Painting gas locker with jotamastic 87 epoxy

[agg221]

4 minutes ago, dmr said:

This chemco stuff sounds too good to be true (😀). I might get some and give it a go, but if its so good why does everybody keep using Jotun and International etc???? I had a look at their website but its "corporate" rather than technical.

I know people tend to end up sounding like a walking advert for it, but I don't have any affiliations. There are several advantages, the first being that it is sold directly so is cheaper, the second that it is solvent free (100% solids) which makes it nicer to handle and coincidentally it also means it works on a wet surface which can be handy, although I try to dry the surface anyway. The main reason it is not more widely known is because of familiarity I suspect. International and Jotun are well known brand names in the marine world and they have a deservedly good reputation, however if you transfer to a different sector with similar needs (offshore oil and gas in this case) you find there are different brands used. Most people tend to stay within a sector so there can be little crossover in terms of awareness with consequent lack of technology translation. Coincidentally, I have made a living out of this fact for the last 20yrs so I am well aware of it!

 

The website points you at a coatings advisor and I have found their technical advice to be excellent. I suspect they do this because they want to check they are providing a solution which will work rather than damage their reputation when someone inadvertently buys the wrong product having mis-read some guidance online. Coincidentally I buy other paints from HMG Coatings South (Andover) for the same reason, and not from HMG in the NW which is headquarters, as I don't find their technical advice to be as good. No, I am not a paint snob, but I don't really enjoy painting so I like to buy paints which will do the job for as long as possible before I have to do it again.

 

Alec

[blackrose]

14 hours ago, agg221 said:

It does help to get everything clean and degreased before painting. Given the weather forecast I would be inclined to use a good detergent in water rather than a solvent - plenty of time for it to dry before you apply the first coat. I would also consider using a phosphoric acid rust converter before painting as it will take out a lot of the rust you can't get to down the pits. 

 

No. The last thing you want to do is get the prepped steel wet before painting. It will just start gingering. And rust converters are not recommend under epoxy paints. 

[Bargebuilder]

6 minutes ago, blackrose said:

The last thing you want to do is get the prepped steel wet before painting. It will just start gingering.

Of course, if the Chemco coating is used, wet gingered steel will have no detrimental effect on its adhesion or performance.

[Bargebuilder]

12 minutes ago, Bargebuilder said:

Of course, if the Chemco coating is used, wet gingered steel will have no detrimental effect on its adhesion or performance.

I should add, that  Epo-chem™ RS 500P is the perfect wet and surface tolerant two pack epoxy primer to use if your boat is going to be wet grit blasted or very high pressure water blasted, as the wet bright steel will ginger before your eyes before you get a chance to paint it.

 

Chemco also supply their superb glass flake epoxy coating for a premium super hard wearing finish.

 

Let them advise you.

[blackrose]

40 minutes ago, Bargebuilder said:

Of course, if the Chemco coating is used, wet gingered steel will have no detrimental effect on its adhesion or performance.

 

Jotamastic 90 can handle damp gingered steel too, but I'd rather start with a good dry substrate.

 

Anyway, that's all very well but Chemco or J90 are not the paints that the OP has. He was specifically asking about Jotamastic 87, so while I'm sure it might be of interest to others contemplating doing similar jobs, I'm not sure banging on about Chemco is really very helpful to the OP. 

 

Personally I'd rather use Jotamastic than Chemco on my boat because I know the products and know how to use them. I don't believe that a paint you slap onto wet rusty steel will ever be as good as an epoxy applied to a properly prepared dry surface. But at the end of the day like everything else it's all down to personal choice. 

Edited July 9, 2022 by blackrose

[dmr]

If you paint on to a wet surface where does the water go?

[blackrose]

1 minute ago, dmr said:

If you paint on to a wet surface where does the water go?

 

My thoughts too. It might be tolerated but it certainly can't help. 

[agg221]

43 minutes ago, blackrose said:

 

No. The last thing you want to do is get the prepped steel wet before painting. It will just start gingering. And rust converters are not recommend under epoxy paints. 

Most of the year I would agree with you, but under the very specific weather conditions which the OP is working (high air temperature and low humidity) it will be possible to clean and degrease the surface and wipe it dry again with the residual surface water film being evaporated off before gingering occurs. If I was working in a similarly confined space I would do that in preference to being exposed to high concentrations of solvent vapour which would be increased due to the current weather conditions (rate of evaporation will be high).

 

Phosphoric acid as a rust converter, as per my original comment, is fine under epoxy, since you are simply bonding epoxide groups to phosphate, rather than to oxide (even bright clean steel has an oxide layer at the surface since it forms within seconds). The type -not- to try and coat over with epoxy as a general rule is a rust converter which forms a film, usually the chemical reaction being formation of a tannate. The film is often latex (Vactan) but sometimes PVA. This is a less effective combination as the epoxy is then not in direct content with the inorganic surface but is separated by a more weakly bonded polymer layer. That said, if I had nothing else to hand I would still use Vactan or similar as an intermediate step, then wire brush it back off before painting, on the grounds that the areas where it was not removed (down deep pits) would still be better as converted, coated phosphate or tannate than as loose rust.

 

Alec

 

[Marc Pyn]

Hey folks. So this is as far as have got and feel we can go with the tools we have. We haven't wiped it down but can anyone advise if it looks ok to go forward with epoxy at this stage once we have. We've used all the tools suggested and spent a good couple of days so hoping we can? Pics not great but looks ok. Many thanks for your input

[dmr]

Thats good enough, well done, but looks like you have not finished bottom right?  also go up the side wall at least a couple of inches. I used Armourguard rather than Joton, its a nice light grey. If I was using Jotun I would get it in light grey or similar rather than black to make it nice and light inside that locker, then maybe paint the sides in Danboline to match. If you have black put that on for now and order some light grey for the final coat. Once you get into epoxy any that you buy will not go to waste,   inside any side lockers, well deck, back deck etc etc.,

[Marc Pyn]

5 minutes ago, dmr said:

Thats good enough, well done, but looks like you have not finished bottom right?  also go up the side wall at least a couple of inches. I used Armourguard rather than Joton, its a nice light grey. If I was using Jotun I would get it in light grey or similar rather than black to make it nice and light inside that locker, then maybe paint the sides in Danboline to match. If you have black put that on for now and order some light grey for the final coat. Once you get into epoxy any that you buy will not go to waste,   inside any side lockers, well deck, back deck etc etc.,

Thanks Dmr. Yeah this is as far as we can get. With the bottom and partway up sides. Can we use the epoxy now once it's wiped? Its all we have here

[Bargebuilder]

25 minutes ago, blackrose said:

Personally I'd rather use Jotamastic than Chemco on my boat because I know the products and know how to use them. I don't believe that a paint you slap onto wet rusty steel

The Chemco product might just be superior, but you'll never know if you always stick to the same familiar coating.

 

My barge was in a boat yard next to a steel boat that had been wet grit blasted and had gingered badly. The owner turned up and started painting on the Chemco primer mentioned. About half way through painting, it started to rain, heavily, but for whatever reason he continued painting the steel that was dripping with water. Eventually, the roller tray containing the primer collected enough rain to cover the surface of the paint and he continued, pushing the roller through the water to pick up the primer. Needless to say I was horrified, thinking to myself that he was wasting his time and the coating and the blasting that was far from cheap.

 

My fit-out took 4 years and the painted boat sat next to me for all of that time and no rust showed through in all of that time. He hadn't even applied a second coat, let alone a top coat.

That is what converted me to the Chemco rage, well, that and the excellent price.

 

I applied 80Kg of Chemco primer and glass flake epoxy to my barge and 11 years later it is entirely intact and shows no sign of thinning or needing re-coating.

 

When I sold my barge, the coating was one of the things that the buyer identified as making my vessel more desirable than others he viewed.

 

Try something new, you may be converted.

 

 

25 minutes ago, blackrose said:

Personally I'd rather use Jotamastic than Chemco on my boat because I know the products and know how to use them. I don't believe that a paint you slap onto wet rusty steel

The Chemco product might just be superior, but you'll never know if you always stick to the same familiar coating.

 

My barge was in a boat yard next to a steel boat that had been wet grit blasted and had gingered badly. The owner turned up and started painting on the Chemco primer mentioned. About half way through painting, it started to rain, heavily, but for whatever reason he continued painting the steel that was dripping with water. Eventually, the roller tray containing the primer collected enough rain to cover the surface of the paint and he continued, pushing the roller through the water to pick up the primer. Needless to say I was horrified, thinking to myself that he was wasting his time and the coating and the blasting that was far from cheap.

 

My fit-out took 4 years and the painted boat sat next to me for all of that time and no rust showed through in all of that time. He hadn't even applied a second coat, let alone a top coat.

That is what converted me to the Chemco rage, well, that and the excellent price.

 

I applied 80Kg of Chemco primer and glass flake epoxy to my barge and 11 years later it is entirely intact and shows no sign of thinning or needing re-coating.

 

When I sold my barge, the coating was one of the things that the buyer identified as making my vessel more desirable than others he viewed.

 

Try something new, you may be converted.

 

 

[ditchcrawler]

2 hours ago, blackrose said:

 a properly prepared dry surface. But at the end of the day like everything else it's all down to personal choice. 

In which case you have to blast, have the correct steel temperature and the correct humidity.

[agg221]

2 hours ago, Marc Pyn said:

Hey folks. So this is as far as have got and feel we can go with the tools we have. We haven't wiped it down but can anyone advise if it looks ok to go forward with epoxy at this stage once we have. We've used all the tools suggested and spent a good couple of days so hoping we can? Pics not great but looks ok. Many thanks for your input

 

I know this isn't what you want to hear, but I think you at least need to get the paint off in the bottom right hand corner. I know how tedious this is - if it isn't shifting with a brush of any sort then sharpening up the end of something to use as a sharp chisel/scraper may make life easier. It could be anything - old hacksaw blade with tape wrapped round the handle, sacrificial wood chisel that gets sharpened up again afterwards, even grind the end of a piece of bar or an old bolt down to a sharp edge. If you don't, it will still last a decent amount of time but that's the area where it will eventually fail earlier than if it's clean.

 

Sorry.

 

Alec

[Marc Pyn]

Not at all - really appreciate everyones insights - Hammer and chisel worked well for my dad but left the front corner part where the red paint didn't appear to be rusted and that corner looks to be the same as the side. We didn't get to painting on the sat and will be moving on tomorrow so will be looking at next options while not in a marina. Thanks again to everyone for their responses. Great forum

Edited July 11, 2022 by Marc Pyn

[Marc Pyn]

One last question - aside from the chemco option - which I have messaged them about - is there any compatible rust converter / protector / whatever the right term is - that I can apply to the current preparation that would be beneficial? One that ideally I could buy from the shelf as we will be on the move now but somethijg that protects the current state of prep and ideally compliments the application of the epoxy 87? I'm aware that it will be a couple of weeks before I can complete the job now we are moving as we will be without gas for the 2 x 24 hours it takes to dry - and also feel I should put something on the steel to protect it in case any water gets in from the drainage holes. Its a new (to us) boat so as they are a few inches above water line im guessing this may happen when moving. I saw phosphoric acid mentioned by  @agg221 but Im not sure where to find. Would this be a good solution for our current prep with the epoxy 87? Many thanks 

[blackrose]

50 minutes ago, Marc Pyn said:

One last question - aside from the chemco option - which I have messaged them about - is there any compatible rust converter / protector / whatever the right term is - that I can apply to the current preparation that would be beneficial? One that ideally I could buy from the shelf as we will be on the move now but somethijg that protects the current state of prep and ideally compliments the application of the epoxy 87? 

 

One last answer: NO.

 

Jotamastic 87 is designed to be applied directly to steel without using any rust converters. You should mechanically remove the rust with power tools to preparation standard SA 2 - SA2.5 Understanding surface preparation grades when painting steel (rust.co.uk). You can achieve this with grinders, wire wheels, cups and wire brush attachments for drills for the corners. 

 

Read the TDS for the product. Jotamastic 87 Technical Data Sheet Application Guide

[dmr]

As your prep is pretty good the use of rust converters will be counter-productive. If, when you come to paint, you have a bit of surface rust then just do a quick going over with your wire brush in the angle grinder, the rust will come off really easily. Maybe a hand wire brush will be adequate.

[agg221]

Personally, I would degrease first using something as basic as soapy water, wipe the surface as dry as possible and then apply a rust converter, following the instructions which usually require leaving for a period of time and then wiping off the excess. Immediately before painting I would then run the wire brush in the drill over it to remove as much of the converted coating as possible. The reasons for this are that in the meantime it will seal up the surface if any water splashes in whilst moving, making it easier to get it dry again, and it will give a better surface than any residual loose rust down the pits where your cleaning can't remove it. SA2-2.5 cannot realistically be achieved on steel with reasonably deep pits without either grinding back, needle gunning or media blasting, none of which would be practical in this case. Most of the surface is clean, which is good enough, but pragmatically I would rather have the small areas which are not (where rust is still there in the bottom of the pits, and in your photograph the bottom right hand side) converted to a sealed phosphate than left loose as if you get any break-through it will start from those areas, particularly if they have been wet.

 

Rust converters come in two basic types. One is simply an acid solution which forms an insoluble salt on the surface (usually orthophosphoric forming a phosphate); the other is an acid solution which also contains a dissolved film-forming polymer, usually latex (Vactan) or PVA. This type often uses tannic acid to form a tannate as it does not degrade the organic material which forms the film. If you do apply a rust converter, go for the type which does not form a film. Jenolite Rust Remover is a good bet. Avoid Hammerite Kurust. Where are you currently and what towns are you passing through that may be able to sell you something?

 

Once you are ready to paint, you run the power wire brush over the surface which takes off most of the phosphate, wipe out the dust with a bit of solvent on a clean rag or paper (white spirit, meths, isopropyl alcohol hand sanitiser, all are good). Then allow the surface trace solvent to rapidly evaporate off and get the paint on.

 

Others will take a different approach but this is how I would do it, and is in fact pretty much what I am doing inside my counter as it gets wet in there every time I open the weed hatch.

 

Alec

[Marc Pyn]

 Thanks everyone - much appreciated