Ultra high pressure water cleaning

[Captain Zim]

Hello. Having had only tyre-kickers interested in the barge so far I am beginning to think I might not sell up. In order to epoxy her I need to blast the hull but would much rather use water. Does anyone know of a mobile UHPW service? I know mso marine offer this service in dock but they are not returning my calls or emails (anyone would think they don't want 20 grands worth of work...) so I am starting to look at alternatives.

 

Thanks

[by'eck]

Bear in mind a UHP water jet can cut through 3" thick steel - up to 3000 bar is used!

[DaveR]

On the ships we use 10,000 psi water to clear rust before painting. This sort of pressure will cut through electric cable but not steel. All rust is removed and the salts below the rust are washed out. The resulting surface is classed as SA2.5 which is the same achieved by gritblasting. It will be expensive as the diesel driven pump and associated kit costs a lot. As far as PPE is concrned then good boots, apron, good gloves and face shield are all that our operators use.

Dave R

[DHutch]

Sounds good to me, particularly with places increasingly not wanting the mess and cleanup of grit blasting.

 

 

Daniel

[Captain Zim]

I wasn't thinking of doing a DIY job. And I don't necessarily want SA2.5 but since there are mobile grit blasters I wondered if there were mobile water chaps. Either way will cost a bit but it's the lower clean up issues that make me more inclined to go with water

[ditchcrawler]

http://marinerepairs.co.uk/UHPBlasting.htmlis the first google hit

[blackrose]

Any water jetting will by definition leave flash rust on the surface so you'll need to use a surface tolerant epoxy such as the Jotamastic 87 range.

 

http://www.jotun.com/we/en/b2b/paintsandcoatings/products/jotamastic-87.aspx

 

I've just had my boat grit blasted (what a mess!) and I'm using 2 coats of Jotamastic 87 with aluminium, followed by two coats of Jotamastic 87 (black). The black will turn grey as its not really a topcoat but it's just cosmetic and I don't mind grey.

Edited May 29, 2015 by blackrose

[ditchcrawler]

Any water jetting will by definition leave flash rust on the surface so you'll need to use a surface tolerant epoxy such as the Jotamastic 87 range.

 

http://www.jotun.com/we/en/b2b/paintsandcoatings/products/jotamastic-87.aspx

 

I've just had my boat grit blasted (what a mess!) and I'm using 2 coats of Jotamastic 87 with aluminium, followed by two coats of Jotamastic 87 (black). The black will turn grey as its not really a topcoat but it's just cosmetic and I don't mind grey.

Maybe they use an inhibitor in the water

[DHutch]

Large number of paint systems will tolerate flash rust, but you are right, you do need one that does.

[Captain Zim]

http://marinerepairs.co.uk/UHPBlasting.htmlis the first google hit

That's perfect, thanks. For some reason I couldn't find one on google. I take it from replies so far no one has ever used one themselves. I will give these chaps a call and report back on prices

[John V]

watching with interest !!!

[Captain Zim]

Okay, one quote I got, I won't say who as I don't think that's fair, £2235 ex VAT to do 72m2. 35000psi. 3 day job. Clearance of at least half a metre needed in the dock.

[larkshall]

I shall wait for the results of this one with interest.

[ditchcrawler]

Okay, one quote I got, I won't say who as I don't think that's fair, £2235 ex VAT to do 72m2. 35000psi. 3 day job. Clearance of at least half a metre needed in the dock.

How does that compare with normal air/grit or water/grit blast

[Rebotco]

I asked a local boatyard why they didn't use this method, and their reply was that although it could get back to metal, it left the surface too smooth for good adhesion. So they continue with grit blasting for the roughness they need.

[DaveR]

I asked a local boatyard why they didn't use this method, and their reply was that although it could get back to metal, it left the surface too smooth for good adhesion. So they continue with grit blasting for the roughness they need.

 

Both water blasting and grit blasting achieve the same surface profile - that is the designation SA2.5 - so the yard saying they get a better finish with grit blasting is not quite right.

I can understand the yard's preference for grit blasting as the initial outlay is much less than the purchase of the water blast unit.

The safety with grit blasting is much higher than the 10,000psi water, with the water the danger zone is only around 12" from the outlet.

However the cost difference between the two systems soon swings the other way when there is little or no clean up required and no grit to constantly replace.

Edited June 5, 2015 by DaveR

[Neil Smith]

The cost to grit blast my 58 footer was £350 all in and I think they had a sort of hoover to suck back grit as it bounced back then sifted and recycled which saves money for them and as lot less cleaning up for you.

 

Neil

[ditchcrawler]

The cost to grit blast my 58 footer was £350 all in and I think they had a sort of hoover to suck back grit as it bounced back then sifted and recycled which saves money for them and as lot less cleaning up for you.

 

Neil

Where was that carried out, it sounds a good price

[Neil Smith]

The shell builder got it done in Nottingham, a mobile chap.

 

Neil

[the barnacle]

you can rent one here - http://www.ebay.co.uk/itm/Falch-T25-ultra-high-pressure-washer-2500-bar-from-top-South-West-dealer-/321756117146?pt=LH_DefaultDomain_3&hash=item4aea28b89a

 

 

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