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Best is two pack epoxy. What have you got on it at the moment? Snag is that it doesn't like being applied over bitumen , therefore you have two choices, sandblast it back to bare steel then apply epoxy or apply a couple of coats of bitumen or something similar and resign yourself to doing it every 3 years or so instead of 4 or 5 or longer. 

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11 minutes ago, Adamwalker64 said:

Iv got bitumen on I think iv just brought the boat and taken it out of the water and given it a high pressure jet wash so I guess I’m looking at bitumen any recommendations for paticular manufacture 

thanks for your suggestion 

Take a rag, apply a bit of diesel, rub your blacking with it. If the rag goes black, it's bitumen.  If it is, I use Rylards - others are available.

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Good advice ...almost.....wipe it once with a spirit covered rag....it will be dirty black.

 

Wipe it again with a spirit covered rag in the same place.

If it's black this time it's bitumen.

If it's almost clean , it's a different coating which could be comastic,  epoxy 2 pack, gloss hammerite,  ..or something else not dissolvable by white spirit.

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It's still February. It's still cold .... well apart from this weekend. Don't be a numpty and try and paint when the steel temp is near the dew point. Wait till April or May if possible. Read the paint manufacturers instructions. The paint will fall off if there is condensation on the surface. I wouldn't paint unless you know the temp is going to get to 15C. Most paints will work well if you follow these guidelines.

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16 hours ago, Sea Dog said:

Take a rag, apply a bit of diesel, rub your blacking with it. If the rag goes black, it's bitumen.  If it is, I use Rylards - others are available.

Ditto. Just seen Mattys post. Good advice. Didnt know that trick.

 

Edited by Nightwatch
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21 hours ago, Dr Bob said:

It's still February. It's still cold .... well apart from this weekend. Don't be a numpty and try and paint when the steel temp is near the dew point. Wait till April or May if possible. Read the paint manufacturers instructions. The paint will fall off if there is condensation on the surface. I wouldn't paint unless you know the temp is going to get to 15C. Most paints will work well if you follow these guidelines.

Bob its been over 15 degrees here for a couple of days ?

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1 hour ago, peterboat said:

Bob its been over 15 degrees here for a couple of days ?

I know. Isnt it great. Trouble is, its brought every out. Passed at least 6 boats today.

Just about warm enough to paint on the sunny side but the water is still cold and so the steel temp on the shady side will be low enough for condensation.

Tomorrow it might get a couple of degrees warmer.

Smelly must be many miles away!

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2 hours ago, Liznoproblem said:

Friends heat the blacking up when doing it in winter, which thins it a little, then apply, it cools quickly and gets into any pitting alot better that way. I was dubious at first but seeing it done I can see the logic and impressed.

Dont do this!

The reason it doesnt stick in the winter is because of moisture on the surface. Heating the paint will not remove the moisture. Make sure the steel temp is 3 deg above the dew point. It may not be if the boat is sitting in cold water. Heating the coating by leaving it indoors is a sensible idea but if it is too thick then it is likely too cold.

How are you going to heat it? Use a blow torch...put a pan on the stove????? Dont be daft man! These are flammable materials. You dont go heating paint other than leaving it in a warm room.

If you heat it up to 30 or 40C then you will likely see pigment settlement which is also not a good idea.

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5 hours ago, Liznoproblem said:

Friends heat the blacking up when doing it in winter, which thins it a little, then apply, it cools quickly and gets into any pitting alot better that way. I was dubious at first but seeing it done I can see the logic and impressed.

I'm with @Dr Bob on this one Liz, only rather than the paint science answer I just say if the steel feels cold to the touch it's too cold to black it. Either way, wait til spring. :)

 

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As already mentioned I use Sealex B which is very thick  and I almost always warm it up using a hot air gun otherwise  it is difficult to apply . I have found that the cheaper bitumen is so thin that it never needs warming up . I'm with Dr Bob on not blacking when the temperature is too low though . One other point make sure you paint the bottom plate if at all possible . Many owners don't as many  dry docks / slipways don't raise the boat sufficiently high to be able to get access .

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2 hours ago, Troyboy said:

As already mentioned I use Sealex B which is very thick  and I almost always warm it up using a hot air gun otherwise  it is difficult to apply . I have found that the cheaper bitumen is so thin that it never needs warming up . I'm with Dr Bob on not blacking when the temperature is too low though . One other point make sure you paint the bottom plate if at all possible . Many owners don't as many  dry docks / slipways don't raise the boat sufficiently high to be able to get access .

Troyboy. Please, please do not encourage people to kill or badly injure themselves.

Sealex B has a flash point between 23°C and 60°C. It is therefore very flammable. It contains flammable solvent. The makers do not post their MSDS sheet on the internet so I cant see the solvents they use but with that sort of flash point, the likleyhood of igniting the xylene or ethyl benzene or wotever is significant if you have a red hot element next to the open can.

I once was involved in a paint job where the painters were doing the internals of a tank with a coating with a flash point of 90°C. 3 painters died when a non flameproof light bulb fell on the floor and smashed and ignited the evaporated solvent/air mix. Ok it was indoors but doing what you do, someone can get badly burned. I am very happy you carry on with a dangerous practise but not a good idea to push this as 'the way to do it'

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28 minutes ago, Sea Dog said:

And how long does that take with 10mm steel exposed at one side only between 2-3 feet below the waterline? ;)

 

No idea other than it will take longer to rust through  if painted . Not all of us are fortunate enough to own a boat with a  10mm baseplate but  I realise unlike me many do not have access to a slipway that lifts boats high enough to be able to paint the underside . 

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52 minutes ago, Troyboy said:

Yes when they eventually rust through . 

A baseplate won't rust through in any timescale for which any of us will be on this planet.

 

It could suffer electrically induced or chemically aggravated corrosion and while a protective coating will help to a degree, this sort of corrosion will find the gaps in the coating and act at that spot.

 

With the best will in the world you won't be able to maintain a coating on the baseplate for long before bare metal is exposed somewhere.

 

While I would advise blacking the baseplate if it's accessible I wouldn't advise going out of your way to ensure it's done. It doesn't buy very much additional protection.

 

JP

 

 

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45 minutes ago, Sea Dog said:

And how long does that take with 10mm steel exposed at one side only between 2-3 feet below the waterline? ;)

 

This is a 1994 boat with little or no pitting on the sides, the baseplate from the front angle to swim was covered in deep pits, 3 ,4,and 5mm being uncovered over a wide area within reach.....the rest looked just as bad.

20190205_134022.jpg

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2 minutes ago, Captain Pegg said:

A baseplate won't rust through in any timescale for which any of us will be on this planet.

 

It could suffer electrically induced or chemically aggravated corrosion and while a protective coating will help to a degree, this sort of corrosion will find the gaps in the coating and act at that spot.

 

With the best will in the world you won't be able to maintain a coating on the baseplate for long before bare metal is exposed somewhere.

 

While I would advise blacking the baseplate if it's accessible I wouldn't advise going out of your way to ensure it's done. It doesn't buy very much additional protection.

 

JP

 

 

I'm fairly certain I once read somewhere that a narrowboat  had a baseplate rust through but maybe I am mistaken . I'll carry on painting mine as the surveyor that last surveyed my boat made a positive comment in his report . 

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3 minutes ago, matty40s said:

This is a 1994 boat with little or no pitting on the sides, the baseplate from the front angle to swim was covered in deep pits, 3 ,4,and 5mm being uncovered over a wide area within reach.....the rest looked just as bad.

20190205_134022.jpg

Thanks for that Matty I'm not sure if Sea Dog or Captain Pegg  will now believe baseplates can rust through .

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