Portable snadblaster

[Conachair]

Anyone recommend a good portable sandblaster? I live on a 33' steel cutter and I'm looking for something with which I can prepare small areas inside then paint. Don't know much about them but thinkingthat I could hire a compressor / vacuum locally.
TIA
Padz -Conachair

 

[Lakesailor]

You don't want to be snadblasting (sic) if you're living on board. What a mess.
There are some supposed closed loop blasters that eat up their own detritus, but it's a very messy process.

 

[rogerthebodger]

Don't grit blast inside if you live on your yacht. I stripped my new yacht out to grit blast and it took 4 of us 3 days to remove most of the grit and even after painting the inside we are still finding grit.

I have tried these small grit blast units and they do not work. I guy who did my grit blasting used a compressor like is used on the roads for pnumatic drills.

For small areas the best I found is a pnumatic needle descaler like this
attached to this

 

[Norman_E]

Re: Portable sandblaster

I agree that a needle gun would be much better to use than sandblasting, but have found a MOD Publication which specifically advises against using needle guns to prepare surfaces on HM ships.
The section reads as follows:-
2.17.1 The use of Needle Guns should not be used to prepare surfaces for coating. The
reasons for this are twofold:
2.17.1.1 Whilst needle guns are effective in removing coatings their action tends to
peen the surface and this can lead to the entrapment of corrosion and other
contaminents in what superficially appears to be a clean surface. This leads
to premature failure of the coating system applied.
2.17.1.2 The HSE (Health & Safety Executive) have issued several Guidance Notes
on the subject and advise employers to use alternative methods.

The last point probably refers to the dangers presented by the dust created.
Personally I think that you would remove much more rust than any which became trapped below the metal surface. If however the rust is superficial, why not look for a chemical means to render it inert and safe to paint over? I am sure I have seen such systems, but cannot remember the trade names.

P.S. Did you notice that the MOD cannot spell "contaminants"?

 

[Conachair]

Found these comments on metal boat society:

"A friend said he saw the Vacu blast working. It involved a small sandblaster with the nozzle runing into the centre of an elbow which was hooked up to a shop vac. The sand only bounced once before being picked up by the vacuum, and there was no dust whatever.
The only way to deal with the problems you have ,is sandblasting followed by at least three and possibly more coats of epoxy tar. "

"Princess auto in Winnipeg had a vacu blast, but you can make your own. Just run your small shop sandblaster nozzle thru a hole in the side of a 1 1/2 inch elbow, then hook a shopvac up to the elbow.The sand bounces once and the vac inhales it along with all it's dust.
I've never found a rust converter that lasted as well as epoxy over sandblasted metal. "

Anyone seen anything like that?

 

[Lakesailor]

There is the equipment and there are contractors.
One here (South Africa) VacBlast but I would certainly want to see it working on (someone else's) site before inviting them into my home.

 

[rogerthebodger]

The SA company is agent for a UK company here

VacBlast is in Stingo's neck of the woods but next time I am in Durban I may contact them and try to get a demo.

Lots of blasting done in Durban ship yards by where Stingo's new cat is being built.

 

[chamac]

I work with sandblasters every day of the week. I have never seen a truly dustless open sandblast system and there are plenty that are called dustless. Even the ones with brush head bristles surrounding the nozzle with powerful suction will leak some dust, and thats on flat surfaces like polished stone at low pressure. If you are trying to get into corners or uneven surfaces you can forget it. The low pressure spray gun type suction ones are worse, they just create dust and don't do much in the way of rust removal. I would not use a sandblaster inside a boat unless it was a new hull before fitting out. Certainly not in a boat I live in. The dust will go everywhere no matter what you use.
I think the needle gun sounds like a better way to deal with local rusting in conjunction with a vacuum cleaner. It will be way better than a wire brush anyway.

 

[Conachair]

Thanks all. I love this forum, stacked full of experience. I think needlegun it is. Gotta be better than wire brush and chipping hammer. Anyone recommend one?

TA

 

[Ships_Cat]

You are actually far (like miles far) better off with a grinder than a needle gun - grinding is always the second choice if blasting is not possible.

To get into tight places/corners use a die grinder and for tighter places/corners again a Dremel (or similar). Get a good clean "bity" finish and prime as soon as possible, like within minutes. However, the result will still not be as reliable as blasting.

John

 

[rogerthebodger]

This is how the inside of mine yacht looked during blasting

and the outside

 

[DinghyMan]

Agreed - we built a canal boat a few years ago for a client and removing the sand from inside the bare hull took days - have to get every bit out as the sand absorbs water and then rusts. We used a compressor and blew most of the sand to one end first which is much easier on a barge due to the shape. The sand just gets inside all of the channels and you will keep fnding for ages.