Polishing the Hull

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Excellent tutorial here Hull Polishing tutorial

Summary of Yahoo Group Discussions on Hull Cleaning Feb 2012

Problem: "I need to clean and polish the hull of my boat and would be grateful for any recommendations for a good cleaner. Is it possible to buy polishing/cleaning pads (other than lambs wool covers) for an angle grinder to apply the cleaner "

Replies on type of Polishing Machine to use:

"I wouldn't use an angle grinder… much too fast."

"A slow speed polisher is not ridiculously expensive, though. You can often find them on offer."

"We bought a Clarke sander polisher from machine mart for approx £80 which is excellent and has variable speed. Even that I don't use above about half speed otherwise it just sprays the universe with polishing compound."

Replies on what to Polish with:

"Sanding papers are to my mind not a good idea" "We used Farecla polishing paste which comes in two (or more?) grades. I think we used G3 which is quick, cleans well and still gave a good enough polish for what we want. "


"My bodywork repair tenant swears by the 3M Fast Cut product. I think I paid about 20 quid for a large bottle"

Other cleaning (prior to polishing) suggestions: "Starbrite hull cleaner removes the yellow waterline staining. No rubbing; just apply, leave and rinse off."

"Sugar soap, the old decorator's standby"

"AutoGlym's engine cleaner"

"Cif cream (Jif as it used to be known)."

"We find oven cleaner is excellent for cleaning waterlines and hulls which are oily/tarry "

Polishing a Fulmar Hull

Most white gel coats can become stained over time. Initial treatment with an Oxalic Acid based product like Y10 will give good results. This will remove any staining, but not restore a shine to the oxidised gel coat. For a perfect polished finish, the gel coat will still need to be compounded. It sounds daunting, but the difference can be amazing. A polishing machine should be used with foam pads and cutting compound comes in various grades. The process involves keeping the pad and hull damp with water (use a plant spray) and apply the coarsest compound first. Work an area of the top sides about 500mm wide. A stable trestle table is the best platform to work on as some effort can then be put on the polishing machine. Whilst working is it wise to have goggles on to protect your eyes and old clothes as the compound can easily be sprayed.

Using Cutting Compound
                                            Use a Trestle able for support
                                                 Nice Shine!

Once the coarse compounding has been completed, then a finer compound will put a better shine on the hull, before finally a sealing coat of wax is applied. Expect each application to take a day, so allow 3 to 4 days for a 10m boat. Gel coat is generally about 2 to 4 mm thick, so do not worry about cutting through the protective gel coat to the glass fibre layers below. A good online guide can be found here [1] Look under Fibreglass Projects and then Polishing guide.

Restoring painted gel coat to original shine. The transom of my Fulmar was painted red when I purchased her and I decided to sand it all off. I found there were 5 different colours of red paint applied. Everyone thought I was mad as I could just paint it white. The final result was dazzling and the doubters were converted. I started using a Fein multi-tool with 80 grit sanding discs, reducing to 400 grit, followed by coarse and fine compounding, then polish. How Concerto looked when purchased,



Half way
                                                                  Nearly all sanded off!

                                                                  Finally polished. 


                                                  With the colour scheme finally finished and fully antifouled.

Presentation to ECG May 2020

Presentation in both Powerpoint and PDF.

File:Gel coat renovation Powerpoint 19May2020.pptx

File:Gel coat renovation 19May2020.pdf