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Bottom paint.....what if you don't know what it is?

My boat will need the bottom paint recoated in the spring.......now the problem is, I have no way of finding out what's on it. Prev. owner has no idea, and has no bill for it. So what's a guy to do if you can't tell what it is, as I have read you should only recoat with same stuff.?

2005 Rinker 270 FV Volvo Penta 5.7Gi

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    LaReaLaRea Member, Moderator Posts: 7,626 mod
    The choice of bottom paint is driven by local conditions.  Talk to some local yards and ask what type of paint they usually use for express cruisers.  Chances are it's ablative, and you can coat with another ablative.
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    Michael TMichael T Member Posts: 7,227 ✭✭✭✭✭
    edited October 2015
    As LaRea said ask at your local shipyards/marinas. IMO If you still aren't sure what is on your boat get someone to look at it who does. Some of the newer antifouling paints can NOT be applied over a number of the older types. The result would be an almost immediate peel. This happened on a 42 foot Regal near me and the  new bottom coat is all flaking off taking the original with it leaving the sanded fiberglass hull. Someone should know by looking at your hull and maybe trying to wipe a bit off with a white cloth (soft ablative) or a piece of sand paper (hard ablative). If for some reason you can not find out what was on there I think you would be okay with something like Interlux BottomKote NT (hard ablative dual resin), Pettit Unepoxy (modified epoxy) or West Marine Hard HCT (hard ablative dual resin hybrid). Many of the new slick and hard vinyl composites will not stay on a lot of the older style ablatives. Be careful and ask questions. IMO The real prep trick to a successful re-coat that won't flake is to get all of the sea weed and sea crud off your hull by spray washing and scrubbing with a stiff bristled brush. In some cases it is best to sand the hull lightly first. Any good paint tech should know exactly what to do.
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    BellevilleMXZBellevilleMXZ Member Posts: 732 ✭✭✭
    Thanks guys!
    2005 Rinker 270 FV Volvo Penta 5.7Gi
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    MarkBMarkB Member Posts: 3,969 ✭✭✭✭✭
    Most people strip the old stuff off and paint with the latest stuff. 

    Boat Name: King Kong

    "Boat + Water = Fun"

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    BellevilleMXZBellevilleMXZ Member Posts: 732 ✭✭✭
    How is it removed soda blasting etc?
    2005 Rinker 270 FV Volvo Penta 5.7Gi
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    MarkBMarkB Member Posts: 3,969 ✭✭✭✭✭
    I think most pros will sand it off. I'm not sure if soda blasting is avoided to prevent old paint from engraiming into the fibreglass or gel coat. 

    Boat Name: King Kong

    "Boat + Water = Fun"

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    Michael TMichael T Member Posts: 7,227 ✭✭✭✭✭
    Yes, and soda should not pit a surface as much as sand - as well as being relatively inert and able to be washed off with water. HOWEVER, IMO what you do depends on what was originally done as prep to the hull. For example when my new 360 arrived from the factory its hull was de-waxed, cleaned, lightly  sanded - more like a buffing - then a number of barrier coats were applied, before the final epoxy coats. IMO, if you went past the outer coatings and removed some/all of the barrier coats you would have to do the entire process over again. For my 360 that was a $5,000.00 cost. Therefore, I was told when it came time to re-coat my hull the process would be to pressure wash the hull and scrub it with a stiff brush then LIGHTLY sand the final outer coat making sure not to touch the barrier coats. The re-coating would be done with the same type (dual resin epoxy) as the original to ensure compatibility. IMO This is really a job for a professional, not some part time seasonal hire at a boat yard.
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    Michael TMichael T Member Posts: 7,227 ✭✭✭✭✭
    BTW a lot of the new final coats in a bottom coating process leave what is referred to as an orange peel surface. The wisdom being that this type of surface creating air bubbles that release the hull from surface tension and allow it to slip through the water easier, faster and with better fuel mileage. Many racers sand their hulls in 45 degree cross hatch patterns to increase speed. Of course this is not meant for we cruisers. my point is that proper bottom coating requires EXPERTISE. I can's tell you how many times I have seen 18 year old seasonal hires slopping crappy low-cost bottom coat on hulls. How much efficiency do you think that will cost you? BTW #2 how efficient do you think the drive (picture that was recently posted) where the whole drive and SS props were painted will be going through the water?
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    BellevilleMXZBellevilleMXZ Member Posts: 732 ✭✭✭
    Ouch...... I hope I can get an idea what this is, without stripping the whole bloody thing. I'm already looking at a whole new camper top, and GPS this winter, which is going to kill the budget. Plus whatever else I find wrong this winter on a 10 yr old boat new to me.  
    2005 Rinker 270 FV Volvo Penta 5.7Gi
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    Michael TMichael T Member Posts: 7,227 ✭✭✭✭✭
    I'm sure a decent tech can tell you what is on your hull. I say this because I had to find-out what was on my hull. If your bottom coat has been on your hull for a couple of years my money would be on a hard surface epoxy with a slow ablative action. I'm thinking an epoxy final coat that slowly ablates otherwise it would have worn-off and be showing print through. If no one can tell you what is on it I'd go with Interlux BottomKote NT. That should last three summers or maybe more and is very reasonably priced. It should cost about $350.00 for three gallons. It is a dual resin hard coat slow ablative. If you decide to not lightly sand your hull then I recommend to make sure they get all of the sea weed and "bits" off your hull before it is painted or they just paint over the crud which will release next summer taking the new bottom coat with it. The result will be that "flaking" look visible on many cruisers.
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    BellevilleMXZBellevilleMXZ Member Posts: 732 ✭✭✭
    Thanks ......Its coming out this weekend so I'll have a closer look at it. Is this usually a once a year thing ?
    2005 Rinker 270 FV Volvo Penta 5.7Gi
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    Michael TMichael T Member Posts: 7,227 ✭✭✭✭✭
    @BMXZ, that depends entirely on the final coats. So, you have your gel coat then if bottom painting is done right that's sanded, barrier coats are applied then a FINAL coat. How FINAL that coat is can range from one year to five years, depending on the composition of the paint and the environment. For us the cooler fresh water of the St. Lawrence is a big help. Interlux BottomKote, (on my hull), which is just one of MANY Interlux bottom coatings comes in FOUR versions that differ in how fast they ablate off. MY Interlux BottomKote comes in - four versions: regular BottomKote, Pro, XXX and NT. I have the NT version which on the St.Lawrence should be good for three or four years.
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    BellevilleMXZBellevilleMXZ Member Posts: 732 ✭✭✭
    Thanks!
    2005 Rinker 270 FV Volvo Penta 5.7Gi
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    MarkBMarkB Member Posts: 3,969 ✭✭✭✭✭
    I put on 4 coats of Interlux Interprotect, and 2 coats of Micron CSC. My 4th season and we are still only having to do minor touch ups to the Micron CSC.  Just power wash, and paint onto two or three areas that need it. It's really simple.

    Boat Name: King Kong

    "Boat + Water = Fun"

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    Michael TMichael T Member Posts: 7,227 ✭✭✭✭✭
    That's very interesting Mark. I was discussing that product yesterday . It may be the one I go to when replacing my BottomKoat NT. I'll ask Interlux if I can overcoat with that.
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    Michael TMichael T Member Posts: 7,227 ✭✭✭✭✭
    edited October 2015

    @MarkB and @ BellevilleMXZ and any other interested boaters out there. I finally got through to two supremely competent bottom coating experts. One at Interlux Paints and one at a technical yacht services chemical composition division.

    * In Canada in the BottomKote line of bottom coatings we probably only get Interlux ACT and XXX brands. So, MMKZ I probably do NOT have BottomKote NT.

    *Yes, we can paint Interlux Micron CSC over either BotomKote product.

    * To re-coat: Wash the hull thoroughly getting EVERYTHING off. Let dry well. Lightly "scuff" the surface with 80 grit paper to re-coat ACT but for XXX take it ALL off, then clean thoroughly. Apply two coats of the bottom coat, as per instructions.

    *Question asked: "When will I know it's time to re-coat?" Answer: "Two ways, you get excessive fouling and/or you can see areas where it has worn off - as in it looks thin."

    * Question: "How long should it last?" Answer: "Depends - salt water=worse, very warm water = worse, high fouling=worse. In the cooler, fresh water like our St. Lawrence that is low to low-moderate fouling, three or four years would be reasonable. You may need the odd touch-up."

    *Question: "So, I don't have to re-coat every year". Answer: "Not unless you are running aground on a lot of sand bars, LOL!!!  We'd like to sell you a lot of paint but you shouldn't need it every year in your area."

    So Mark and BMXZ .....I think we have it. I'm NOT going to let my marina re-coat my hull this Fall and IF they do next year it will be done according to the method  suggested by the experts NOT the way they prefer to do it or have been doing it.

    P.S. many bottom coatings have a special window of time from coating to launching so that the active anti-fouling ingredient does not dry-up.

    Post edited by Michael T on
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    MarkBMarkB Member Posts: 3,969 ✭✭✭✭✭
    Like I said I have micron CSC as my anti-fouling in Lake Ontario (west basin). The areas you can see need touch up are NOT fouled, it just looks thin, you can see some of the white interlux kind of showing up, mostly close to the water line. The stuff on the very bottom of the boat is 4 years old and still looks brand new. So there may be areas like 3 ft x 1 ft that we recoat, here and there. It literally takes more time to clean it than it does to paint it. It's not a big job. I pay my gelcoat guy like $100 to $150 each year before it goes into storage to touch up the bottom. It isn't a big expense.

    Boat Name: King Kong

    "Boat + Water = Fun"

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    Michael TMichael T Member Posts: 7,227 ✭✭✭✭✭
    @MarkB - you did it right Mark. After $5,000.00 for my original job I'm still trying to find-out what the marina put on my hull, for a final coat. If it was  Interlux BottomKote ACT I'm told I can scuff it and change to Micron CSC but if it was BottomKote XXX (which I have a bad feeling it was) I will either have to get it all off to switch to a better type or just re-coat with XXX. It is so depressing having to check everything that is done to see if it is done right!
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    BellevilleMXZBellevilleMXZ Member Posts: 732 ✭✭✭
    Thanks for the great info, a GREAT help!
    2005 Rinker 270 FV Volvo Penta 5.7Gi
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    Michael TMichael T Member Posts: 7,227 ✭✭✭✭✭

    @MT..... I am VERY HAPPY today! Just returned from our boat. Met with a bottom coatings specialist and looked at a number of products. He looked at my hull. He says I do not have Bottomkote XXX on my hull. He dislikes that coating as it is old technology. I dislike it as you can not re-coat it with any of the newer technology paints - even those from Interlux unless you sand ALL of it off right to the barrier coats. I was scared sh*tless that it was XXX. GOOD NEWS - He says my coating is a much better product and is an great condition. He said I could easily re-coat it with Micron CSC or any other top quality coating. He did say that no matter what re-coating product is going to being used - if I want to "do it right" - I need to sand the old coating. He says IHO all hulls should be sanded at least lightly before re-coating is done if you want to "do it right". He recommended #80 sand paper, to properly prepare ("rough-up") the surface, then clean the surface and follow the instructions of the new product. He also said he favors two final coats.

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    BellevilleMXZBellevilleMXZ Member Posts: 732 ✭✭✭
    That's good news......will have a closer look at mine once its out, should be this coming week.
    2005 Rinker 270 FV Volvo Penta 5.7Gi
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