removing bottom paint

[kickingbug1]

    how would one go about removing bottom paint to get to the original gelcoat? i have seen some photos of a boat where they did just that and were able to buff out the bottom till it looked new

[NateD]

I don't know who said it first, but "The best tool for removing bottom paint is your checkbook." I took the paint on my CP16 down to the gelcoat with a combination of chemical strippers and a palm sander, and it was a terrible, terrible weekend. A 7" grinder would have sped things up, but when it comes time to remove the paint from my 23 I plan to pay for soda blasting.



https://picasaweb.google.com/105772036807205996083/StrippingBottomPaint

[MacGyver]

Kick, start with a pressure washer
It may wash off if you hit it hard and close.

Start there, then move to sanding

Mac

[crazycarl]

kick,

watch where the runoff goes.  when i power washed ours, the old paint went down the drive and into the lawn.  killing a large area.


carl

[Bob23]

I like Nate's idea. If I could find a reasonable soda blaster, I'd write the check. But after last seasons great results with Interlux Aqua bottom paint, I'm gonna pass on removing the paint. Other matters are more pressing.
Bob23

[capt_nemo]

Only problem with SANDING is that when you're close to the gel coated bottom the sanding not only visibly scratches the gel coat, requiring more work to polish out, but also drives the paint and anything else present into the microscopic gouges and pores. Then you have MORE WORK to clean and polish.

Seems to me that the least aggressive, yet effective way, would be much preferred. If that means chemicals then so be it.

capt_nemo

[Salty19]

It might have an epoxy barrier coat too.  That's going to be a bear to sand off..hard as a rock stuff.

[skip1930]

Church and Dwight/Arm and Hammer soda blasting with a pressurized Schmidt blast pot and a Solaire air compressor-250 scfm diesel compressor.

Removing the bottom paint down to the gel coat with out profiling the molded fiberglass surface.
Soda blasting was developed in the 1980's to de-paint miss painted soft surrounds [RIM] for front and back body color crush zones on automobiles.

Just like any blasting operation, one square foot per layer can be expected.

I rented the blast pot, the Solaire, and purchased the bags of baking soda media to clean and refurbish 17 batch paint bake ovens for Ekco-Glaco Corporation.

At a Binks dealership I demonstrated that the clear coat could be removed, and stop. Then the color coat removed, and stop. And finally the electrodeposition primer removed, and stop. Just a 1/2 gallon of water from a garden hose per minute mixed with the air/soda keeps the dust down. The baking soda lowers the pH of the soil and will kill the grass. Use a parking lot.

The blast media dissolves in water but the paint taken off will not. Shovel the paint up and put this waste into the garbage can.

This system also works great de-grease the fifth wheel on semi's. Makes a roll [like cookie doe] that can be shoved up and tossed into the dumpster.  

skip.