I bought a boat! 2 pack or not 2 pack...

[JGL]

So I have just *TODAY* bought my first narrowboat. Super excited to get on the water!

 

The surveyor was impressed with the steel, saying it was impeccable condition... largely because the hull was shot blasted and had a very good layer of 2-pack epoxy put on when it was only 2 years old (it's now 17).

 

The surveyor thought that after the first epoxy layer it then then been blacked with bitumen. Meanwhile the previous owner said that this was not the case it's always been re-epoxy'd.. clearly without the shot blasting each time. I've no reason to doubt the previous owner, and a plausible explanation seems to be that the boat has never had any bitumen, but the subsequent coats of epoxy (after the first one) were not adhering very well (perhaps the old surface wasn't being prepared properly?)

 

I'm not sure whether to just get it jet-washed and then put normal bitumen blacking on (this was the surveyors suggestion, an approach he was keen on and thought was sensible) or whether to try and get the epoxy re-done properly... thoughts?!

 

Any input appreciated!

[OldGoat]

I'm not an expert on this matter - probably duch will post while I'm typing this.

My thoughts suggest that if you can find a good yard who are prepaterd to examine the blacking and IF their opinion is that theblacing is easy to remove - leaving a good base for more epoxy  - then do that.

Contrarywise if they feel that the underliying coating is poor - then proceed to shot blast and re epoxy.

 

If you don't intend to keep the boat for any real length of time, perhaps just black it..

The real cost of epoxy is the shot-blasting phase - hence my suggestion.

 

Happy to be corrected by folks whose boats are on the acid canals...

[JGL]

No, that makes sense.

 

What I want to avoid is the shot-blasting (because, as you say, that's the most expensive bit). 

As far as I know it's only ever had epoxy on since the first coat, but for whatever reason subsequent coats haven't stuck well...

[Alan de Enfield]

26 minutes ago, JGL said:

Any input appreciated!

Presumably you are not planning to have this done until next May / June, in which case you have plenty of time to plan, get quotes and book a yard.

[JGL]

Just now, Alan de Enfield said:

Presumably you are not planning to have this done until next May / June, in which case you have plenty of time to plan, get quotes and book a yard.

Well actually the boat is out of the water at the moment, so seems to make sense to get it done. The cold/wet shouldn't matter with the right hardener.. I think.

29 minutes ago, JGL said:

So I have just *TODAY* bought my first narrowboat. Super excited to get on the water!

 

The surveyor was impressed with the steel, saying it was impeccable condition... largely because the hull was shot blasted and had a very good layer of 2-pack epoxy put on when it was only 2 years old (it's now 17).

 

The surveyor thought that after the first epoxy layer it then then been blacked with bitumen. Meanwhile the previous owner said that this was not the case it's always been re-epoxy'd.. clearly without the shot blasting each time. I've no reason to doubt the previous owner, and a plausible explanation seems to be that the boat has never had any bitumen, but the subsequent coats of epoxy (after the first one) were not adhering very well (perhaps the old surface wasn't being prepared properly?)

 

I'm not sure whether to just get it jet-washed and then put normal bitumen blacking on (this was the surveyors suggestion, an approach he was keen on and thought was sensible) or whether to try and get the epoxy re-done properly... thoughts?!

 

Any input appreciated!

Having thought all this through I guess my questions are actually:

 

1) How can I tell categorically one way or the other whether there is any bitumen on the hull currently? Soak a rag in white spirit and see if it rubs off? I guess epoxy shouldn't rub off.

2) Assuming there is no bitumen currently on... what do I need to do to prep/prime the old paint for a new coat?

[Alan de Enfield]

1 minute ago, JGL said:

Well actually the boat is out of the water at the moment, so seems to make sense to get it done. The cold/wet shouldn't matter with the right hardener.. I think.

I think it will. With either 'bitumin' or 2-pack

 

Be careful not to waste your money.

[JGL]

2 minutes ago, Alan de Enfield said:

I think it will. With either 'bitumin' or 2-pack

 

Be careful not to waste your money.

.. I'm trying to not waste it... that's why asking questions!

On the epoxy front I'd looked at Jotamastic 87 winter grade, which seems to be used in quite harsh environment. This is what their data sheet says.

 

 

[Dr Bob]

31 minutes ago, JGL said:

Well actually the boat is out of the water at the moment, so seems to make sense to get it done. The cold/wet shouldn't matter with the right hardener.. I think.

 

NO!

The wet is an absolute killer. Any moisture on the surface will stop an epoxy sticking to grit blasted steel. The steel temperature has to be at least 2-3°C above the dew point - difficult in the winter. Yes you can get epoxy hardeners to work down to 5°C but how do you expect the solvent to evaporate properly at those low temperature. Applying epoxies at low temps is a compromise and I wouldnt do it at less than 15°C.  At this time of year you need a well heated paint shop and even then your steel temp will be low. If you are spending £5K, I would wait until May or June.

 

31 minutes ago, JGL said:

 

1) How can I tell categorically one way or the other whether there is any bitumen on the hull currently? Soak a rag in white spirit and see if it rubs off? I guess epoxy shouldn't rub off.

 

If it is a coal tar epoxy (very good coatings for this type of use...but now banned) then you will see brown rubbing off but not as much as a blacking coating.

 

Use a sharp pen knife to see if you can prise the coating off. Try it at a dozen places all over the boat. If it comes off in chips/small pieces then that substrate will be no good to do a 2 pack coating without grit blasting. It may be worth then to give it a few coats of blacking and do the epoxy in a couple of years time. Blacking also requires a dry surface and you have to get the solvent out between coats so again it needs a decent temperature.

Edited November 25, 2019 by Dr Bob

[ditchcrawler]

The hardest bit will be getting the right dew point to apply it especially if you have to grit blast.

[Sea Dog]

14 minutes ago, JGL said:

Well actually the boat is out of the water at the moment, so seems to make sense to get it done. The cold/wet shouldn't matter with the right hardener.. I think.

That, for me, has answered your question: I'd definitely not be using bitumen with the steel cold.  A winter cure 2 pack may be your only choice short of having to black her indoors.  @Dr Bob might be along to advise on winter 2 pack.

Edited November 25, 2019 by Sea Dog
Well, like Santa, he's been whilst I was wasn't looking!

[cuthound]

27 minutes ago, JGL said:

Well actually the boat is out of the water at the moment, so seems to make sense to get it done. The cold/wet shouldn't matter with the right hardener.. I think.

Having thought all this through I guess my questions are actually:

 

1) How can I tell categorically one way or the other whether there is any bitumen on the hull currently? Soak a rag in white spirit and see if it rubs off? I guess epoxy shouldn't rub off.

2) Assuming there is no bitumen currently on... what do I need to do to prep/prime the old paint for a new coat?

 

My boat was epoxied from new and this year has been retreated. At 12 years old the hull is still in excellent condition.

 

1) Will prove if it ha been coated in bitumen of domestic, as the white spirit soaked cloth will dissolve these coatings, but not epoxy.

 

2) For my boat they roughed up the existing epoxy with a wire brush wheel in an angle grinder where the coating was sound. In a few areas around the stem post, the costing was beginning to fail. Here they used an angle grinder to remove the loose coating back to bright bare metal. They then applied additional coats of epoxy.

 

As Dr Bob says, the success of epoxy coating is weather dependent. I booked my boat in for blacking in August to ensure that high ambient temperatures were more likely.

 

I would wait until the summer for reblacking. The hull won't deteriorate in that short time.

Edited November 25, 2019 by cuthound
To add the last paragraph

[Dr Bob]

5 minutes ago, Sea Dog said:

That, for me, has answered your question: I'd definitely not be using bitumen with the steel cold.  A winter cure 2 pack may be your only choice short of having to black her indoors.  @Dr Bob might be along to advise on winter 2 pack.

 

13 minutes ago, JGL said:

.. I'm trying to not waste it... that's why asking questions!

On the epoxy front I'd looked at Jotamastic 87 winter grade, which seems to be used in quite harsh environment. This is what their data sheet says.

 

 

As I said above, I wouldnt use this type of coating in the winter.

Jotamastic 87 contains around 25% solvent (so likely a mix of xylene and ethylbenzene - it will be on the MSDS sheet). How the heck do you get that solvent to evaporate below 10°C. At those temperatures I might think about patching damaged areas but not multiple coats. Also if you read the tech data sheet it says you need to add thinners to get the flow right so that does mean adding xylene and ethylbenzene which is what their thinner no.7 contains. That's even more solvent to get out.

Any low temperature epoxy coating is a compromise over the standard grade. It is designed for use in areas where it is impossible to do the application properly. You will not get the adhesion that the standard coating applied at a reasonable temperature will give. There is a higher risk you will waste your £5K. Wait until next May/June. Your application is not an area which is impossible.

About a year ago, we had someone come on here saying that their 2 pack epoxy (winter grade) had been applied and was still soft after a few weeks. I organised some samples and got them tested which proved the application was at fault ie the boat yard. This was an independent test which was backed up by the findings of the paint manufacture who had to test it (they weren't happy) because we had the data to force them to do it. What on earth do you do when you have spent £5k on a coating that should last 10 years and it hasnt been put on properly?

[JGL]

14 minutes ago, Dr Bob said:

NO!

The wet is an absolute killer. Any moisture on the surface will stop an epoxy sticking to grit blasted steel. The steel temperature has to be at least 2-3°C above the dew point - difficult in the winter. Yes you can get epoxy hardeners to work down to 5°C but how do you expect the solvent to evaporate properly at those low temperature. Applying epoxyies at low temps is a compromise and I wouldnt do it at less than 15°C.  At this time of year you need a well heated paint shop and even then your steel temp will be low. If you are spending £5K, I would wait until May or June.

 

If it is a coal tar epoxy (very good coatings for this type of use...but now banned) then you will see brown rubbing off but not as much as a blacking coating.

 

Use a sharp pen knife to see if you can prise the coating off. Try it at a dozen places all over the boat. If it comes off in chips/small pieces then that substrate will be no good to do a 2 pack coating without grit blasting. It may be worth then to give it a few coats of blacking and do the epoxy in a couple of years time. Blacking also requires a dry surface and you have to get the solvent out between coats so again it needs a decent temperature.

Thanks Bob this is really useful.

So... point taken re: weather, that sounds like I should wait until next year (If I do, should I get the hull jetwashed now, or leave the 'several years' worth of green stuff on it?)

Next, I don't want to grit-blast at all (if that was required then I'd probably just fall back to normal blacking - if that makes sense?) The only way I'd continue with the epoxy is if it's got a decent base for new coats (which I *think* it does). I'll aim to use your method to tell whether it's any good or not... 

 

4 minutes ago, cuthound said:

 

My boat was epoxied from new and this year has been retreated. At 12 years old the hull is still in excellent condition.

 

1) Will prove if it ha been coated in bitumen of domestic, as the white spirit soaked cloth will dissolve these coatings, but not epoxy.

 

2) For my boat they roughed up the existing epoxy with a wire brush wheel in an angle grinder where the coating was sound. In a few areas around the stem post, the costing was beginning to fail. Here they used an angle grinder to remove the loose coating back to bright bare metal. They then applied additional coats of epoxy.

 

As Dr Bob says, the success of epoxy coating is weather dependent. I booked my boat in for blacking in August to ensure that high ambient temperatures were more likely.

.. this was the sort of approach I was hoping would be viable.. but even so, wait until next year?

[Dr Bob]

2 minutes ago, JGL said:

Thanks Bob this is really useful.

So... point taken re: weather, that sounds like I should wait until next year (If I do, should I get the hull jetwashed now, or leave the 'several years' worth of green stuff on it?)
 

Impossible to say without seeing it but its not going to harm it by leaving it until the summer as cuthound says.

If it has had blacking on then you are ultimately going to have to grit blast before an epoxy is applied so you could water blast it and slap a bit of a 'tolerant' blacking on the bad bits ...ie Keelblack. Never tried it myself but it should help and might get you through more than a year.....but only do this IF it has been blacked before as it will need grit blasting if you then decide to put epoxy on. If it hasnt had blacking then you will still need to grit blast for epoxy to remove loose old coating but it could be a lot less work.

I spent a large number of years managing a team developing surface toleratant epoxy coatings so know how they work, how they dont work and what makes them go wrong. We bought our first narrowboat 3 years ago and have blacked it twice. For me hull corrosion is not a 'top of the list' item. There is enough steel there for years. I will get round to a 2 pack maybe in 18 months when it is due for blacking again but I cant get excited about it. Far more important things to consider like toilets, pram covers and ecofans......and learning about your batteries! I do understand your question as the boat is out of the water.

 

[cuthound]

15 minutes ago, JGL said:

but even so, wait until next year?

 

Yes, any further deterioration between now and next late Spring or Summer will be minimal.

 

I would not jet wash it until it goes in for blacking, as there is a small risk that jet washing will lift any areas of blacking that are not well adhered to the hull.

[The Dreamer]

1 hour ago, JGL said:

get it jet-washed and then put normal bitumen blacking on

Someone round these parts, but can’t remember who, reminded me that this is effectively what they do to cruise ships (epoxy first, then paint on top).  These boats don’t come out the water from one decade to the next, so I’d say it’s a good call.

 

BTW, was desperate to find a suitable Tupac quote, but was hampered by the legends lack of interest for inland waterways.  Some rappers just have no taste!

[Alan de Enfield]

I was 2-packing our boat in September - it turned out to be a disaster.

 

Every morning was a very heavy dew, I'd wipe it down with Kitchen roll and get it dry, by the time I'd finished the start was damp again with dew.

 

I thought I'd managed to get a coat on, but 3 days later it was still 'wet', you could push the paint up into a 'wave' with a paint brush. It just didn't 'set'

 

I've given up until late Spring.

[mark99]

Whirling hygrometer. 

[Bee]

What Dr. Bob says about testing the coating to find out if its bitumen or epoxy is quite true. Coal tar epoxy is now banned but if you give it a wipe with thinners or white spirit you may well get a bit of brown rubbing off. This might have misled the surveyor, it might also mislead the boatyard. If the previous owner said its epoxy I would believe him, it is very likely coal tar epoxy.

[cuthound]

Dr Bob's penknife test will prove it. Bitumen based coatings are soft and I able. 2 pack is hard.

 

However most epoxy coatings do not contain coal tar.

[Dr Bob]

1 hour ago, cuthound said:

Dr Bob's penknife test will prove it. Bitumen based coatings are soft and I able. 2 pack is hard.

 

However most epoxy coatings do not contain coal tar.

Coal tar epoxies are commoner than you think. In the 80's, 90's and 00's they were the 'go to' coating for BP for anything to do with water ie all splash zones, jetties tank bottom internals where water might be the bottom layer (crude tanks). They are disappearing now as coal tar is deemed unsafe but they were very very good coating with slightly more flexibility than standard epoxies. Not a clue how widespread their use was on the canals.

[JGL]

14 hours ago, Dr Bob said:

Far more important things to consider like toilets, pram covers and ecofans......and learning about your batteries! I do understand your question as the boat is out of the water.

 

@Dr Bob - thanks. I think you may have saved me from a silly mistake. I'll wait until the new year and go from there. Kind of amazes me that the yards in the business would be happy to take my cash, when presumably they know (or might at least have an inkling) that it isn't the most sensible route forward...

I think the plan is put her back in the water in her new home (The Lancaster Canal), wait until warmer weather, in the mean time try and find somebody who knows their way around the issues and come up with a sensible plan (the surveyor's advice to pressure wash and then put normal blacking on is starting to make more sense now too).

 

??

18 minutes ago, Dr Bob said:

Coal tar epoxies are commoner than you think. In the 80's, 90's and 00's they were the 'go to' coating for BP for anything to do with water ie all splash zones, jetties tank bottom internals where water might be the bottom layer (crude tanks). They are disappearing now as coal tar is deemed unsafe but they were very very good coating with slightly more flexibility than standard epoxies. Not a clue how widespread their use was on the canals.

I'll hopefully get back to the boat with a rag and some thinners later.. let's see what happens.

[JGL]

14 hours ago, The Dreamer said:

BTW, was desperate to find a suitable Tupac quote, but was hampered by the legends lack of interest for inland waterways.  Some rappers just have no taste!

Glad somebody noticed the potential play on words with the title.. from Shakespear to Tupac was always the intention. You could go with this:

 

"Don’t change on me. Don’t extort me unless you intend to do it forever." - I think he was trying to say make sure you shot blast the hull before applying a new coat of epoxy ?

[sirweste]

I'd say if you're keeping the boat for 3 or more year the 2-pac is worth the extra initial cost. I assume the yearly cost will work out to be very similar if considered against getting it out of the water for reblacking every 2 years.

 

Mine was 2-pac'ed before I bought it,  as a live-aboard I'm so glad I don't have to faff about getting it re-blacked every couple of years.

[Detling]

At this time of year even rust works very slowly, like all chemical reactions it is temperature sensitive.  You may find that any boat yard that can do grit blasting is already booking next summer, some are booking 18 months ahead.