Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 06-07-2007, 12:06   #1
Registered User

Join Date: May 2007
Posts: 96
Have I just ruined my boat ?

Yesterday I sanded the hull of my 12m wooden boat. I am new to boat repair as this is my first boat.

Everything seemed to be going well - I used my grinder with the sanding disc attachment and a no. 50 sanding disc (well 10 of them).

It was only when I was putting on the primer coat that I realised that the surface is covered with flat "facets" rather than being a nice smooth convex shape.

I finished putting on the primer coat as I wanted it protected from the sun and heat ( here in fethiye, Turkey it is 48 C ).

So, I think that I have just discovered that there is more to sanding a boat that I thought !

Can this be "fixed" ? Should I hire someone to re-sand the boat to get back the nice shape - is that called fairing ?

I'd appreciate your comments and help, I am feeling a bit low !
Thanks.
__________________

__________________
Dave-Fethiye is offline   Reply With Quote
Old 06-07-2007, 12:16   #2
Provocateur & Raconteur
 
knottybuoyz's Avatar

Cruisers Forum Supporter

Join Date: Nov 2005
Location: Iroquois, Ontario
Boat: Bateau.com TW31 Modified
Posts: 3,583
Images: 87
What you need to get/make is a "long board". It'll look something like this.



You use long sheets of sandpaper and make long strokes (elbow grease required). This will help you fair out the flat spots left by the circular sander. You can probably make your own out of a pice of 1/4" ply and a couple of old doorknobs. 3M77 adhesive works well to hold the sandpaper on. Make it as long as you can comfortably use because the longer the better.

There are pneumatic versions as well.

__________________

__________________
Yours Aye! Rick
~^~^~^^~^~^~^~^~^~^~^~~^~^~~^~^~^^~~^~^
"It's not the boat "you built" until you've sworn at it, bled on it, sweated over it, cried beside it and then threatened to haul the POS outside and burn it!"
knottybuoyz is offline   Reply With Quote
Old 06-07-2007, 12:18   #3
Senior Cruiser
 
SkiprJohn's Avatar

Cruisers Forum Supporter

Join Date: May 2006
Location: Kea'au, Big Island, Hawaii
Boat: Cascade, Sloop, 42 - "Casual"
Posts: 14,192
Aloha Dave,
Yes, its called fairing. Many boats have the facets you have talked about because owners use what you did to sand their boats. A more appropriate tool would be your sander/grinder with an 8" soft pad and 120 to 150 grit to get rid of old paint.
At this point a long flexible board with a long piece of sandpaper from a belt sander glued to the bottom might take most of the wows out if they are not too pronounced. If they are really bad then you might want to use filler and then the long board (fairing).
Send us a photo and some other folks might have another suggestion.
Kind Regards,
JohnL
__________________
SkiprJohn is offline   Reply With Quote
Old 06-07-2007, 12:20   #4
Senior Cruiser
 
SkiprJohn's Avatar

Cruisers Forum Supporter

Join Date: May 2006
Location: Kea'au, Big Island, Hawaii
Boat: Cascade, Sloop, 42 - "Casual"
Posts: 14,192
Rick, You beat me by two minutes.
Dave, Make certain the board flexes to the contour of the hull.
JohnL
__________________
SkiprJohn is offline   Reply With Quote
Old 06-07-2007, 14:07   #5
Senior Cruiser
 
roverhi's Avatar

Cruisers Forum Supporter

Join Date: Aug 2005
Location: Kona, Hawaii, Carlsbad, CA
Boat: 1969 Pearson 35 #108 & 1976 Sabre 28
Posts: 6,003
Send a message via Yahoo to roverhi
Never ever use a grinder with the hard rubber pad on anything you want/have to look at afterwards. If you must use a grinder, and I do a lot, get the 8" or so foam rubber pads, that replace the hard rubber pad, to which you glue a sheet of sand paper. The foam pad allows you to run the sanding disk parallel/flat on the surface and floats over irregularities sanding down the highs and leaving the lows. It's relatively easily to get a smooth even surface and take off a lot of material quickly. It is possible to gouge but you have to be pretty ham fisted to do it with the foam pads.

FWIW, I've also glued an 8 1/2" plywood disk to the foam pad and glue the sand paper to the plywood. On flat surfaces, this works like a drum sander/planer, and about $500-$2,000 cheaper than buying one of those expensive tools.

One last thing, get a grinder that turns at 3,000 rpm or less. They are usually advertised as sander/polishers at that rpm. The lower rpm won't burn and melt FRP as you sand and are a lot more forgiving of inattention on any material.

Aloha
Peter O.
__________________
roverhi is offline   Reply With Quote
Old 06-07-2007, 14:20   #6
Senior Cruiser
 
Alan Wheeler's Avatar

Cruisers Forum Supporter

Join Date: Dec 2003
Location: Marlborough Sounds. New Zealand
Boat: Hartley Tahitian 45ft. Leisure Lady
Posts: 8,038
Images: 102
Dave, don't panic as yet. You are only half way there with your process. At thi point, the next easiest step to take is to use a high build undercoat. You then long board this to smooth off the surface and contour it. If the hull were Glass, you would use fairing compound, but it really isn't neccessary with timber. So you paint it on, sand it off with a long board and paint on some more and repeat till you get the smootness you want to achieve. If the hollows are very deep, then a fairing compound maybe your best bet for extra high building of the hollows. But no, you haven't ruined the hull. It's long hard work and one major reason why you want to use a very good paint system that lasts. It may cost more, but you only want to do this as least often as you can.
__________________
Wheels

For God so loved the world..........He didn't send a committee.
Alan Wheeler is offline   Reply With Quote
Old 06-07-2007, 16:58   #7
Moderator
 
Boracay's Avatar

Cruisers Forum Supporter

Join Date: Feb 2004
Location: Pelican Bay, Great Sandy National Park
Boat: Steel Roberts Offshore 44
Posts: 5,175
Images: 18
Do yo want a seaworthy boat or a work of art?

Bringing a boat into perfect condition is a much overrated pastime.

If I understand your previous posts this is not an expensive boat.

If you are mainly interested in getting the boat into seaworthy condition then there is no need to fair and smooth the hull. In fact excessive fairing could take too much off the planks.

Water flow along the hull will be very little different.

The rough surface left by the grinder should give a good key for the paint.

I would suggest a light sand (course paper, ideally used lightly by hand with a rubber backed sanding block) after each coat ( but not on the final coat).

Using high build paints will give a good paint thickness.
__________________
Rust never sleeps
Boracay Blog.
Boracay is offline   Reply With Quote
Old 06-07-2007, 18:53   #8
Senior Cruiser
 
44'cruisingcat's Avatar

Cruisers Forum Supporter

Join Date: Sep 2006
Posts: 7,453
Images: 69
If you want to get it fair, than as has been said, a longboard is the way to go. The longer the better too - if you can get someone to help you with it, make a two-man board. There's a builder in Brisbane who has a 3 man board!
__________________
44'cruisingcat is offline   Reply With Quote
Old 06-07-2007, 19:53   #9
Senior Cruiser

Cruisers Forum Supporter

Join Date: Mar 2006
Location: Whangaparaoa,NZ
Boat: 63 ft John Spencer Schooner
Posts: 956
I was tlking to a professional last week who is facing longboarding a 100' mega yot. They are using six foot torture boards.
__________________
dana-tenacity is offline   Reply With Quote
Old 06-07-2007, 19:59   #10
Registered User
 
cat man do's Avatar

Join Date: Aug 2006
Location: Brisbane Australia [until the boats launched]
Boat: 50ft powercat, light,long and low powered
Posts: 4,409
Images: 36
Quote:
Originally Posted by dana-tenacity
I was tlking to a professional last week who is facing longboarding a 100' mega yot. They are using six foot torture boards.
First 2 year's of my sentence at "Lloyd's Ship's" in the '80's was doing exactly that.

http://newimages.yachtworld.com/1/5/...?1161372769000

Overhead doing deckhead's was especially pleasurable....................NOT.

Don't call 'em torture board's for nothing.

Dave
__________________
"Money can't buy you happiness but it can buy you a yacht large enough to pull up right alongside it"...............David Lee Roth
Long Distance Motorboat Cruising – It Is Possible on a Small Budget
cat man do is offline   Reply With Quote
Old 06-07-2007, 22:08   #11
Senior Cruiser
 
delmarrey's Avatar

Cruisers Forum Supporter

Join Date: Mar 2003
Location: Now in Blaine, WA
Boat: Modified Choate 40
Posts: 10,702
Images: 122
Dave,

Welcome to the school of hard knocks.

If you had a steel boat, all would have went well. But seeing that your boat is well seasoned it doesn't really matter too much. Just chalk it up as experience. It's better to learn your mistakes on a project boat then a new one.

Some of us here have been working on boats for more then 40 years and not using something like a grinder disk would have been common knowledge amongst us.

Myself if I want to take off large quantities of paint I use chemicals and a scraper. Then finish up with a large orbital sander. They won't dig in unless one gets crazy with it.

If anyone notices all the little crescent marks, just tell them it is a textured finish of a Muslim design.
__________________
delmarrey is offline   Reply With Quote
Old 07-07-2007, 00:34   #12
Registered User

Join Date: Nov 2006
Posts: 976
Images: 6
Here is a section of an article on fairing that l wrote recently for the MBS quartely............... Due to the fact that l am going to sand, the wind will have arranged itself to blow in the general direction of my face. That is of course unless l am sanding from underneath, in which case there will be no wind. Donning the usual armour l then do my warm ups, breathing exercises and meditation, for l am about to use “The fairing board”. This diabolic piece of equipment consists of a flexible board about 700 mm long with a handle at each end. Covered on its surly underside is the coarsest grit sand paper your already aching body can handle. (In my case 80 grit.) Mine is made of masonite and the sand paper is attached with contact cement. You then attempt to remove filler in a precise and even manner to your desired level. This is to be blunt; impossible. The tiny amount of dust removed is neatly transferred from the hull to your ears. This has the curious effect of turning your arm muscles to jelly and back into spasms. After absorbing this punishment for a more than reasonable time, the power sanded is brought into action, allowing for a speedy series of uneven bumps and holes to be produced. This in turn requires the process to be repeated from the beginning. .........have fun. ; )
__________________
cooper is offline   Reply With Quote
Old 07-07-2007, 00:37   #13
Registered User
 
cat man do's Avatar

Join Date: Aug 2006
Location: Brisbane Australia [until the boats launched]
Boat: 50ft powercat, light,long and low powered
Posts: 4,409
Images: 36
Quote:
Originally Posted by delmarrey
If anyone notices all the little crescent marks, just tell them it is a textured finish of a Muslim design.
Not that there's anything wrong with Muslim's , eh Del.

Dave
__________________
"Money can't buy you happiness but it can buy you a yacht large enough to pull up right alongside it"...............David Lee Roth
Long Distance Motorboat Cruising – It Is Possible on a Small Budget
cat man do is offline   Reply With Quote
Old 07-07-2007, 00:41   #14
Registered User
 
cat man do's Avatar

Join Date: Aug 2006
Location: Brisbane Australia [until the boats launched]
Boat: 50ft powercat, light,long and low powered
Posts: 4,409
Images: 36
Quote:
Originally Posted by cooper
Here is a section of an article on fairing that l wrote recently for the MBS quartely............... Due to the fact that l am going to sand, the wind will have arranged itself to blow in the general direction of my face. That is of course unless l am sanding from underneath, in which case there will be no wind. Donning the usual armour l then do my warm ups, breathing exercises and meditation, for l am about to use “The fairing board”. This diabolic piece of equipment consists of a flexible board about 700 mm long with a handle at each end. Covered on its surly underside is the coarsest grit sand paper your already aching body can handle. (In my case 80 grit.) Mine is made of masonite and the sand paper is attached with contact cement. You then attempt to remove filler in a precise and even manner to your desired level. This is to be blunt; impossible. The tiny amount of dust removed is neatly transferred from the hull to your ears. This has the curious effect of turning your arm muscles to jelly and back into spasms. After absorbing this punishment for a more than reasonable time, the power sanded is brought into action, allowing for a speedy series of uneven bumps and holes to be produced. This in turn requires the process to be repeated from the beginning. .........have fun. ; )
Pussy,

I thought STANDARD torture board paper was Roadbase, then 36 grit.

80 grit's for fairing the Highbuild.

Oh and Rick, those pic's are short board's, they are long board's when they get to 3 ft plus.

Dave
__________________
"Money can't buy you happiness but it can buy you a yacht large enough to pull up right alongside it"...............David Lee Roth
Long Distance Motorboat Cruising – It Is Possible on a Small Budget
cat man do is offline   Reply With Quote
Old 07-07-2007, 01:52   #15
Senior Cruiser
 
delmarrey's Avatar

Cruisers Forum Supporter

Join Date: Mar 2003
Location: Now in Blaine, WA
Boat: Modified Choate 40
Posts: 10,702
Images: 122
Quote:
Originally Posted by cat man do
Not that there's anything wrong with Muslim's , eh Del.

Dave
I hope you weren't pulling something out of nothing.
__________________

__________________
delmarrey is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

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

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Do Boats Have 'Souls' ? sail_the_stars General Sailing Forum 77 14-11-2010 15:25
Buying a boat nightmare... cchris0411 Multihull Sailboats 31 06-10-2007 23:54
Grifters! (watch out) ssullivan General Sailing Forum 61 14-11-2006 22:19
Changing the Boat's Name sjs General Sailing Forum 4 24-05-2004 08:15



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 00:38.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.