Epoxy on top of bitumen?! Witchcraft!

[Llamedos]

31 minutes ago, captain flint said:

If - and it's *the* big if - the coating works as advertised, then that price would seem well worth not having to get in there every 3-5 years! 

I hope to be able to share them soon. Despite what the designer told me, my plan would be to remove all the bitumen and needle gun the tank. Tbh the main thing for me is it's impossible to grit blast inside the tank. Any reliably adhering epoxy coating without grit blasting sounds great. There are plenty of folk on here who reckon they've managed it, but most reliable folks I know reckon it's grit blast or bust, when it comes to being confident on an epoxy coating adhering. 

I had pretty much reached the point you have and was ready to pay the money. I was quite enthusiastic but then they stopped replying to me and I suppose I just cooled off. If you're interested I'm happy to send you their quote so you can compare it with what they send you.

 

My other issue was my general ability to work in the confined space of the tank - I'm 67, not exactly skinny and had visions of getting stuck down there. When the chap at our Marina offered to do it at a very reasonable price I took up his offer. He's done a reasonable job but I think I could have done better. I'm now going to fully empty and dry the tank each winter and maintain it as I go along, treating each area where the rust has started to appear with Vactan and more Bitumen. I won't be able to do that for ever of course, I know it will beat me in the end but I'll see how it goes.

Edited May 7 by Llamedos

[blackrose]

20 hours ago, cuthound said:

I would think that using epoxy over an existing coat results in an epoxy that is only adhered as strongly to the steel as the coat to which it is applied, unlike putting epoxy onto grit blasted steel, where the epoxy adheres as strongly as its designer intended.

 

Exactly. And that's all you have to understand to realise much of the waffle in the OP is irrelevant. Not having a pop at you Capt. Flint, just the guy that told you it could go over existing coatings such as bitumen. Once the bitumen starts coming off because its bond to the steel becomes weakened over time, then it doesn't matter how good the epoxy on top is.

Edited May 7 by blackrose

[captain flint]

6 minutes ago, Llamedos said:

I had pretty much reached the point you have and was ready to pay the money. I was quite enthusiastic but then they stopped replying to me and I suppose I just cooled off. If you're interested I'm happy to send you their quote so you can compare it with what they send you.

 

My other issue was my general ability to work in the confined space of the tank - I'm 67, not exactly skinny and had visions of getting stuck down there. When the chap at our Marina offered to do it at a very reasonable price I took up his offer. He's done a reasonable job but I think I could have done better. I'm now going to fully empty and dry the tank each winter and maintain it as I go along, treating each area where the rust has started to appear with Vactan and more Bitumen. I won't be able to do that for ever of course, I know it will beat me in the end but I'll see how it goes.

Yeah, it's a pretty grim job. Luckily I'm slim and short. 

 

Conversations I had when I wanted it done last:

 

Boat yard no 1:

 

- Can you do water tanks? 

 

- I can. But I won't. 

 

Boat yard no 2:

 

- water tanks? 

 

- no chance! 

 

- anyone on the river you know who will do them? 

 

- yes

 

- anyone you'd recommend? 

 

- no chance! 

 

Friendly (and clued up) boat yard lackey:

 

- I'm looking for someone to do my water tank. Interested? 

 

- ha ha ha ha ha ha no

 

- how can I find someone to do it? 

 

- what you need is someone slim and short and [gives me a hard look] has a vested interest in getting it done. 

 

I got the message. 

 

It is hard with these things to think a yard will do a really good job. Then again the yard who I finally found (some time after don't it myself) who could do it seem to be pretty good in general. They're only a few days' cruise away, though it involves going through London, which is a drag. 

 

 

2 minutes ago, blackrose said:

 

Exactly. And that's all you have to understand to realise much of the waffle in the OP is irrelevant. Not having a pop at you Capt. Flint, just the guy that told you it could go over existing coatings such as bitumen. Once the bitumen starts coming off because its bond to the steel becomes weakened over time, then it doesn't matter how good the epoxy on top is.

Fair enough, and it doesn't sound like you're having a pop at me at all don't worry. I do waffle, safe in the knowledge  nobody is forced to read what I write! 

 

As I said in an earlier post, the designer didn't think it would be an issue, but as I also said, I'd be removing all the bitumen, anyway. Just kind of interested in what he said. 

[blackrose]

43 minutes ago, captain flint said:

 

As I said in an earlier post, the designer didn't think it would be an issue, but as I also said, I'd be removing all the bitumen, anyway. Just kind of interested in what he said. 

 

Ok, if you remove the bitumen you'll get a much better job. 

[Hunter1]

 

1 hour ago, blackrose said:

 

Exactly. And that's all you have to understand to realise much of the waffle in the OP is irrelevant. Not having a pop at you Capt. Flint, just the guy that told you it could go over existing coatings such as bitumen. Once the bitumen starts coming off because its bond to the steel becomes weakened over time, then it doesn't matter how good the epoxy on top is.

 

My personal experience is that this is a reasonable claim from the sellers. I was sold a 2-pack for the hull (from PDI paints) that claimed to be fine over bitumen... I got as much bitumen as I could off, and applied the 2-pack. Pulled her out after 4 years and she could've gone straight back in - no issues with peeling.

 

I think with decent prep (not just slapping in on over, but mechanically removing as much bitumen as wants to come off) the results will still be good. No job will ever be perfect (without sandblasting, perhaps), and I understand your logic... but in reality, my experience indicates good results from a product with similar claims. 

 

I've been waiting for a potable-water friendly version of the same product, so I'm very interested to see if the OP goes ahead - and the cost too. 

[vicafloat]

Talking about the hull, my boat is out of the water at the moment and has just been grit blasted.

My experience indicates that 2 pack on steel which has not been grit blasted will fail; some paint will stick

most will not; even where it sticks there is a danger that water will creep under the epoxy.

[RAP]

Hello vicafloat,

Where did you get your boat grit blasted? 
Thanks, RAP

[vicafloat]

Hesford Marine at Lymm  01925 754639; Nigel Hamilton also runs Thorn marine at Stockton Heath.

Very helpful.

[RAP]

Thanks vicafloat, appreciated. I’m on the wrong side of the breach (L&L) to reach either of those boatyards.

[captain flint]

I've found someone who reckons they can shot blast inside my integral water tank! So my plan is to get that done then apply the potable epoxy mentioned in this thread