'BITUROSS' & water-tank crying.

[Slim]

6 hours ago, Bee said:

Screwfix sell stainless socket screws and the nuts to fit, I use them a lot. Might not be big enough though so you might have to look around a bit, they are not very expensive but I you are asked for lots of money then keep looking!

I just googled my local 'nuts and bolts supplier) Orbital Fasteners. For A2 S/S countersunk socket screws 8mm x 25mm they want £11.85 per 100. Anytime I've bought small quantities from them they charge pro rata on the smallest on line quoted price so under £2 for 10 and so on. Just a guide price ?

Edited August 4, 2020 by Slim

[Lady_Why]

Thankfully I screwed my brain back on and realised it might be worth emailing various paint suppliers. Turns out Bituross was a bitumen. Would have saved me a lot of confusion and faffing if I'd done that on day 1 - I'm on a messy learning curve with this water tank. ? I'm also learning about millscale for the first time & what it looks like. I just want to say: this group is a life saver in terms of picking up vital pieces of info. ❤️

Still, hard to tell what is dark millscale or remains of very old bitumen. And I'm running out of time. I've seen that some just Vactan their tank, but since I have the time to overcoat this weekend, I'm thinking to brave it with Epoxy. I know it won't marry well with either millscale or any missed bits of bitumen, but I'm hoping (quite possibly crazily) that the sheet of Vactan will hold onto the surface and, gently abraded, hold any Epoxy on top of it.

I am half expecting an explosion of "NOOOOOO"s to follow on this happy-go-lucky statement.... In which case, I'll jump the bus and get potable bitumen instead.
 

(I kind of know I shouldn't Epox it, since I haven'd done sufficient prep work on the steel)

 

On 04/08/2020 at 15:03, Slim said:

I just googled my local 'nuts and bolts supplier) Orbital Fasteners. For A2 S/S countersunk socket screws 8mm x 25mm they want £11.85 per 100. Anytime I've bought small quantities from them they charge pro rata on the smallest on line quoted price so under £2 for 10 and so on. Just a guide price ?

Thank you for the google info! The boat yard told me they've got the screws, so I will leave this part to their expertise. They are still fighting to get all of the brass bits out from the previous screws...

 

Edited August 7, 2020 by Lady_Why

[dmr]

from me its a "probably best not" rather a "NOOOOOO".

 

If you get all the loose stuff off the epoxy will likely stick, though not as well as it would to bare steel, and epoxy is better paint than anything else, though more expensive.   Two problems worry me.  Epoxy is strong, almost like a sheet of plastic, and whole areas might detach and so trap water behind them. This will be more troublesome on the tank sides than the tank bottom. The second bigger problem is that it might not last too long and you will need to remove at least some of it before redoing, and sanding/grinding through epoxy can be hard work and very unpleasant.

 

.................Dave

[Lady_Why]

Thank you, Dave! The tank is currently Vactaned & I've been lying in it (not crying, but slightly annoyed with myself) to have a think about my options based on what I've read up so far:

1. The boat yard thinks Epoxy is a good idea, but I don't. I've seen the work still to be done in the tank; they've only glanced at it. Areas of millscale alone makes it risky.
 

2. Whack Bitumen on the Vactan (but this may fall off the millscale too, if I don't succeed to abrade it? and then also be a real bother to take off if I want to do Epoxy next time).
 

3. Just stick to Vactan, empty it once a year to work a little bit more on it & re-apply Vactan (I assume this is doable while in the canal, as long as plate is warm enough?). By spending 3 years removing all of the old bitumen gradually, I can then do the epoxy next time I'm craned out for blackening.

.

The last option seems the most sensible, but also lazy. And I always start to suspect myself when the lazy option sounds good! I was brought up that hard work is good work, but I simply don't have the time or heart to start from scratch again to do it all right. 

 

[dmr]

If you really do have millscale (is this a very new boat?) then I think you are correct, just do it in anything for now and maybe do a bare steel/epoxy in a few years time when you are better prepared. In fact even if its not millscale I would postpone the epoxy for a while.

Note that there might be an argument for using Vactan over lightly rusted steel but not over bitumen or anything else. I believe its not a good primer, its only attraction is that it bonds to rust. Any potable blacking is likely the best option.

 

If you do the big epoxy job in summer you will not need to take the boat out of the water which might be much easier, though ideally do it at a boatyard or otherwise get access to a needlegun to remove the stubborn bits.

[Tracy D'arth]

18 minutes ago, dmr said:

 

 

If you do the big epoxy job in summer you will not need to take the boat out of the water which might be much easier, though ideally do it at a boatyard or otherwise get access to a needlegun to remove the stubborn bits.

I would disagree unless .the water in the canal is over 15 degrees, epoxy will not cure properly below that temperature. Its easier out of the water, the condensation in the tank by the operator breathing is lessened.

 

If you want to get this job over and done with, slap 2 coats of bitumen on, its all that was used long before we were born and it worked then.

Going all fancy with epoxy is fine but if the prep is not correct, ie. bare steel, its not right and possibly a waste of time and effort. You know bitumen will work.

 

Its like when they were re-roofing York Minster after the fire. The choices were steel or oak trusses, they could not decide. Steel was faster and cheaper. oak took time and skilled workers.

Someone asked how long the steel would last, they could not get an answer so the went for oak because they knew from history that it would last for at least 200 years.

[Lady_Why]

26 minutes ago, dmr said:

If you really do have millscale (is this a very new boat?) then I think you are correct, just do it in anything for now and maybe do a bare steel/epoxy in a few years time when you are better prepared. In fact even if its not millscale I would postpone the epoxy for a while.

Note that there might be an argument for using Vactan over lightly rusted steel but not over bitumen or anything else. I believe its not a good primer, its only attraction is that it bonds to rust. Any potable blacking is likely the best option.

 

If you do the big epoxy job in summer you will not need to take the boat out of the water which might be much easier, though ideally do it at a boatyard or otherwise get access to a needlegun to remove the stubborn bits.

No, not a new boat. The bitumen must have come off and the exposed steel gotten millscale. OR it was millscale on it from the very start in 1987 and people have just painted over it for some reason. There is a definite difference between the clean steel & dark millscale.

I could do a blacking, but I guess I'm concerned at the hard work of taking it off to do an Epoxy later. Ultimately, I want to work towards an Epoxy given the all around concerns about bitumen in water tanks.

4 minutes ago, Tracy D'arth said:

I would disagree unless .the water in the canal is over 15 degrees, epoxy will not cure properly below that temperature. Its easier out of the water, the condensation in the tank by the operator breathing is lessened.

 

If you want to get this job over and done with, slap 2 coats of bitumen on, its all that was used long before we were born and it worked then.

Going all fancy with epoxy is fine but if the prep is not correct, ie. bare steel, its not right and possibly a waste of time and effort. You know bitumen will work.

 

Its like when they were re-roofing York Minster after the fire. The choices were steel or oak trusses, they could not decide. Steel was faster and cheaper. oak took time and skilled workers.

Someone asked how long the steel would last, they could not get an answer so the went for oak because they knew from history that it would last for at least 200 years.

Thanks, Tracy! I think bitumen might have to be it...  still attracted to Epoxy in the long run. Sounds like you have to do the job less often once the Epoxy is on.

[dmr]

3 minutes ago, Tracy D'arth said:

I would disagree unless .the water in the canal is over 15 degrees, epoxy will not cure properly below that temperature. Its easier out of the water, the condensation in the tank by the operator breathing is lessened.

 

If you want to get this job over and done with, slap 2 coats of bitumen on, its all that was used long before we were born and it worked then.

Going all fancy with epoxy is fine but if the prep is not correct, ie. bare steel, its not right and possibly a waste of time and effort. You know bitumen will work.

 

Its like when they were re-roofing York Minster after the fire. The choices were steel or oak trusses, they could not decide. Steel was faster and cheaper. oak took time and skilled workers.

Someone asked how long the steel would last, they could not get an answer so the went for oak because they knew from history that it would last for at least 200 years.

 

Mine was done in the water though I confess I have not been back in to see how well it has lasted. We had no condensation problems and the epoxy set nicely. We had the option of a low temperature hardener but the standard stuff was fine. 5 degreeC was the lower limit and that's no problem. I used the lovely Armourguard ST which is sadly no longer available, but I suspect Joton offer something equivalent?.

 

.................Dave

[Man 'o Kent]

I may have missed it but why has nobody suggested grit blasting?

 

It'd take less than a day and provide an ideal surface for painting.

 

On the downside if it cannot be operated from outside then it would be a truly evil job requiring good protective gear. Cleaning all the detritus out afterwards would be "interesting" too.

 

So what have I overlooked?

[dmr]

3 hours ago, Man 'o Kent said:

I may have missed it but why has nobody suggested grit blasting?

 

It'd take less than a day and provide an ideal surface for painting.

 

On the downside if it cannot be operated from outside then it would be a truly evil job requiring good protective gear. Cleaning all the detritus out afterwards would be "interesting" too.

 

So what have I overlooked?

 

I think you have answered your own question ?.

[Man 'o Kent]

4 hours ago, dmr said:

 

I think you have answered your own question ?.

Yes and no. My experience with grit blasting is confined to small jobs in a cabinet with them long rubber gloves. (Yes Matron )

There must be other circumstances where an operator will not fit for one reason or another. Would then there not be a sufficient demand for the development of extensions/devices, something along the lines of a pressure washer wand or what-have-you to make such work economic/possible?

Therein lies the  purpose of my post, to see if there are Forum members out there with more knowledge of the grit blasting process, its advantages and its limitations that could be prompted into a useful reply.

[Boaty Jo]

An alternate approach??

 

Perhaps a chat with these folks?

 

https://www.maxkote.co.uk/shop/maxline-100-flexible-water-tank-lining/#:~:text=MLI 100 – Flexible water tank lining,-SKU%3A MLI100 Tags&text=Maxline 100 flexible lining and,protection against erosion and corrosion.

 

https://www.corrolesseastern.co.uk/services/tank-reline-tank-linings/

[Chewbacka]

19 hours ago, Lady_Why said:

No, not a new boat. The bitumen must have come off and the exposed steel gotten millscale. OR it was millscale on it from the very start in 1987 and people have just painted over it for some reason. There is a definite difference between the clean steel & dark millscale.

I could do a blacking, but I guess I'm concerned at the hard work of taking it off to do an Epoxy later. Ultimately, I want to work towards an Epoxy given the all around concerns about bitumen in water tanks.

Thanks, Tracy! I think bitumen might have to be it...  still attracted to Epoxy in the long run. Sounds like you have to do the job less often once the Epoxy is on.

Just information for you - mill scale is formed as part of making (rolling) the steel plate in the steel mill.  It does not form later, so once it has gone it has gone forever.  As to why it wasn’t removed in the first place?  Well as you are finding it is hard work, and if hidden in a water tank the original buyer would have no idea it was there, so very tempting to leave it.