Where to get the best deal on Vactan?

[jetzi]

I am refitting my aftmost room. First stripping out the horrible fibreglass/MDF lining and 50mm polystyrene insulation. Wire brush and wipe clean with damp cloth. Then treating the rust with Vactan. Skipping painting the vactan i think. Then using sprayfoam to stick Celotex boards down, taping the joints with aluminium tape.

 

The polystyrene was stuck down with some sort of silicone adhesive which is tough to get off. Removing as much as I can with a stripping knife and then I'm not sure - orbital sander maybe?

 

Where can I get the best deal on this Vactan stuff? Are there any just as good generic brands? Here is a 5L on eBay for 58.2 GBP plus 10 postage. This says it will be good for 40sqm which is more than I need but will surely come in handy. Does it go off?

 

https://www.ebay.co.uk/itm/121067559041

 

Also one sense check - am I being foolish to not scrub right down to metal and prime? If so, what primer do you recommend?

 

Here is a pic so you can see what I'm working with.

 

 

[Captain Fizz]

Rotary wire brush in an angle grinder to remove the surface rust(wear a dust mask) then vacant/fertan then prime.

[MtB]

2 hours ago, ivan&alice said:

Does it go off?

 

Yes. Pot life once opened, 6 months IIRC.

 

 

 

[TheBiscuits]

2 hours ago, ivan&alice said:

The polystyrene was stuck down with some sort of silicone adhesive which is tough to get off. Removing as much as I can with a stripping knife and then I'm not sure - orbital sander maybe?

Nothing will beat an electric multitool with a scraper blade on it.  They are about £25, and come in handy for more boat jobs than you can think of.

 

Aldi or Lidl have them in occasionally, Screwfix or Toolstation stock them permanently.

 

[jetzi]

7 hours ago, Captain Fizz said:

Rotary wire brush in an angle grinder to remove the surface rust(wear a dust mask) then vacant/fertan then prime.

I am not sure about taking a power tool to the rust if I am going to be using Vactan. You still want enough rust for it to adhere don't you? I was planning on using a manual wire brush to remove the flaky bits. If I was going to use an angle grinder wouldn't it make sense to get the rust off completely and then prime?

 

I have been put off fertan by other posts in this forum. The fact that you need to rinse it, plus the fact that it doesn't prime by itself.

 

What is the reason for priming after Vactan? Just an extra layer of protection or are you not confident in Vactan's priming ability? Or is it to cover the bits that Vactan won't stick to due to lack of rust?

 

Do you have a primer that you could recommend, or anything in particular I should look for?

 

5 hours ago, Mike the Boilerman said:

Yes. Pot life once opened, 6 months IIRC.

OK. I better buy just enough then. Thanks.

 

5 hours ago, TheBiscuits said:

Nothing will beat an electric multitool with a scraper blade on it.  They are about £25, and come in handy for more boat jobs than you can think of.

 

Aldi or Lidl have them in occasionally, Screwfix or Toolstation stock them permanently.

 

Do you mean the oscillating ones? I am not sure it will get close enough to the surface to take all the gunk off, but it would get most of it I'm sure. Perhaps the angle grinder with wire brush would handle the rest.

 

[Sea Dog]

6 hours ago, Mike the Boilerman said:

 

Yes. Pot life once opened, 6 months IIRC.

 

 

 

It says something like this on the instructions,  but I've had a litre which came in a plastic bottle for a couple of years or so now. Kept in the cool and dark place, it still seems as good as ever when used as first aid on upper deck rusty bits to stem the tide before a more permanent paint repair. 

[Murflynn]

why is it so important to remove the adhesive?  it ain't going anywhere, and I wouldn't expect any rust to form underneath it.

you don't need to leave a level surface because you are going to use expanding foam adhesive to stick your boards in place.

if you apply an all-over coat of spray adhesive (as opposed to dabs) then you will have effectively primed the surface - why apply another primer?

Edited June 6, 2019 by Murflynn

[jetzi]

10 minutes ago, Murflynn said:

why is it so important to remove the adhesive?  it ain't going anywhere, and I wouldn't expect any rust to form underneath it.

you don't need to leave a level surface because you are going to use expanding foam adhesive to stick your boards in place.

if you apply an all-over coat of spray adhesive (as opposed to dabs) then you will have effectively primed the surface - why apply another primer?

I guess it isn't so important. Where it has come off, it has taken the paint with it and rust has formed there since it was unproteted metal. I suppose I really just want to be certain that I don't have patches rusting away under my nice new lining.

Is the "all over coat of spray adhesive" that your are referring to the spray foam adhesive?

Perhaps I'm being overly dilligent here. Quick once over with a wire brush, vactan, then spray foam might be enough?

[WotEver]

8 hours ago, Mike the Boilerman said:

 

Yes. Pot life once opened, 6 months IIRC.

So the label says, however I’ve successfully used a bottle that had been opened three years previously with total success. 

1 hour ago, Sea Dog said:

It says something like this on the instructions,  but I've had a litre which came in a plastic bottle for a couple of years or so now. Kept in the cool and dark place, it still seems as good as ever when used as first aid on upper deck rusty bits to stem the tide before a more permanent paint repair. 

Ahh... beaten to it. Yes, agreed. 

[WotEver]

41 minutes ago, ivan&alice said:

Perhaps I'm being overly dilligent here. Quick once over with a wire brush, vactan, then spray foam might be enough?

Yes. Manual wire brush just to get any loose stuff off. Vactan the whole area and wait for it all to go black. In my experience Vactan sticks well to sound paint, so no need for a separate primer and definitely no need to prime on top of Vactan. 

[WotEver]

47 minutes ago, ivan&alice said:

I suppose I really just want to be certain that I don't have patches rusting away under my nice new lining.

The important thing here is not to try to avoid any gaps between the new insulation and the steel but to ensure that all gaps and seams between the new insulation are sealed. So once the insulation is in place fill any large gaps with expanding foam and cover all the seams with metallic tape. You are aiming to create a vapour barrier between the inside of the boat and the steel.