Boat Building Forum

Find advice on all aspects of building your own kayak, canoe or any lightweight boats

Re: sanding fill coats
By:Dean Trexel
Date: 8/19/2000, 8:15 pm
In Response To: sanding fill coats (Doug)

Doug,

Start sanding on one of the places where you need to feather, like the overlap of the deck cloth over the side of the hull, or (if your Coho is like my Tern) on the overlap at the center of the deck. Avoid the shear seam and start feathering the edge of the cloth down to the hull side panel. You will see the fiberglass cloth show up plain as day. It will look like a white cross-hatching on the off-white epoxy. The big tip then is: when you see this in places other than where you need to feather, stop sanding there and move on. You will inevitably start sanding into the cloth somewhere you don't want to, but don't get all torn up about it. If you don't linger in that area with the sander, you'll still have some strength there, and varnish will wet the area out and make the exposed weave transparent again.

You will find out how much you need to sand as you go. The sanded surface will be a flat off-white color, sanding dust will fill in the low spots, and you will think you've done a pretty good job. But give the boat a wipe with a damp cloth, and you'll see some shiny spots that you've missed, and you'll need to sand down further. Eventually both your arms will have fallen off, the whole boat will be dull-looking, and you'll be done. It's a great feeling to apply the varnish and see the wood shine through again.

If your Coho is like my Tern and has 2 pieces of cloth on the outside of the deck that overlap in the center, I have some advice: I didn't sand very far into the overlap because I didn't want to weaken the cloth. As a result, I have bit of a bump there. I talked with Pygmy after the fact, and they recommend just sanding the whole overlap right off. You now have a weak spot, because the cloth is essentially butt-jointed with no overlap, but it is in an area that's reinforced with the cockpit coaming, so strength probably isn't much of an issue. I understand that this makes better use of the cloth, and makes the kit cheaper, but next time I would shell out the extra cash to use a single piece with a bit more scrap.

Dean

: I am ready to begin sanding the fill coats on my Coho (at last!)

: How can I tell when I have sanded enough or better put, how to I avoid
: sanding too far?

: There is a glass seam just below the shear where the deck glass overlaps the
: hull glass. I think this is the part where the 'danger' of oversanding is
: the greatest. Any tips would be helpful.

: Thanks in advance

Messages In This Thread

sanding fill coats
Doug -- 8/19/2000, 1:59 pm
Re: sanding fill coats
Dean Trexel -- 8/19/2000, 8:15 pm
Re: Amount of cloth Pygmy provides
TomF -- 8/22/2000, 11:46 am
Re: CLC skimps too
todd -- 8/22/2000, 9:00 pm
Re: Thanx Dean
Doug -- 8/21/2000, 3:17 pm
Re: sanding fill coats
Lance Alldrin -- 8/19/2000, 4:35 pm