23/...Hull repair and painting.

I am getting the hang of your website and enjoying the content. It seems more appropriate for me to ask my questions here, so perhaps you could ignore the e-mails sent a few minutes ago. I have a Roberts 40 Ketch which I have owned for around three years. The hull has rust bleeds on a number of places on the topsides but no major cracking, or exposed mesh. A year ago I stripped all the paint off the hull and while there are some epoxy repairs overall the hull is quite good, although not very fair. I have always had a problem with peeling paint and the rust bleeding through within 6 months of painting. Is there a better way, or better product than the single pot paint I have used and what are the pros and cons of having the hull faired and epoxy sheathed? Would this stop the rust bleeds/protect the hull? Andrew Darroch. Refuge, Sydney.

Andrew Darroch....andrewd@cityplan.com.au

 Hi Andrew, in this instance it appears that you probably have some tie-wire ends etc that are poking through the protective layer of plaster to the surface. Because most paints are porous it is only a matter of months before the rust stains will begin appearing. You need to follow the schedule given in my book 'Ferro-cement Boats', then prepare and paint as per usual. There are a number of different paint processes you can use according to the time and money available. Cheapest is 'Chlorinated Rubber Paint', often described as 'swimming pool paint'. And dearest is a full two-coat epoxy system complete with prep epoxy sealer coat and filler-coat. If you want more on these paint systems I will post.Regards

Colin Brookes...colb@xtra.co.nz

 Thanks Colin. More on the painting would be appreciated.

Andrew Darroch...andrewd@cityplan.com.au

Hi Andrew,I have just been through this exercise myself on similar size boat.I got specs done by Akzo Nobel(epiglass),Altex Devoe, and Resene Santano.The cost of a full epiglass system consisting of sealer,various undercoats and reaction laquer topcoat was pretty close to $5000 NZ.The Resene Santano product Durepox appeared to be cheap at $320 per 20 litres,but when the cost of the hardener was added in it got up to around $28 per litre,and their topcoats were among the most expensive.I decided after much soul searching to go the cheap way and use chlorinated rubber paint.The cost to do the whole boat including topcoat was about $2500.(including antifoul).The only company I could find in N.Z. that makes it is Altex Devoe.You can find the specs on all their products on their website www.altexcoatings.co.nz They probably have an Australian site as well.However when I contacted them to buy the paint they would not recommend the use of chlorinated ru!
bber paint directly on to the ferro cement.They do recommend it if it is going on over old antifoul etc. but not on to the bare ferro. They sell a product called Altra-Lock 577,which is a thin clear sealer.Theoretical coverage rate is 25sqm/litre.It sinks right into the ferro and locks up any loose flakes of rust,paint etc.That could be a good product to take care of your rust bleed problem,trouble is you then have to use another of their products which is compatible before you can put anything else on.There don't seem to be any real cheap options.In the end I decided to go with all Altex products,ie- sealer,2pot epoxy undercoat,spot-fill where necessary,and 2 pot topcoat.All-up cost is expected to be around the $4000 NZ mark.Hope this is some help to you. Regards,

Dave Carroll...davecarroll@postbox.co.nz

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