DIY blasting - what are the cons?

[dgadee]

Two or three of us are planning to Coppercoat. One of the three suggested a diy approach. I am not enthusiastic having heard negatively from a friend (now sadly dead) who tried it but can't remember what he said.

What are the arguments against this approach if you have tried it? Skill level is my main concern given that to do it properly you would be working with powerful equipment on a thin get coat. I can see the positive - it could be cheap.

 

[KevinV]

Define "cheap" - creating and working in clouds of toxic dust while using equipment that is quite dangerous of itself doesn't sound very clever to me - a slightly loose mask or suchlike and you're in a world of grief.

Getting primer onto the keel fast, and the coppercoating itself, are quite knackering enough.

If you have 3 boats lined up for the blaster that'll bring the costs down.

 

[Rum Run]

"Blasting" covers a number of methods too - grit for de-rusting steel/iron on barges etc, soda for paint on softer surfaces, slurry for same I think.
Hiring the kit won't be free, purchase of the PPE either, so with three boats the contractor price could be close, plus they should be insured if they bollix the job up....

 

[rogerthebodger]

I had my steel boat grit blasted 10 years ago by a company and seeing it done I would not diy as it's a dirty job requiring pressure air fed helmets and allover protection.

The clean-up is also a dirty job

You need to choose the grit carefully so as not to damage hull too much

 

[scozzy]

So three of you at the bar ... one says "I've bought a blaster and all the kit off ebay , ill do it tomorrow"....
And you're going to let him loose on your pride and joy with no experience with power tools and a bag of salt?

Me neither

 

[dgadee]

I agree with you all. We did have someone blast over the past few months, but using sand and a pressure washer. It ended up taking months and he still had to do a whole lot of scraping. Very nice finish, but not my idea of pleasure. And there are bags and bags of expensive sand he had to collect from the yard ground. I don't think you can re-use it either.

 

[B27]

If it's just antifoul you want to remove, then wet sanding it can be surprisingly easy and quick, provided you do it soon after hauling out.

Alternatively, it often chips off quite easily after a few months ashore. I found a slightly blunt chisel effective.

In between those states, it seems to be a lot tougher.
Of course your paint might be different.

 

[dgadee]

If it's just antifoul you want to remove, then wet sanding it can be surprisingly easy and quick, provided you do it soon after hauling out.

Alternatively, it often chips off quite easily after a few months ashore. I found a slightly blunt chisel effective.

In between those states, it seems to be a lot tougher.
Of course your paint might be different.

Will you do it for me?

 

[Tranona]

If it's just antifoul you want to remove, then wet sanding it can be surprisingly easy and quick, provided you do it soon after hauling out.

No good for the Coppercoat they intend to apply.

 

[Tranona]

I agree with you all. We did have someone blast over the past few months, but using sand and a pressure washer. It ended up taking months and he still had to do a whole lot of scraping. Very nice finish, but not my idea of pleasure. And there are bags and bags of expensive sand he had to collect from the yard ground. I don't think you can re-use it either.

We have a contractor who comes in frequently to blast for club members. Takes a morning and the medium he uses is collected in a big tarp underneath . He takes it away and dries it out for re-use. Takes typically a morning and leaves little mess, usually just a light coating of dust when the residue dries out. it is done in a dedicated tarmac area which will take 2 boats at a time if necessary.

 

[PCUK]

No good for the Coppercoat they intend to apply.

Why?

 

[Refueler]

"

DIY blasting - what are the cons?"​

Honest answer ? The fact that you are considering doing it without any experience of blasting ..... even with slurry / Soda .... the potential for damage far outweighs any cost savings etc.

 

[AntarcticPilot]

I looked into DIY blasting when I decided to use Coppercoat. Basically, methods that didn't risk taking all the gel-coat off were slow; and professional equipment is quite expensive to hire and that's not counting gaining the skill to do a good job. I decided to get a professional in. After seeing his equipment and the level of skill required, I am very pleased I did; I could not have done as good a job, and I would probably have skimped on protective gear - he was dressed up in something approaching a space-suit. Also, the equipment he used allowed a fierce blast on the cast-iron keel and a much gentler blast on the hull. The former did a fair job of removing the rust and inclusions; the latter left a finish as smooth as a baby's bottom ready for Coppercoat.

If three of you did it DIY, the last boat you did might be OK; the first two would be rough!

 

[AntarcticPilot]

Why?

You need to get right down to gel coat to apply Coppercoat. Sanding is unlikely to get that far, unless you've been really rigorous about removing every last trace every time.

 

[B27]

You need to get right down to gel coat to apply Coppercoat. Sanding is unlikely to get that far, unless you've been really rigorous about removing every last trace every time.

When you say 'gelcoat' would you mean removing any sound previous epoxy coatings?

 

[AntarcticPilot]

When you say 'gelcoat' would you mean removing any sound previous epoxy coatings?

No. Coppercoat is epoxy based, so a SOUND epoxy coating is fine.

 

[Refueler]

You need to get right down to gel coat to apply Coppercoat. Sanding is unlikely to get that far, unless you've been really rigorous about removing every last trace every time.

Yard guy used orbital sander on my 38 .... he removed all traces of previous A/F ... took him a few days ... hard work. But hull was beautifully smooth before priming and high Copper Content VC Tar applied :

 

[thinwater]

I have done blasting ... when I was 25. It is a lot more involved than the OP thinks, a lot more miserable, and a lot more expensive in rentals than the OP realizes. Not a DIY method, at all, unless the DIY is young and has done it before.

And unless you tent the boat, install an air filtration system, and cover the ground, you could be paying for a lot of clean-up and detailing some nearby boats. Most yards (mine for certain) won't permit this by DIYs.

Pro method.

 

[Lucy52]

As above, you will need to tent up, clean up, and have the PPE required. In any case, the yard might not let you, have you asked?

 

[AntarcticPilot]

Yard guy used orbital sander on my 38 .... he removed all traces of previous A/F ... took him a few days ... hard work. But hull was beautifully smooth before priming and high Copper Content VC Tar applied :

Blasting gets it done in a few hours - a morning or an afternoon. And my hull was beautifully smooth, too.

My point is that sanding to the same finish as blasting will be a slow and laborious task. And yes, I did once give my brother a hand sanding and scraping all the antifoul of his small yacht - never again!