Mark's C21

[mmachonis]

Thank you. Once I get it cut out, I will send new pictures to find out what to do next.

[Fuzz]

Here is what I am talking about.

They will eat glass and anything else they touch,

The black disks are something new I found at a boat shop. They eat glass like it is butter. Not good on wood but I have never seen anything eat glass like they do.

[mmachonis]

So is there a specific disk I should be looking for? I see they are made by Zec. I went to their website and they have many types. They have Flexible, Semi-Flexible, and Plastic. Within those groups, there are different grades. Do I use the Silicon Carbide or the Aluminum Oxide abrasives? Will either of these cause a problem when later bonding with the next layer of epoxy?

[Jeff]

Mark, I sent a note to Jacques to review your thread!! Jeff

[jacquesmm]

I do not intervene when the thread is going in the right direction. I agree with fallguy:

Try rewetting first with heat even.
Then if that doesn't work sand it out with 50-60 grit.

I would not worry much about a secondary bond, that is more a problem for polyester but to be safe, do a light grinding.
I would do that with an angle grinder but them I am a fiberglass butcher, not an artist like some of you.
Whatever the grinder, open the surface with a grit 40 to 80 and apply more resin.

If the reason for the whitish spots is contamination, it will stay white. If that happens, you must grind down to the wood and apply a patch overlapping the good fiberglass.

[OrangeQuest]

After you get your setup ready practice on something that you don't mind destroying! Like Fuzz stated "They eat glass like it is butter. Not good on wood but I have never seen anything eat glass like they do."
Keep your grinder moving and very little pressure. They are called angle grinders because you use them at an angle to the surface you want to grind.
Also because they remove so much so fast you can expect a small dust storm. This is what my area looked like after a few minutes of grinding epoxied glass.

[Fuzz]

I would go with the plastic for the black disks. I do not think type will matter too much. The flapper disks can be bought at places like Home Depot so that might be easier for you. 36-80 grit will all get er done just be careful as they will move a lot of material quickly. I am not sure I would use the Zec disks unless you practice some first and need to move a lot of glass.

[mmachonis]

Hello all!

I hope you are all enjoying your summer. I've been slowly working on my C21 and I am about to put a skeg on the bottom. I read Jacques's post about skegs, strakes and spray rails. The only thing I didn't pickup on for the skeg was the height. I realize it should start a little forward of the middle of the boat and end a few feet from the transom. I was thinking about starting about three feet forward of the center of the boat with a 3 inch high by 2 inch wide piece of dimensional lumber rounded on the outside edge(feel free to make suggestions on which type of dimensional lumber) and run it to 4 feet from the transom where it would gradually rise to 6 inch high by 2 inches wide . What do you think?

Thanks.

Mark

[jacquesmm]

That maybe a little too large. A 2x2 or 1x2 on edges is enough.
A 2x2 is really 1.5x1.5".

[mmachonis]

So the skeg should be at its largest 1 inch wide by 2 inches high beginning 3 feet forward of the center and ending 4 feet before the transom?