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AuthorMessage
VickiShaw
VickiShaw

Posted: Sat Aug 22, 2009 8:56am

Post Subject: Applying primer

Hello. My partner and I have started to tackle rust spots on our boat with the goal of repainting the whole roof and have a few questions regarding the application of primer. Can we paint primer over an old top coat that has been sanded down to key it? Is it suitable/okay/preferable to paint primer over an old top coat? My thoughts are that we will end up with more paint layers in the end which will give extra protection to the steel. My only concern is that the old top coat and the new primer layer will not be chemically compatible somehow, leading to a poor finish. Thank you in advance for your help. Best wishes, Vicki

Tony-B
Tony-B

Posted: Sat Aug 22, 2009 12:46pm

Post Subject: Applying primer

Dear Vicki, This another one for Phil so you will have to wait for him. TO be honest even he might not be able to answer it unless you tell us what primer you intend to use. For instance I have had some of the fast drying anti-rust primers lift the feathered edges of the old paint around the base patch. I note that you say that you think more coats will give extra protection, but are you aware than most primers and undercoats are actually porous? Just in case Phil takes a long time getting back to use I will give my "engineers" idea. Personally I would rub down the whole roof to the ready to paint state. Then rub the rusty spots right back to bare metal, rub all around to give a feather edge to the hole in the paint, in some way treat the rust. Trying to abrade away and if that is not possible use a chemical rust treatment. Then apply one of the non-fast drying anti-rust primers and if the rust pits & area are too deep follow that up with a high build primer. Using a block rub over the area and use your finger tips to feel for any low spots. If there are any another coat of high build primer - still spot priming. If the rust areas are too deep you can use car body filler to fill them. Once the surface is a smooth and flush as you can get it either apply a "holding coat" of top coat to seal the area until you can paint the whole roof. Otherwise (because time has passed a rub down with fine abrasive over the whole roof, de-dust, one or two coats of undercoat and similar for top coat. I stress that this is my idea and you need Phil to give you a definitive answer. Tony Brooks.

VickiShaw
VickiShaw

Posted: Tue Aug 25, 2009 5:21pm

Post Subject: Applying primer

Dear Tony, Thank you very much for taking the time to reply and for your help and guidance. We really appreciate it. We have another question to ask you. If we sand between the different paint layers, can we just use a roller to apply the paint? Or do you get a better finish if you use a roller and paint brush to smooth off each layer? I look forward to hearing from you soon. Best wishes, Vicki

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