Painting over Alkalyde Paints
- Thread starter carboman
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I cant answer that question, but i have had some disasterous results doing similar things, sometimes the new paint will react with the old paint, and give a result called crazy paving, where it all cracks in a similar size to a broken car window. You can get a sealer that you paint over the old paint to stop this, but that adds another coat, epoxy paint, usually dosent react with other paints, and may be able to go straight on, but i would try on a hatch cover or something first. I am doing pretty much the same thing myself, but i decided to stripp all the old paint, before i re paint it, i have been using citri strip, which takes the paint off, without damaging the fiberglass. I dont know if i will re paint, or attempt to polish it, but if i do re paint, i will make sure every bit of the old paint is off.
What condition is the paint you're painting over? Adhesion will only be as good as what is underneath, as i'm sure you know. Personally, I have painted over alkyd paint w/both urethanes and epoxys with good results. It's all in the prep. The epoxys wear great and provide a super wear resistant finish but are a bit difficult to work with. I always contact tech services of finish manufacturer and explain what I want to do. They have always been very helpful since they want to sell their products.
Good luck and happy sailing!
Vic H.
Good luck and happy sailing!
Vic H.
Found this while surfing Sherwin Paints website
Q: How can I upgrade a coating system from an alkyd to a urethane or epoxy without completely removing the old finish?
A:In many cases, the application of a high-solids universal primer or barrier coat will allow the application of a strong solvent-based epoxy or urethane over a previous coating. Using a barrier coat reduces the likelihood of the solvents in the topcoat lifting previous finishes and eliminates the need for costly and time-consuming removal of all existing paint.
Good Luck
P.S. some other comments
As a general rule you cannot put an epoxy over an alkyd. There are, however, exceptions for some surface tolerant epoxies. If you're done it and got away with it then you may be OK but I would not recommend doing this in the normal way. Normally an alkyd will blister and crack when an epoxy is put on top. If this has happened and you cannot see it because of the epoxy you will have destroyed the adhesion of the alkyd primer and water will get into the mahogany.
It sounds as though your epoxy is a filler. This will be very hard and should be suitable for use underwater but it will not tolerate much movement if the wood is designed to move. I would recommend a polyester filler for use above the water line and I assume that is where you are working since you have an alkyd paint. They are generally compatible with alkyds and more flexible than epoxies. It is best to put the filler over a primer rather than a finish.
You can paint an alkyd over a cured epoxy but need to get a good mechanical key as there will be no chemical bond between the two.
Q: How can I upgrade a coating system from an alkyd to a urethane or epoxy without completely removing the old finish?
A:In many cases, the application of a high-solids universal primer or barrier coat will allow the application of a strong solvent-based epoxy or urethane over a previous coating. Using a barrier coat reduces the likelihood of the solvents in the topcoat lifting previous finishes and eliminates the need for costly and time-consuming removal of all existing paint.
Good Luck
P.S. some other comments
As a general rule you cannot put an epoxy over an alkyd. There are, however, exceptions for some surface tolerant epoxies. If you're done it and got away with it then you may be OK but I would not recommend doing this in the normal way. Normally an alkyd will blister and crack when an epoxy is put on top. If this has happened and you cannot see it because of the epoxy you will have destroyed the adhesion of the alkyd primer and water will get into the mahogany.
It sounds as though your epoxy is a filler. This will be very hard and should be suitable for use underwater but it will not tolerate much movement if the wood is designed to move. I would recommend a polyester filler for use above the water line and I assume that is where you are working since you have an alkyd paint. They are generally compatible with alkyds and more flexible than epoxies. It is best to put the filler over a primer rather than a finish.
You can paint an alkyd over a cured epoxy but need to get a good mechanical key as there will be no chemical bond between the two.
I would consider a high pressure power wash to remove any loose paint and clean the surface regardless of any other prep.
Are you also redoing the non-skid? If you are you probably want to do all of the smooth surfaces with your paint of choice and then mask and paint the non-skid.
Are you also redoing the non-skid? If you are you probably want to do all of the smooth surfaces with your paint of choice and then mask and paint the non-skid.
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