Jump to content

Twin pack or Bitumen


Featured Posts

Its your decision...what condition is your boat in and how long do you want it to last?

Two pack is a lot more expensive, the stuff itself is expensive, and the boat must be shot blasted which is costly.

With bitumen you need to redo it every two years, three at the most. You will likely see quite a bit of rust on the waterline, and some pitting by this time.

Two pack will only last 10 years if you use your boat very little, if you use the boat a lot then all the usually impacts, especially on some of  the narrow locks with protruding metal bits (such as Birmingham) will scrape off a bit of the epoxy. You should maybe get the boat after 4 years but you wont have to start from scratch, just repair any scrapes and put another coat or two on top. 

If you have any pitting then 2 pack should pretty much stop it dead.

Of course some boats rust from the inside out so it won't matter what you put on the outside.

If its an old low value boat and money is tight then its bitumen, if its an expensive or treasured boat then it should be 2 pack.

..................Dave 

  • Greenie 1
Link to comment
Share on other sites

49 minutes ago, dmr said:

Its your decision...what condition is your boat in and how long do you want it to last?

Two pack is a lot more expensive, the stuff itself is expensive, and the boat must be shot blasted which is costly.

With bitumen you need to redo it every two years, three at the most. You will likely see quite a bit of rust on the waterline, and some pitting by this time.

Two pack will only last 10 years if you use your boat very little, if you use the boat a lot then all the usually impacts, especially on some of  the narrow locks with protruding metal bits (such as Birmingham) will scrape off a bit of the epoxy. You should maybe get the boat after 4 years but you wont have to start from scratch, just repair any scrapes and put another coat or two on top. 

If you have any pitting then 2 pack should pretty much stop it dead.

Of course some boats rust from the inside out so it won't matter what you put on the outside.

If its an old low value boat and money is tight then its bitumen, if its an expensive or treasured boat then it should be 2 pack.

..................Dave 

Exactly my findings. We switched to two pack (ours is well used live aboard) and it is far more hard wearing. 

Link to comment
Share on other sites

I think these days most would go for something other than blacking but the problem is if you have a hull coated with bitumen it all has to come off before you can consider what to replace it with. The cost and hassle of grit blasting probably puts most owners off so they carry on with the laborious routine of a weeks docking every two years. 

But if I bought a boat "conventionally" blacked the first thing I would do would be have the stuff stripped off and use a 21st century solution for protecting the hull. 

   

Link to comment
Share on other sites

57 minutes ago, Neil2 said:

I think these days most would go for something other than [bituminous] blacking but the problem is if you have a hull coated with bitumen it all has to come off before you can consider what to replace it with. The cost and hassle of grit blasting probably puts most owners off so they carry on with the laborious routine of a weeks docking every two years. 

This.

Certainly while epoxy is not the only durable long lasting finish, if your paint is falling off in 2-3 years in this day and age, your using crap paint.

Daniel

Link to comment
Share on other sites

1 hour ago, Dylan said:

Exactly my findings. We switched to two pack (ours is well used live aboard) and it is far more hard wearing. 

 

1 hour ago, Neil2 said:

I think these days most would go for something other than blacking but the problem is if you have a hull coated with bitumen it all has to come off before you can consider what to replace it with. The cost and hassle of grit blasting probably puts most owners off so they carry on with the laborious routine of a weeks docking every two years. 

But if I bought a boat "conventionally" blacked the first thing I would do would be have the stuff stripped off and use a 21st century solution for protecting the hull. 

   

Absolutely - ours is 2 pack epoxy from new. Took her out of the water after 7 years, very little wear apart from high impact areas and a scratch from something we had scraped along underwater and no pitting, all the hull was cleaned and fresh coats applied on top with a good result. We also live aboard and move regularly, so glad we went down the 2 pack route.

Link to comment
Share on other sites

I know I bang on about this quite a bit but it never ceases to amaze me how many boats built within the last ten years you see still using bitumen, and the number of folk I meet who have spent (in some cases tens of) thousands on a cabin repaint but still slapping tar on the hull every 2/3years.  

Link to comment
Share on other sites

2 hours ago, DHutch said:

This.

Certainly while epoxy is not the only durable long lasting finish, if your paint is falling off in 2-3 years in this day and age, your using crap paint.

Daniel

Yes, unfortunately bitumen based blacking is crap paint with a recommended duration of 2-3 years between docking and repainting. It doesn't need to be falling off to need repainting. When I used to use bitumen I used 4 coats (2 x Rylards Rytex and 2 x Rylards Premium). That's about the best blacking you can get. I did more prep than most yards but the rust spots on the waterline still came back after 3 years. 

Bitumen is fine if you don't mind getting the boat out frequently and redoing it.

16 minutes ago, Dave Bebb said:

Thanks all for your comments i rang the chap who is going to do the job and he said he will pull her out go all over with a three something grinder and tell me witch is best to put on the boat 

If he's just using a grinder then forget about using two pack. It need to be properly gritblasted.

Edited by blackrose
Link to comment
Share on other sites

10 hours ago, Dave Bebb said:

Thanks all for your comments i rang the chap who is going to do the job and he said he will pull her out go all over with a three something grinder and tell me witch is best to put on the boat 

 

10 hours ago, blackrose said:

 

If he's just using a grinder then forget about using two pack. It need to be properly gritblasted.

I'd be a bit worried if he's going to "go all over" with a grinder, frankly. Blackrose is right, a grinder isn't the right prep for two-pack, so it won't help either preparation for that or in the decision imho.  When I black my boat (with the Rylards products mentioned as it happens) the object is to preserve as much metal as I can. A grinder takes metal off. They serve a purpose, but need to be used only where necessary and very sparingly at that. Old blacking also tends to melt and clog power tools that produce heat due to friction so, when conventional blacking, hand tools are certainly my preference where possible. I'm blacking my boat at the moment, just about to start coat No3, and guess how much I used a grinder in the preparation? (Not at all).

Whoever is doing the job for you may be absolutely excellent and I wouldn't wish to knock a professional's technique. Do be careful though, cos they all look pretty good once the blacking is on as the key bit, the preparation, is then unseen. The proof is in how long the stuff stays on, which is bad enough at 2-3 years even if very well done!

Do your research before you commit - a search here will reveal some lesser caring companies having them out and back in a day or two,  whereas it needs at least that just to harden off between final coat and relaunch.

Link to comment
Share on other sites

I've just noticed Dutton drydock, operated by Claymoores, are advertising that they used Lieghs Paints (now Sherwin Williams) Resistex M535 blacking 'as we have done on our hire fleet for years' .

This is the paint we have used on EmilyAnne an for the majority of her life, after an original Epoxy based blacking, very happy with it.

Daniel

Link to comment
Share on other sites

I used a glass flake two pack epoxy, over a surface tolerant glass flake two pack epoxy primer from Chemco International. I understand that it is now £12-£15 per Kg so not at all expensive for a coating that could last for 15 years or more if you don't scrape it off! Mine has been on for 8 years without any sign of deterioration at all. 

It is one of the hardest and best steel coatings available due to the inclusion of graded flakes of glass which align themselves with the surface of the steel and form a finish that is extremely resistant to abrasion.

If it should get a scratch or two, just clean off the area and touch it in with more of the same. They are happy to supply it in 1kg pots (plus activator) for this purpose.

They usually sell it in light grey, but they will supply it mixed to order in black which is what they did for me.

Link to comment
Share on other sites

On 15/08/2017 at 08:55, Sea Dog said:

 

I'd be a bit worried if he's going to "go all over" with a grinder, frankly. Blackrose is right, a grinder isn't the right prep for two-pack, so it won't help either preparation for that or in the decision imho.  When I black my boat (with the Rylards products mentioned as it happens) the object is to preserve as much metal as I can. A grinder takes metal off. They serve a purpose, but need to be used only where necessary and very sparingly at that. Old blacking also tends to melt and clog power tools that produce heat due to friction so, when conventional blacking, hand tools are certainly my preference where possible. I'm blacking my boat at the moment, just about to start coat No3, and guess how much I used a grinder in the preparation? (Not at all).

 

I assumed he meant a grinder with wire wheels - not a grinding disc! Lapping (flapwheel) discs can be used but they will also take off metal.

13 minutes ago, Bargebuilder said:

I used a glass flake two pack epoxy, over a surface tolerant glass flake two pack epoxy primer from Chemco International. I understand that it is now £12-£15 per Kg so not at all expensive for a coating that could last for 15 years or more if you don't scrape it off! Mine has been on for 8 years without any sign of deterioration at all. 

It is one of the hardest and best steel coatings available due to the inclusion of graded flakes of glass which align themselves with the surface of the steel and form a finish that is extremely resistant to abrasion.

If it should get a scratch or two, just clean off the area and touch it in with more of the same. They are happy to supply it in 1kg pots (plus activator) for this purpose.

They usually sell it in light grey, but they will supply it mixed to order in black which is what they did for me.

Jotamastic 87 epoxy also comes in a glass flake grade which is meant to be highly abrasion resistant. I've never used it myself. I used the Jotamasic 87 with aluminium grade when I did my boat.

Link to comment
Share on other sites

We've recently had a boat out at Langley Mill Boatyard which is 30 years old.  Covered in 2 pack and regularly cruises. No pitting and very minimal rust patches after being in the water for 10 years since the last docking...... It's made me think about whether I switch over at some point.....

 

Dan

Link to comment
Share on other sites

Flap wheels and cup brushes are not recommended for steel preparation prior to coating as both have a polishing effect, actually making the surface profile more 'slippery' and harder for any paint to stick to on a microscopic level. As always, the quality and logevity of any paint finish is primarily down to the standard of the preparation; assuming, of course, it is a good product to start with.

Link to comment
Share on other sites

10 minutes ago, Bargebuilder said:

Flap wheels and cup brushes are not recommended for steel preparation prior to coating as both have a polishing effect, actually making the surface profile more 'slippery' and harder for any paint to stick to on a microscopic level. As always, the quality and logevity of any paint finish is primarily down to the standard of the preparation; assuming, of course, it is a good product to start with.

On an optical level the steel may appear polished, but on a microscopic level you'll actually find steel that's been prepped with a wire wheel is anything but polished. Epoxy sticks to steel prepped with wire wheels just fine. 5 years ago I worked prepping the bilges of two c1890s Thames steam launches and we only used wire wheels because needle guns and any other method were thought to be too aggressive. We had technical advice from the people who worked on the Cutty Sark project and I think they know what they are talking about. Flap wheels actually give a good key but they also take off metal.

I had the lower hull of my own boat gritblasted prior to painting with epoxy but prepped the bow deck with wire wheels and used the same paint. It's stuck really well.

Edited by blackrose
Link to comment
Share on other sites

There was a boatyard in the North West that was offering an epoxy coating service without grit blasting a few years ago, they tried used a scabbler to remove the blacking...  This enterprise did not last very long.
 

Link to comment
Share on other sites

Just in case anyone is considering the cost of dry docking and applying as I did £1600 worth of two pack, anticipating many years of maintenance free service, please think hard about investing in the best possible preparation.

Of course the coating will stick to wire brushed steel, but no manufacturer would recommend this form of preparation over grit blasting, because the resulting surface profile isn't as 'grippy' to the epoxy. The very point of using this super tough product is to end up with the best possible level of protection for the longest possible period of time and so cutting corners at the preparation stage is a false economy.

 

Link to comment
Share on other sites

I will be having my boat 2 packed in September  it was shot blasted and 2pacted 4 years ago  so I will see first hand how good this as stood up ,in my mind for something to last 7/ 10years   under water I have my doughts ,but the proof will be in the pudding  come September 

 

Link to comment
Share on other sites

As I mentioned, mine is exactly the same in appearance now as it was 8 years ago when it was applied; no rust, no pitting, no flaking.

The preparation was wet grit blast, the coating was glass flake epoxy and the hull has been in sea water for the entire 8 years, which is much more aggressive than fresh water.

Link to comment
Share on other sites

8 hours ago, Neil2 said:

There was a boatyard in the North West that was offering an epoxy coating service without grit blasting a few years ago, they tried used a scabbler to remove the blacking...  This enterprise did not last very long.
 

It would take about 30 seconds to jam the scabbler with melted bitumen :P 

Link to comment
Share on other sites

On 8/15/2017 at 20:19, Dave Bebb said:

Think i will go for Bituman this time and think about twin pack when the bank balance looks better  

I think that's a sound decision. You don't know how long the blacking will last (1) in you home water and (2) with the amount of use you get from the boat. These both affect the periods between applications. 

Another aspect is that periodic blacking isn't the only reason for dry-docking/slipping the boat. For one thing, the anodes may need replacing but you can't tell, if the boat is still in the water.  

Link to comment
Share on other sites

Mine is zingered I still take it out every 2 years to repair the impact damage :blush: the cost of this is not expensive in comparison to the cost of doing the job in the first place. Plus it allows me to check the prop etc, boating is a rough world and the only boats that dont need that maintenance are the ones that dont move

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.