Brutal sanding job!

[Crocodile69]

Hey all, new here so please be gentle.

Just bought a 1999 34' cutter rigged sailboat...big project. The first thing on the long list of 'to do' items is to fix the horrendous 'sanding' job, prior to my purchase...brutal. Looks like someone used a grinder to take off the bottom paint and in doing so left gouges clear into the fiberglass in several areas throughout the entire hull below the waterline.

I want to fix this right the first time so my idea was to just sand off the rest of the remaining gelcoat and apply several layers of epoxy (Raka?), while finishing her off with 4-5 coats of Interprotect 2000 E, then gelcoat.

I attached a pic, though I apologize the pic is not that great.

Thanks in advance for any information/ideas you may have,
Chris

 

[jbcurt00]

Re: Brutal sanding job!

Interprotect 2000E is an epoxy based paint product, I don't think you want to apply gelcoat over it.

How long has it been in dry dock?

 

[jigngrub]

Re: Brutal sanding job!

Aw heck, that'll buff right out!

... seriously though, you'll want to skim your hull with a fairing compound to smooth everything out.

I don't know about the compatibility of the Interprotect and gel coat, but I do know epoxy and gel coat aren't compatible... but you can make up your own fairing compound with polyester resin and a powdered filler of your choice.

A lot of us here like the USComposites products, resins and fillers:
Fiberglass , Epoxy , Composites, Carbon Fiber - U.S. Composites, Inc.

If you aren't real familiar with the powdered fillers be sure to read the description of each one before ordering, some are for epoxy resin only.

 

[Bob_VT]

Re: Brutal sanding job!

What is the goal? I would just smooth it slightly, paint it and float it. I have never in the last 50+ years got overly concerned on a boat's bottom. I am just trying to save you time and labor unless you are doing it to improve it's resale value.

 

[Crocodile69]

Re: Brutal sanding job!

Thanks for all the info. She's been on the hard for about 2 years. No blisters. I was initially told to sand it down a bit more and just go with an epoxy primer...with no gel coat. So yes, I completely forgot about the incompatibility of epoxy and gelcoat. Though I was told by one of the builders that the vessels first few layers are epoxy with poly laid up on the inside of the hull...possible? I thought that epoxy could be used on poly, but not poly onto epoxy.

If this was the case, how do I have gelcoat on that epoxy? Much to learn...

 

[jigngrub]

Re: Brutal sanding job!

Thanks for all the info. She's been on the hard for about 2 years. No blisters. I was initially told to sand it down a bit more and just go with an epoxy primer...with no gel coat. So yes, I completely forgot about the incompatibility of epoxy and gelcoat. Though I was told by one of the builders that the vessels first few layers are epoxy with poly laid up on the inside of the hull...possible? I thought that epoxy could be used on poly, but not poly onto epoxy.

If this was the case, how do I have gelcoat on that epoxy? Much to learn...

Poly laid up first on the inside and then the epoxy layups over that.

 

[Crocodile69]

Re: Brutal sanding job!

Thanks for everyone?s input, it has been very helpful.

So I?ll keep the original gelcoat (hull has no blistering, just gouging?it?s not extremely deep, just deep enough to expose the fiberglass in areas).

I was told that this hull MAY have been laid up by the builder with epoxy on the outside (though not positive on this), and poly on the inside. Thanks for the info on how to find the difference between the two. I?ll have someone who is more in tune with this at the yard have a look at her regarding that.

I guess my last question I have (which seems there are varying opinions) is what?s the real difference between an epoxy resin coat and an epoxy barrier coat? I would imagine they?re pretty much the same thing?

My plan was as follows? after dewaxing, sanding, filling and fairing the gouges with an epoxy filler, I was looking at around 5-6 coats of epoxy below the waterline for peace of mind. I was told that I can simply do this with Raka 127 resin or Raka 900HP (same as West System, though much more affordable) and a simple layer of InterProtect 2000E over that to act as a primer for bottom paint. No re-gelcoating.

The reason for using 5 layers of Raka vs. 5 layers InterProtect is simply cost, though I don?t want to cut any corners. Does InterProtect have more flex/durability/denser than Raka? Is it not possible to reliably paint directly onto Raka 127 resin with a 2 part epoxy paint below the waterline before antifouling? Or just skip the 2 part paint and just put antifouling bottom paint directly onto the Raka or InterProtect?

OMG, I feel like there are 10 million products out there over complicating something that can simply be fixed with epoxy resin and paint reliably. Still, I want to do it right and at the moment I have the funds to do so.

Thanks again,
Chris

 

[greenbush future]

Re: Brutal sanding job!

Some of the bottom anti-fouling paints are not good to breath, be sure to buy a quality respirator if you are sanding old stuff off and don't know what it is.

 

[Crocodile69]

Re: Brutal sanding job!

No worries there, a good respirator is always at the top of my list.

 

[zool]

Re: Brutal sanding job!

Personally, I would go with the Interprotect 2000e and a compatible antifoul....it acts as a sealer from blistering and a sandless primer to chemically bond to the bottom paint...You dont necessarily need 5 coats, you just need 10 mils(0.010 inch) ...too thick is not good for curing. Be sure to honor the recommended induction time if you go with the Interlux 2 part.

 

[ondarvr]

Re: Brutal sanding job!

Straight epoxies are difficult to sand, plus they tend to sag and run easily, so epoxy primers were developed to overcome this and make them easier to use. And being clear, epoxy can be hard to see when fairing, so adding pigment will help to ensure the surface is good before painting.

Painting the hull prior to antifouling paint isn't needed.

They don't use a combination of epoxy and polyester laminates in any normal build on hulls (after saying that I know someone will find an oddball hull someplace that was built that way). They may use a different resin for the first layer though, a VE skin and a thicker polyester laminate behind it is somewhat normal on hulls.

 

[Crocodile69]

Re: Brutal sanding job!

Great information from everyone. I've picked many brains over this one. I will:

1. Properly sand the hull around the exposed fiberglass areas.
2. Fill and fair the gouges with epoxy
3. Add a few coats of epoxy resin over everything
4. Add 10 mil (0.010inches) of InterProtect 2000E
5. Antifouling

Thanks again everyone.

 

[zool]

Re: Brutal sanding job!

Great information from everyone. I've picked many brains over this one. I will:

1. Properly sand the hull around the exposed fiberglass areas.
2. Fill and fair the gouges with epoxy
3. Add a few coats of epoxy resin over everything
4. Add 10 mil (0.010inches) of InterProtect 2000E
5. Antifouling

Thanks again everyone.

You dont need step 3, its redundant...and you may want to solvent wipe the repair areas before and after sanding...with a wax/grease remover, or at least acetone.