Sand Blasting Anti-fouling ?

[abl1111]

I had a local sandblasting company take a look at some sand blasting I wanted done and we got to talking about sand blasting the bottom of the boat to removing anti-fouling - he gave a very good price and when I asked about 'dangers' about blasting and gelcoat damage, he said he has done many many boats with no issue.

Is there a real concern having a sandblaster remove bottom paint ? I certainly would not use it if there is. My plan would be to remove bottom paint and then epoxy seal…

Thx

[flyingfrizzle]

Originally Posted by abl1111

I had a local sandblasting company take a look at some sand blasting I wanted done and we got to talking about sand blasting the bottom of the boat to removing anti-fouling - he gave a very good price and when I asked about 'dangers' about blasting and gelcoat damage, he said he has done many many boats with no issue.

Is there a real concern having a sandblaster remove bottom paint ? I certainly would not use it if there is. My plan would be to remove bottom paint and then epoxy seal…

Thx

I would opt for soda blasting, it is less damaging and will still clean it up good. Less risk for damage. Sand is too abrasive for a bote bottom... my 2cents

[pelican]

that's the only way to go !

for a long time - I had a friend who did sand blasting,he blasted no less than 30 boats for me

an experienced sand blasting guy will cause no damage


barrier coat:

pay attention to this:

it's NOT the amount of coats,it's thickness

get 2 gallons - one white and one grey,there's a reason for this

alternate the colors - this will assure proper coverage

this can not all be done in one day - there's a company in nj,the company does a barrier coat and bottom paint in one day - I assure you,that's impossible...

if you would like advice,ask...

[Ed]

Originally Posted by abl1111

I had a local sandblasting company take a look at some sand blasting I wanted done and we got to talking about sand blasting the bottom of the boat to removing anti-fouling - he gave a very good price and when I asked about 'dangers' about blasting and gelcoat damage, he said he has done many many boats with no issue.

Is there a real concern having a sandblaster remove bottom paint ? I certainly would not use it if there is. My plan would be to remove bottom paint and then epoxy seal…

Thx

It all depends on the skill of the operator. At the yard where I work, I have managed roughly 20 blasting projects over the last few years. Most projects have been a volcanic ash & water slurry, glass media and soda.

Soda is typically blasted at very high pressure. 80-100psi. If not done properly, the operator can leave ripples like those you see in the sand at the beach (this happened to my personal boat - a guy out of Malden, MA really screwed up the bottom of my former Grady White). You also need to sand the entire hull with 80 grit when done.

Volcanic ash and water (farrow system is a brand name but there are others)...is typically blasted at much lower pressure - say 40-50 psi. This is probably my favorite. Plus you don't have to sand when finished.

Glass media also leaves a very nice texture.

Considering you live on Long Island, I would contact that fellow in NJ who does Farrow blasting in the tri-state area.

Remember, saving $400 now only to have spend 4 days sanding and fixing your hull from a poor blast job is not worth it!

[pelican]

Originally Posted by Ed

It all depends on the skill of the operator. At the yard where I work, I have managed roughly 20 blasting projects over the last few years. Most projects have been a volcanis ash & warer slurry, glass media and soda.

Soda is typically blasted at very high pressure. 80-100psi. If not done properly, the operator can leave ripples like those you see in the sand at the beach (this happened to my personal boat - a guy out of Malden, MA really screwed up the bottom of my former Grady White). You also need to sand the entire hull with 80 grit when done.

Volcanic ash and water (farrow system is a brand name but there are others)...is typically blasted at much lower pressure - say 40-50 psi. This is probably my favorite. Plus you don't have to sand when finished.

Glass media also leaves a very nice texture.

Considering you live on Long Island, I would contact that fellow in NJ who does Farrow blasting in the tri-state area.

Remember, saving $400 now only to have spend 4 days sanding and fixing your hull from a poor blast job is not worth it!

please elaborate on this damage ?

[Ed]

The soda blast operator turned up the pressure and rushed through the job. The bottom of my boat looked like ripples in the sand at low tide. The bottom was completely wavy and took three days of sanding to get right. He also blasted two inches above the waterline and never blasted the trim tabs - too lazy to disconnect.

In contrast, the two other blasters we use on a regular basis (one from Brunswick, Maine and one from Kittery, Maine) do an excellent job. When they are done, the bottom is fair, burn through is non-existent or minimal and the profile left for barrier coating is next to perfect.

[abl1111]

So…'my guy' uses sand only as a medium. It sounds like it's not as dangerous as I've heard. Is there anything I should watch out for ? Or request ? I figure I'll let him take it to gelcoat and then I will be using an epoxy barrier coat.

This all started because I want to glass and core under my gunnels and figured that sandblasting the roving under there is a h*ll of a lot easier than sanding by hand !