Keel Strip Options ??

[Ben Fuller]

Did you notice that it says "Use indoors, unless noted"?

We have been using it in block form in lots of outdoor apps such as boat skids so I am not sure what the use indoors is. Maybe the adhesive. I don't understand the use of velcro tape and other rough stuff for keel strips; seems to me that these are pretty draggy. Packing tape has no abrasion resistance and not much strength.

I am going to order some up and try it out.

Ben

[billvoss]

However, the hook tape approach I could implement this evening, and still paddle tomorrow!

I stuck a strip on my bow last night, and paddled today. So far, pretty good, and

extremely good considering how cheap and easy.

-Bill

[alec]

Did you notice that it says "Use indoors, unless noted"?

I did see that. I imagine it is UV sensitivity - they also list a UHMW with UV stabilizers (though not with adhesive) and I know the rope vendors talk of uv protection. It seems it discolors in the light - though it appears to be a beige anyway. I have no idea whether the adhesive would survive seawater, but if it sticks to polythene you would think it has no problems sticking to gel coat.

Anyway I doubt velcro is rated for outdoor use!

I would like to hear back from Ben Fuller before deciding this is the stuff.

After seeing all the great ideas here it is tempting to put a bunch of strips of the different materials on the boat and do a more scientific study of what works.

[pikabike]

..Hmmm... Certainly runs counter to my experience with gelcoat or clear-hull epoxy and ester surfaces. Again, I've had Velcro 2" keel strips on my Cat5 for THREE years with only very slight end-corner "lift", easily trimmed with a razor.

Its glue is indeed completely waterproof...that's not the issue. The problem is having a clean enough NON-plasticky surface to adhere to.

I've noticed that this stuff, like most adhesives, will NOT adhere to PE, PP, or any other "greasy" plastics, but interestingly will adhere to painted ABS (car bumpers) if the surface is cleaned well enough. As well, its glue is quickly compromised by dirt or contact with an inappropriate application, so you have to use "virgin" stuff.

In your case I think maybe 70% rubbing alcohol may not have been enough, especially if the surface was damp (residual water) from porosity. Typical 91% would be better, as would of course laquer thinner (contains a mix of toluene/acetone/alcohol and NO water).

The surface I stuck the Velcro to was the floor of a new stitch-and-glue kayak--epoxy, not polyethylene. I could have used either 70% or 91% rubbing alcohol, since I buy the 91% whenever possible. Also, I waited a few minutes after cleaning with the alcohol, to make sure the surface really was completely dry (it only takes a few moments in this dry air). The tape was brand new. Whatever the reason was, the Velcro did not survive more than a few paddling sessions when used to hold the seat to the floor.

The kayak had never been paddled before, but it had sat indoors several months (in late winter/early spring) after all the epoxy work had been finished. So the epoxy was well-cured and I had previously cleaned it of any "bloom". Although the Velcro tape was new, who knows how long the tape had sat on the store shelf. That's the only reason I can think of that the tape did not stick...other than the possibility that the stuff really isn't intended for sustained waterproof outdoor use. After all, you don't constantly drag a keel over rocks but a seat is always under pressure with movement.

[subaruguru]

Well after three years I must admit that 2" Velcro's glue is giving up, so I just wrote to 3M asking for a sample of their tough, waterproof 41mil #8641.

Anyone try it?

They also make tough "leading edge" tapes for propellers, and now windvanes, that are uv resistant. Anyone try these?

The small piece of GRAY 3m step tape (no alum oxide to rip skin) I tried seems to be hanging on ok, as I suppose it's waterproof enough for outdoor horizontal surfaces, so I may try replacing the peeling Velcro with that in the meantime.

Finding something that's easily molded around corners without puckering AND being abrasion resistant and waterproof isn't proving easy. A gorilla just won't do!

[pikabike]

Well after three years I must admit that 2" Velcro's glue is giving up, so I just wrote to 3M asking for a sample of their tough, waterproof 41mil #8641.

Anyone try it?

They also make tough "leading edge" tapes for propellers, and now windvanes, that are uv resistant. Anyone try these?

The small piece of GRAY 3m step tape (no alum oxide to rip skin) I tried seems to be hanging on ok, as I suppose it's waterproof enough for outdoor horizontal surfaces, so I may try replacing the peeling Velcro with that in the meantime.

Finding something that's easily molded around corners without puckering AND being abrasion resistant and waterproof isn't proving easy. A gorilla just won't do!

That gray step tread material sounds like the same stuff I put on a wood ramp for the dog kennel, which has a roof overhead but is otherwise outdoors. The stuff eventually began peeling back at the edges. I just glued them back on using Barge Cement (letting both surfaces tack up a bit before sticking on) and they've stayed solidly put ever since.

I wonder if AquaSeal (the stuff I've used for sealing neoprene holes) would be even better for this kind of use. It's flexible, tough, sticks to both porous and nonporous materials, and waterproof. Just a thought. Too bad it's grippy, or else you could just paint it on as a keel strip by itself.

[Brian Nystrom]

They also make tough "leading edge" tapes for propellers, and now windvanes, that are uv resistant. Anyone try these?

Yes, I have used leading edge tape and other than the fact that it has the most tenacious adhesive I've ever seen, I'm not impressed with its durability when used as a keel strip. Leading edge tape is designed primarily to provide resistance to airborne sand. It's a relatively soft material that resists sand abrasion by absorbing the minute impacts. It does not stand up to rocks, barnacles, boat ramps and other hard/abrasive surfaces. In other words, it's a lot less durable than gelcoat. It shreds quickly and you're left with mess on the hull that adds drag and is difficult to remove. I've pulled a bunch of chunks off of the boat I tested it on, but eventually I'm going to have to try to get the rest of it and the adhesive off, a chore I'm not looking forward to.

[subaruguru]

Thanks, guys!

3M's sending me a few YARDS of each. The #8641 is 41 mils (1mm) thick, so may be tougher than the leading edge soft stuff. We'll see.

I find that AquaSeal is a ridiculously limited adhesive, partly because it uses a too-volatile toluene as a thinner. Maybe great because it's so aggressive with neoprene, but for gluing edges a drop of SuperGlue has worked well on these strips for years...until LARGE sections of original adhesive fail.

I'm hoping the #8641 has the adhesive of the leading-edge but the abrasion-resistance of the velcro. That's be nice....

If not, then maybe the 3M gray step tape is the best compromise, and may have less theoretical drag than the loopy Velcro?

[Pintail]

Re "leading edge" tape, I would second Brian's opinion that it is not strong enough. It is one thing to protect against sand and debris; but quite another to protect against rock collision and scraping. It is quite thin stuff, after all...

In South West Africa (sorry: Namibia) many owners of Land Rovers used to paint the front of the wings with a black bitumenous goop to protect against sand-blasting in high winds when driving among the dunes; but that is a messy solution to this problem (leading edge tape would be perfect <there>!) and I also think there is nothing like extra gelcoat. Go for a strip of kevlar if you really want durability?