Latest News: Forums Technical Painting and Inner Hull Repair

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  • #4006
    Pete Lock
    Member

    Evening Folks.

    As promised on my introduction a few days ago, here is a couple of many questions.

    I spent last weekend stripping my recently purchased MKII down to work on the hull over the winter. The decks and inner hull have been painted twice over the years. This is starting to look a bit tatty now, with the top white coat scratching off revealing the petrol blue coat underneath. In some places especially in the inner hull both layers have flaked away revealing the original cream GelCoat.

    I have spent today scraping out some of the loose paint and also sanding the foredeck area. I haven’t sanded it to much as I do not want to go down to deep disturbing or thinning the Gelcoat. I think with a couple of hours with wet and dry the foredeck may be ready for a couple of undercoats.

    So can any one suggest a good paint to use for the top deck and inner hull/cockpit areas

    Moving onto the inner hull/cockpit. The previous owner/s have been using the dinghy without the floorboards being secured, which I suspect are not original. Because they have been moving around during use they have been chaffing against the inner hull on the starboard side, wearing the Gelcoat away. The fibre matting is now showingand can be felt. This has happened in a number of place. Any suggestions on best way of fixing this.

    Have much more to ask….but will save the questions to rainier days and as the work progresses.

    Regards from a somewhat unusually sunny Belfast.

    Pete

    #8585
    Anonymous
    Inactive

    I would imagine that a layer of fine mat, then painted over with gel coat should do the job. Make sure it is very dry first though.

    As to paint, please can someone answer this as I would like to do the same myself.

    #8586
    SeaHolly
    Member

    If weight of requests helps, can I add my request to answer the painting question – the inner part of my hull is in need of some tlc by way of a lick of paint too.

    #8591
    BluTak
    Participant

    I sanded my inside (through the gelcoat in places) with a random orbital sander and grinder. I then used 2 coats of Danboline bilge paint – International Paints – made for internals of lockers on fibreglass boats. I think it only comes in white and grey – I used white. Its semi gloss and after 4 years still looks ok. The important bit is that you must sand well to achieve a key or the paint won’t stick to the gelcoat. It does create a lot of dust! I didn’t do the tank bulkheads – just the “rough” part of the hull

    #8592
    BluTak
    Participant

    sorry I didn’t read properly. To cover rough patches use glass woven mat/tissue – say 150gsm (lightweight) in epoxy or fibre glass resin. Again you must abrade well as gelcoat contains wax which floats to the surface so that it goes off.
    Nothing sticks well to unabraded gelcoat. not paint, epoxy, or glass resin

    Woven tissue adds a lot of abrasion resistance
    Robert

    #8596
    admin
    Member

    I am doing much the same with my Mk II, and although I am not there yet, I intend to use Danboline for inside the bilges as recommended above.

    I would say however that gelcoat or glassfibre resin (polyester resin) would not be my choice as this type of resin works by cross-linking the polymer chains which works fine with fresh resin, but after a few years the hull resin will no longer cross-link and you will simply be painting on top the existing construction. Epoxy however is a real adhesive (as in Araldite) and will make a strong and tough repair.

    I would recommend that before you start the repair, go over the area with a de-waxer and de-greasant (I have a tin of the stuff by Blakes which seems to do the trick) keep turning the cloth to ensure you are lifting contaminants off, not just rearranging the grime of ages over the task area. Then abrade the surface using something like 60 or 80 grit abrasive paper and complete the repair using epoxy resin and woven glass cloth (not chopped strand mat which has an adhesive that will not dissolve in epoxy). Finish by washing the amine blush away with water and a Scotchbrite after curing and after a light rubbing with finer abrasive paper especially at the edges of the cloth, give it the Danboline treatment.

    As for the external paint system I have used International Paint products successfully before, I would suggest you use Toplac, do not use the two-part Perfection on top of anything you are not sure of. I am using Brightside, but distressingly, IP have just withdrawn that range from sale; fortunately I have bought quite a lot (about £200 worth)

    #8601
    Pete Lock
    Member

    Thanks guys for the advise. Well let you know how it all goes over the next few weeks. Have plenty of work to be getting on with.

    Stripping the paint of the inner hull to reveal the gelcoat to get the woven matting onto the repair area might be tricky. Is it possible to use paint stripper on Fibre glass.

    Pete

    #8602
    BluTak
    Participant

    Paint stripper is definitely a no no! I’d use a 4″ angle grinder with flexible backing pad 40 – 80 grit sanding discs (buy a box of 50 from an ironmongery supply you’ll need lots). Go gently – you’ll get the hang of it and don’t worry if you go through the gel in a few places as long as you paint over – the gel isnt structural – it only waterproofs. Use a mask and eye protection and try to do it outside then hoover out. Good luck – its not that bad!!! – You’ll sand in a day then its easy. Make sure its dry. Don’t do the bulkheads (assuming they’re ok)

    #8604
    admin
    Member

    I use a “flap wheel in an angle grinder, sort of tabs of emery cloth attached to a backing disk on a the spindle. It works a treat and goes into corners, just keep the touch light and creep up on the abraded finish you want rather than charge at it. Good luck, keep us posted how you get on. Here is the undercoat going on mine, (there were too many dings and repairs to keep her white, the hull is going to be dark blue).

    #8605
    BluTak
    Participant

    Looks really good.I’m not showing a picture of mine!! Flapwheels are very good but expensive so I’d save them for the tricky bits
    Get all your sanding requirements from a trade outlet in boxes of 50 or 100 – not in packets of 5 which are outrageously expensive
    Robert

    #8606
    Pete Lock
    Member

    hi Don,

    Couple of questions….Which Brand of paint and type and what did you use on the outer Hull repairs. Have af ew that need doing.

    Pete

    #8607
    admin
    Member

    Not sure if you mean me…

    I used International Paints Pre Kote undercoat, the filler was a Plastic Padding Gelcoat Filler, which is a polyester resin based filler which sands down fairly easily. Go easy with the catalyst, especially in warm weather.

    The trickiest part I find is filling pin holes. I don’t know if they were already there or whether my rubbing down of the original gelcoat has opened them up, but there’s hundreds of the little bu**ers!. The filler seems to get pushed out by air pressure as you try to knife it in, paint also does not want to fill them. Maybe the best way would be to open them up a little with a small drill bit.

    First coat of the new finish today, dark blue International Brightside (discontinued – use Toplac from International). A litttle patchy but a very nice colour and deep shine. Apply the paint with a foam roller, then “tip” it with a foam Jenny brush. More photos next weekend.

    #8610
    Pete Lock
    Member

    Sorry Mike,

    Getting names mixed up here….have that many things going on on different forums….

    #8633
    Colin Parkstone
    Participant

    Mike,

    Did the first coat of paint cover the pin holes??

    Did you find the holes were just holes,or burst gel bubbles, if gel bubbles I tend to think you may still have water in the hull and its finding its way out still!!

    CP 😕

    #8637
    admin
    Member

    Colin, with a bit of working in, the first coat of finish paint has filled the pinholes. These were not Gelcoat bubbles, I think I had rubbed away a bit too much gelcoat in my efforts to remove the old paint or where I had made a repair. I experienced something similar when I restored an Enterprise a few years ago, whose previous owner told me that he used to use a lamb’s wool bonnet on an electric drill to T-Cut the hull each year; in places that hull had no gelcoat left so a new paint skin was vital to protect the lay-up.

    I have noticed an acetic acid smell when I removed the rudder pintles/gudgeons, I guess this is telling me that some osmotic action is taking place in the ply pads that are glassed in for fixing high load components. Suffice to say the boat is being kept dry, upside down and if I am in any doubt I will put a few “illegal” tungsten lamps under there to keep her warm while I finish the job. I will order some black Sikaflex 291 to bed everything in and to seal screws into the hull.

    There is a bit of a pause at the moment while I recover from Badger Flu but I will upload photographs as the job progresses – I just hope I can get the deck finished before it gets too cold for the paint to cure properly.

    Oh and my tow-car just failed it’s MOT.

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