No Gelcoat?

[Paulus]

I scraped and sanded the bottom of my Mariner Ketch back to a layer that resists further removal - is hard paint - perhaps barrier coat - some orange and some light blue... The surprising thing is that where I accidentally went through this layer (largest "chip" being about 1/2 inch square), all I see is glass mat or roving.

By the way, no blisters - zero, nada...

A few questions:

1) How likely is it that some PO sanded (or blasted) off the gelcoat and then covered it with some kind of hard paint?

2) Is there any way to identify/confirm the presence of barrier coat?

3) those "chips" mentioned above, I intend to mix up a batch of epoxy (resin) and cover those with a spacle knife, then sand smooth before applying fresh bottom paint - any thoughts on that?

[Hirilondë]

1. Quite possible
2. You can carefully sand through the layers and try to ID them as you go. I am not sure how successful you will be, not sure how successful anyone would be either really. If the hard layers you speak of are sound and your new bottom paint adheres well to it, I am not sure it is important.
3. I would thicken the epoxy to help it stay where you put it until cured, but that method is probably fine. If the loss of the chip went to glass you should have a good clean base, maybe scuff it up some to make a good bond.

[Homer]

Agreed. If the coatings are nicely attached, just prep and recoat, particularly as you have no blisters. Blisters can be tricky, though. You must make your first observations immediately upon hauling as those under a coating may not be apparent after drying out. If you are still bent on figuring out the layers on the hull, a regime of various strippers can tell the story. They vary in strength and what they remove. I was able to eventually figure out everything on my hull before stripping and grinding it all off. I realize this was kind of an insane thing to do, but it can be done.

[Quetzalsailor]

It would be of interest to know what that hard paint is, from a compatibility/repairability standpoint primarily.

Dad painted the bottom of his Morgan 27 with graphite racing bottom paint. Rock hard, burnishable to a very smooth, supposedly slippery surface. That was the separation point for any subsequent bottom paint. What a pain!

[Paulus]

Pics of rudder (wood) and bottom paint...

Maybe I should rename her "Rainbow"...

[Zach]

If you are wearing a respirator, does it have a carbon filter? Gelcoat smells like chalk and styrene when you grind it... rather than the dusty paint that tastes like bottom paint. An N95 or N100 respirator cartridge just takes out the particulate, not whatever locked in solvent is still around.

There is an orange barrier coat on the market... I forget what brand it is right now, but a buddy of mine uses it on one off customs.

Zach