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Is two pack blacking more resistant to ice rubbing?


eid

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On 11/09/2020 at 16:41, eid said:

I had my boat blacked a couple of years ago in September. The following January the canal froze for a couple of days and when I moved about the boat the ice must have rubbed at the paint, because by the summer it was showing signs of rust. What a waste of money that was.

 

My question: Is Two-pack paint more resistant to this?

 

Any other tips (apart from "don't move") would be much appreciated.

Everything is relative but 2 pack is far more resistant to damage from ice. Ice for a couple of days doesn't sound a lot but how much did you move it and just how much rust? It could be normal but it sounds like the original job may not have been good.

Time to do a 2 pack will vary dependent on temperature. In the summer you could just do it in a week but that's pushing it and I wouldn't agree to that. As it cools off, even in a paint shed, if the temp is down to 15 deg C then you need a couple of days between coats to let the solvent out and a bit longer before it goes back in the water. Getting the solvent out the coating is important. 4 weeks seems a bit excessive but check with the yard for why they are taking 4 weeks, there may be a good reason. You need to be recoating within a few days as a second coat needs to be applied while the surface of the first coat is 'active'. 

Problems do occur with 2 pack application and we tested the coating off a boat a few years back that was significantly undercured. In BP, we always employed paint inspectors. Not easy for an individual.

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20 hours ago, nicknorman said:

Unlike bitumen, it doesn’t really dry, it cures. Usually it needs to stay out of the water for a couple of days (depending on the temperature and the exact product) after which it will seem hard, but it will continue to fully cure (underwater) for the next few weeks. Which is another way of saying try not to bash it too much until a couple of weeks have elapsed!

Interesting. And thanks, I'll keep that in mind.

Edited by eid
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1 hour ago, Dr Bob said:

Everything is relative but 2 pack is far more resistant to damage from ice. Ice for a couple of days doesn't sound a lot but how much did you move it and just how much rust? It could be normal but it sounds like the original job may not have been good.

Time to do a 2 pack will vary dependent on temperature. In the summer you could just do it in a week but that's pushing it and I wouldn't agree to that. As it cools off, even in a paint shed, if the temp is down to 15 deg C then you need a couple of days between coats to let the solvent out and a bit longer before it goes back in the water. Getting the solvent out the coating is important. 4 weeks seems a bit excessive but check with the yard for why they are taking 4 weeks, there may be a good reason. You need to be recoating within a few days as a second coat needs to be applied while the surface of the first coat is 'active'. 

Problems do occur with 2 pack application and we tested the coating off a boat a few years back that was significantly undercured. In BP, we always employed paint inspectors. Not easy for an individual.

To clarify, the ice damage (if this was in fact the cause) wasn't done by moving the boat. It was me moving inside the boat, causing it to rock.

I did move the boat once through ice, but it was very thin and mostly already broken up, I'm confident that little if any ice actually touched the sides (I was watching very intently as you can imagine), though there was some damage to the bows.

 

These were taken one year after the blacking was done (8 months after the freeze):

 

20190902_105547.jpg.bdb8a6ec5c9d75d9e0a005aead2cbf18.jpg20190902_105604.jpg.8dccaffcabdd59d1550c6bde3c9f649f.jpg20190902_105611.jpg.5a0a01688995e5ed3880f5ea9f3f9cf4.jpg20190902_105629.jpg.4eef7877baa955368783a2e8b776ec47.jpg

 

 

The marina wasn't interested in looking at it..

 

 

Thanks for the advice on the two-pac procedure. I'll keep that in mind when getting quotes. I believe the one I'm interested in has underfloor heating (pictured above).

 

 

 

Edited by eid
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Ah I think we misunderstood the question! I don't think the damage visible in your photos was to do with the boat rocking in ice. I think it is just wear and tear on "normal" blacking, perhaps not well applied. The rust showing below what is presumably a sink drain or other water outlet, clearly wasn't created by ice. Worth bearing in mind that "ordinary" bitumen blacking is dissolved by diesel or oil floating on the water.

 

We had our boat 2-pacced in 2012. 5 years later we lifted the boat out to check it. Having scrubbed the gunge and weed off near the water line, it was impossible to see where the waterline was. Absolutely zero rust along the water line. We gave it an abrasion and another coat but I don't think that was really necessary, except that the blacking had faded to a grey colour. So personally I would always go for 2-pac blacking. It is a lot more expensive than ordinary blacking because the boat has to be grit blasted, but it is worth it to not see rust developing along the water line for the second year of its life, and long term I think the costs are similar due to the long life of the 2-pac.

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3 hours ago, eid said:

To clarify, the ice damage (if this was in fact the cause) wasn't done by moving the boat. It was me moving inside the boat, causing it to rock.

I did move the boat once through ice, but it was very thin and mostly already broken up, I'm confident that little if any ice actually touched the sides (I was watching very intently as you can imagine), though there was some damage to the bows.

 

These were taken one year after the blacking was done (8 months after the freeze):

 

20190902_105547.jpg.bdb8a6ec5c9d75d9e0a005aead2cbf18.jpg20190902_105604.jpg.8dccaffcabdd59d1550c6bde3c9f649f.jpg20190902_105611.jpg.5a0a01688995e5ed3880f5ea9f3f9cf4.jpg20190902_105629.jpg.4eef7877baa955368783a2e8b776ec47.jpg

 

 

The marina wasn't interested in looking at it..

 

 

Thanks for the advice on the two-pac procedure. I'll keep that in mind when getting quotes. I believe the one I'm interested in has underfloor heating (pictured above).

 

 

 

That doesn't look like very well applied blacking. There are two areas where the most recent coat looks to have been applied over loose areas of the previous blacking, suggesting completely inadequate preparation. It also looks as if blacking may have been applied over bubbling rust just above the water line.

 

The area below the sink (?) outlet shows that regular exposure to soapy water is enough to dissolve the blacking.  Not surprising it has failed completely along the water line.

 

I don't think ice had anything to do with it.

Edited by David Mack
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1 hour ago, nicknorman said:

Ah I think we misunderstood the question! I don't think the damage visible in your photos was to do with the boat rocking in ice. I think it is just wear and tear on "normal" blacking, perhaps not well applied.

Sorry I didn't intend to go into all this at the start so I just repeated what they told me. I knew I hadn't damaged it by travelling through ice so assumed it must have been the boat rocking on an icy morning. The boatyard told me (without looking at it) that:

 

Quote

Parts of the canal waterways are highly affected by pollution and this affects and damages the blacking. Also the ice we endured last winter will also affect the blacking by scraping it off when on the move. Unfortunately these and other waterways factors are out of our control.

 

My opinion at the time was that it wasn't applied properly.

 

1 hour ago, David Mack said:

That doesn't look like very well applied blacking. There are two areas where the most recent coat looks to have been applied over loose areas of the previous blacking, suggesting completely inadequate preparation. It also looks as if blacking may have been applied over bubbling rust just above the water line.

 

The area below the sink (?) outlet shows that regular exposure to soapy water is enough to dissolve the blacking.  Not surprising it has failed completely along the water line.

 

I don't think ice had anything to do with it.

 

Exactly! The bubbling made me think the problem was below the paint. Unfortunately due to lack of experience I grudgingly accepted their explanation.

 

 

 

By the way, is two pack more resistant to diesel too?

Edited by eid
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17 minutes ago, eid said:

 

 

My opinion at the time was that it wasn't applied properly.

 

 

Exactly! The bubbling made me think the problem was below the paint. Unfortunately due to lack of experience I grudgingly accepted their explanation.

 

 

 

By the way, is two pack more resistant to diesel too?

I agree with David Mack. That blacking doesnt look like it was applied properly....but that's not difficult considering the weather we have in the UK. Slap it on, hope for the best, but those photos dont look good. 2 Pack will be far far more resistant to diesel.

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16 minutes ago, Dr Bob said:

 

I agree with David Mack. That blacking doesnt look like it was applied properly....but that's not difficult considering the weather we have in the UK. Slap it on, hope for the best, but those photos dont look good. 2 Pack will be far far more resistant to diesel.

 

The weather was warm and dry every day when this was done. I remember because I couldn't stop buying choc-ices.

 

I got a quote from Debdale. They have heated facilities but I think I'll wait till the spring anyway.

 

Thanks for the help.

Edited by eid
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