Originally Posted by caps38
Caps38 here. Thanks for the reply. Did you mix sand with the portland cement and epoxy or just portland cement and epoxy. We have done some experiment
mixes with portland, sand and 2 part epoxy and it is rock hard. We have a large area that needs repair and getting the right clean sand is a bit of a problem. Do we need to use sand. Also we have insured our boat for liability only. Friends of ours were going to insure with Edward William who say they will insure ferro yachts but they were concerned it might not be the real deal so havent done so. We will pass out yacht onto our son who is a keen yachtie. But that wont be for a long time yet!
I tried the mixture after reading it in one of the books
on ferro cement boat building, I think it was Bruce Binghams book.
After experimenting I found that equal parts
of portland cement and the combined mixture the epoxy, (I used the West System) seemed to work the best.
I also tried using the microbeads West use as a bog but didn't get such a good result, it tended to be spongy and sag.
The problem you face is that when the filler expands and contracts it must be exactly the same as the ferrocement hull.
After mixing you find the mixture turns pitch
black, a tiny amount of this ended up on my drill and I needed a chisel to remove it when it was dry.
This tends to go off pretty quick suggest you use in the cool of the evening but not if it's a damp one.
The areas which I filled using this method were maximum the size of a piece of half A4 paper. When I hit the steel
after grinding out the cement area with a grinder with a metal cutting disc, I carefully ground the steel
clean, removing any rust, then lightly painted it with kill rust paint
, this provided a good key for the mixture.
I'm not sure that you need sand unless you have really large area, I once helped someone fix a ferro cement boat after it had run onto rocks leaving a huge hole in the bow she had been salvaged into the marina hardstand
in Darwin, after straightening the steel-mesh out he simply hired a concrete mixer then re-plastered the area, he then watered it on and off for 2 days, he was very happy with the result !!
The hull of my yacht was counterstern so I had one area where I had to apply this against gravity however
I applied a small amount let it dry then applied the finishing fill, from memory it didn't even sag. These area's never showed any problems after, some were also above the waterline, I ended up removing all the paint
then re-epoxying 2 coats then the whole hull primed and couple of top coats of 2 pack paint.
I also used this bog to fix a damaged part of the toe rail where the previous owner had hit a jetty and damaged the staunchion and broken away the concrete toerail, I used Ramset chemical bolts to reattach the base of the staunchion into the concrete deck
The insurer I used was Club Marine
who were happy to give a very good price
for liability insurance for Cullen Bay marina in Darwin after the survey.