How to remove hull paint from bottom of a fibergalss sail boat, plus a few general questions finish restore?

Question

I recently purchased a sailboat that was kept in the water at one time. I dry dock the boat. I have been considering removing the bottom paint all together to bring the hull it back to its original condition.

A few questions in I think hardest to easiest order -

1. Should I even waste my time?

2. How to remove the paint.

3. While we are here, how do you repair cracks in the fiberglass - I think they are called spider cracks - not deep, not big. I tied my boat off to a larger boat and I think the waves cracked the gelcoat a bit.

4. How to repair pits in the fiberglass (they could be called chips)

5. How to repair bubbling of the fiberglass. There are a few areas where a bubble is starting to form. The bubble is about 2 mm if that.

6. How to restore the chalky look to its original shine?

Thanks in advance!

Answer 1

2 ways to remove the paint. With chemicals or by blasting. There are companies that will remove the paint with soda blasting and some with sand blasting. A good job will leave the finish a little rough and ready for the first coat of paint. You could use paint remover but thats a mess. There is a company that has a product you put on and cover in paper and then peel away. That might be the name of it also. Peel Away. Blasting is more expensive but works tha best.

You do not have to re gelcoat the boat. Cracks and chips can be spot repaired, if you want it looking mint then have a pro do it. If you want go to a marine supply store and get gelcoat repair mix. It comes in a tube and you can match the color. To bring back the shine get 3M Fiberglass Restorer Wax and follow the directions. Its great stuff.

Its all up to you how far you go with a boat. If you want it looking mint then do the above work. However you may never get the investment back.

Answer 2

1 you must clean area down to glass,because gelcoat(paint) and resin will not stick.Use an electric right angle grinder with a flapper disk. This will cut the grinding time in half.Use a good quality resin and cloth in repair.If you are doing layers sand with 80 grit between layers for best possible bonding.

For chalky look wash boat first then use a fiberglass resin polish.

Answer 3

You should be able to hire a jetwash unit from your local hire shop. Get one with a gritblast attachment that introduces grit or sand into the water stream under fairly high pressure.

This will efficiently remove several layers of paint and crud and will open up any blisters if present.

   It makes a horrendous mess and you need to wear suitable protective clothing, but is a reasonably cheap and quick option.

Open up any fine cracks with a Dremel or similar tool and fill with gel coat filler. Sand down with fine wet and dry paper when cured and polish.

  Small areas of bubbling are probably best just washed and filled after opening them up.

  Chalky gelcoats usually respond to polish and elbow grease, unless deeply scored, in which case you may have to paint.

Enjoy!

Nigel

Answer 4

1. Should I even waste my time?

A:  No - just scrape and sand to a level you are happy with.   The bottom is in the water anyways.  You will slightly better performance out of an absolutley smooth bottom.  The only reason to go all the way down to the bare hull, is if you choose a new type of bottom paint that is inconsistent with the kind already on there.  It's important to make sure the type of bottom paint is consistent with what is already on there.   West Marine has a great chart in the catalog which will tell you what can be used with what.

2. How to remove the paint.  

A:  As said above, scrape and sand unless you really want to get back to the original hull, then you will likely need some chemical paint removers.   It's likely that if you sand off all the existing paint, you will have damaged the old gelcoat to the point, where you might need to add more gelcoat before repainting.   Make sure you clean well before repainting.

3. While we are here, how do you repair cracks in the fiberglass - I think they are called spider cracks - not deep, not big. I tied my boat off to a larger boat and I think the waves cracked the gelcoat a bit.

A:  There are several products out there.  I use epoxy resin mixed with a filler.  You can purcahse different density fillers depnding on how thick you need the repair material.  You can go very thin for cracks.  Sand lightly.  Repeat if necessary.  

4. How to repair pits in the fiberglass (they could be called chips)

A.   Scrape and clean well.  Mix a larger filler in with your resin.   Fill the chip and level with a plastic puddy scraper.  I like the slightly flexible ones you can get at the automotive stores.   Sand afterwwards and repeat if necessary.  It's really important you have a clean surface.  Hint:  Sand just after it cures.  Expoxy resin will get even harder after a few days and it's much easier to sand just after it cures.

5. How to repair bubbling of the fiberglass. There are a few areas where a bubble is starting to form. The bubble is about 2 mm if that.

A:  Bubbles or Blisters are caused when a little bit of water gets between the layers of fiberglass and causes them to delaminate.    Chisel out the blister and let it dry out for a long time - i.e out of season, not just overnight.   It's imporant to chisel out all the rotten, weak fiberglass or teh problem will continue.    Depending on the damage, you may end up wiht a divit much larger than the original blister.   Repair in the same fashion as the the chip you mentioned above.    If you choose not to repair the blister, keep an eye on them to see if they get worse.  If they do, you definately want to take care of it before you run into serious delamination problems.  Some boats get a few small blister's but they don't get worse with time and are not a structural concern, but blister's can also potentially lead to serious problems.

6. How to restore the chalky look to its original shine?

A:   Depening on how bad it is, you may see improvements with a light sanding and chemical referbishers as mentined in other answers, but most old sailboats get painted at this point.  

Last thought:

I had my previous boat stored in a boat yard in Florida.   Upon arrival, I repainted the bottom which took about half a day as well as the sidewalls which took a another day and a half.   It was fast, functional improvement which looked reasonble, but didn't have that immaculate shiny refurbished look.  The guy working on the boat next to me explained how with 10 or so layers with lots of sanding in between you can get shiny deep looking new look.  I declined and left the next day for a month of sailing in the Bahamas.  When I returned, he was just finishing up his paint job.  It looked amazing.    He had an incrdible looking paint job after a month's work.  I had a reasonable paint job and a month of Bahamas sailing.   What's your priority?

Answer 5

The Fiberglass Boat Repair Manual

By   Allan H. Vaitses

Date   October 1, 1988

Format   Hardback, 192 pages

ISBN    0071569146 / 9780071569149

+ More Information

Edition Number 1

LanguageEnglish

AudienceCollege/higher education

ImprintInternational Marine/Ragged Mountain Press

PublisherMcGraw-Hill

CountryUnited States

Copyright1989

Dimensions6.9 in Width x 0.71 in Thick

Weight0.882 lb

DOI10.1036/0071569146



Your Price

$29.95

Overview

"This book will save you money and grief before you can say woven roving."--Sailing

"A comprehensive and accurate work that should benefit almost any owner of a fiberglass boat."--SAIL

"This book will prove a valuable addition to the library of any boat builder or owner who is seriously interested in doing his own repairs, as well as intercepting minor problems before they become major projects."--Boatbuilder

Are there hairline cracks in your boat's deck or topsides gelcoat? Have her color and luster faded over the years? Does she have deck leaks? Has she been holed? Is her hull oilcanning in a sea? If your answer to any of these questions is yes, this book is for you. This is the definitive guide for fiberglass boat repair and beautification, covering not just cosmetic dings and scratches, but also major repairs of structural damage to hull and decks. It will show you how to:

replace deteriorated gelcoat, or repair the flaws in an existing gelcoat and recoat it with polyurethane or marine alkyd enamel paint;

strengthen a weak and overly flexible hull or deck;

tab in loose hull liners and joinerwork;

make templates from the good side of a hull to reshape large shattered or missing areas on the other side;

repair or replace water-saturated deck cores;

repair keels, rudders, and centerboards;

rebed and refasten underwater and on-deck hardware;

rebed, refasten, and strengthen hull-to-deck joints;

fix broken hatches, and make new ones when necessary;

treat the symptoms and causes of overstressed hulls.

That beautiful craft swinging at anchor or nestled dockside, her topsides reflecting water and sky like a polished mirror, could be yours. Here's how.

Table of contents

Preface

Acknowledgments

1 Materials and Construction

What fiberglass is; Boatbuilding resins; Resin products: glues and putties; The glass fiber materials; Constructing the fiberglass boat; Gelcoat and paint finishes; Interior parts; Other fiberglass parts

2 Restoring the Surface Finish

Gelcoat dullness and fading; Scratches, dings, and breakouts; Gelcoat cracks that won't stay puttied; Bubbles, blisters, and boat pox; Regelcoating versus repainting fiberglass

3 The Art of Fiberglassing

Gelcoating; Hand lay-up; Laying up core materials; Repairing or applying reinforcements; Tabbing parts to hull and deck

4 Fractures, Small Holes, Delaminations

Grinding and Cutting; Rebuilding; Patching cored construction; Delamination

5 Dealing with Core Problems

Saturation--an introduction to the problem; Confined and accessible area of deck saturation; Total deck saturation; Core saturation in hulls; Crushable cores

6 Rebuilding Large Holes and Shattered Areas

Is she worth repairing?; Salvaging the boat; Working out a repair schedule; Backing damage with sheet stock; Working the boat back into shape; Backing compound curves; Framing in a missing shape; Taking a mold off another boat of the same model; Making the piece

7 Undercured, Resin-Rich, and Cooked Laminates

Go back to the manufacturer--if possible; How to repair undercore--if you must; Resin-rich and cooked laminates

8 Repairing Keels and Other Underwater Parts

Damage to hollow fiberglass keels; Weeps around metal hardware; Fixing fin keels and separate skegs; Damage to interior reinforcing members; Lead-ballasted fin keels; Bolted-on iron fin keels; Centerboards and centerboard trunks; Repairing the centerboard case; Rudders and skegs

9 Troubles on Deck

Leaks around fittings; Leaks around deck joints, rails, and railcaps; More about leaks; Hatches and portlights: leaks, fractures, and other troubles; Treating the overstressed boat

Index

Review quote

``The aroma of resin wafting out of this manual is refreshing. This book will save you money and grief before you can say woven roving.''

Review quote

``The definitive book on cosmetic repairs, as well as major structural repairs to hulls and decks, delamination, refinishing, blistering, etc.''

Biographical note

A resident of Mattapoisett, Massachusetts, Allan Vaitses retired from full-time boatbuilding in the early 1980s after a 45-year career, including 30 years building custom and semicustom fiberglass boats. In his second career as a marine surveyor (a profession he still pursues), Vaitses has witnessed just about every flaw and form of damage or deterioration a fiberglass boat can suffer. In his third career as a writer, Vaitses has imparted his knowledge of boatbuilding, troubleshooting, and repair through such books as Lofting, Covering Wooden Boats With Fiberglass, Boatbuilding One-Off in Fiberglass, and What Shape Is She In? A Guide to the Surveying of Boats.

Answer 6

I would take the time to take the paint off of the bottom if there are Jel Coat blisters showing.  These blisters will only get worse and might possibly spread deeper into the hull.  I used to work on boats and we had the last boat bead blasted down to the original surface.  It is recommended to look for all signs of water or resin weeping out of the hull.  After the paint is removed,  open up the blisters and let them drain.  The fluid might be red.  After they dry out carefully grind into the boat and just remove the infected area until there is no  evidence of the blister.  Fill it with fiberglass repair and sand it smoothly.  The only answer that I have heard of to stop the Gel Coat blisters is to paint the bottom with epoxy to seal it from any water source.  I would not under any circustances remove the paint from the bottom and leave it.  You have an advantage that it it is not in the water all of the time.  To restore the gel coat above the water line you can wash it and spend probably forever trying to bring it back.  Once you start putting any heavy fiberglass compounds on the glass work you will have to wax the hull frequently to keep the hull protected.  You are removing possibly several layers of gel coat to get at the shine.  Waxing is the only way to keep it safe.  I found that lots of clean rags really help the job go faster.  If the rag gets dirty and you don't change it you will just move the dirt over the whole boat and it doesn't get the desired effect.  Sometimes you can't get the boat back to this condition and it will require repainting.

Answer 7

I have an answer to restoring the chalky look to original. I bought a 1970 2+2 2 years ago that is Mariner Green. It was chalky and kind flat looking. After reading posts to the O'Day owners forum I orderred Poly Glo. A 2 step process simple to use and not expensive. $69.00 for enough for about 2 more years. It is easy to use and the result is unbelievable and it has been moored for this full season and still looks great.

Answer 8

If your fiberglas hull has been painted, it might be a lot of work to remove that without wrecking the gelcoat. It is more likely that the color is part of the product and covered by the gelcoat.

There are guys who can restore these and that will usually involve spraying on a new gelcoat to fill the cracks and eliminate teh chalky look. You would repair the bubble first.

If it does not leak and sails good, you might just want to wait a year.