01/10/2021 at 1:14 pm #22572
Finally finished varnishing my self built GP14. No matter how clean the work area particles are present in the finish, but all was not lost as I start to polish the decks, seats and thwart. All the solid hardwood parts have come up sparkling as has the decks but the polish now highlights some sort of imperfection down in the layers or even under the layers of varnish in the the deck areas. My wife quite rightly points out that all this will not effect the dinghy’s sailing performance and that is of course true but I would like to understand just what has gone wrong in the varnishing process. I have searched the internet with no success and the page on varnishing under Maintenance on this site seems missing. All coats were applied with-in allowed temperature ranges, 9 coats in all with 1st. 3 coats being applied so as to chemically key then a mechanical key (320grit) 3 more chemical keyed etc. When viewed with the sun behind yourself there appears to be some patchy milky cloudy-ness in a few small areas. When viewed looking toward the sunlight all looks perfect. All varnishing was done on warm dry days so I’ve ruled out moisture in the finish as I think this would be more wide spread. I understand that timber reflects the light and can seem changed when viewed from different angles but this is not the case here. This is my first attempt at a New Build and at Varnishing although I have years of experience brushing and spraying lacquers. No point in attaching photos as file size allowed to small.
Advice is therefore sought from this very knowledgeable GP14 forum. Thanks in advance.
01/10/2021 at 9:03 pm #22576ChrisParticipant
Anything milky or cloudy is almost always moisture. What varnish did you use? Is it visible outside? Flourescent light shows imperfections that afrenmt really there. Sometimes it will bleed out over a few weeks/months. Some of the two pack brands are mixed by weight and its very, very critical to get right. If it isnt right, its not fully cured and if you wet flat it……..
Same applies if its insufficiently stirred.
- This reply was modified 3 weeks, 3 days ago by Chris.
01/10/2021 at 10:45 pm #22578
Chris, thank you for replying. The varnish is 2 pack Perfection Plus. 2 parts base to 1 part hardener all poured through 190 micron filter into measuring pot and well mixed. All applied during July and Augusts very dry weather in my workshop. The lighting is all LED, not sure if they show imperfections like Fluorescent but actual sunlight through window showed up the lighter shade areas on foredeck today when looking at deck with sun behind me. This shading disappears when looking at the deck facing the sun, ie. the shading disappears, strange. As I said earlier all solid mahogany shows no imperfections only in small areas on the ply of the decks and on closer inspection appears to be under not in the varnish so it may be a problem in the epoxy coats. If this is so then some day in the future will get sorted during a refurb.
02/10/2021 at 7:35 am #22579ChrisParticipant
Artificial light shows all sorts of “defects” that are otherwise invisible.
I would be inclined to not worry about it.
It could be amine blush from the epoxy – did you scotch it with hot soapy water before rubbing out down? If its this you’ve got to back to virtually nothing to eliminate it, which if you cant see it outside is a pretty major task for not a lot of gain – annoying though it is! I saw someone’s OK do this a couple of weeks ago also varnished this summer on you can clearly see it outside. What resin was it?
- This reply was modified 3 weeks, 2 days ago by Chris.
02/10/2021 at 1:11 pm #22585
Hi Chris, I used Sicomin SR5550 which is solvent free all measured <span style=”color: #000000; font-family: Roboto, ‘helvetica neue’, helvetica, arial, sans-serif; font-size: 15px;”>meticulously on fine scales. No I didn’t wash and scrub with hot soapy water ( Oh dear ) but I did use copious amounts of acetone to wipe when fully cured. Some of the shading is adjacent to the rubbing strips down each side which were bonded on and not screwed. The bonding contained silica which I’m told can be seen after varnishing but all was well taped up to protect from contamination so don’t think it’s that. My wife thinks like you and says not to worry, just get on the water lol. which I will be doing after my RYA1 course in 2 weeks time.</span>
Thank again, Windy
12/10/2021 at 9:00 pm #22621
Polishing of the varnish now complete. I have been through the polishing cycle 3 times as each time the finish gets better but Iv’e had enough now. The afore mentioned defects are still there and accepting advice from you knowledgeable guys I think the defects are probably the amine blush that Chris mentioned down under the layers of varnish. I’m told that blocks and fittings are difficult to get hold of at the moment so waiting for the kit supplier to come and rig the dinghy. Covers have been sourced from rainandsun.co.uk in Southampton.
Hopefully a couple of photos attached.
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13/10/2021 at 1:17 am #22624Oliver ShawModerator
Well I had thought that my own varnishing was good, but this is excellent. Well done!
If you are concerned about imperfections in this finish you are setting yourself an exceedingly high standard!
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