Repairing Canoe Floatation bags

[oldpaddler]

I've got a couple of purple Dagger end bags for my OC2 Caption, that no longer hold pressure for a half-day's trip. I cannot find any specific hole, so think I let them overpressurize and create a leak (or two...). Anybody got a suggested method for leak identification and attack... I've tried the "inflate them and look for bubbles in the soap solution trick....but can't identify a leak location. Is there some kind of treatment I can do to the entire bag, kinda like a "flat-fix" for floatation bags?

Suggestions appreciated.

Leaking in Texas

[ezwater]

My approach has been to go to a quiet room, dampen one hand, lean on the bag, and use my wet hand to feel for cool streams of air escaping. Sometimes you can hear them also.

Places to check include spots that hold the permanent mark of wrinkles. These may have leaks because they show where the fabric has been rumpled repeatedly by the wind while carried on the car. This can cause delamination of the inner plastic from the outer fabric.

Another place to check are the ends of "darts," places where the manufacturer seamed the fabric together to achieve a certain shape.

Friction leaks can occur under the bag, where the bag rubs against sand and grit that gets in the boat. Watch for areas where the fabric appears fuzzy or worn.

Seams may be well done over most of their length, but at the ends or corners of the bag they are more likely to leak.

Look around the base of the inflation tube and see if the flange has partly detached from the fabric. Also, if you suspect the inflation valve, try doubling the tube back and clamping it to see if the bag holds air. The valves can be cleaned or replaced.

I have always been suspicious of old dump valves. You might clean them and then coat the surfaces with 303. Also check their flanges for possible detaching from the fabric.

I've been assuming that you have fabric rather than vinyl bags, but some of what I said can be applied to vinyl.

I use Seam Grip for very small leaks, because it really soaks into the fabric. Aquaseal doesn't soak in as well, but works better for larger leaks.

Some leaks you can learn to spot by eye, but usually you'll have to either soap the bag or use my method of the wet hand.

[oldpaddler]

They are fabric bags...

I now have a to-do list. Thanks.

[sbroam]

I remember an old NOC catalog that had a tip for fixing air bags with elusive leaks - fix-a-flat...

[ezwater]

Fix-A-Flat........ Just don't smoke or strike a spark when you open the dump valve!

[sbroam]

Boy howdy. Smoking is bad for your health. I think the tip did also include a recommendation that your purge the bag a couple of times after the gunk set up... I never did try that tip out myself.

[Eric Nyre]

To find mystery bubbles I'd fill a bathtub with water, the bag with a little air, and hold it down until you see something. A calm lake will work too, but the tub is handy.

Many years ago I bought some stuff to recoat the floor of my tent. It was a runny liquid that re-waterproofed the tent floor. You might go to a good backpacking shop and see if something like that is still around. It wasn't the best (flaked off in spots) but it was better than before.

Third option is to take advantage of NRS's sale and buy some new bags. http://www.nrsweb.com/shop/product_list.asp?deptid=1979

[oldpaddler]

Thanks for the tent waterproofing treatment idea. Hadn't thought of that.

(BTW, I used the tent waterproffing stuff on one of my tents a couple of years ago....the liquid seemed strangely familiar...because I had just refinished some furniture. I didn't have enough of the branded tent waterproofer to finish...so I mixed up some Guardsman Furniture Polish (polish, plus water) to pump-spray on the tent rain-fly. To the observer, the liquid seems to be the same @#$%! stuff as the stuff sold as tent waterproofer.

And it worked. The tent has only been tested in light rains...so I don't know how durable the furniture polish finish really is....)

As for the air bags mentioned in the first note. I found and patched one hole in one bag last night. Can't get the other two to leak, sitting in the living room. So maybe the problem was dirt in the dump valves that worked its way out. Still futz-in about.

[Cantuck88]

Anybody know where to get new dump valves for fabric float bags?

[Peter K.]

I use the raft dump valves that you can get on the internet. My newest Mohawk bags came with them and I have found that they are readily available on-line.

[the great gonzo]

I have successfully used Toobseal to seal off several air bags with a bunch of pin holes. Open the dump valve, pour some Toobseal in the bag, close the dump valve, inflate the bag and then start spinning the air bag in all directions for about 15-20 minutes. Now my bags hold air for days again.

TGG!

[Paddle Power]

Sounds interesting.
How much did you use per airbag?
It seems to only comes in a quart bottle. At a quart size it cost a few dollars but could probably repair quite a few air bags.

[the great gonzo]

Not sure any more how much I put in, not a lot, maybe about 1/2 cup.
It worked really well, I repaired the bags about 4 years ago and they still hold air like they did on the first day.

TGG!