Foam Bumper

I just bought some foam, (like the flip flop foam) for my front bumper, I just cut it to the shape of my IOM bow but it came out kind of jagged? How do people finish this foam? Can it be sanded (tried by hand , did not work) will try with belt sander when kids go to bed?

A very sharp knife or razor is needed to avoid ragged cuts. You can sand the stuff with the belt sander but you’ll probably need to make up a few scraps of wood into a holder. My best results have been through the use of a bench grinder. Take off small bits at a time. The stuff will burn the surface into a gooey mess if you grind or sand too hurriedly.

Another scheme is to fold a thinner foam part into the shape of a bumper. Leave the skin side out and it will accept paint. When folding to shape, contact cement will hold it there. It may take a few tries to get the exact shape you want but it will result in a nicely finished bumper. Ever wonder how the upholtery people make the foam interior of a cuishon conform or make taper edges of a cuishon. Easy. Coat the edge of a foam slab with contact cement…Bring the two corners together. Voilla! a tapered edge.

Don’t forget to check the rules for your sailing class (if you are in one) to see if bumpers are even allowed.

I just use a bead of RTV rubber or silicone stuff. Bumpers don’t need to be too big or thick, as they only need to protect from an occasional bump or scuffing.

If this is for your IOM then the bumper has to be at least 10mm deep. I have used flip flop foam with good success and I have found that it sands quite well. I can’t remember what grit I used but it seems to me that it was either 180 or 220. I ran tape along the hull back aways from the bow so that I wouldn’t sand through the fibreglass of the hull. But it worked out fine. I think I roughed it to shape with an orbital sander and then finished it by hand.

I’m about to do another one so I’ll re-check my method and let you know.


bdf 233,
yes it is for my new IOM (not register as I have no one to race with yet). I ended up cutting it with a sharp knife then sanding it with special sand paper I had for sanding drywall filler, it is like a mesh with holes in it and it worked great. I did not think of sanding it attached to the hull so it is a little shy of the outer edge but I think it will work. Thank you all for your ideas.

I have made many bumpers using black dense foam. The trick is, as mentioned before, to tape up the bow with ‘duck’ tape, glue on the foam, still in block form, and then use one if these long ‘snap off’ craft knife blades. It must be brand new. Taking care not to amputate a finger, trim down the foam until the blade is nearly touching the taped hull. Then, using a rough glass paper, gently shape the foam to a final shape. Take your time, as the foam will squish out of shape if too much pressure is applied. Finish with some finer grit paper then stand back and admire!