Preparing Bottom for Paint

Discussions about Cape Dory, Intrepid and Robinhood sailboats and how we use them. Got questions? Have answers? Provide them here.

Moderator: Jim Walsh

Post Reply
Bill

Preparing Bottom for Paint

Post by Bill »

Hello to all

I think the subject of sand blasting the bottom of a boat as opposed to sanding it has been discussed here, but if not I'll ask! Yesterday I witnessed a marina worker blasting a boat bottom with a mixture of fine sand (#4) and water at fairly low pressure. The boat is an older (70's vintage) and the bottom (and boat to for that matter) is in pretty sad shape. It sure made the old paint come off easily, but what did it do to the gelcoat? I dont have the experience to tell if it did amy damage in light of the condition of the boat.

Since Rhapsody will be getting a new bottom job following this season, I guess I am looking at all the options (read not looking forward to sanding) for bottom prep.

Any opinions?????

Thanks & fair winds!

See you in Niantic.

Bill



cd25d@rhapsodysails.com
sloopjohnl

Re: Preparing Bottom for Paint

Post by sloopjohnl »

bill,
i've sandblasted the sheetmetal in restoring a 1953 ford pickup and i would not go near a good boat with sand. there are other types of media used to "sandblast" such as plastic beads, shells etc. but i've never used them. it could prove pretty costly to use a media other than sand. how about "peel away" - less muss, less fuss!

Bill wrote: Hello to all

I think the subject of sand blasting the bottom of a boat as opposed to sanding it has been discussed here, but if not I'll ask! Yesterday I witnessed a marina worker blasting a boat bottom with a mixture of fine sand (#4) and water at fairly low pressure. The boat is an older (70's vintage) and the bottom (and boat to for that matter) is in pretty sad shape. It sure made the old paint come off easily, but what did it do to the gelcoat? I dont have the experience to tell if it did amy damage in light of the condition of the boat.

Since Rhapsody will be getting a new bottom job following this season, I guess I am looking at all the options (read not looking forward to sanding) for bottom prep.

Any opinions?????

Thanks & fair winds!

See you in Niantic.

Bill
Fred

Re: Preparing Bottom for Paint

Post by Fred »

Bill wrote: Hello to all

I think the subject of sand blasting the bottom of a boat as opposed to sanding it has been discussed here, but if not I'll ask! Yesterday I witnessed a marina worker blasting a boat bottom with a mixture of fine sand (#4) and water at fairly low pressure. The boat is an older (70's vintage) and the bottom (and boat to for that matter) is in pretty sad shape. It sure made the old paint come off easily, but what did it do to the gelcoat? I dont have the experience to tell if it did amy damage in light of the condition of the boat.

Since Rhapsody will be getting a new bottom job following this season, I guess I am looking at all the options (read not looking forward to sanding) for bottom prep.

Any opinions?????

Thanks & fair winds!

See you in Niantic.

Bill
Its been my experience that sandblasting with sand will generally tear up the gelcoat. Walnut shells work very well, however you must still sand the bottom before applying bottom paint or a barrier coat. The reason for this is the shells have a tendency to polish the surface of the gelcoat as it removes the bottom paint. With a large compressor and sandblaster with a big "hopper" you can remove the paint from any boat cd made in less than 6 man hours.



fred@hotsheet.com
Tom

Re: Preparing Bottom for Paint

Post by Tom »

Bill wrote: Hello to all

I think the subject of sand blasting the bottom of a boat as opposed to sanding it has been discussed here, but if not I'll ask! Yesterday I witnessed a marina worker blasting a boat bottom with a mixture of fine sand (#4) and water at fairly low pressure. The boat is an older (70's vintage) and the bottom (and boat to for that matter) is in pretty sad shape. It sure made the old paint come off easily, but what did it do to the gelcoat? I dont have the experience to tell if it did amy damage in light of the condition of the boat.

Since Rhapsody will be getting a new bottom job following this season, I guess I am looking at all the options (read not looking forward to sanding) for bottom prep.

Any opinions?????

Thanks & fair winds!

See you in Niantic.

Bill
I haven't done it personally, but people around here use talcum powder in the sandblaster rather than sand to strip paint w/o damaging gelcoat.



TomCambria@mindspring.com
Post Reply