Adamwalker64 Posted February 20, 2019 Report Share Posted February 20, 2019 Any suggestions on best stuff to use when blacking bottom half of boat cheers Link to comment Share on other sites More sharing options...
Bee Posted February 20, 2019 Report Share Posted February 20, 2019 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. Link to comment Share on other sites More sharing options...
Adamwalker64 Posted February 20, 2019 Author Report Share Posted February 20, 2019 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 Link to comment Share on other sites More sharing options...
Sea Dog Posted February 20, 2019 Report Share Posted February 20, 2019 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. Link to comment Share on other sites More sharing options...
Adamwalker64 Posted February 20, 2019 Author Report Share Posted February 20, 2019 Brillant thanks Link to comment Share on other sites More sharing options...
Troyboy Posted February 20, 2019 Report Share Posted February 20, 2019 I use SealexB on my boat every two years and am quite happy with it . What I would advise is any areas that are rusty clean with a wire brush and then apply a coat of Vactan before blacking . Link to comment Share on other sites More sharing options...
matty40s Posted February 20, 2019 Report Share Posted February 20, 2019 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. 1 Link to comment Share on other sites More sharing options...
Dr Bob Posted February 20, 2019 Report Share Posted February 20, 2019 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. Link to comment Share on other sites More sharing options...
Nightwatch Posted February 21, 2019 Report Share Posted February 21, 2019 (edited) 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 February 21, 2019 by Nightwatch Link to comment Share on other sites More sharing options...
Sea Dog Posted February 21, 2019 Report Share Posted February 21, 2019 1 hour ago, Nightwatch said: Ditto. Just seen Mattys post. Good advice. Didnt know that trick. Diesel is just a bit easier to find for a quick and dirty check but @matty40s has posted a rather better refinement I think. Link to comment Share on other sites More sharing options...
peterboat Posted February 21, 2019 Report Share Posted February 21, 2019 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 ? 1 Link to comment Share on other sites More sharing options...
Dr Bob Posted February 21, 2019 Report Share Posted February 21, 2019 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! Link to comment Share on other sites More sharing options...
Liznoproblem Posted February 22, 2019 Report Share Posted February 22, 2019 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. Link to comment Share on other sites More sharing options...
Dr Bob Posted February 22, 2019 Report Share Posted February 22, 2019 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. Link to comment Share on other sites More sharing options...
Sea Dog Posted February 22, 2019 Report Share Posted February 22, 2019 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. 1 Link to comment Share on other sites More sharing options...
Troyboy Posted February 22, 2019 Report Share Posted February 22, 2019 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 . Link to comment Share on other sites More sharing options...
Sea Dog Posted February 22, 2019 Report Share Posted February 22, 2019 1 minute ago, Troyboy said: Many owners don't as many dry docks / slipways don't raise the boat sufficiently high to be able to get access . And do they sink? Link to comment Share on other sites More sharing options...
Troyboy Posted February 22, 2019 Report Share Posted February 22, 2019 2 hours ago, Sea Dog said: And do they sink? Yes when they eventually rust through . Link to comment Share on other sites More sharing options...
Dr Bob Posted February 22, 2019 Report Share Posted February 22, 2019 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' Link to comment Share on other sites More sharing options...
Sea Dog Posted February 22, 2019 Report Share Posted February 22, 2019 18 minutes ago, Troyboy said: Yes when they eventually rust through . And how long does that take with 10mm steel exposed at one side only between 2-3 feet below the waterline? Link to comment Share on other sites More sharing options...
Troyboy Posted February 22, 2019 Report Share Posted February 22, 2019 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 . Link to comment Share on other sites More sharing options...
Captain Pegg Posted February 22, 2019 Report Share Posted February 22, 2019 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 Link to comment Share on other sites More sharing options...
matty40s Posted February 22, 2019 Report Share Posted February 22, 2019 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. Link to comment Share on other sites More sharing options...
Troyboy Posted February 22, 2019 Report Share Posted February 22, 2019 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 . Link to comment Share on other sites More sharing options...
Troyboy Posted February 22, 2019 Report Share Posted February 22, 2019 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. Thanks for that Matty I'm not sure if Sea Dog or Captain Pegg will now believe baseplates can rust through . Link to comment Share on other sites More sharing options...
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