Blakes SFE200 or Gelshield 200?

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andybussell

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Danbouy posted the following in April. No reply so I'm reissuing the query as I have just had the old epoxy blasted off my hull:

"Does anyone have experience of using Blakes SFE200? I need to 'top up' the 20 year old epoxy on my Dehler, Blakes say it only needs 2 coats but its thick, Gelshield needs 4 or 5. Which is likely to be best to apply in UK spring weather and will it last? "
 
Have you thought about VC Tar, have used this this product on many occasions and worked realy well.
It needs more coats but gives better protection. it's also very strong and difficult to remove, so does not get damaged as much when scraping the bottom.

Just re-doing mine at the moment.


Darren
 
can't comment on Blakes but I did do five coats of Gelshield this spring - so if you have any questions on that please ask.

rob
 
Thanks Robih, I'd just like to hear the pros and cons of Gelshield. Con is probably having to do 5 coats, any practical probs in application? Did you do a comparison with Blake before chooring Gelshield?
 
Epoxy gives protection by virtue of film thickness as even epoxy is water permeable. Gelshield goes on at 50 microns per coat versus 200 plus microns per coat from SFE200 which is solvent free. We did our last boat many years back with SFE200 and it was excellent, we put on 4 coats and each time put a telltale coat on a spare piece of formica which we monitored with a micrometer for thickness when dry, our 4 coats came to over 800 microns. To acieve the same with Gelshield would need 16 coats! Unfortunately International do not recommend more than 5 coats max or you risk solvent retention, so 250 microns is the best you can do, IMHO a waste of time, the epoxy is little more than an expensive primer.

SFE200 we applied by roller and it went over a shot blasted (but not gel removed) bottom, the paint film 'tensioned' as it cured and levelled off the surface smoothing the dimpled effect of the shot blasting. We applied each coat to a slightly higher waterline so as to avoid a hard ridge. The primer coat had to go on with the last coat only just dry so more careful timing than between coats 1-4 but worth the effort to get right so the antifoul sticks properly. We used Blakes primer but International Micron antifoul, Blakes agreed it would be OK.

Our current boat was epoxied professionally with 5 coats of Gelshield as a protection. I enquired with both International and Blakes about putting on more but neither thought it worth it because to remove the antifoul completely would likely remove a good bit of the Gelshield and to recoat properly would be the same job were osmosis to eventually develop. The consensus was leave it alone, only do it if needs be - seems like good advice that applies in all cases, why bother unless you have to!

Robin
 
Andy,

Gelshield 200 was chosen through recommendation from surveyors and a good deal of research of the products' capability. I see another poster hereon has reported Gelshield as being of no value - well that's a concern to hear but there seems to be a huge amount of smoke and mirrors around the subject. There was comment that there was a maxmimum of five coats applied - I don't think that is correct - it is a minimum of five coats as I understand it. As for application problems - no, it was very easy to apply and resulted in a smooth tough finish over which we applied two coats of Seajet Emporer antifoul.

We had scraped back ten years of a/f to the original epoxy coating applied when new so in effect we were reinforcing the prophylactic coating that was already there. I cannot of course vouch for it's anti-osmosis effect as I only applied it three months ago - we shall see over the next ten years or so. I do not intend coming out for the annual six weeks ashore hereafter - all year round afloat now.

For what its worth I was very pleased with the ease of application and finish of Gelshield and if it does offer the anti osmosis protection as claimed then I consider it an excellent product. It's a little copper antifoul this - you'll never know whether it works until five years have passed by!

rob
 
Andy,

To supplement further what I have said above the following is lifted directly from the Gelshield manual:

"Gelshield 200 is an epoxy primer with specific formulation characteristics developed to offer easy application by a variety of methods whilst consistently delivering a high level of protection against osmosis. The solvent based epoxy technology delivers extremely good adhesion to the surface and very good tolerance to a wide range of application conditions and temperatures. To augment the barrier properties of the epoxy, layered mica has been incorporated within the formula that creates an interlocking Microplate® effect within each coat, which is highly effective in combating water penetration."

This is a direct link to the product manual:

http://www.yachtpaint.com/superyacht/sy/pdf/Gelshield%20Plus%20Application%20Manual%202004.pdf

Hope this helps.

Rob
 
Daz, Robih & Robin - thanks all for your help. I think my next step is to ask International for their response to your convincing argument Robin.

Andy
 
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