Well it worked kinda. Very slow process. I will get pictures up soon but the video should work for now. Next I'm going to try a bigger pressure washer and maybe a heavier grit.


https://m.youtube.com/watch?feature=...m-upload_owner

Set up, ready to go. I elevated the bucket cause I read reports of water flowing back to the bucket. No problems with that the whole time

http://i1326.photobucket.com/albums/...psd731af5f.jpg

Before sand blasting. That is what I've scrapped so far.

http://i1326.photobucket.com/albums/...psdb876ab1.jpg

After about 7 min.

http://i1326.photobucket.com/albums/...ps06573b6f.jpg
http://i1326.photobucket.com/albums/...ps9ffb37d3.jpg

Maybe another 7 min on the underside amidships
http://i1326.photobucket.com/albums/...ps48e84f28.jpg

Waterline about 5 min.
http://i1326.photobucket.com/albums/...ps8a9208e6.jpg

Total 25 lbs of fine walnut shell lasted about 20 minutes

You need more psi. its not taking it off fast enough, your going to go through alot of agent and water. Its looks great you just have to move along a little faster. You need 4200psi washer with a 0 degree tip, you will cover triple the area in the time you are now.

Do you think the fine grit is ok or should I go more coarse? Or try just the stronger pressure washer with the same grit?

The boats we've had soda blasted at the yard end up with a rougher finish than what you're getting.
You could try a higher grit, might go a little faster.
Planning on painting or leaving it gelcoat?
If your painting, the texture left after a soda blast with a quick once over with 80 grit is perfect for a few coats of interprotect 2000 then bottom paint.

If your going to leave it gelcoat I'd stay with a finer grit, but get ready to spend some time under the boat.

A quality pressure washer will take off 70 to 80% of the bottom paint. Then you can hit the remainder with a DA sander in progressive grits.

This is how I removed 10-15 years of bottom paint from a 25 Parker. Then sprayed it with Awlgrip.

i'd like to not paint the bottom as I keep it on the trailer and never in the water over night. i've only ever used regular bottom paint on any of my boats so i'm not sure what to put on the bottom. i know i have some blisters on the port side at least at the bow anyway so those will have to be dealt with. I can just use a few coats of epoxy barier coat on the bottom and that will be fine right?

I will try a 3500 pressure washer this week with just water and then will try some with the recycled walnut shells that i sweapt up after the first try (after i screen it of course)

I used about 200lbs of crushed glass media for a 23'. Looks like what u have is working but will take forever.

Tried a different pressure washer, 3300 psi alone with no sand. Just water and it took 75% off fairly easy. Did the majority of the starboard side in about an hour. In the last pic below you can see where the fiberglass is exposed. I don't know if it's from the washer or 40 years of use and abuse. I bet another 25 lbs of walnut shell would get almost the rest of the paint off that side.

http://i1326.photobucket.com/albums/...ps2536a2a3.jpg

http://i1326.photobucket.com/albums/...psc7d93a4a.jpg

http://i1326.photobucket.com/albums/...ps5827c2fa.jpg

Use the rougher grit and the high psi washer, then hit it with 80 grit. Use 2 to 3 coats of barrier coat then bottom paint it is going to take too much time and patients to get back the gelcoat. If you are going to trailer the boat get a bottom paint with less ablatives so the loading of the trailer is not always marking it up. I used interlux VC and seemed to work great, you can also burnish it to a shine.