This weekend I did some outfitting that included kneeling pad installation.
I used the Dap in the red can like I always do. That stuff works great for me on all my boats … with but one exception. I take my Malecite to the into the ocean once or twice a year and paddle it twice a day for a week or two.
And, every time I do, at least one of my kneeling pads comes loose shortly afterward. I always figured it was the salt water, but I didn’t know why until I watched something on the discovery channel about how salt expands when it dries. Apparently the Egyptians used to use it to split stones.
So, I guess that’s the mechanism loosening up my kneeling pads. A little bit of salt water gets in and expands when it dries. Next day a little more gets in, then a little more. After I get home, the pads eventually dry out completely, the salt expands and my pads are coming out.
Here’s my question. I’ve heard of silicone calk being used for kneeling pads. Anyone try it? What are the pros and cons? I’m thinking it may be better at keeping the salt water completely out from under my pads.
Haven’t tried it - but here’s a caution
I’ve heard that using silicon caulk makes it more difficult to get any other type of glue to stick to a surface if the silicon doesn’t work out and you then want to try something else.
Silicone
is generally used as a sealant, as opposed to as an adhesive. Most silicones that I am familiar with don’t have much in the way of shear or tensile strength.
I’m not sure what the “DAP in the red can” is however I will give you a few suggestions. If you’re boat is Royalex or some sort of vinyl, Vinabond generally works very well. Barge cement also works very well on composites, not quite as well on vinyl. Pliobond works similarly to Barge cement. In all cases, make sure all surfaces are clean before applying the cement and scuff sand them as well with 80 grit sandpaper.
I’ve outfitted boats that have spent extended time in saltwater and I’ve never had a pad come loose.
Marc Ornstein
Dogpaddle Canoe Works
Custom canoe paddles and cedar strip canoes
thanks Marc and a question
My kneeling pads are really "in" salt water. I launch and recover from the beach in goodly sized breaking waves. There is always several inches of water or more in the boat ... at least till I can bail.
The boats you mentioned you outfitted ... do they spend time "in" saltwater, or are the boats paddled in saltwater?
If it is salt getting under the pads, incidental wetness may not be the same thing as bathtub conditions.
Thanks in advance.
I use it
I use clear silicone calk foe all my kneeling pads.It holds well and will clean completly off if you need to remove them when you sell the boat.Clear holds better than white.I have used it on kevlar and roylex boats.I also use it to fasten my compass.Be carefull not to get past dated stuff-it doesn’t harden!I always use the GE stuff.
Turtle
how does it hold up?
Do you ever have pads come loose in fresh water? How long have you been using it?
On thing I’d be concerned about is getting rid of the residue. For instance, if I had to do any repairs to the fiberglass, I’d be concerned the resin would not bond to silicone.
I didn’t think that stuff ever came out, unless you’re on glass or something like that where you can pound it with acetone or MEK.
Thanks.
No problem
The pads in my Osprey have been in for 3 years and wet a lot.The pads I had in the front of my Prospector got kicked loose on a trip by a bow paddler with big hiking boots on and a rough approch.When the calk dries and you peal it all off I don't think ther is any residue left.If anything is there a little acetone would clean it right off.Silicone just bonds to the surface,it doesn't penitrate.There are stronger glues to use for this job,but as I said,nothing that I know of that will peal off and leave the surface pristene.
Turtle
To the
best of my knowledge the pads that I have installed have not been left submerged in salt water for extended periods of time but have experienced conditions of being wet with salt water for several days at a time. I suppose that may make a difference.
That being said, after reading some of the other responses, silicone may be worth a try. It’s limitations regarding adhesive strength may not be significant enough to preclude it’s use for this purpose. My bigest concern would be the residue issue if it didn’t work out and you needed to resort to something else. Any silicone residue must be completely removed before anything else will fully bond to a surface.
This summer I may do some experimenting with silicone. It seems like it may have additional applications.
Marc Ornstein
Dogpaddle Canoe Works
Custom wood paddles and canoes
Thanks turtle
I plan on doing some experimentation with small pieces on up near the gunnels of both Royalex and composite boats. I’ll see how it holds, and then see how it comes off.
Thanks for the feedback.
Silicone bonding strength
Installed a sliding door in the shower. The frame was aluminum, and I put clear silicone caulk under the aluminum to prevent leaks. Years later, I had to take the frame off during some repairs. Took the srews out of the frame, but it would not budge. Began working the top end with a bar, and pulled off the first few tiles with the frame. Darn, now I’m doing a retiling job, too! But, trying to minimize the retiling, I tried to get something between the tile and the frame to pry the frame off and leave the tile on the wall. This worked, sort of. The bond between silicone, aluminum and tile was so strong that I separated the tile! The caulk pulled off the glazed surface layer of tile, while the remainder of the tile stayed on the wall. So, maybe its not the strongest stuff, but it sticks good.
The only marine application where I’ve used this is to seal the bulkhead on my fiberglass kayak. Seems to work, but that application doesn’t require strength, just the ability to seal a crack.
~~Chip