Glen-L.com

Hi Everyone!

I am planning to build a TNT in the near future and I am currently in the planning phase. Anyway, I was wondering how you prep the fiberglass for paint. I have seen people coat the surface with what appears to be a filler (ie bondo) for ease of sanding. Can you paint the glass directly and still get good results? Thanks in advance!

You should use a primer that is compatible with your topcoat and is compatible with fiberglass. Any primer that goes on a production GRP boat will work exactly the same way on your boat with the epoxy and glass combination. Interlux makes good stuff for this application. Also, automotive paints will work as well but those you'll have to spray to get professional results. The Interlux people claim that their product can be applied with a good china bristle brush and will flow out to a fine finish that rivals sprayed finishes. But I'm not there yet. As soon as my boat's ready for paint, I'll learn.

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Isn't it amazing!! The person that never has the fortitude to pursue his own dreams, will be the first to try and discourage you from pursuing yours.

Just finished painting the hull of my father-in-law's 23' cabin cruiser using Interlux (International) Toplac, I used the roll & tip method and I can confirm that you can indeed get a very good finish.
I've been spraying paint for over 25 years and I think I'd have had problems getting as good a finish as I did on this boat with a spraygun, I amazed myself despite having used the stuff before with good results, that was on a much smaller scale though.
Just wet sand the glass/epoxy of your TNT to key it and get it nice and smooth, wash with clean water and allow it to dry, then roll on a coat of Pre-Kote undercoat.
When that's dry sand it and apply a second coat (if you are using a colour topcat you may want to make this second coat a 50-50 mix of undercoat and topcoat for a deeper colour). Let it dry and sand again, then apply two coats of Toplac sanding lightly between coats.
Take your time and do it properly, in a dust free atmosphere, and just remember the final finish will only be as good as your preparation.
And make sure you only use foam rollers, the kind used for gloss paint, any other kind will produce an "orange peel" finish that will need a lot of sanding.

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Graham in Shepperton, England

Good, Quick, Cheap, pick any two.

Just to let you know something about Toplac......I used toplac on my squirt hull on the sides and bottom since the boat spends most of its life on the trailer and not in the water. It is a brilliant finish, but lately I have noticed that where the trailer has been resting on the wet trailer bunks, the paint has bubbled and blistered a bit. The carpet on the bunks obviously stays wet for a long time and this moisture damages the toplac over a period of time.

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David McAdam
Squirt Gallery - Its BACK!!
http://one.xthost.info/boatbuilder/boat/
BOAT IS NOW SOLD

That's useful to know David. As you know I painted my Squirt hull with epoxy so this shouldn't be a problem, but I intend to paint my new skiff hull with Toplac left over from this cabin cruiser job and it'll spend most of it's life sitting on its trailer.
In the light of your comment I think I'll finish below the waterline with epoxy and hopefully avoid this problem, this is obviously why Toplac and Brightsides are only recommended for above waterline use.

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Graham in Shepperton, England

Good, Quick, Cheap, pick any two.

And THAT'S why this forum is SOOOOOOOOO beneficial. I too was planning on using these paints for my Zip. You just headed off some problems for me as well. thanx to the both of you, Graham and David

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Isn't it amazing!! The person that never has the fortitude to pursue his own dreams, will be the first to try and discourage you from pursuing yours.

Thanks for all the good info guys!

I am looking forward to starting this project. I figured by asking questions before the project has begun could save me some serious headaches in the future.

Gentlemen - I had a similar problem with Interlux Brightside. I used two coats over prekote on the Pee Wee. The boat is trailered and covered with a quality boat cover, but is stored outside. After an extended period of rain and damp weather where the cover remained wet, the surface of the boat that was in continuous contact with the wet cover became quite rough - - almost like micro blisters - - it felt like large grains of sand in the paint. After the cover and the boat dried, the process seemed to reverse itself to a degree, but it will never be the same as when originally finished.

Robert A

Thanks for the good advice about the topside paints.. I too was going to use the Interlux Brightside topside paint below the water line, even though my little Dyno Mite will also live on the trailer for most of the year. But I didn't want any issues as described here. Thanks for saving me some headaches later. I'll go the extramile and use the bottom paint for the bottom.
GOT A Question for anyone out there..Is it possible to uses " Bondo" 3M brand aouto body filler just about the same as the marine grade stuff. I also have found other boat builders in my area using a product called "Rage" made by evercoat. These builders swear by this filler. Though mostly intended for "Auto" applications.. it works great for boat building as well.. Has anyone used anytype of body fillers to help smooth out the rough parts of the hull Above and below the waterline... any advice in this area would be much appreciated.

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Think safety. stay afloat

Bondo is polyester resin and I won't use it on a boat. I use microballoons and epoxy for an easily sanded filler. Its even the same sort of purple color so maybe folks confuse it with bondo.

As far as Brightsides and primer and wet issues I have used it with the Interlux Epoxy Barrier Kote primer (2 part) on two boats. I regularly leave my sailboat in the water for a week. Never a sign of any paint issues at all. I think actually the primer may be the issue with the wet trailer bunks and covers here not the Brightsides. Easily sanded primers have talc which absorbs water. Won't use the stuff. The Barrier Kote primer is hard tough stuff. Once mixed it has a 5 hour pot life but drys fast on the boat. I can usually get 2 or 3 coats on in the 5 hours with no sanding between. But do it outside or with good ventilation. It takes a special, very nasty smelling thinner.

Toplac makes a great topside paint though. If your boat trailer was on rollers instead of carpet bunks, it'd probably be fine below the waterline too

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David McAdam
Squirt Gallery - Its BACK!!
http://one.xthost.info/boatbuilder/boat/
BOAT IS NOW SOLD

Steve - Thanks for the tip on sandable primers. I used Interlux Pre-Kote sandable primer under Brightsides poly. My problem was as noted above. I will consider using the Barrier Kote in the future.

Robert A

Interesting that the little product discription says above the waterline but if you dig deep enough on the Interlux website you can read the data sheet on this stuff. It is ok below the water line with some finish systems.

It says: "Epoxy Barrier-Kote is a multi-purpose two part epoxy primer for use above and below the waterline. Epoxy Barrier-Kote can be used with any topside paint but it is the recommended primer for use with two-part finishes such as Perfection and can also be overcoated with Toplac, Brightside, Interlux Yacht Enamel, Interdeck and Bilgekote. It is also used as part of a system to re-surface cracked and crazed gelcoat prior to the application of topside paint. Use Epoxy Barrier-Kote over clear epoxies as a sanding surfacer and to eliminate the effects of amine blush. Epoxy Barrier-Kote is bright white, which makes it ideal for priming bilge and locker areas. Epoxy Barrier-Kote can also be used in some underwater systems."