Down to gel coat

[bajo]

Would gladly like some of that good advice from this forum.My old Galion 22'' is presently having all those many many years of antifoul taken off and already down to the gel coat in most areas.I would like a step by step procedure to follow to bring it back to the stage just before painting. I am going to use west system material .[note lots of fancy stuff is probably not available here] Thanks very much for any help.Dave

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[oldsaltoz]

G'day David,

If you plan to plan to coat the area below the water line with epoxy, you will have to remove all the old paint, and don't forget to make a record of the measurements taken to re-establish the water line. at the bow and both sides of the transom as well as midship.

if you are planning a complete re-seal, you will also have to consider removing any fittings that may reduce access, under 'P' brackets, thru' hull fittings, anodes, cooling plates etc.

Let us know if this is what you plan and we can better advise you.

Hope this helps...





<hr width=100% size=1> Old Salt Oz /forums/images/icons/cool.gif Growing old is unavoidable. However, growing up is still optional.

 

[ashanta]

You need to take a moisture reading and confirm the water content is at or below the paint epoxy manufacturers stated level. If your boat is "wet" you will need to dry the hull before application otherwise you will be creating a serious problem in the future. There are a number of ways to reduce the water content but DIY is not an easy way. Boat yards bring boats inside and use Infra red heating lamps.
When applying the epoxy you will have to ensure the temperature is correct, so doing the job in the winter could prove to be difficult unless the boat is inside and heaters are available.

Regards.

Peter

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[john_morris_uk]

When we had the hull of our Sigma taken back by the yard with grit/slurry blasting, the surveyor advised us to fill any imperfections with epoxy (ie not a whole epoxy treatment - just the odd void that had been revealed by the blasting) and then prime and antifoul. We used West epoxy and microballoons for the filling and fairing. International antifouling primer for the priming and varous A/F since and have never looked back. Hope this helps. J

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[bajo]

Hi Brian,thanks for your response,I only plan to do the area covered by antifoul and just a spray over of the top side.How far up on the top side would [min] I have to rub down to make a satisfactory job. I have no plans to go to gel coat above the water line.Thank you and all others for advice.I am doing all this high up on the beach in Barbados[ warm ],not indoors.and I intend to place plastic sheeting around the boat from just above the the W/L after it is sanded down.Honestly I feel a bit out of my depth.

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[oldsaltoz]

G'day David,

Warm here too at the moment, 10 PM and it's still 28 c.

I assume your antifouling is about 40mm above the actual water line, (this hides the brown stain line you see on many boats), so you should mark and measure this line and sand all antifouling off to expose a clean gel-coat: Don't forget to use a good quality dust mask...

Wash the area with plenty of fresh water and let it dry. You should now check any areas that show signe of water rejection, or beading of water, use some acetone to clean the area, it will be oil or silicone contamination.

Having done that, now would be a good time to fill and small chips or marks, you can use closed cell balloons and epoxy resin mixed to a toothpaste consistency for this: I find the back of an old straight-back hand saw perfect for this as the blade can be angled and pulled over large areas filling all the minor low spots and chips as you go, add a little more resin if it starts to thicken. After this all goes off, you should first wash it with fresh water and check again for any areas rejecting water, wipe with acertone. You are now ready to give it light sanding, you only need to take the sine off. Another wash and dry and you are ready for the next step.

Run some masking tape along the top of the area you want to antifoul to (this should be the same as the sanded line). Mix a small amount of epoxy resin, say 0.25 of a litre and apply with a roller designed for use with epoxy resin (the standard household type will fall apart).
A medium nap is a good choice, starting at one end of the boat, work from the tape down to the centreline under the boat, cover an area about 300 mm (a foot) and then go back over the fresh resin with a 75 mm (3 inch) long bristle brush, use it very lightly, you just need to tip it off, this will give you a mirror finish.

When you have completed the first lap, check your starting point, if it is very tacky but not fully cured, you can apply a second coat and save yourself a lot of sanding, but don't re-cover any area that has dried.

After your first (or first with second over it) has cured, wash it down with fresh water, you will notice that all the new resin will reject water, this is because of the residue left on the surface after curing has completed, it is easy to remove with one of those little green plastic kitchen scourers, start at the top and work down to ensure it gets a good rinse and you can check if its not rejecting.

Having done this you can now add another coat of resin. I apply 3 coats as a minimum. 4 if the hull has had any signs of osmosis or failure of the gel-coat.

When the last coat has cured, wash as before, starting at the top. When dry give it another light sanding just to remove the gloss and apply a coat of 2 pot epoxy paint: International make several suitable paints for below the water line that are designed to go over epoxy resin and reduce water ingress.

To ensure your antifoul never flakes, you can put a light coat over the 2 pot epoxy paint just before it cures, this mixes a small amount on the surface and provides a very good key for the next (full) coat.

Well this is a bit of a long post, and I'm sure some of our other forumites will pass on more information to help you along your way, so no need a bit out of your depth as you said in your post. If you have any further questions on the above, please let us know.

Good luck...



<hr width=100% size=1> Old Salt Oz /forums/images/icons/cool.gif Growing old is unavoidable. However, growing up is still optional.

 

[bajo]

Hi Brian,Thanks for the advice,will tell you how I make out, and keep in touch.Dave

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[bajo]

Hi Brian, I have a young man doing the job for me now,who works on boats and has some experience,I cant say how much, but certainly more than me.He has taken off all the gel coat as it was not that good.I am unable to get any 2 pot epoxy bottom paint here.I can get 420 barrier coat additive which i intend to use.The bottom is looking pretty clean and smooth now.I would still be happy to recieve info from you. Dave

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