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It appears my boat has two pack anti-fouling, two questions.

1, Can I cover with plain bitchumastic.

2, If I stick with two pack can I mix with two pack from different companies. 

I have no idea which two pack was used previously and the marina advises I cant pain over with two pack from a different manufacturer.

Any help or information would be most welcome.

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Scrub hard with white spirit, epoxy 2 pack will not wash off. I suspect that the makers like to hook you into their product, but epoxy is just epoxy, it seems to be compatible across the board.

Once you have used bitumastics you lose all the advantages of 2 pack, like 10 to 20 year life. Ordinary blacking will not adhere well to 2 pack either.

If you want 2 pack at a sensible price ask Sherwin-Williams in Bolton, used them for years. My hull has done 20 years with 2 touch ups only using their epoxy and it is perfect.

 

Sam

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22 minutes ago, Boater Sam said:

Good point, got Narrow minded there, sorry if I am fouled up.

The mistake (if any) lies with the OP - he has a narrowboat and mentions "bitchumastic"> Bitumastic is not an antifoul coating is it?

It's quite common for folks to confuse antifoul with a protective coating.... 

It would be a great shame to overcoat with bitumastic because to revert to two pack epoxy at a later date would be very expensive. To shotblast and prepare for that would be £75 per foot (I've just been looking at getting a quote from a well respected outfit).   

 

 

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Just found the original paint spec quote, Undercoat two pack polyamide cured epoxy/zinc phosphate resistant steal primer. Top coat for bottom plates two pack epoxy polamide/coal tar pitch black.

Which means little or nothing to me.

HELP lol

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7 minutes ago, John Hartley said:

Just found the original paint spec quote, Undercoat two pack polyamide cured epoxy/zinc phosphate resistant steal primer. Top coat for bottom plates two pack epoxy polamide/coal tar pitch black.

Which means little or nothing to me.

HELP lol

Ok, so we now know what it is. Now, before we slap some other stuff on top, are we sure there's a problem with it? 

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That spec sounds exactly like what I used on mine, zinc Phosphate first, black second. Ask Sherwin-Williams but it would seem to me to be the same stuff. They will sell you the paint, you will only need the black not the zinc primer, and tell you when it is made. You can then collect from works in Bolton, or Decorators Supply co will order but its much dearer and plus delivery charges. The black comes in 4 ltr (3+1 hardner) cans, you will need 2. Last I bought was around £10 a ltr.

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17 hours ago, OldGoat said:

 

It would be a great shame to overcoat with bitumastic because to revert to two pack epoxy at a later date would be very expensive. To shotblast and prepare for that would be £75 per foot (I've just been looking at getting a quote from a well respected outfit).   

 

 

I agree about not painting over the two pack with bitumen, bitumastic, etc, but i had my widebeam grit blasted up to the rubbing strake for £350.

It's obviously best to stick to the same brand of two pack epoxy, but if that can't be done then I'm sure a different brand of epoxy would be compatible. Just give the existing coating a good key with a med/fine grade paper, dust and spirit wipe to clean the surface with the appropriate thinners for the new paint first. Follow the min and max overcoating times for subsequent coats to ensure good bonding. 

Some of these products don't have all the instructions on the tin so you need to download the datasheets and application instructions. Proper mixing by volume (or sometimes by weight) is critical.

Edited by blackrose
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John - why didn't you ask me more about this yesterday.

Please don't be tempted to put Bitumastic over the 2-pack. It might be cheaper short term but it will cost much more longer term your two pack blacking will only require re-coating every 5 years (or more) bitumastic needs to be done at least every 3 years and those costs for slipping and coatings mount up even if you apply it yourself.

You should be able to apply any 2-pack coating over what you have so long as it is properly prepared. A 2-pack coating cures within hours of application unlike Bitumin which stays slightly soft for years.

The biggest problem you will have is getting the product at a reasonable cost. We used to nip across to Dacrylate to get supplies on an ad-hoc basis but they only sell to large account holders now

Give me a call. I asked hundreds of questions of anyone who had an ounce of understanding about this subject before we chose 2-pack for Python and, on the back of that we got 2-pack on our boat too. Having made the switch and seeing how it had held up on Python when she was slipped last year (even where it was applied OVER bitumin) I don't think we will go back. The main thing is 2-pack tends to go grey as the light gets to it and not everyone likes to see a grey finish. It varies by vessel where the rubbing strakes are and which seam you black up to but on Python there is a band below the gunwales and above the waterline we can slap some bitumin on to make her look smart and black. It doesn't actually need to do much in the way of protection there so it is just to smarten things up

 

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8 minutes ago, cheshire~rose said:

Having made the switch and seeing how it had held up on Python when she was slipped last year (even where it was applied OVER bitumin) I don't think we will go back.

 

So are you saying 2 pack has adhered to bitumen on your boat????? Everyone has said gritblast first, as 2 pack won’t stick.

I’ve always fancied 2 pack but have been put off by the cost of grit blasting. 

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1 minute ago, jenevers said:

So are you saying 2 pack has adhered to bitumen on your boat????? Everyone has said gritblast first, as 2 pack won’t stick.

I’ve always fancied 2 pack but have been put off by the cost of grit blasting. 

When Python had a new bottom and footings it made sense to use 2-pack on the new steel but inevitably above the new steel there was a LOT of bitumin that had been applied over the previous 80 odd years of her life. The surveyor assured us it was fine to apply it over the bitumin. He said the bitumin was fairly old and stable and while it might not stick everywhere if it did fall off it was because there was good bitumin behind it so the steel was still protected. He said he has been doing this with his own historic craft for around 15 years and slowly but surely each time he re-applies the 2-pack there is a little less bitumin and a little more 2-pack but the hulls stay protected.

Based on this we opted to have it applied to our boat too. Now, because it was not applied as per the manufacturers instructions the boat yard warned us they were not willing to offer a guarantee with it which we knew but when asked what the boatyard owner would do if it was his boat he was in no doubt that he would be applying the 2-pack!

We have not had our boat out of the water since to see how it is bearing up but it was applied a few weeks after Python's coating and when Python came out last year the blacking looked really good after a year in the water

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  • 1 year later...
On 16/03/2018 at 08:19, cheshire~rose said:

John - why didn't you ask me more about this yesterday.

Please don't be tempted to put Bitumastic over the 2-pack. It might be cheaper short term but it will cost much more longer term your two pack blacking will only require re-coating every 5 years (or more) bitumastic needs to be done at least every 3 years and those costs for slipping and coatings mount up even if you apply it yourself.

You should be able to apply any 2-pack coating over what you have so long as it is properly prepared. A 2-pack coating cures within hours of application unlike Bitumin which stays slightly soft for years.

The biggest problem you will have is getting the product at a reasonable cost. We used to nip across to Dacrylate to get supplies on an ad-hoc basis but they only sell to large account holders now

Give me a call. I asked hundreds of questions of anyone who had an ounce of understanding about this subject before we chose 2-pack for Python and, on the back of that we got 2-pack on our boat too. Having made the switch and seeing how it had held up on Python when she was slipped last year (even where it was applied OVER bitumin) I don't think we will go back. The main thing is 2-pack tends to go grey as the light gets to it and not everyone likes to see a grey finish. It varies by vessel where the rubbing strakes are and which seam you black up to but on Python there is a band below the gunwales and above the waterline we can slap some bitumin on to make her look smart and black. It doesn't actually need to do much in the way of protection there so it is just to smarten things up

 

Good afternoon,

 

Are you still trying to get hold of Dacrylate products?

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John, the biggest problem I can see is that you  have a coal tar based product on your hull.

This has been banned by the (pillocks at) EU, and is non longer available.

My next out of water experience is going to be expensive as Comastic is non longer available.

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1 minute ago, matty40s said:

John, the biggest problem I can see is that you  have a coal tar based product on your hull.

This has been banned by the (pillocks at) EU, and is non longer available.

My next out of water experience is going to be expensive as Comastic is non longer available.

His query was 18 months ago though and has since been dealt with

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