Blacking or epoxy coating?

[steve hayes]

As we need our 70ft narrowboat blacked this year we might go down the 2 pack route the quotes we have had range from £2000 - £2500 is this about the norm for a 70ft narrowboat, I am just trying to get some idea of costings. Those prices are for the work to be done and include vat etc.

Cheers

 

We paid about £1,400 about three years ago for a 58ft'r

 

Steve

[nicknorman]

As we need our 70ft narrowboat blacked this year we might go down the 2 pack route the quotes we have had range from £2000 - £2500 is this about the norm for a 70ft narrowboat, I am just trying to get some idea of costings. Those prices are for the work to be done and include vat etc.

Cheers

Does that include gritblasting? As I understand it 2pac should be applied to bare shiny steel, or over old 2pac that has been abraded.

[Ex- Member]

As we need our 70ft narrowboat blacked this year we might go down the 2 pack route the quotes we have had range from £2000 - £2500 is this about the norm for a 70ft narrowboat, I am just trying to get some idea of costings. Those prices are for the work to be done and include vat etc.

Cheers

 

Hi les

 

 

 

I would definitely highly recomment 2 pack, after applying his myself i understand it;s properties. Read through this thread which describes the painting process. We applied 6 coats of jotun on a shot blasted surface. Shott blastting and paint cost a grand.

 

2k + vat seems about right, I would insist on 1 coat barrier primer if on shot blasted urface, 2 coats jotun 87 and 2 x hardtop,paint cost about £600 in paint inc v.a.t

 

 

http://www.canalworl...pic=20642&st=40

 

Just noticed your pm, will post tthis regardless, let me know if you want more info.

Edited January 30, 2013 by Julynian

[lesrollins]

Thanx i will ask about it being primed first. After it as been shot blasted

[tmy5645]

I wasnt joking when i said POLYUREA..

 

Applied to blasted steel, High build spray applied coating which cures in under 10 seconds.

 

www.polyteccoatings.co.uk (fully mobile spray units)

Edited February 3, 2013 by tmy5645

[oasis]

I wasnt joking when i said POLYUREA..

 

Applied to blasted steel, High build spray applied coating which cures in under 10 seconds.

 

www.polyteccoatings.co.uk (fully mobile spray units)

 

In a previous life I was an engineer in pulp/paper mills and I used to have tanks lined with fabric backed plastic sheeting. These were simply epoxied into place and the joins overlapped and hot air welded. Worked well in submersed and abrasive applications with huge side entry mixers. Most linings were done in PVDF or ABS depending on the chemicals involved.

 

What I am seriously considering is doing this to the hull of my narrowboat. 2 or 3 mm thick with epoxy paint "glue" joining the fabric backed sheet and hull, providing a secondary protection. As has been pointed out on this thread all my hull scrapings are above the waterline so I am considering replaceable panels of the stuff in the damage prone areas. Corrosion? Electrolysis? Weeds? Things of the past methinks.

 

So Polyurea is not something to be scoffed at

[Philippe]

Hammerite

[tmy5645]

In a previous life I was an engineer in pulp/paper mills and I used to have tanks lined with fabric backed plastic sheeting. These were simply epoxied into place and the joins overlapped and hot air welded. Worked well in submersed and abrasive applications with huge side entry mixers. Most linings were done in PVDF or ABS depending on the chemicals involved.

 

What I am seriously considering is doing this to the hull of my narrowboat. 2 or 3 mm thick with epoxy paint "glue" joining the fabric backed sheet and hull, providing a secondary protection. As has been pointed out on this thread all my hull scrapings are above the waterline so I am considering replaceable panels of the stuff in the damage prone areas. Corrosion? Electrolysis? Weeds? Things of the past methinks.

 

So Polyurea is not something to be scoffed at

 

"Polyurea is not something to be scoffed at" it sure isnt..

 

Polyurea is usually applied to a DFT of 2 - 2.5mm although it can be applied to vertually any thickness. (it is NOT paint)

 

Why people are still using bitumen etc in this day and age, i dont know. (obviously cost and DIY friendly is the main reason)

[Timleech]

"Polyurea is not something to be scoffed at" it sure isnt..

 

Polyurea is usually applied to a DFT of 2 - 2.5mm although it can be applied to vertually any thickness. (it is NOT paint)

 

Why people are still using bitumen etc in this day and age, i dont know. (obviously cost and DIY friendly is the main reason)

 

Maybe nobody has actually seen a boat which has been coated with polyurea and bashed around the canal system for a few years?

 

Most people will be wary of paying out serious money for something which is unproven in this context.

 

Tim

[tmy5645]

Maybe nobody has actually seen a boat which has been coated with polyurea and bashed around the canal system for a few years?

 

Most people will be wary of paying out serious money for something which is unproven in this context.

 

Tim

 

Whats the average bashing that goes on? (on average)

 

I read that most bitumen blacking suffers from water line damage rather than bashing into things?? Do you rate bitumen as good/bad protection from impact and abrasion? Or just the the fact its easy to apply?

 

How does the above compare to the epoxy coatings?

 

Finally, what else has been tried and tested over the years?

[Ex- Member]

Whats the average bashing that goes on? (on average)

 

I read that most bitumen blacking suffers from water line damage rather than bashing into things?? Do you rate bitumen as good/bad protection from impact and abrasion? Or just the the fact its easy to apply?

 

How does the above compare to the epoxy coatings?

 

Finally, what else has been tried and tested over the years?

 

Bitumen is popular for boat hulls, and it is very cheap. Howerer it really is not fit for purpose, it will degrade quite quickly at the water line especially if it comes into contact with oils or diesel spillage, which it will almost certainly do quite quickly. The water line is he area most susseptable to rust as it has constant access to air and water, so there seems little sense on applying a product that will degrade quickly in the place you need it most.

 

Bitumen/tar can be scraped from a hull using your thumbnail. On the canals you will encounter all sorts of debris that can potentially scratch and remove tar from the hull, the biggest effects of scratcing will come from mooring and having to navigate close to canal banks when passing otther boats. Fenders will help protect paintwork but not 100%, then you have your gener bumping and scraping in locks and wih other cratf generally.

 

Our boat was on the water for 18 months, prior to this tthe sides were given 4 coats of bitumen. When the boat came out the water the majority of bitumen had disappered about 3 inches either side of the water line, a line of light rust replaced it all around the boat. Lots of bitumen was scraped and missing on many parts of the hull. Although we were on the water for 18 months we didn't navigate that far, possibly 50 to 60 miles up and down the canal, for 6 months we were on a winter mooring and hardly moved.

 

Bitumen is a complete waste of money.

 

At minimum use a product that won't degrade when in contact with surface oils & greases.

 

2 pack paints are expensive but extremely hard and applied to a shot blasted surface extremely difficult to remove. We've given our boat hull sides 6 coats of Jotun 2 pack, the rest of the boat 5 coats and base plate 3 coats This cost around £600 in paint, but we saved money painting ourselves.

Edited February 5, 2013 by Julynian

[Lizzy]

Hi, digging up an old thread here that I found when searching for scratches on epoxy blacking. Everybody here seems to agree that epoxy is extremely hard wearing. I had 2 coats of Hempadur applied last coat Fri two weeks ago. Professionally done as far as I can tell in a boatyard with a good reputation. When I went back into the water last week and travelled through 8 locks (no significant impact other than the normal touching the lock walls and tying up on the towpath) a lot of it has scratched off on the rubbing strake and also below it. The scratches go right down to the primer. I was shocked by this as I hadn't expected this to come off so quickly. When contacting the boatyard I was told that no blacking survives impact of a multi-ton boat and that this is normal. 

 

I am convinced that something has gone wrong here, no idea what. After almost two weeks drying time I can still easily scratch it with my fingernail. It has rubbed off just from where the tyre fender touches it too.

 

Should I be able to scratch it so easily? I am not sure how to come back to the boatyard, but I guess fingernails is a pretty objective kind of measure versus me trying to prove that I didn't bang into anything. )I have scratches even at the stern and I don't know how I would even have done that without reversing hard into something!

[rusty69]

I wouldn't think you should be able to scratch it that easlily. I would get the boat back to them for their opinion.

 

ETA Did they gritblast it prior to application? How long was it allowed to cure for and at what average temperature (its been a bit chilly lately).

Edited October 4, 2018 by rusty69

[Lizzy]

12 minutes ago, rusty69 said:

I wouldn't think you should be able to scratch it that easlily. I would get the boat back to them for their opinion.

 

ETA Did they gritblast it prior to application?

Yes gritblasting, primer, and sprayed two coats epoxy. It cost a fortune. It rained on the second coat shortly after application and got some surface grey markings from that, but they told me it's not a problem for the curing or durability.

[rusty69]

5 minutes ago, Lizzy said:

Yes gritblasting, primer, and sprayed two coats epoxy. It cost a fortune. It rained on the second coat shortly after application and got some surface grey markings from that, but they told me it's not a problem for the curing or durability.

Very disappointing. Hopefully some epoxy experts will be along shortly.I would think an epoxy coating would be hard if properly cured, unless the wrong ratio of epoxy to hardner were used,or the temperature too low for curing, or not left to cure for long enough before immersion.

 

Stick around, you'll probably get some better informed opinions than mine.

Edited October 4, 2018 by rusty69

[bizzard]

Something goe wrog I reckon. Probably dampness between the primer ad top coats.  Ordinary bitumen blacking wouldn't scrape off with just a finger nail.  I'd mention Trading Standards,  but don't threaten them with it, be diplomatic, and say something like, ''If it was anyone else they'd be getting in touch with Trading Standards''.

[Lizzy]

They have a five star reputation online and they are the only boatyard doing gritblasting in the area. I hope I can convince them to have another look at it. 

[Bee]

Well I'm not an expert but that all sounds disappointing, epoxy is hard stuff, rubbing strakes will soon lose their paint but you really should not be able to shift it with a fingernail and I think you might have to take a deep breath and return to the boatyard, my guess is that they used the wrong hardener or the wrong ratios. It might be a good idea to get in touch with the paint makers and get an opinion as to what has happened, they will not want their paint to get a bad reputation. Good luck - keep us posted.

[peterboat]

On 05/09/2012 at 16:13, NB Lola said:

Timely debate

 

I considered the zinga option but was too much for my wallet.

 

The boat has blacking at present so we are bringing it out early October to check steel and decide. Once we have reviewed quality we will decide on treatment based on degradation since last it was out . I am keen to also see baseplate and understand extent of pitting, with some spot welding if needed. Just two years ago it had 8.4 integrity from 10 at the most pitted point.

 

Intwresting how well some boats fare re epoxy and if the price is right I would do that (bearing in mind shot blasting will need to be paid for) and lift her out annually anyway for a look at her nether regions.

I did the zinga option it was no more expensive than epoxy it is lasting very well so I can recommend it ?

[Rob-M]

We've just got our boat out of the water having had it grit blasted and epoxy coated nearly three years ago. Only bits with damage to the coating is the rubbing strakes.

[rusty69]

Well, perhaps if you are lucky, the yard in question has a representative on this site, so may get in touch? 

[Detling]

You cannot avoid oil on the water and if you use the boat you cannot avoid rubbing stonework. Bitumen fares badly in both these cases and although epoxy suffers from rubbing it is no worse than bitumen.  Several of the boats caught up in the river lee oil pollution incident this year had to be reblacked. even though they had been blacked only months/weeks before. They are still waiting for compensation.

[matty40s]

It sounds like it has been done outdoors, which at this time of year is a no-no. The coat rained on might as well not have been done and if the next coat was applied whilst still damp then the whole coat will never cure properly as damp has bee n embedded to the coating. I expect to lose Comastic off rubbing strakes over time,not below or above, hence my wonderful 25 years survey.

 

[Dr Bob]

4 hours ago, Lizzy said:

Hi, digging up an old thread here that I found when searching for scratches on epoxy blacking. Everybody here seems to agree that epoxy is extremely hard wearing. I had 2 coats of Hempadur applied last coat Fri two weeks ago. Professionally done as far as I can tell in a boatyard with a good reputation. When I went back into the water last week and travelled through 8 locks (no significant impact other than the normal touching the lock walls and tying up on the towpath) a lot of it has scratched off on the rubbing strake and also below it. The scratches go right down to the primer. I was shocked by this as I hadn't expected this to come off so quickly. When contacting the boatyard I was told that no blacking survives impact of a multi-ton boat and that this is normal. 

 

I am convinced that something has gone wrong here, no idea what. After almost two weeks drying time I can still easily scratch it with my fingernail. It has rubbed off just from where the tyre fender touches it too.

 

Should I be able to scratch it so easily? I am not sure how to come back to the boatyard, but I guess fingernails is a pretty objective kind of measure versus me trying to prove that I didn't bang into anything. )I have scratches even at the stern and I don't know how I would even have done that without reversing hard into something!

Lizzie, if you can mark the coating with a finger nail after two weeks, then there is a problem with the coating. Get the yard out to inspect it and take a video of you making that mark with your finger nail. If the won't come out, then threaten them with the county court. Then contact Hempel and complain to them with the video. Hemel should send out a tech to do a surface hardness measurement but your video will be the evidence you need. 

I would advise looking at a bit of the hull not affected by scratches or rubbing strakes and scratching it with various object, i.e. Finger nail, cocktail stick, plastic stick, screw driver etc to assess which makes a mark. Video it for evidence. If it is soft them you should push the yard.

Feel free to pm me. I can then give you advice over the phone. I used to formulate epoxy coatings in a previous life.

I will look up the relevant surface hardness tests - I should know them but my brain is getting old. They test surface hardness with a sharp probe! I think we used a screwdriver.

The yard who did the work maybe very defensive but Hempel should try and get to the bottom of it.

There are many reasons why the coating would be soft - 80% down to the yard and 20% to Hempel (give or take 20%).

[Dr Bob]

9 hours ago, Dr Bob said:

Lizzie, if you can mark the coating with a finger nail after two weeks, then there is a problem with the coating. Get the yard out to inspect it and take a video of you making that mark with your finger nail. If the won't come out, then threaten them with the county court. Then contact Hempel and complain to them with the video. Hemel should send out a tech to do a surface hardness measurement but your video will be the evidence you need. 

I would advise looking at a bit of the hull not affected by scratches or rubbing strakes and scratching it with various object, i.e. Finger nail, cocktail stick, plastic stick, screw driver etc to assess which makes a mark. Video it for evidence. If it is soft them you should push the yard.

Feel free to pm me. I can then give you advice over the phone. I used to formulate epoxy coatings in a previous life.

I will look up the relevant surface hardness tests - I should know them but my brain is getting old. They test surface hardness with a sharp probe! I think we used a screwdriver.

The yard who did the work maybe very defensive but Hempel should try and get to the bottom of it.

There are many reasons why the coating would be soft - 80% down to the yard and 20% to Hempel (give or take 20%).

Lizzy, now the effect of last nights beer has worn off, I can again think again.

To quantitatively test the hardness of a coating, you need a test meter. However most paint inspectors will assess hardness via a simple test and that is all you need for now. Get hold of a small sharpish pen knife. Push the blade into the coating at around 30 to 45 degrees as if you are trying to make 'curls' on a slab of butter. Use reasonable force...i.e. Half way between full force and nothing. One of three things is going to happen.

1. The blade will slip over the surface and maybe leave a slight scratch. Coating cured ok.

2. The blade will chip off a piece of hard coating. Cured ok but maybe not good adhesion between one of the coats.

3. It will make a paint curl with the coating looking Cheesey. Coating not cured properly. 

I would try this out at a number of points around the hull to see if it is an isolated issue. Video it and let me see the video. Important to check it if the boat has been predominantly turned one way to the sun in the past 2 weeks. Test in the sunny area and in the shady area. Were is the boat located. The south east has been quiet warm but the north west not.

If your tests show it is cheesey, then call the boatyard and get them to check it. Also call Hempel. If it's  cheesey all over then it sounds like a full grit blast and repaint job. The yard are not going to be happy. 

Report back after the knife test and let's take it from there.