Carvel iroko hull built 1968 Limpetite sheathed now requires removal to bare wood of build up of anti-fouling etc from below water line.Burning off is prohibited in my lay-up yard. Is sand blasting a sensible option?
I had my clinker wooden hull blasted using the Farrow System to very good effect. The operator, now out of business, knew his stuff and it did not cost an arm and a leg. Try a search for "Farrow Systems" on google; I know that they still advertise in PBO magazines.
Blasting can raise the grain of the wood or leave it a bit "wooly". It will also tend to blow away any filler. Are the yard going to allow blasting if they don't allow burning off ?
Many thanks for all responses. My concern is as much with the caulking as with the grain lifting. Does anyone have actual experience of being sand blasted? And if caulking is gauged out what are my options?
Hi
I actually do it, yes you can use softer media but it will take a deal longer, plus the stuff costs more, more time equals more money. Try asking for a trial blast to see what you get, there maybe a regular blaster on the yard. One of the pluses is that it clears everything away so you can see exactly what you need to do.
Burning off antifouling paint is banned because it has a strong effect on the operator, varying between seriously poisoned and death. Don't even think of going there! I'd recommend some form of mechanical removal, possibly belt sander or hand scraper. I use the latter.
Peter.
I saw a professional gang of shipwrights using a piece of old van or truck leaf spring as a scraper. There was a sharp 90 deg plus bend in it which was possibly the original shape of the spring. It was used by dragging the sharpened end across the planking.
Looks as though scraping is my only option. My pull out yard forbids bottom burning off or use of heat gun due toxic fumes. Their quote was £1, 700 for blasting (payable in advance) subject to various conditions: far too much for an OAP.
Teak hull - much the same as iroko I would think. The effect was marked. I would not choose to do it again.
Using a hot air gun or a blowlamp is not much fun because apart from the toxic fumes issue most antifoulings are chorinated rubber based and these do not burn off readily - they tend to melt, fuse together and block the scraper.
I did it again four years ago by hand scraping with a Sandvik scraper and this was surprisingly effective. I did wear a decent mask. I was able to get the antifouling off without damaging the primer (four coats of Blakes' grey). I reckon you could probably do the same and save the Limpetite. Worth a try on a patch, anyway.
altho Removall 610 is designed for GRP susbstrate, the company make a variety of other products for paint removal, and i wd definitely use google to find local supplier, ask them and test a small area before using somethying aggressive like blasting. The products don't use acid to lift the paint but nonetheless it is left floppy and easily removed by a scraper after aplication and leaving overnight. Two of us stripped 5 layers and then compeletly cleaned a 76 foot (grp) boat in under 24 hours including sleeeping whilst the removall did its stuff.
Many thanks to all who have replied. I have now transferred my affections to a more accomodating yard, wooden boat friendly. Burning or heat gun now possibilities. This is Solent based, a pp will divulge name. Still options: do I burn or scrape?
With a wooden hull, hard antifouling, access issues and the toxicity of antifouling in general, I use the sandvik (Bahco) 50mm two handed scraper. I make it the first job on hauling whilst the paint is potentially softer. One hard w/e does a 26' hull. I get through three blades each winter on the principle that it is less work and gives a better finish. Tried one blade, gets very frustrating about half way through. Sanding is a no no for the sake of health and the sheer number of disks it eats. Good mask, overalls, hat and goggles essential. Despite being fully covered, when finished I have the urge to fight General Custer. I have to lie under my boat and work through the trailer for access. I would consider chemicals but it creates a bigger waste disposal issue not to mention being covered in sludge as it is removed. The scraper with practice is capable of producing a finish which needs minimal further flatting. Currently looking with envy at the adverts for an electric scraper, cannot be that good........can it?
It was the sleeping bit that I found the easiest when using the removall /forums/images/graemlins/laugh.gif Seriously, it was surprisingly effective and fast, although the fastest way to clear the residue was the power washer. Good thing about the material was that water neutralised the removall.
Another option that has been covered in PBO was a dry ice blast. The big advantage is that you dont have any of the blasting media left at the job site!
If your yacht is in the solent area, there is now a "Farrow System" operator that covers the central south coast. Their site is www.tephratech.co.uk
Give them a try, the system certainly works very well.
Sandblasting is good PROVIDED you have someone good to do it and who has done it before (ask for references). Obviously try a bit first to check that you are happy with the finish. Be prepared to coat quite soon after blasting as the wood can dry out quite quickly. Epoxy tar is very good & still available from Blakes/Hempel when I last tried.
Good Luck