What am i doing wrong when varnishing?

[Sumara of Weymouth]

Personally I wouldn't give up on conventional varnish just yet. I'm rather surprised your wash boards look so worn so quickly as vertical surfaces normally last the longest. Six coats is the usual recommended minimum amount of coats, after that you can top up with one or two a year. You were cutting it a bit fine with four coats. I am wondering if perhaps you have been sanding a bit too vigorously or with too coarse a grit. Although 120 is fine for the bare wood after that 240 for the second coat and then 320 or 400 grit. The trick is to be very thorough but also very light with the sanding especially near the edges. Very fine abrasive pads used wet can work well between coats. You need to build up the thickness. Instead of thinning the varnish you might want to consider diluting it with Owatrol which is a conditioner compatible with conventional varnishes. You can add a lot to the first coat for penetration, and just a little to the top coats to help the brush marks flow out. Once you get the build up thickness, conventional yacht varnish does look good and is quite easy to maintain - but you must keep on top of it!

 

[jamie N]

..... Instead of thinning the varnish you might want to consider diluting it with Owatrol which is a conditioner compatible with conventional varnishes. You can add a lot to the first coat for penetration, and just a little to the top coats to help the brush marks flow out.

Welcome. I've a varnished boat, and have never heard of the Owatrol thing, and am (of course) fascinated by it!
Would you expand on this......?

 

[pyrojames]

I use trad varnish from Jotun. All my external timber is teak, except the spars. From bare timber I use 50% thinning with alkyd thinners then 30, then 10 for a couple of coats. 7 total is absolute minimum for the teak, and 10 to 12 for spars. I rub down gently for every coat after the first four coats. It will normally go two years before needing touch up and another 3 to 5 coats.

 

[KAM]

Looks like the wood was very weathered beforehand there are some shakes and splits in the wood and not enough varnish was applied. I've tried lots of different varnishes on teak over the years. My thoughts are don't use 2 pack it might last a bit longer but is very difficult to repair and patch in. As for conventional varnishes I've tried lots of different brands and can't say I've noticed much difference in either ease of application or longevity. I just use the cheapest. Even degreasing doesent make a lot of difference. For getting a good finish warm weather is essential. As others have said you need a lot of coats and need to keep on top of it. Just a couple of coats can look good but doesent last. Conventional varnishes are easy to patch up and overcoat. The best thing I found is to cover it during the winter. A canvas tiller cover and plastic guttering over coach roof grab rails save an enormous amount of work.

 

[Sumara of Weymouth]

Welcome. I've a varnished boat, and have never heard of the Owatrol thing, and am (of course) fascinated by it!
Would you expand on this......?

Owatrol is a bit of a magic concoction. It is widely used to treat rust on barges. It will force out moisture and provide a base for priming. It is also used as a paint conditioner suitable for any paint which requires white spirit for cleaning up brushes. It retards the drying time so that the wet-edge can be maintained. It is very useful when working in not ideal conditions, such as wind or sun, and also when trying to maintain a wet-edge on a large surface area such as a hull. I use it 50/50 on my first coat onto my iroko hull. Handy stuff.