MarkJohnson12345
Well-Known Member
What is involved in epoxying the hull??
Does the gelcoat have to be worked on in a big way??
TIA
Does the gelcoat have to be worked on in a big way??
TIA
Epoxying?
- Thread starter MarkJohnson12345
- Start date
Bilgediver
Well-Known Member
Depends if there is a problem in the gelcoat or hull and how bad?????????
beneteau_305_553
Well-Known Member
I removed all antifouling and sanded with 120 grit. Wish I had paid to have it shotblasted.
VicS
Well-Known Member
Go to the website of the epoxy supplier and follow the advice there to the letter.
www.yachtpaint.com/UK if you are using one of International's Gelshield products.
www.yachtpaint.com/UK if you are using one of International's Gelshield products.
MarkJohnson12345
Well-Known Member
Showing my ignorance here I know but......
I understand that epoxying a boats hull is a preventative job re osmosis.
My Sadler is supposed to have been epoxied twice in its 28 years so the previous owner told me. I have no receipts or anything else to prove it, other than a hull that is osmosis free. (Am not doubting him for a mo.)
The link that Vic gave me seems to be more about repairs than preventative work.
This my original question still stands.
After the antifoul is removed completely, is it just a matter of sanding down the gel coat before applying the epoxy?
Do you epoxy above the waterline?
Assume one needs reasonably dry weather for the process.
Whilst the gel coat is sanded down it it worth waiting a month for any moisture to go?
TIA
I understand that epoxying a boats hull is a preventative job re osmosis.
My Sadler is supposed to have been epoxied twice in its 28 years so the previous owner told me. I have no receipts or anything else to prove it, other than a hull that is osmosis free. (Am not doubting him for a mo.)
The link that Vic gave me seems to be more about repairs than preventative work.
This my original question still stands.
After the antifoul is removed completely, is it just a matter of sanding down the gel coat before applying the epoxy?
Do you epoxy above the waterline?
Assume one needs reasonably dry weather for the process.
Whilst the gel coat is sanded down it it worth waiting a month for any moisture to go?
TIA
cliff
Well-Known Member
Yes, Yes, Yes and finally.....Yes for prevention. If curing then gel coat really needs removed and the hull dried out.
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Artificial Intelligence is no match for Natural Stupidity
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Tomkat17
Well-Known Member
I epoxyed my hull last year. The preparation is the hard work part ensuring the surface is clean of all previous applications and the surface has been etched. Applying the epoxy was quite easy and similar to anti-fouling, you just follow what it says on the tins and make sure you apply enough coats to build up the thickness of protection. It is a good idea to use different colours between coats to ensure even application. You can get this with two colours if you don't use a full tin for each layer.
bluedragon
Well-Known Member
Hi Mark...you might ask yourself why you're doing this. I went through the same thought process myself and spoke with epoxy coatings people at the SBS. If the existing epoxy coating(s) is sound, and has been applied in the correct thickness, then just leave it be. I've seen an example of a subsequent coating applied without perfect preparation, and it all began to peel after a few seasons..and that was a hell of mess to get off. I know the temptation is there to re-epoxy if you've gone to all the trouble to remove the AF (I had the same temptation but short of blasting couldn't get the hull clean enough), but will it really bring benefits vs. the risk of a botched job?? Have a word with International or Blakes. I think it was the latter that said "if it 'aint broke, don't fix it" when asked this question...!! I thought they'd want to sell me loads of expensive epoxy /forums/images/graemlins/grin.gif
Cloven
Well-Known Member
I commissioned a new kit built Hunter 4 seasons ago and they recommend using 2 coats of Gelshield. I also followed the recommendations on the Gelshield tin of applying 6 coats plus further advice from the chandlers.
1. Preparation - bearing in mind this was a new boat "straight out of the mould", the first thing I had to do was completely sand the shine off the gelcoat for all underwater surfaces to which you plan to apply the Gelshield and this includes the boot-top. This was a thoroughly tedious job and took about two days. On a previous older boat where I had to remove old antifoul etc, I had this done for me by a professional sandblasting outfit. They also applied the Gelshield of which more later.
2. Once the hull is prepared, the recommendation is for six coats of Gelshield. It comes in two colours – green & grey and the idea is to put coats of alternate colours so you can easily see to get good coverage. I applied it with a small roller as used for antifoul. To give you an idea of coverage, a 2 ½ litre tin gave one coat on a 32ft hull. Curing time is temp dependant and doing the job in the spring, I managed 1 coat a day. There are recommendations about max time between coats of Gelshield but I can’t remember these. They are however on the tin. I put the first 5 coats on one week and then the rest the following week so you can leave it for some days between coats.
3. The most important thing is timing from the last coat of Gelshield to the first coat of antifoul. Ref para 1 above, the people who did the sandblasting/Gelshield application on the previous boat said I could go straight to antifoul. What they omitted to tell me was if you want to avoid using an antifoul primer, the first coat of antifoul has to be applied before the final coat of Gelshield has cured – i.e. on the same day. Result was most of my new antifoul flaked off and I had to take it all off before priming and then re-antfouling.
4. Learning from this experience, on the new boat, I put on the first coat of antifoul the same day as the last coat of Gelshield so they formed a chemical bond. I also followed the recommendation of the supplier and that was to make that first coat hard antifoul of a different colour to the final self-eroding antifoul. The idea was that you could then see when the self-eroding antifoul had worn away, particularly if the hull is scrubbed at lift out. I used white hard antifoul & 2 coats of dark blue self-eroding antifoul. To further avoid any risk of incompatibility, I used the hard & self-eroding antifoul the same make as Gelshield (International Paints?)
5. In summary there were a total of 9 coats: 6 Gelshield; 1 hard antifoul; 2 self-eroding antifoul.
6. Results so far have been excellent. Absolutely no problems of adhesion and after jet-washing on lift out, a straightforward re-coating of self-eroding antifoul before re-launch.
7. Obviously after only two seasons I cannot comment on any osmosis but at least I feel I have peace of mind.
I hope this helps.
1. Preparation - bearing in mind this was a new boat "straight out of the mould", the first thing I had to do was completely sand the shine off the gelcoat for all underwater surfaces to which you plan to apply the Gelshield and this includes the boot-top. This was a thoroughly tedious job and took about two days. On a previous older boat where I had to remove old antifoul etc, I had this done for me by a professional sandblasting outfit. They also applied the Gelshield of which more later.
2. Once the hull is prepared, the recommendation is for six coats of Gelshield. It comes in two colours – green & grey and the idea is to put coats of alternate colours so you can easily see to get good coverage. I applied it with a small roller as used for antifoul. To give you an idea of coverage, a 2 ½ litre tin gave one coat on a 32ft hull. Curing time is temp dependant and doing the job in the spring, I managed 1 coat a day. There are recommendations about max time between coats of Gelshield but I can’t remember these. They are however on the tin. I put the first 5 coats on one week and then the rest the following week so you can leave it for some days between coats.
3. The most important thing is timing from the last coat of Gelshield to the first coat of antifoul. Ref para 1 above, the people who did the sandblasting/Gelshield application on the previous boat said I could go straight to antifoul. What they omitted to tell me was if you want to avoid using an antifoul primer, the first coat of antifoul has to be applied before the final coat of Gelshield has cured – i.e. on the same day. Result was most of my new antifoul flaked off and I had to take it all off before priming and then re-antfouling.
4. Learning from this experience, on the new boat, I put on the first coat of antifoul the same day as the last coat of Gelshield so they formed a chemical bond. I also followed the recommendation of the supplier and that was to make that first coat hard antifoul of a different colour to the final self-eroding antifoul. The idea was that you could then see when the self-eroding antifoul had worn away, particularly if the hull is scrubbed at lift out. I used white hard antifoul & 2 coats of dark blue self-eroding antifoul. To further avoid any risk of incompatibility, I used the hard & self-eroding antifoul the same make as Gelshield (International Paints?)
5. In summary there were a total of 9 coats: 6 Gelshield; 1 hard antifoul; 2 self-eroding antifoul.
6. Results so far have been excellent. Absolutely no problems of adhesion and after jet-washing on lift out, a straightforward re-coating of self-eroding antifoul before re-launch.
7. Obviously after only two seasons I cannot comment on any osmosis but at least I feel I have peace of mind.
I hope this helps.