epoxy to ferro

[hooked on water]

No She was in South Hobart for a few years where the hull was done, and then taken to devonport where I bought it from
The bloke in devonport did the weighting of the keel in lead, and completed the deck and cabin
I now have fitout and full completion
cheers
Greg

[MidLandOne]

Thanks Greg - as I said was just a long shot. I had seen a bare hull sitting seemingly going nowhere out at Margate for the year or so that I was going out that way and thought maybe someone had picked it up and started giving it some love.

All the best with your project - is a lot of work in a boat.

John

[drew.ward]

So I just had my first day of poking around and cleaning up my new purchase -- a project ferrocement ketch.

After cleaning things up I got to looking into why the deck looked so horrible. I chipped away a few layers of paint to discover that the original owner had layed epoxy (or resin) over the fc deck. Unfortunately it looks like he did this as an afterthough.

I'm thinking he wasn't happy with how the decks turned out (and unlike the rest of the boat they are pretty rough) and decided to smooth out the surface with epoxy. Only prob is he had already done some other sort of coating on them first. I have no clue what it is, but it holds water and at first jab I thought it was actually wood.

Anyway, so am now at a point where I have discovered that there is a layer of moisture against my concrete that is trapped in by an epoxy layer and then encased in paint.

I think this would be a big thign to watch for, as now I predict about 2 months of scraping and brushing to get back down to the raw cement before I can do repairs and get a proper decking material on.

[hooked on water]

yeah I know
the right epoxy needs to be used and make sure it is prepared properly including drying

I am doing mine in stages to allow this and ensure proper adhesion and curing
sounds like he could have had another coating that does not go with epoxy though. my deck was the same with the coating coming straight off the epoxy (two pack urethane was there). same product as the hull, but the hull paint is good so must be a contamination issue - water or otherwise
wrong dew point even for the day

thanks guys
Cheers Greg

[drew.ward]

Since my boat is dry as a bone even though the cement's surface was wet under the epoxy I don't think the epoxy actually had any benefit other than perhaps protecting form the elements.

I'm just planning on stripping mine down to raw cement, bleaching it and maybe doing a light acid treatment to get a good clean surface. Then dry it fully and put a skim coat or two of self-leveling cement.

Once that's done and I've repaired a bit of edge damage (it was a katrina boat and has chips and such along the edge), I'm planning on gluing down a wood deck on top and being done with it all.

[hooked on water]

sounds like a bit of work for you
I know the feeling
mine has been sitting for about 4 years since the deck was painted, and the epoxy is sound, only the urethane had a problem, so must have been how they prepared it
good luck it all takes time

[Alan Wheeler]

You're on the right track drew. Rip that epoxy off and get back down to the cement. I am not so sure about self leveling cement though. Won't the deck have a curve or slope or anything other than level surface? The self leveling does exactly that. You can not keep it in place, it simply runs where it will. You are best to use a troweling Epoxy morter. But you need to be very careful of one very critical thing. Don't apply to thick a layer and create excessive weight on the deck. Keep it as light as possible.

[drew.ward]

Well the deck is very flat by design. I'm like you, it seems like it should have some sort of curve to it. Currently though it's mostly flat with some high and low spots here and there.

It's strange because the guy did a beautiful job on the hull, and somehow he must have just forgotten to read the book on how to lay a deck

I have to repair the edges where the deck meets the sides of the hull. It had some rub damage and chipping from the hurricane as well as having most of the railing ripped off.

My plan is to drill some small holes into the sides vertically and then tie into the existing rebar. Then I'll have some steel plate cut into long straps and make a new edge for the railing to bolt into (current setup was bolting into a concrete lip). Finally I'll use a form to cover all this with new concrete to seal everything up.

Once that is in I'll have an edge and then the self-leveling stuff should work well. I'm not using it for strength since the existing deck is fine in that regard. I just want it to get rid of the waviness the deck has in spots and to seal things up.

I figure I'll sand down the sides about two feet down, then once everything is tied back in together I'll use a good 10 year concrete sealant on it.

I'm going to cap the new lip of the hull in trim wood to both protect the concrete edge, make it look nice, and provide the edge for the decking material I'm going to lay down.

Final thing is going to be wooden decking material over the whole thing. The stuff I found is pretty nice and gives you a cool pattern. It's tested and warranted for use on boats and glues to concrete. Plus there's going to be very little cutting so it will be something I can do myself and still get a nice result.

Here's a pic of the stuff I'm planning on using:


It's actually sold in the pieces like this. So it goes down a lot like tile with the pattern matching up till you get to the edge. It's only 3/4 inch thick, so shouldnt be too heavy.

[Alan Wheeler]

Ummm, certainly different :-)

[hooked on water]

yeah that is some interesting effect
Is that treated pine
would be interested to see how it goes
keep us posted please

hooked

[GordMay]

Your deck needs to be crowned, with a continuous slope (2 - 4%) from c/l to rail.
All penetrations should occur at raised housekeeping pads.

[Boracay]

All those small gaps are perfect for filling with fresh water which will then saturate the wood, break the glue bond and be warmed by the sum into perfect conditions for dry rot. Even treated pine will rot under those conditions.

Anything glued to reinforced concrete will pull the concrete away from the reinforcing.

Don't forget that ferro cement will flex.

I would recommend saturating all exterior wood with thin epoxy resin, with a finish coat of straight resin. Nowdays I like to add a touch off thinner so it really penetrates, but that my preference.

My strong recommendation is to make your decks of two layers of ply, glued together using WEST system or similar with a layer of epoxy saturated fibreglass on top. Dave Gerr's book "Elements of Boat Strength" will tell you how thick to make it.

[cooper]

Ok there seems to be a problem with definition. Epoxy as in the liquid stuff used as paint works very well with ferro. Fiber glass as in laminating glass matt/ribbon/orwhatever causes problems. Concrete (cement and stuff..chose your own stuff) does not bond well to existing cured concrete. Concrete bonders (essential PVA derivatives) are use, but not as a water tight seal. Epoxy works well. In small repairs epoxy with a suitable bulking agent works. It does not fall out later, like a miss matched tooth filling. If anybody is interested I can give a method of fixing small breached hull holes. On substantial areas of breached hull as close as possible to the original "concrete" is necessary because of the dissimilar expansion and contraction rates. This is exactly the same as laminating a skin of fiber glass over the top of a ferro surface. A lump of your choice of epoxy, cured onto the surface of your choice of cement will remove a surface layer of cement if physically forced. The fact that it does not rip a hole in the boat has nothing to do with either the bond strength or the suitability of ferro. Swimming pool paint was popular as a finish on ferro boats for many years. There is a problem with the chemical reaction between certain paints and partially cured or non reacted concrete....but hey no body seems to care these days....Sorry get a bit jaded...done 7 years defending/explaining ferro....and I still have a 40 year old boat that floats and it does have a 3/8th inch hull and thats "buggerall" thickness to the metric people like me out there.

[Alan Wheeler]

Good post Coops'.