Bottom Paint Removal

In fall 2004, my initiation into boat ownership began by sanding bottom paint off a Cape Dory Typhoon.

Fall 2004 - backyard bottom job on 2nd Chance. 

Blisters filled and bottom paint gone... time for some barrier coat.

She made the road trip to FL in a fresh application of barrier coat.

Since then I have spent many days driving orbital sanders and disk grinders in pursuit of a bare hull.  Determined there must be a better way…  I researched chemical strippers.  These all appeared fraught with a new realm of mess and hazards.  Soda or sandblasting appears to be a good alternative, but hiring out the job ran against my DIY grain.  I could find no one was willing to load out the extensive and expensive blasting machines. 

A friend of ours in Beaufort with decades more boat experience than I suggested using a very sharp chisel or scraper (Thanks TD).  I recalled a recent Practical Sailor Article (“Digging Into Bottom Paint Removal” March 2014) that also favored using a very sharp scraping device.

With nothing to lose, I collected an assortment of impliments. After some experimentation with chisels, putty knives, paint scrapers, etc.  I found my weapon of choice to be a stiff, 3” wide scraper with a 20⁰ angle in the blade.

Permanently stained bottom paint blue from the task. 

The model I settled on was purchased from Lowes Hardware.  The business end must be sharpened to a knife-like edge and this edge maintained frequently during the removal process.  I set up a sharpening station with a bench grinder and whetstone just outside the tented hull.  A little time behind the scraper and it will be obvious when the tool begins to lose its edge.

The layers of bottom paint come off the hull in large (pea to dime size on Pilgrim) flakes rather than the fine dust generated by sanding or grinding.  Care must be taken to avoid gouging into the substrate below the bottom paint.  

Working in approximately four foot wide strips vertically along the hull, I used the blade to remove the bulk of the bottom paint.  I then revisited the area with 80 grit paper on an orbital sander.

I am a convert to the use of a scraper for removing bottom paint.

Tinted blue and sweating despite the comfortable March temps. 

It took me eight hours split over two days to remove the remaining bottom paint from Pilgrim’s hull.  The job is still a messy, taxing affair that requires every effort to avoid contact with bottom paint.  I don disposable coveralls, a cotton balaclava, a 3M full face mask with particle filters, and heavy duty rubber gloves for the job. 

Looking down the exposed hull.

I am pleased the task of removing Pilgrim’s bottom paint is complete.  We can now move forward with repairing 38 newly uncovered blisters… to be continued.

For more images and notes from this project check out our Bottom Job Photo Album.