For what it is worth. If it is a new boat shell, then I would feel it would be worth grit blasting, to get rid of mill scale etc. If it is a shell that has been painted and used now its time to repaint then: To use twin pack epoxy (TPE) on the hull, then the steel has to be spotless, or it don't stick, if you want to go this route then grit blasting is the way to go, but there are some yards that use a tool that is made up of several wire brushes, I have heard about one being used in Enfield dry dock, never seen it, but have been lead to believe it will clean the metal suitable for twin pack, this tool is not your 41/2 in angle grinder but a bigger machine. I have heard several things about two pack epoxy and they are all good, if the metal is prepared properley then it does stay on the metal. One report is of a boat in the yard that was TPE ten years before having to come out for a survey, the outside of the boat was as good as when it was done as I say ten years previously but what the survey found was the hull had gone very thin in one place and when the owner thought about it, the thin patch was where the shower had leaked into the hull, and the hull had rusted from the inside out. The second report was another boat in our yard, the owner being very fussy etc decided he wanted the TPE taken off the hull cleaned and re TPE, again this had been done about tenish years before, the epoxy was well stuck to the hull, the owner wasted his money. Other coatings like Bitumen or similar will do a good job for a couple of years, then it needs re-doing, Black Tar Varnish is good need to make sure the metal is clean will last three years before needs redoing. But the above does mean that you have to do the preperation to the letter. On the cabin sides etc tools are so much better and cheaper, then I would say do it by hand. When you are grit blasting it will go in all the boat oriffices, and they will all need protecting etc. Some yards won't allow grit blasting etc. Remember the 7 P's Pi** Poor Prep Produces Pi** Poor Performance Hope it helps Moose
To: [EMAIL PROTECTED]: [EMAIL PROTECTED]: Fri, 22 Feb 2008 18:16:04 +0000Subject: [canals-list] Re: shot blasting Thanks everyone. I was wondering about cabin and or hull. Practical advice like getting paint on again quickly and no damp conditions help-ful. I'm wondering whether all new boats opt for 2 pot blacking, and if not why not - is it not all it is cracked up to be? What if it gets scratched? Does it mean hull blacking every 4 years instread of every two? How about treating again - does it need shotblasting every time?For cabin etc, is shot blasting generally as efficient as working for a lot longer by hand?Cantoris _________________________________________________________________ Get Hotmail on your mobile, text MSN to 63463! http://mobile.uk.msn.com/pc/mail.aspx [Non-text portions of this message have been removed]
