Soda Blasting, how much should it cost?

Blasters on the south cost often charge by linear foot of boat length. Last year they were £14 - £15 for slurry and £18 - £20 for soda.
Price always depends on travel distance, ease of access and how busy they are
 
Anyone know of recommendable blasting companies within sensible travelling distance of Forth?

Also, if you had VCTar on your hull and were considering blasting antifouing off, would you suggest leaving the VCTar in place or take it away as well to gelcoat? Referring back to my Coppercoating thoughts in another thread. :D
 
Make sure you cover all your varnish work and some painted surfaces as soda can mark them quite badly - if thick enough it will strip some coatings.
Also keep well clear while being used, it can burn skin and seriously effect your eyes.
 
Can anyone give me an idea how much soda blasting should cost? I'm about to ge a quote for my MG 27....

Ian

My personal view is I would never have a grit/soda blast or paint stripper anywhere near my gel coat.

A few years ago at lift out a friend had his 1987 Fairline corniche at the side of my 1988 corniche.
He wanted me to join him for a slurry blast of 'gentle soda'.
I wasn't keen even when offered a two for one deal and declined.
My mate went ahead and I saw the damage the following weekend

Whole hull was riddled with small holes in the gel coat.
The whole boat had to be filled and epoxy coated.
At some stage a section of 1 ft by 2 ft on my bow had also been blasted.
It is unclear if
they started on the wrong boat.
they hit it by accident
they wanted to see if my hull would also be wrecked
they thought it was such a good job I would want mine done


My 'test' section was also covered with pin prick holes that I needed to fill.
I was pleased a small section had been tested as it confirmed to me that GRP shouldn't be grit blasted unless it needs an osmosis treatment.
A friend was then kind enough to clean my hull with an electric chisel, the old antifoul came off and left beautiful white shinny gelcoat with no visible signs of weakness.
It is clear that older boats have naturally occurring bubble holes deep within the gel coat that are created during the mixing. These bubbles are fine and will not cause a problem unless the Gel coat is overpolished with compound, over sanded or slurry/grit blasted.

The slurry blast had not made the holes but it had exposed voids that had been water tight for 15 years (moisture reading were very good).

The grass under the treated boat has still not grown back and turned into a bog for a while.

From my experience I would only have a slurry blast on a modern boat that had used a vacuum technique to mix the gel coat and so reduce the amount of bubbles.

If you read the professional sites they warn about this in a round about way " leaves a nice key finish ready for filling and epoxy coating " shouldnt the surface be ready for AF Primer ?
 
Also, if you had VCTar on your hull and were considering blasting antifouing off, would you suggest leaving the VCTar in place or take it away as well to gelcoat? Referring back to my Coppercoating thoughts in another thread. :D

I have experience of this. The Coppercoat people suggested abrading the old VC Tar (which is epoxy-based and has no tar in it, as you probaby know), then applying a primer coat of new VC Tar before Coppercoating.

It seemed to work but after a couple of years adhesion problems became apparant, and flakes of Coppecoat fell off. It was obious that the Coppercoat had adhered well to the new VC Tar, but the new Tar had not stuck well to the old.

So I'd take off all the old VC Tar - but also investigate why it was applied in the first place. Was is a precautionary moisture barrier, or a response to some perceived issue? You may want to consider applying a new barrier coat if the hull moisture readings are low enough.

I'd also suggest you discuss the matter with the Coppercoat people (who know of my experience with VC Tar). They're able to supply barrier coat epoxy (cheaper than West System and not so prone to West's bluddyawful amine blush).
 
14 months ago I paid about £350 for Fox's in Ipswich to do my 31 fin keeler. Not sure what they used (slurry on the hull and grit on the keel I think). Almost perfect job, left the hull epoxy intact & able to paint after about 30mins touching up the odd bit not quite finished.
 
Antifoul removal

Just ripped the antifoul off my Fulmar.

Did it with a Linbide scraper and a good set of overalls taped up at the sleeves!

It really wasnt that hard at all to get it back to the gelcoat and although I left a few deep scratches when working at an angle, the finish was fine. Whole job took 2 of us an afternoon.

Those Linbide scrapers are fantastic so dont be put off by it being a lot of hard work. Once you get a short snappy stroke, the stuff just falls off.

Still have the keel to do which a blast company quoted £150 for so I can epoxy fill it. I might well put a grinder to it myself.

Can I ask how you will mark the waterline for when you repaint it? Not sure yet what I should do. I thought about a thin chisel line into the gelcoat.
 
Make sure you cover all your varnish work and some painted surfaces as soda can mark them quite badly - if thick enough it will strip some coatings.
Also keep well clear while being used, it can burn skin and seriously effect your eyes.

I think this statement is somewhat confused and misleading, Bicarbonate of Soda (BOS) as used in soda blasting does not burn skin or affect the eyes any more than most things that get in your eye. Most things that do not belong in your eye will irritate it. A solution of BOS is actually used to treat mild burns of the skin such as sunburn and is also used for the relief of an eye condition known as Blepharitis. You will find BOS in products such as toothpaste (Arm & Hammer) as well as being used as a gargle for the relief of mouth sores and for freshening the breath. The BOS used in soda blasting is food grade and is used in the production of numerous foods most notably bread.

The action of soda blasting is mechanical in nature, not chemical and it is normally used dry except where dust is a problem. This does not tie up with "thick enough ......" etc. It will not strip varnish or paint unless blasted at the coating. It was actually developed and used in the USA to clean the Statue of Liberty, they needed a method that would not damage the nearby waterways and eco system or the soft copper plates of the statue itself.

I do not know what sort of method you saw in action or heard about but the record needs setting straight, it was NOT soda blasting, soda blasting does not do what you say.

How do I know all of this?
I am a soda blaster and before any of you cry "Advertising", no I am not, I am nowhere near the south coast or indeed any other coast so I am not looking for your business. I just do not want you misinformed.
 
The action of soda blasting is mechanical in nature, not chemical and it is normally used dry except where dust is a problem.

How do I know all of this?
I am a soda blaster and before any of you cry "Advertising", no I am not, I am nowhere near the south coast or indeed any other coast so I am not looking for your business. I just do not want you misinformed.

Informative post, thanks. Refreshing to have a few facts thrown into the rumour pot.
 
Farrow System

I have done work with this and the ending result it amazing. Yes it is a slurry mix however, the low blast pressure design and grit that is used is soft enough to shatter at low psi and light enough to bounce off the exisiting gel coat while removing the antifoul and old bottom coating. Look into it! Here's the website... www.farrowsystem.com
 
I have done work with this and the ending result it amazing. Yes it is a slurry mix however, the low blast pressure design and grit that is used is soft enough to shatter at low psi and light enough to bounce off the exisiting gel coat while removing the antifoul and old bottom coating. Look into it! Here's the website... www.farrowsystem.com

Just to avoid confusion, Soda blasting and the Farrow system are not the same thing. The Farrow system is carried out wet. Soda Blasting can be done wet or dry, which gives it distinct advantages when electrical systems are in the vicinity. The original question related to Soda Blasting. To get in touch with your nearest Soda blaster take a look at www.soda-blast.co.uk . They will put you in touch.
 
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