Changing colour of gelcoat question

Scott Danforth · Aug 25, 2025

sawzall with a long flexible blade or an oscilating tool.

MikeSchinlaub · Aug 25, 2025

Recip saw with a long blade works sometimes. It has to be a long blade so it can rest on the higher side while you bend it while working the saw.

carlos515 · Aug 25, 2025

The problem I have is that the stringers are bedded with resin and milled fiber. I will get a few new sawzall blades and try. My diamond 4.5 inch disc does work to a degree.

MikeSchinlaub · Aug 25, 2025

You just have to grind the rest out. It's easier when they're actually rotten. You can usually just whack a pry bar under the rest and it pops out.

carlos515 · Aug 25, 2025

I was going to replace the little ribs running perpendicular to the stringers with plywood stringers. Now I am thinking just using 2x2 fir.
Now is there any benefit to using 4lb pour in foam? I also was going to change to a bunk trailer, but my rollers are new and all hardware. Also, it is easier to load and unload the boat. The 4lb would add more stiffness to the hull?

carlos515 · Monday at 6:08 PM

A little progress today. My order of 16grit disc came today. This is to grind the stringer bedding resin. What grit is good for the final pass to improve adhesion?

MikeSchinlaub · Monday at 7:16 PM

What you have would probably be fine. We use the 40 grit roloc discs in our grinders, or the 5 inch discs. We rarely have to bust out the big grinders like that.

carlos515 · Monday at 10:01 PM

Thanks, last time I did not sand enough. This time, I plan on making sure the bond is good. The 7 inch is for the bedding resin, also to speed up grinding. Still chiseling out the old "new" wood stringers.

todhunter · Thursday at 2:46 PM

36 or 40 grit on a 4.5" grinder worked well for everything on mine, including the bedding compound. It was softer than the glass. I'm sure you know, but be really careful spinning up those big discs. My 4.5" flap wheel took a chunk out of my finger, and I've got the scar to prove it.

MikeSchinlaub · Thursday at 7:34 PM

todhunter said:
My 4.5" flap wheel took a chunk out of my finger, and I've got the scar to prove it.

Those things are dangerous. Boss told me he once saw one come apart on a guy and cut open his neck.

The air pressure was low, so he kept lifting it up to build speed and setting it back down.

carlos515 · 2025-09-06T06:26:34-0600

Thank you, todhunter and MikeSchinlaub. Yes, I have worked around the tools for a fair many years, but reminders of the danger are always welcome. I have seen grinder cutting wheels shattering.

Changing colour of gelcoat question

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