I did a search and I couldn’t find another post that mentioned this stuff, but if someone else has… I apologise.
It’s called Sugru, and its a mouldable self setting silicone type product, bonds to most materials and I have been following its growth for a few years.
Now, it’s available in DIY stores in the UK and it suddenly occurred to me that it would make great bow bumpers and I was also thinking of sealing water entry points with it.
I have used two-part silicones poured into a mold before. In fact, I made the mold from a flexible polyurethane compound in such a way that I can tape the mold to the (roughed up) bow of the boat, and pour the silicone into it. Once the silicone sets up, pull the poly mold off and your bow has a bumper molded on. You can color the silicone with a few drops of acrylic artists paint, to sort of match the color of your boat.
@Astute Composites, Thanks for sharing your silicone discovery. It was an interesting read on their website and the Technical Data Sheet PDF as well. It seems well suited to the task of a Boat Bumper with one drawback. I noticed the the material density on the product is 1380 and that’s at Kg/M(cubed). As a comparison, Balsa Wood sits at 170 on the same density scale and Cork at 193.
For several reasons, I have made Model Boat Bumpers out of Cork. Its accessible, cheap, very workable, paintable if desired, extremely light, and it was always accepted by my sailing peers in regattas and class racing, as bumper material, even though I seemed to be the only one using it. I used to buy those cork rings used in fishing rod construction as handle material. I just stacked them on top of each other until I had the correct height and epoxied them together. A couple cuts to make a wedge then sand to the correct curves to fair the lines of the bow and then just epoxy to the bow plate. Yes, there had been incidents where my cork bumpers were tested as to their performance. No one had ever complained that their boat was damaged, scratched or chipped by my cork bumper.
At this point I would have to agree with A.B. and look for a lighter choice of Materials.
Just an add-on to Marc’s earlier link - and using silicone (100%) to make bumpers. I’ve used the idea a long time, but always hated to wait for the silicone to cure. Ran across this “Instructable” and found adding cornstarch will decrease time to one or two hours for a cure. Also, you can use the same stuff to make a mold, and paint with lacquer as a release. The silicone caullk is extremely inexpensive, and thinning with naptha or acetone allows the product to be painted on for waterproofing ! I even tried a few rubberbands and they worked great for securing the batter packs.