Prepping Iron Keels - SailNet Community
LinkBack Thread Tools
post #1 of 1 Old 08-28-2000 Thread Starter
Contributing Authors
Join Date: Jan 2000
Posts: 266
Thanks: 0
Thanked 12 Times in 8 Posts
Rep Power: 18
Prepping Iron Keels

When you're painting the bottom, just how "fair" is "fair enough?" I’m getting ready to paint the bottom of my 1970 Ericson 23, but there is some rust on its cast-iron keel that is not sanding out easily. How smooth does the surface need to be before I use a filler and before I paint?

Tom Wood responds:

There is no question that a buffed racing bottom is faster than a traditional, rolled-on, and somewhat lumpy cruising paint job. But not many of us want the attendant prep and finish work required to get a perfectly fair bottom job, and a few brush marks, deep scratches, and roller stipple marks are only going to slow the boat a few tenths of a knot anyway. I've seen boats with bottoms cratered very much like the moon's surface that seem to sail along very well, especially when the breeze is up. I suspect that their light air performance suffers, though.

Cast iron keels present a more difficult challenge. As the fairing compound or other coating begins to fail, they will bubble up in large blisters of rust that sloughs off even fresh paint. These rust spots only get worse with age. So, once in a while it is necessary to use a very aggressive metal grinder (a metal grinding disc on a large angle grinder is not too much) to cut these pockets of rust back to bare iron, then immediately etch the bare metal and prime with a metal primer. Once this is done, fairing with epoxy putty will provide a smooth surface for the final coats of bottom paint. This treatment, if done properly, will last quite a long time before another pocket of rust pox breaks out in the same area—but it may break out somewhere else next year. So keep the grinder in the dockbox and at each bottom job make the compromise between the work involved and the fairness of the finished job.


Tom Wood is offline  
Closed Thread

Quick Reply

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Posting Rules  
You may not post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is Off
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome