kittyhair (evercoat) sounds like same product..
It is basically the same as the marglass, their equivalent and I've used it also, just prefer the marglass. I think it sands and shapes a little better.
The two products are waterproof, not water resistant, very important. I think we have to remember that to do a proper repair regardless of if you used one of these or the epoxy based fillers that you use these to fill and shape the surface. They are not structural components of the repair. If you need strength you are going to have to use glass also.
The process doesn't end there and you don't just put a bottom paint over them. You need to put a good epoxy barrier coat over them and that will further waterproof what you are doing and is needed as when you sand the fillers down you will still get back to metal at high points and you need to keep the moisture away from the metal and a bottom paint won't do that.
I apply an epoxy primer on all the metal work I do. I'll put two coats on our trailer, hopefully soon, when I finish up with this second axle deal. Then I'm using a good urethane paint over that.
Bondo got such a terrible name since a lot more guys use to work on their cars themselves and would bondo an area and then paint it with rattle can primer and drive it sometimes for months like that. The primer wasn't waterproof and the bondo with its talc filler soaked up water like a sponge. The water went through the bondo to the bare metal under it and started rusting. After the rust built up and broke down the bond the bondo popped off and everyone though it was junk. If they would of used a good 2 part epoxy primer over the bondo nothing would of happened.
About this keel, seeing the shape it is in I wouldn't feel safe with it unless I could find a place that could possibly magnaflux it for hidden cracks. If a machine shop could do that it wouldn't probably be expensive and you would feel a lot better about going out with it and putting money into it.
Then I would do as you said and have it media blasted. Then build the area back up with the filler of your choice as long as it is waterproof. Shape it with 36-40 grit using a long board sander. When it is to the right shape sand the 36-40 scratches out with 80 grit.
Then if I wanted to do a really nice job I would get a 2 part high build primer that is also waterproof and spray about 2-3 heavy coats of that on. Block sand it with 180 or 220 dry paper. Repeat if there are low spots. I would use a guide coat of paint for all of the steps including the shaping of the filler. You will instantly see low spots using it. It is cheap and comes in spray cans.
Once you have sanded with the 180/220 for a boat I would probably stop there and move to the epoxy barrier paint and then in the right application window put on the bottom paint.
It sounds like a lot of steps, but it could be done in a day or two. The key to getting it done quick is to put on enough filler to bring the whole surface up past where you want it. Shape it with the 36 grit paper on a long board (a hand one, don't use an air one if you don't have experience) using the guide coat so you can see low spots. Work the filler just after it 'kicks' don't wait a couple days and let it get rock hard. Work on only one side at a time and then the front leading edge.
Then go sailing
,
Sum
Note: For autobody work after the 180 or 220 I'll spray on more high build primer and go to 400 or 600 wet before putting on an epoxy sealer and then the top coats.
Our Trips to Lake Powell, UT - Kootenay Lake, Canada - Priest Lake, ID
Our Mac Pages
Mac Links
