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01-07-2022, 04:42
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#1
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Nearly an old salt
Join Date: Jun 2009
Location: Lefkas Marina ,Greece
Boat: Bavaria 36
Posts: 22,801
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Sandblast or power wire brush , keel
Just wondering , i need to strip some old layers of paint from my iron keel and seal and prime and re anti foul
Should I contract out to have it blasted ( expensive ) or thinking of doing it myself with a power wire brush.
What are the views
What do you guys recommend as the paint process. ?
Thanks
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Interested in smart boat technology, networking and all things tech
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01-07-2022, 19:19
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#2
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Registered User
Join Date: Mar 2011
Location: Southport CT
Boat: Sabre 402
Posts: 2,695
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Re: Sandblast or power wire brush , keel
It's your money. Either way will work. Figure out what paint you're using BEFORE you start. Some of them may call for application immediately to bared metal (to slow rust), or for a primer layer first.
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01-07-2022, 20:50
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#3
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Registered User
Join Date: Dec 2019
Posts: 486
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Re: Sandblast or power wire brush , keel
I would use a heat gun and scraper first to remove the bulk of the old paint layers. You can also try a needle gun which works ok on thick paint. A wire wheel should work fine but they can still be prone to clogging, use a course wire brush. Another alternative is a 7" buff/sander with course disk's, still cloggs up but easy to change disk's. 3M also make paint removal pads for them that work well. Go at a slower speed so as not to melt the paint too much with either method.
My go-to for bare steel is a zinc primer then whatever epoxy paint system you prefer. If you can't get it all back to bright steel then phosphoric acid can help get into the pits of the casting.
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01-07-2022, 22:00
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#4
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Marine Service Provider
Join Date: Sep 2014
Location: Auckland, NZ
Boat: Compass 790 , 7.9 metres or 26 ft
Posts: 2,803
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Re: Sandblast or power wire brush , keel
I'd recommend epoxy coal tar paint for yr primer if you can get it. Do not use zinc primer underwater as you risk bubbling is my tip. Had good results with Ameron epoxy topcoat but you need lots of coats. I cleaned steel with an angle grinder using a pipeliner type wire brush,17years no rust on steel keel except where we struck rocks .
Agree phosphoric acid treatment good too. We arent allowed any sandblasting on club slipway.
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02-07-2022, 07:39
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#5
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Nearly an old salt
Join Date: Jun 2009
Location: Lefkas Marina ,Greece
Boat: Bavaria 36
Posts: 22,801
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Sandblast or power wire brush , keel
Thanks , what time should I allow for a 36 footer standard 1.6 m keel. I’ll probably coarse power wire brush as my yard has a dedicated sand blast area and I want to avoid multiple yard movements.
I’ll research with the chandleries what paint options I have
I’ll have to see if I can get phosphoric acid locally , I have 5l at home but that’s 2000km away !!!!
__________________
Interested in smart boat technology, networking and all things tech
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02-07-2022, 07:47
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#6
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always in motion is the future
Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 18,757
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Re: Sandblast or power wire brush , keel
Try a “stripper wheel” on an angle grinder.
__________________
“It’s a trap!” - Admiral Ackbar.
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02-07-2022, 07:58
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#7
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Nearly an old salt
Join Date: Jun 2009
Location: Lefkas Marina ,Greece
Boat: Bavaria 36
Posts: 22,801
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Re: Sandblast or power wire brush , keel
Quote:
Originally Posted by s/v Jedi
Try a “stripper wheel” on an angle grinder.
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What’s that look like
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Interested in smart boat technology, networking and all things tech
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02-07-2022, 08:28
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#8
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always in motion is the future
Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 18,757
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Re: Sandblast or power wire brush , keel
Quote:
Originally Posted by goboatingnow
What’s that look like
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I recommend to get them for an angle grinder but this video shows the difference well:
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“It’s a trap!” - Admiral Ackbar.
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02-07-2022, 16:16
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#9
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Registered User
Join Date: Jan 2016
Location: Portsmouth, UK
Boat: Westerly Conway 36ft
Posts: 961
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Re: Sandblast or power wire brush , keel
Brilliant. Thanks.
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02-07-2022, 16:55
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#10
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always in motion is the future
Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 18,757
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Re: Sandblast or power wire brush , keel
I once had 700 small blisters in old polyester based coppercoat… I ground them all out by hand and the stripper wheels were the easiest tool to use.
__________________
“It’s a trap!” - Admiral Ackbar.
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02-07-2022, 17:29
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#11
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Registered User
Join Date: Mar 2022
Location: Ontario Canada
Boat: Jeanneau SO 389
Posts: 1,969
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Re: Sandblast or power wire brush , keel
If you are allowed sand blast it yourself , blast it yourself. You can rent the gear. I’d like to understand this keel do you have photos. It’s fibreglass over iron or raw iron coated. You’d be surprised how well steam wand will reduce stripping time. If you have dry pits in the glass working weak structure with grinder or rotary anything can quickly cause damage. May be better to use a Vinylester waxed gel coat. Or System west and then gel.
Don’t use bottom paint with tin or copper on any underwater gear including water pick ups
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02-07-2022, 18:20
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#12
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Moderator
Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 21,134
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Re: Sandblast or power wire brush , keel
Quote:
Don’t use bottom paint with tin or copper on any underwater gear including water pick ups
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Huh? And why not?
Jim
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Jim and Ann s/v Insatiable II, lying Port Cygnet Tasmania once again.
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02-07-2022, 19:30
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#13
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Registered User
Join Date: Mar 2022
Location: Ontario Canada
Boat: Jeanneau SO 389
Posts: 1,969
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Re: Sandblast or power wire brush , keel
Cause Yamaha Mercury Yanmar say so.
The paint for bottom gear has Neither Tin or copper and it will turn the aluminum into the sacrificial anode.
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02-07-2022, 19:41
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#14
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Registered User
Join Date: May 2010
Location: Sydney Australia
Boat: Fisher pilothouse sloop 32'
Posts: 3,413
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Re: Sandblast or power wire brush , keel
Quote:
Originally Posted by Rumrace
Cause Yamaha Mercury Yanmar say so.
The paint for bottom gear has Neither Tin or copper and it will turn the aluminum into the sacrificial anode.
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Perhaps you are not aware that most running gear is either stainless steel or one of the bronze's or a combination thereof, all just fine with copper based antifoul products. Tin based product has been banned for years now in most parts of the world.The page you referred to addresses the problem of aluminium drive legs, not anything else.
__________________
Rob aka Uncle Bob Sydney Australia.
Life is 10% the cards you are dealt, 90% how you play em
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02-07-2022, 19:42
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#15
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Registered User
Join Date: Mar 2022
Location: Ontario Canada
Boat: Jeanneau SO 389
Posts: 1,969
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Re: Sandblast or power wire brush , keel
Even a concentration of 1 ppm copper ion solution is known to perform serious corrosion on the aluminium surface. The metals that can cause deposition corrosion of aluminium are referred to as 'heavy metals'. Some important heavy metals are copper, mercury, tin, nickel, and lead.May 20, 2020
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