Re-Epoxy of Hull?

[neil1967]

We are in the last stages (hopefully) of buying an Oyster 406. As far as the hull went, she had a clean bill of health from the surveyor regarding osmosis/dryness. She was re-epoxied in the late 90's. She has been out of the water for the last 18 months, other than our test sail, and I expect to keep her out of the water for another few months whilst I get her ready to sail from Ipswich to the Solent where we will keep her for the next 4-5 years. In the long term, we intend her to be our long term liveaboard (maybe another 15-20 years) and possible circumnavigator. Given that she is probably as dry now as she will ever be, is it worth re-epoxying her in March/April, before re-launch? If so, what do people recommend? VC Tar, Gelshield 200 or anything else?

Thanks

Neil

 

[saltylegs]

Since she is dry and you intend to keep her I would epoxy again just for a bit of piece of mind.
I used VC tar last year on a Sigma 33 and in one of the hot days over easter I was able to get 3 coats on in one day by myself, so easy to use and a nice finish.

 

[SailingEcosse]

More epoxy would make sense to me, especially since the hull is confirmed dry.

I used the safeguard product from the guys at the resin store better priced than the big brands, and I couldn't fault it, they are helpful on the phone for advice as well.

Cheers

Alex

 

[Tranona]

If you look a bit further down the page you will find another thread on the same subject.

Given what you hope to do with the boat you might consider having it blasted re epoxied and coppercoat. Once you start using the boat you may not get another opportunity and longer term it will be a good investment.

 

[npf1]

What make you fear that the current epoxy is not working as intended or only has a limited lifespan left?

Whilst I've heard a few people in the marine trade say that it should be done every 7 ish years, I've so far not come anyone saying their epoxy was working but now is now failing. Would be interested to hear of other experiences.

 

[Bosun Higgs]

Given that she is probably as dry now as she will ever be, is it worth re-epoxying her in March/April, before re-launch? If so, what do people recommend? VC Tar, Gelshield 200 or anything else?

Thanks

Neil

The tech manager from West systems told me that any coating including epoxy was permiable to some degree and that the thicker the coating the better.

 

[GrahamM376]

What make you fear that the current epoxy is not working as intended or only has a limited lifespan left?

Whilst I've heard a few people in the marine trade say that it should be done every 7 ish years, I've so far not come anyone saying their epoxy was working but now is now failing. Would be interested to hear of other experiences.

When I scraped all our antifouling off, I found the epoxy coat to be riddled with holes where surveyors had scraped through it over the years to take moisture readings, presumably on surveys. Gave it another 5 coats of Gelshield 200 all over.

 

[macd]

The tech manager from West systems told me that any coating including epoxy was permiable to some degree and that the thicker the coating the better.

Typical epoxies for barrier coat use have a maximum water take-up of around 0.5%, so are not completely impermeable. The recommendations I've seen have been for barrier coat thicknes of a mimimum of 500 microns; more is better.

If the OP decides to beef up the epoxy barrier, like others above I'd be inclined to steer him away from the well-known brands on the basis of cost. AMC (the Coppercoat people) supply an excellent high build barrier coat which is much cheaper than name brands. (You won't find it on the Coppercoat web site: need to mail them). Mind you, I detest West for that bl**dy awful amine blush, so I'm slightly biased.

Bit confused by the OP's reference to "She was re-epoxied in the late 90's". Was that epoxied or really re-epoxied, which would make the next treatment the third?

 

[Boo2]

Since she is dry and you intend to keep her I would epoxy again just for a bit of piece of mind.
I used VC tar last year on a Sigma 33 and in one of the hot days over easter I was able to get 3 coats on in one day by myself, so easy to use and a nice finish.

Did you brush or roll it on can I ask ?

Boo2

 

[neil1967]

Thanks for all the replies so far - most useful. For clarity, the yacht was epoxied in the 90s.

Neil

 

[Clyde_Wanderer]

Since she is dry and you intend to keep her I would epoxy again just for a bit of piece of mind.
I used VC tar last year on a Sigma 33 and in one of the hot days over easter I was able to get 3 coats on in one day by myself, so easy to use and a nice finish.

Dident realise VC tar was still available.
I believe my boat was coated with it when she was completed in the early eighties.
My hull below the waterline doesent have white gel on it but either clear gel or just resin but I would think clear gel as resin can damage moulds.
Is VC tar black in colour?
And as already asked should it be rolled or brushed?
C_W

 

[oldsaltoz]

Dident realise VC tar was still available.
I believe my boat was coated with it when she was completed in the early eighties.
My hull below the waterline doesent have white gel on it but either clear gel or just resin but I would think clear gel as resin can damage moulds.
Is VC tar black in colour?
And as already asked should it be rolled or brushed?
C_W

Have done several hulls and I roll the epoxy on with a 4 inch roller and tip off with a long bristle 2 inch brush, if just rolled and left you get a slight orange peel effect.

Also a good idea to fair the hull first but make sure the filler is a closed cell type, Micro-balloons are good and easy to and, Micro-sphears are a little harder to sand.

Good luck and fair winds.

 

[saltylegs]

Did you brush or roll it on can I ask ?

Boo2

rollered with small mohair rollers

 

[saltylegs]

Dident realise VC tar was still available.
I believe my boat was coated with it when she was completed in the early eighties.
My hull below the waterline doesent have white gel on it but either clear gel or just resin but I would think clear gel as resin can damage moulds.
Is VC tar black in colour?
And as already asked should it be rolled or brushed?
C_W

is available in black and white however the make up is different from the earlier days as they have removed the "pitch" or something so does not go on as thick and Ihave been advised that the black is easier to apply so that is what I used (small mohair rollers).

 

[macd]

The VC-Tar tin says something to the effect of 'contains no tar'. Presumably the earlier formulation did contain tar.

 

[Nostrodamus]

What are the advantages to putting expoxy on the hull and if it is worth doing why don't some manufactures put it on their boats from new?

 

[nimbusgb]

Compared to polyester resins epoxy is far less permeable to water.

paper here

Applying an epoxy coat is a technique for protecting against osmosis.

Epoxy resin is considerably more expensive than polyester but also requires more sophisticated construction techniques ( autoclaves and long cure times ) which is why production boats rarely use it.

International VC Tar 2 is the latest embodiment of the product. It is now an epoxy product that sets to form a membrane that is like a black plastic bag. I got 6 coats on to a grit blasted polyester hull. The coating is probably thicker than 750 microns over the entire bottom. 2 or 3 days after a haulout the moisture readings below the waterline are comparable to those well above the waterline.

 

[Nostrodamus]

Compared to polyester resins epoxy is far less prone to water penetration.

paper here

Applying an epoxy coat is a technique for protecting against osmosis.

Epoxy resin is considerably more expensive than polyester but also requires more sophisticated construction techniques ( autoclaves and long cure times ) which is why production boats rarely use it.

Thank you for that. I can understand it is cheaper to build withoutit but for the relative cost why don't they then paint a barrier on from new... I suppose costs again?

 

[nimbusgb]

Thank you for that. I can understand it is cheaper to build withoutit but for the relative cost why don't they then paint a barrier on from new... I suppose costs again?

Probably. No doubt one could specify it as a coating from new and the builder would delight in charging you for it. 10 litres of VCTar 2 cost me a couple of hundred iirc. No doubt it would add 2k or more to the cost of a new boat.

 

[jwilson]

Probably. No doubt one could specify it as a coating from new and the builder would delight in charging you for it. 10 litres of VCTar 2 cost me a couple of hundred iirc. No doubt it would add 2k or more to the cost of a new boat.

Some boats are epoxy coated from new: it is however not cheap, as the builder has to get every trace of the mould release agent off the hull and matt it down to key slightly (actually quite hard work to do properly), before painting on the coats of epoxy (hopefully they do put on the correct amount, some are reputed not to).

As almost all new boats are now built with a certain amount of isopthalic or vinylester resin in the outer layers (but probably cheapo ortho resins for the remainder) the first buyer usually doesn't bother to pay for epoxying - often new boat buyers expect to trade on or up in five years or so, so it should not affect them.

Most new car buyers don't pay extra either for extra undersealing and corrosion protection, they'll sell on long before it gets rusty.