No sandFunny, I was thinking about this too, I think I may have posted it awhile back.
I think sand would be very aggressive, I guess it depends on what you're trying to achieve.
To simply remove the prior year's paint, I was wondering if you could use that attachment with baking soda, but I was thinking the soda may be dissolved by the water and not effectively provide any scrubbing power.
I'd also be very careful with a high power pressure washer (like a 5000psi one).... that alone can strip things you don't want to strip.
Slug is right, but it also depends on where you are and what the yard policies are. My current yard has a lot of rules, but then I see contractors dry sanding 50' powerboats with no dust collection at all. Technically to control it properly, you should have a tarp on the ground and all waste water needs to be collected and disposed of properly. Not easy.
The sand or walnut shells from the blasting isn't really the issue - it's all the small particulate bottom paint that flows onto the ground. They put skirts around the boat to keep the dust contained (usually).There is one kind of blasting that doesn't make a mess: crushed dry ice. But probably very expensive for a boat hull.
I have done a fair bit of shot blasting steel as in dry media. That is messy and getting quite difficult now and where I am, there are people complaining about noise and environmental issues when in actual fact they just want to shut the boat yard down and are looking for an excuse.
My solution for small stuff is a karcher pressure washer with an attachment and blast media - so wet blasting as per original post. For steel, it is not great, but good for fixing the small areas where an angle grinder can not reach. I also use a drill bit and drill to get rust out of very small areas or deep pitting. For anti foul paint etc. I would imagine a cheap wet blasting unit would work well as it is a lot less harsh. For removing normal paints and varnishes, I have found a small rig using standard pressure washers does not really do much. The great thing for jobs it can handle though is that you just need a pressure washer, attachment, media and water and as people just think you are pressure washing, they leave you alone.
Here is a video:
Yes, I did shot blasting inside my outriggers by cutting an access hole, but I had to get inside to do them as they are 9 metres long and 1 metre diameter. It was not as bad as it sounds as I had a big 12” fan with a long exhaust tube. It can shift 65m3 of air a minute and kept the visibility at a reasonable level. the fan is about $200 and I use it a lot now when I am painting epoxy (brush or roller) and such. It is so effective even in such confined spaces that I do need to wear a breathing mask (Obviously when shot blasting, I use a force fed mask from a fully filtered exterior air supply).Don’t know your
don’t know your project …on a metal boat we cut a hole , perhaps two holes in the bottom ..from the outside …then blast the tank while standing outside , with the tank top on . Then it’s painted …the top comes off, plate welded up and painted
very little work is done with the tank opened