PDA

View Full Version : Tell me about coal tar epoxy-



Frantically Relaxing
09-03-2014, 05:56 PM
We've owned our SkipperLiner for going on 9 years now. Has a steel semi-V hull, dead-flat at the stern, 9 up front. I'm fixing to pull the boat this weekend after 3-1/2 years in the water for some much needed maintenance, the biggie being sandblasting the hull to inspect and repair anything if needed and finishing up with coal tar epoxy.

Not sure if I'm going to do the sandblasting or pay to have it done. For simply the money's sake, I'd rather do it myself. I have access to a diesel blaster with all the goodies, but I don't have a lot of free time, so I'd be doing this on weekends until weather doesn't permit.

Regardless of who does it- What is needed before applying the coal tar? Is primer necessary? If so, what type? If not, what kind of prep is needed to the bare metal immediately before applying the coal tar? Are there different types or grades of coal tar epoxy? Is anti-fouling paint needed?

thanks in advance!

easttnboater
09-04-2014, 06:16 AM
I had coal tar epoxy on my first houseboat. It was blasted and the epoxy was applied that same day. If you leave the hull bare for a while before applying epoxy and it gets surface rust, then you will have to lightly blast it again. The epoxy goes directly onto the bare steel. I think that all coal tar epoxy is synthetic these days. I go mine at a commercial Sherwin Williams store. It is pretty easy to work with and does not set up too quickly. I would apply at least two coats below the water line. - preferably three. It is tough stuff. Anti-fouling paint is up to you. Stuff will grow on the coal tar epoxy paint, but will not harm it.

OLD HOUSEBOATER
09-04-2014, 07:31 AM
This is not a week end project job. The Coal tar MUST be applied right after blasting before any corrosion can form. The second coat needs to be applied within 24 hours of the first coat.

This is a dirty labor intensive job. The upside is that you have a coating on the bottom that needs a chisel to remove. Life on a coating job is 5 to 7 years wit periodic touchups to scrapes and bruises. If you are going to use anti fouling over the Coal Tar, wait a year. Anti fouling doesn't bond well to fresh coal tar. Lee Spry was top notch on Coal Tar jobs but I don't know if he's still in business.

I never needed anti fouling on the Tennessee River.

JTAlberts
09-12-2014, 05:41 AM
I had my Kingscraft blasted and put on Coal tar. It was indeed a messy job. Bottom looks great though and it has held up great.

Frantically Relaxing
09-22-2014, 01:41 PM
Thanks everyone--

Pulling the boat didn't happen, and won't until the water comes up. Sucks when your trailer sticks in the lake bottom before it's in far enough. I even added a tag axle to the back of the trailer in hopes it might roll along the bottom. Didn't help, just something else to plow mud.

I've decided that before I tackle this job, I should probably pay to have the hull inspected. The initial paint on this hull may be coal tar, I'm not sure. In '08 I hit the entire hull with a 4500psi steam cleaner, and the only places the paint budged was where rust happened to be, and under the waterline that added up to about 3 square feet of hull surface, and it was pretty much just surface rust. Along the waterline is where any appreciable rust is forming, and mostly along the last 15' of hull. The worst rust I've found is around the 2 plastic thru-hull drains for the kitchen and lower bathroom sinks. Those drains have always faced west, and both drains crumbled in my hands when I inspected them recently. The metal around them are rusted pretty badly to about 2" in diameter. I did a Macguiver fix to the drains until I can get the boat out.

The only water's that's been on the inside of the hull is the bilge, and 2 years ago when I had a small plumbing leak, that resulting in a few gallons of water that puddled up front in the keel for a few days.

I'm not expecting to find much to do in the way of repairs...

Potis
10-28-2014, 01:34 PM
I also used Sherman Williams product - great stuff and highly recommended. Besides all the good points already made about prep. and when to apply, also be mindful of the temperature as well as the dew point during application and curing.