Unsightly Panty Lines in my Dinghy !

[Nikolina]

MADE YOU LOOK! But it's not what you think, I'm building a minipaw dinghy, stitch and glue method using okume plywood. And I'm going to be painting soon and I would like to get rid of all the fiberglass tape lines (panty lines). Any ideas?

[Nicholson58]

I discovered epoxy and microballoons as filler for a faring compound. US Composites for the materials. Make a paste and trowel it on. It is nicely sandable and very low weight, totally waterproof.

Fillers 3M glass bubbles
Epoxy :*Epoxy Resins and Hardeners 635 resin is VERY slow and easy to use. Takes about 5 days in cool temps to sand. You can use a rasp when it s softish putty.

This is also a good source for cloth and other epoxy stuff. Photos of our rudder. 6 inch thick solid epoxy and balloons. 6 feet long and 3 feet wide. Total 30 gallons mixed. My batch was 7 gallons of balloons, 3 gallons of epoxy using a drill mounted drywall blade to mix. This makes a mix like Kraft Marshmellow Cream. I also use this in higher resin concentration for trowel on and pour in place applications.

[minaret]

Are you finishing bright or painting with actual paint? What kind of paint? If you glassed with WEST I suggest 407. It is the standby. If you glassed with WEST and this is a boat which will not stay in the water fulltime, use 410. You get a much bigger batch with very little 410, it floats on really nice, and it sands much quicker than any other epoxy fairing compound. The compromise is 407 below the waterline and 410 above, but this makes fairing a little tricky unless the transition is near a chine for most of the length of the boat. If you are finishing bright you need a whole different process.

[Nikolina]

Thanks again Nicholson and Minaret, yes I'm using west epoxies. It's a minipaw 6'-6". Not sure what paint I'll be using for the finish, it's not perfect although it's looking good in the early stages so I don't want to screw it up in the end. So fair it with 410 above the h20 and 407 below. The boat is to be stowed on deck so really won't be sitting in the h20. And as far as a decent paint any suggestions, (also do I need to primer after I coat everything with epoxy?)

[minaret]

Originally Posted by Nikolina

Thanks again Nicholson and Minaret, yes I'm using west epoxies. It's a minipaw 6'-6". Not sure what paint I'll be using for the finish, it's not perfect although it's looking good in the early stages so I don't want to screw it up in the end. So fair it with 410 above the h20 and 407 below. The boat is to be stowed on deck so really won't be sitting in the h20. And as far as a decent paint any suggestions, (also do I need to primer after I coat everything with epoxy?)

If the boat will be sitting on deck a lot I'd consider fairing in all 410. The other advantage to that is you'll get a lighter boat, 410 is by far the lightest fairing compound, as well as being the easiest to sand. It just has a slight tendency to blister if immersed for very long periods in saltwater without a barrier coat.
You definitely need to prime for most paints. How are you applying, spray or roll and tip? What is your skill level? What do you want the bottom to look like/be coated with? A hard anti-fouling or just a different color paint?
For a project this small I'd probably use a good quality primer like 545, which really likes to adhere to epoxy, and then think about roll and tipping a one-part solution. Otherwise it will be an expensive little dinghy. Really depends on how nice you want to make it and how much money and time you want to put in.

[heron237]

Nicholson, I don't understand? You formed the rudder out of solid epoxy thickened only with bubbles? I see on inspection of your picture that you were only filling the voids between the rudder armature it could have filled it with any non reactive foam. Then at least clothed up the skin for impact resistance. And mixed it in seven gallon batches? I mean it's exothermic it didn't bubble up in such a large batch? Doesn't make sense to me. Would you mind clarifying, thanks.

[anjou]

Did someone bet you to mention those key words in a sailing thread?

[keepondancin]

You could sand and feather the edges of the glass tape, then give the dinghy another coat of epoxy. That would diminish the lines. You could always sand and coat a third coat, that would eliminate the lines, and you wouldn't be relying on fillers, and could leave your work bright. I am sure you are aware of the amine blush that has to be removed from fully cured WEST before you recoat or prime. Google clcboats, a kit boat company, and they have many videos and galleries that can give you good info on S&G construction and finishing.

[Nicholson58]

Originally Posted by heron237

Nicholson, I don't understand? You formed the rudder out of solid epoxy thickened only with bubbles? I see on inspection of your picture that you were only filling the voids between the rudder armature it could have filled it with any non reactive foam. Then at least clothed up the skin for impact resistance. And mixed it in seven gallon batches? I mean it's exothermic it didn't bubble up in such a large batch? Doesn't make sense to me. Would you mind clarifying, thanks.

Solid 6 inch thick filled epoxy as noted. Total 30 gallons mixed in two pours. (top section and bottom section) The Us Composites 635 is VERY slow. It also costs way less than West. You notice no exotherm and no splitting or shrinkage. After 24 hours it is like cold chewing gum. The compressive strength is about 3000 psi. With a carbon skin over the outside it is probably bullet proof. It hammer rings like a bell. (freaked out the surveyor) It is built over the original welded SS armature. The rudder before rebuild was saturated moldy foam with blisters. I prefer this system especially below water to any balsa or foam system since it will never permit any water in. I built up the steel with fab-mat and epoxy and faired the surfaces to near the level desired for below the skin. Use an aluminum straight-edge like a concrete skreed to find the high spots. Rub it lightly over the surface and the glass bead filler turns black from the aluminum oxide. This shows where to grind. I ahd to add a couple of skin coats to get level. In the end, I had Torresens in Muskegon vacuum bag the carbon fiber. They used West epoxy.

I also use this system to repair my water soaked balsa core deck sections. Drill into the bottom skin with a hole saw; dig out all wet filler. Keep drilling and digging until you reach dry filler. Let it dry for a while. Repair the skin using 635 and fab mat. The holes will appear as clear windows. Mix 635 and balloons and pump it in to totally fill the void. You can see the resin front through the windows.

It can be sanded, polished and painted.