epoxies

xxx Trial On Ferro-Cement Boat

by: Ian McFarlane (11-98)

Presented by: Progressive Epoxy Polymers

Coordinator, Ferro News (a quarterly newsletter for ferro-cement boat owners) ian.mcfarlane@citec.com.au

All boats whether they be constructed from ferro-cement, steel, GRP, or timber require good protection from the harsh environment in which they float - salt water. A coating system is the selection of products and the order of which they are applied to the hull to offer this protection. Typically, this consists of a sealing coat to seal and prime the natural hull surface, followed by several barrier coats to keep the water out, and topped off with a coating of antifouling - a toxic product designed to keep the hull free of weed and barnacles. In the tropics the boat owner can expect to renew this top coating every 12 months. Most hull types can have problems with their coating systems of one sort or other. Ferro-cement hulls are no exception. I have seen many examples of where ferro boat owners have renewed the entire coating system, only to have it "blow off" within the first year. Even more common is a phenomenon where small paint blisters form on the hull, mainly in the solid sections of the keel. These blisters lift the coating reducing the protection afforded and promotes premature fouling of the hull, not to mention the addition labor and cost each year of repairing the paint system. Over the past few years I have taken a special interest in hull coatings and attempted to resolve the problem in my own sailing boat, Lilly Ann, a Hartley 38 South Seas Ferro-cement sloop.

I contacted many of the leading marine coating manufacturers in Australia, to seek an understanding of the problem and the possible solutions. Few showed any interest in the problem, beyond swearing that their products would do the job. Testing a wide range of coatings and preparation techniques over a number of years failed to deliver an adequate solution. The search then lead me to the Internet, and there I found Progressive Epoxy Polymers, Inc., a U.S. based company that claimed to offer an innovative range of epoxy coatings. Inquiries received keen interest in the problem, and the closest answer I've had to the likely causes. It was recommend that I should use their Kevlar(tm) micro-fiber reinforced epoxy). Together with the micro-fiber, the solventless base, and its moister tolerance, it seemed to offer the best hope yet! But being cautious I ordered a sample kit, in-time for the yearly haulout and applied a test patch to a small area badly affected by blistering. The following year I watched with anticipation as Lilly Ann came up the slipway and receive a waterblast. Well! The results speak for themselves. The test area was completely intact. Nothing short of remarkable as far as I'm concerned. I extended the test areas to include approximately 30% of the affected area. Results of this will be available next year. However, I feel confident at this point to recommend all ferro-cement boat owners consider this product. It truly is an innovative product. This product is quite stiff to apply by brush, and leaves when cured a porridge like texture, which some owners may consider to detract from a fair hull. Formulator does now manufacture a product with less Kevlar micro-fiber content making it more fluid to apply. I would recommend this as a general hull coating if one was to replace the entire system. The high micro-fiber product could then be used to patch as required.

Another important advantage of the product is that multiple coats are not required in this application, and the antifouling can be applied within a couple of hours when the epoxy coating is just tacky. This positively binds the antifouling system into the epoxy coating. The two-pack product (1:1 mix ratio) are available in two one-gallon cans (7 Liters)....... 7 Liters has an estimated coverage of 15 square meters.

Since my successful trial, many other ferro-cement boat owners are now ready to give it a try.

Ian McFarlane (11-98)

 Comments from the Supplier (Progressive Epoxy Polymers, Inc. 10/5/01

Since Mr. McFarlane's letter we have sold a fair amount of xxx brand epoxies to ferro-cement hull owners, without any complaints, however we no longer offer this product. We do have newer similar epoxies. See our Wet Dry 700 epoxy paste and Corro Coat FC 2100 F rollable epoxy.

We also sell a water based product called Bio Vee Seal which soaks into concrete surfaces and forms crystals in the pore spaces below the surface (leaves nothing on the surface). This makes the concrete less porous -- i.e. more dense. We think this would be a good and inexpensive treatment for a ferro hull with uncoated concrete exposed.

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