ferro-cement repair - how to?

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CharlesM

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Hello All

Serendipity has a few rust spots. I would like to tap into the large knowledge base here.

I have read one can use the an epoxy to repair small holes in a ferro hull. An epoxy system such as West (406/405 I think). Perhaps by adding some silica to thicken the mix.

What I do not know is how big a hole can be repaired using this stuff.

Assuming I have a rust patch which I chip out (what is the best may of doing this) and clean up the rust (again, what should I use for this?). If the hole is right through the hull and say about 3cm in diameter - can I use the epoxy? What if the hole is 5cm, or 7? - when does one start using a product such as ferrobond instead?

Any advice would be much appreciated.

Cheers
Charles
 
I've used ebalta industrial epoxy it's slow curing though. Other suggestion is Epoxy based concrete repair compound. I've made my own with pure resin mixed with dried sand.
 
Hi
My ferro boat had several holes through it when l bought it. Lucky l tracked down the original designer and builder. Not bad after 35 years! He invited me to lunch and l picked this ferro gurus brains for quite some time. His advice which l followed is this...

1. Clean out the hole of any loose concrete.
2. Tease out the armature and if nesesary chip a little more concrete so that you can lace wire across the hole.
3. Make a spiders web of wire across the hole.
4. Rust convert all exposed metal.
5. Mix up a low slump batch of epoxy (l used west systems).
6. Mix up a un added to batch of epoxy.
7. Coat the entire area with the thin epoxy, and then using the "wet on wet" method stick in your thickened epoxy.
8. Top up and/or sand till you get a fair surface.

l would be happy to fill holes up to 10cm using this method.
 
Hi Idlerboat

Thanks for your description -it is probably the clearest I have had to date. I purchased Ferro Boats by Hartly & Brookes, but that is rather weak on descriptions for the novice.

A question or rather a clarification. I assume wet-on-wet means while the thin epoxy is still wet I add the sump epoxy?

Also, what is the best way of chiping out the concrete? A chisel?

Finally - how long should you leave the repair before it is ready to go back in the water? I assume since an epoxy system it can go in the next day?

Cheers
Charles
 
You would need something to form over a larger hole and hold the material in place I would say size only limited by the formwork. I would suggest small air powered chisels as they are very light and manoeverable
 
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