Epoxy Barrier Coat

[s/v Jedi]

Originally Posted by Cheechako

I guess I'm confused.... are we talking real epoxy resin or just the "epoxy" primer coat like interlux 2000?

I think Interprotect 2000 is also real epoxy with additives. The OP used an epoxy that I am not familiar with, with additives from West System I think.

ciao!
Nick.

[keepondancin]

I think an important reason not to sand is barrier coats need film thickness, and sanding reduces the depth of protection.

[David M]

I would call Interlux and Pettit and talk to their experts. Too much is at stake for this to get screwed up. You don't want an expensive mistake to have to deal with.

Interlux 2000 is indeed a two part epoxy. You are supposed to roll on a certain number of coats in order to have a certain mil thickness. You are not supposed to roll it over any sort of oxidation.

[minaret]

Link to Data sheet for 2000e-

http://www.yachtpaint.com/usa/diy/pr...ProductID=3867



It contains tables with overcoating times for many products with 2000e. I don't think that's what the OP is using though.

[Nicholson58]

Originally Posted by clifflindsey

Could somebody explain to me the importamce of not sanding my epoxy barrier coat(fasrco low viscocity epoxy resin with west system 422 barrier coat additive)? And also why Ive been encouraged to paint the bottom paint so quickly after my last coat of barrier coat?

I happened to have the Pettit and the Interlox reps together when I was picking my antifouling paint. I asked them what I should use for the typical northern Great Lakes cycle that would also let me move into salt water and the tropics later. They both agreed that I should use VIVID. They also both told me to apply it over my 5 coats of INTERPROTECT 2000E immeadiately as soon as it was dry to the touch - typically less than an hour after the last coat of Interprotect or the antifouling would not stick. They also noted that this is contrary to the instructions on the paint labels. The VIVID also had to be applied continuously in three non-stop coats. We arranged some special supports so there were no struts touching the boat below the stripe and applied 9 coats toatal in 2-1/2 days of nice sunny weather. Once the four tall towers were brought to bear using chains and load binders the small supports could be pulled away.

[matauwhi]

G’day, Mates. We installed (ourselves) a new Interprotect 2 part barrier coat 3 years ago. Interprotect’s spec sheets clearly detail that the first layer of bottom paint can be applied without sanding within the time and temperature parameters outlined. Two tips:

1. We ended up applying 6 coats of Interprotect, just the way the pricing per liter costing economically worked out. We put a coloring pigment between the coats to help clearly identify the rolling pattern.
2. Mark out a couple of square meter areas on your hull. I believe the practical coverage should be around 9 square meters per liter. This helps make sure you’re not over/under applying.

The worst part was scrapping off the old bottom paint. Any future owner will reap the benefits of our efforts. Total cost was around $1,500 USD for the materials. You don’t want to know the quote from the yard to do it! Cheers.

[Nicholson58]

We also used the alternating gray - white to see where we'd been. We mixed it two A and two B cans at a time in a 5-gallon pale. I used a drill mounted drywall compound mixer. There is a rest time after mixing before you apply. I found that one 4-gallon batch was one coat. It took two of us about 30 minutes to coat. At the end of each coat, I mixed another batch. We continued over two days untill done and then immediately applied the VIVID.

Removal of the old stuff and repairs was months! We used a 4-foot floor scraper to remove the bulk of the old paint. It had to be kept razor sharp to work. Use a belt sander with 600 grit belt to sharpen. We had it sandblasted and then came the dressing and filling of the blisters. The good news is that Interprotect wants 40 to 60 grit rough finish. This let me fair the hull using a 9" diameter 40 grit right angle buffer.

[matauwhi]

G'day, mate. Good on ya, a bit more surface area than we had. Are you sure about that 4 foot scrapper (looks a bit shorter) or are you using the old "6 inch" measurement system!

I forgot the other tip if you're going to use an ablative bottom paint. If you want to keep an eye on how your paint is doing, use a different color paint on that 1st coat. Cheers.