Wests system barrier coats

[catmandoo]

Anybody got West system on under water hull .

I note from their booklet on replacing Gel cote with their system that they recommend applying 1 to two coats every 4 to 5 years

Does anyone actually do this bearing in mind it means removing all the antifoul paint applied over the last four years ? Or do you strip back every year to bare hull and faithfully apply a fresh coat of whatever ?

 

[oldsaltoz]

I treated a boat some years back before selling her.

I put 5 coats of epoxy on and then added a final thin coat all done wet on tacky to avoid sanding, I then sprayed on the epoxy primer hoping for a better bond.

Spotter in a marina in cairns about 8 or nine years later. still owned by the bloke I sold her to.

His only comment was that after 7 years he thought it would be a good idea to clean off all the old layers of antifoul, Got down to the epoxy primer and found no problems at all, just sanded the rest of high high areas off and gave her another coat or two.

I suspect if on a drying mooring, re coating would be a must with shells rubbish grinding the keel and hull. But I would think it's not worth doing if it's not exposed to any out of the ordinary contact.

Good luck and fair winds.

PS: A lot easier now we have the Cat, no keel to worry about and no need to come out of the water most years, just a fresh wash and slap a bit more on.

.

 

[knuterikt]

Anybody got West system on under water hull .

I note from their booklet on replacing Gel cote with their system that they recommend applying 1 to two coats every 4 to 5 years

Does anyone actually do this bearing in mind it means removing all the antifoul paint applied over the last four years ? Or do you strip back every year to bare hull and faithfully apply a fresh coat of whatever ?

Where did you find this recommendation?

In this doc http://209.20.76.247/ss/assets/howto-pub2/Gelcoat Blisters Diagnosis Repair and Prevention.pdf

I found this

Maintaining the barrier coat
1. Haul the boat and inspect the bottom annually. Check for scrapes or damage to the epoxy
barrier coat. Repair and recoat as necessary to maintain a continuous minimum 20-mil coat.
2. If possible, store the boat out of the water during the off season.
3. When sanding or high-pressure cleaning the bottom paint, be careful not to remove the epoxy barrier coat.
4. After several years of use or if your racing hull gets sanded regularly, apply one or two fresh
coats of epoxy as necessary to maintain the recommended minimum 20-mil barrier coat
thickness. Thoroughly sand the bottom, removing all bottom paint, and apply additional
coats of epoxy/barrier as described earlier in this section. Chemical strippers are not recommended for removing bottom paint applied over the epoxy barrier coat. Strippers that contain methylene chloride may soften the epoxy barrier coat if left on long enough.
5. Avoid an excessive buildup of bottom paint. Remove old bottom paint before applying new
paint

As long as you don't damage the barrier coat it should last long..

 

[oldsaltoz]

The added coats referred to in the article actually refers to racing boats and frequent sanding, usually only a fine wet and dry rub down, so not a 'normal' event for most of us.

Also interesting that they did not include a reminder the hull MUST BE DRY or you will seal moisture inside the hull and this can lead to major problems over time.

Good luck and fair winds.

 

[knuterikt]

Also interesting that they did not include a reminder the hull MUST BE DRY or you will seal moisture inside the hull and this can lead to major problems over time.

Good luck and fair winds.

Did you read the whole docment?

Drying the Laminate
Perhaps the most crucial step of the repair process for a boat which has blistered or absorbed moisture is thoroughly drying the laminate.

http://209.20.76.247/ss/assets/howto-pub2/Gelcoat Blisters Diagnosis Repair and Prevention.pdf

 

[catmandoo]

Where did you find this recommendation?

In this doc http://209.20.76.247/ss/assets/howto-pub2/Gelcoat Blisters Diagnosis Repair and Prevention.pdf

I found this


As long as you don't damage the barrier coat it should last long..

got it from West System " GELCOAT BLISTERS A GUIDE TO OSMOSIS REPAIR PARA 7.4.2 Maintaining the barrier coat
a) Haul the boat from the water and inspect the bottom annually . Check for scrapes and damage to the epoxy barrier coat . repair and re-coat as necessary to maintain a cntinuous minimum 600 micron coat
b) if possible store the boat out of the water during the off season
c) Avoid an excessive build up of anti-fouling paint and remove old anti-fouling before applying new paint
d) When sanding or high pressure cleaning the anti-fouling paint, take care not to remove the epoxy barrier coat
e) After several years of use - normally 4 or 5 - apply one or two fresh coats of epoxy as necessary to maintain the recommended thickness of barrier coat etc etc

Incidentally to achieve 600 micron West say a minimum of 6 coats of WEST EPOXY SYSTEM

So I wonder how many people actually have 600 micron and top up every 5 years beiring in mind the cost of removing antifoul and the cos t of WEST epoxy ?

 

[catmandoo]

6 coats to give a thickness of at least 600 mcrons

The 20 mil referenced in your source equates to just under the 600 microns in the one I read so that is about 6 coats

 

[wotayottie]

Anybody got West system on under water hull .

Yes - I had a cat professionally coated with Westy - twice! West is good strong epoxy but its an old formulation which is prone to amine blush. In my case the yard left the personnel door open whilst they were coating which triggered blush which went unnoticed until a year later it erupted as blisters between the epoxy layers. I have used West since then for structural jobs but I would not apply myself to the outside of the hulls - too sensitive to application conditions IMO.

In contrast I applied Blakes epoxy to another boat in February ( OK it was a good spell of weather ) but this was outside and I had no problems.

As for re-coating. Well the West tech rep who supervised the FOC re-coating of my boat said that epoxy was not impervious to water, just a lot better than polyester. So the more coats the better and additional coats as well.