sand blasting steel boat

[Maurice55]

Hi every body,
I have just been quoted a "promised" maximum of 2000 euros to sand blast an 8 metres steel boat. There is no local competition so I would like to know how it compares with you various experiences...thank you.

 

[MM5AHO]

While not having experience of blasting any boats hulls (but plenty of other things), I'd guess that not bad.
But don't use sand - there are serious health hazards in using sand. There are plenty of better blast media to use.

 

[sarabande]

that sounds reasonable but in a warm moist climate you will need to get the bare metal covered with the proper paint pretty instantly. Can you do this, or will you need to extend the blasting time, and the cost.


And, err, is it being done to an approved standard ? DIN or NACE.


And does the price include shielding adjacent boats, and removal of all blast media and debris afterwards ?

 

[TQA]

Venuzuela Varadero Caribe would be cheaper, that figure would likely include 4 coats of epoxy the first being applied within 30 mins of blasting.

 

[Maurice55]

Thank you for your replies.
They will not be using sand but the approved grit and I am in Corsica and doing it in July so weather should not be a problem + covering with Jotamastic 87 which is surface tolerant so blasting to "silver" white.

 

[TQA]

Venuzuela Varadero Caribe would be cheaper, that figure would likely include 4 coats of epoxy the first being applied within 30 mins of blasting.

 

[Pasarell]

That sounds a very reasonable figure if it includes the 1st coat of epoxy.
The standard you ideally want is Sa2.5, otherwise known as near white metal. Easy to say but difficult to define unless ou know what it means. As a cynical corrosion engineer i've spent too much of my life under ships / rigs telling blasters who know exactly what i want to do it again. Generally they don't know but guess and try to intimidate you.
For a boat that has been in the water, getting the surface salt free is just as important as blast standards. Salt crystals crush wonderfully well into the pores of the steel under blasting, and then start corrosion again very quickly. A really good pressure wash before blasting starts is important, but another after blasting is probably more so. Forget all the talk of getting the first coat of epoxy on within 30 minutes. Give it a good pressure wash, allow to dry and get the epoxy on the same day. Your steel will flash rust but modern epoxiesc ope with that. Jotamastic 87 is one of the best for this job.
Flash rusting if the surface is clean will be ginger. Brush off any powdery material and paint. I f the rust is black you have a contaminated surface so c lean again.
Finally don't skimp on the coating thickness. If you are brushing or rolling it you will apply far less with each coat than you think. It is worth getting a dry film thickness gauge, often for £50 or so from e-bay, to monitor what you apply. Make sure your total dft conforms with data sheet.

 

[Elessar]

But don't use sand - there are serious health hazards in using sand. .

it's (rightly) illegal to do so, too.
Some do though - look under the top bag if you're getting your boat blasted........

 

[Maurice55]

Thank you for the further replies and specially Pasarell. I am using Jotamastic 87 and I will be washing down before painting as advised even so it seems weird I know it's best.