already that might help others -

1. 5 inch holes are easily cut with a m Milwaukee hole saw from the local Ace store. The manager said it's probably the only one he's sold of that size. :)

2. The part of my Pepto-Bismol cowling that was cut away for the oil door makes a great proseal scraper.

I like using a pneumatic sealant gun and the 2-oz cartridge. (about $20 for sealant from Aircraft Spruce) The pistol grip is held on with a quarter turn fastener. It is possible to discount the pistol grip, slide it down the hose, then use it as an inline calking gun. May be able to do that and use a mirror to see where it needs to be applied.

I did the above to get some fillets inside near the nose ribs and skin on my RV-8 tanks before putting on the rear baffle. Worked much better than with the pistol grip on.https://encrypted-tbn0.gstatic.com/images?

Gary, I can't see your picture...

I do have access to a pneumatic sealant gun and some 'load it yourself' cartridges. I think the problem is that I would need a U shaped extension to get through the 5 inch hole and back onto the skin/baffle joint.

I think getting an extension to stay in place under pressure will be tricky. I've tried it with standard RTV caulking guns and mainly succeeded in making a mess. A similar proseal mess would be bad. :eek:

might try a big 'horse' or catheter syringe. i think they might be small enough to get your hand in and apply. Used them a lot when building my tanks, they will lay a nice bead down.

I used 60 ml but even 20s could work.

2-oz pneumatic sealant gun
 

Here is what a 2-oz pneumatic sealant cartridge gun looks like.


The handle removes by turning a 1/4 screw.


With the handle off, it looks like this.


With a short nozzle that comes with the sealant cartrige, it is short enough to fit inside the tank. Shown here laying on the RV-8 tank I sealed last week.


I used these 2-oz sealant cartridges.

Tank repair
 

Gil. I have both of my tanks out repairing for leaks.
A huge help is to get ahold of the lower viscosity proseal or figure
Out a way to thin out the thicker product. Lower viscosity will find its way
To a better seal for existing built tanks. If you figure a way to thin it out please let us know. In my opinion it's a much better way to go. I was able to apply a bit of air pressure to blow it into the repair area.

I used my finger with a thick latex glove. Dip, insert, spread, repeat. I changed gloves every few cycles.

I'm moving towards that method, but for making the fillet.

I borrowed a Semco dispenser and some load-it-yourself 2 oz and 6 oz cartridges. We had 4 inch tips and it looks like a heat gun can give these an almost 90 degree bend. With this bend the gun can be kept outside while the goop is dispensed along the baffle/skin interface through the large 5 inch baffle holes.

Then the gloved finger can make the fillet and force the stuff into the angle and I will then set the tank at a 45 degree angle so any stuff that flows/sags will go in the correct direction. :)

The fickle finger of fate
 

I used mine to smear proseal on a small leak in the bottom baffle seal. Was on both sides of a rib and after I cut the access holes I couldn't get anything in there by way of Popsicle sticks or applicators. So I put on a glove, scooped up a pretty good glob of proseal and got it as close as I could with my finger. Unthinned proseal will flow for a couple hours before it sets; albeit very slowly. So I put a glob on one side of the rib and tilted the tank so the sealant would flow toward the seep. Couple days later same thing on the other side. That was 3 years ago and still good. Hope this helps.

Flamemaster makes a one part pourable sealant that's compatible with their regular 'proseal'. It can be drawn into a flexible plastic tube & directed where you need it. With care, you can run the entire top or bottom seam with it, from one end of the tank.