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How (not?!) to varnish wood quickly
Dear fellow boat and diy enthusiasts,
I am currently remodeling a super-lightweight boat called "Marinekart 338". If you're interested in the whole story: I did some documenting in another forum. It's in German, but the pictures will tell most of the story I guess: https://www.boote-forum.de/showthread.php?t=333210
In the course of the restoration I learned so much from Dan's channel, especially his how-to videos that I thought I'd share some of my finishing work here. The "how to varnish wood quickly" video I probably watched 100 times and I was so intrigued by it that I just had to try it out myself. Since I don't have regular access to a workshop saving time on the finish suited me just right! I added the "not?!" in the title because towards the end I made one colossal mistake and I still don't know what the final outcome will be. I hope you find the pictures and videos useful and maybe if anybody has some advice I'd highly appreciate it!
So the first three photos I attached show the veneering process to show you what the base of the finish is. I used a super thin (0.6mm) mesh reinforced veneer which is just perfect for my project: lightweight, flexible and sturdy. You really need to watch not to sand through it though...
When I realized I wasn't going to get it all finished before our vacation in June I decided to go with epoxy coating only for the time being. So I went with four coats of west system clear hoping it would be enough to protect it from the forces of nature for a couple of weeks. Also this gave me a chance to test whether the veneer would hold before spending more effort and money on the finish. The plan worked out just fine, but when I took off the exterior parts and bumpers again I was a bit shocked to be honest how much the sun had already brightened the (printed - not real zebrano wood!) veneer. It was high time to add some uv protection!
Here you'll see what I mean after applying Epifanes PP a couple of weeks ago: https://youtube.com/shorts/wGJKMytBiAU?feature=shared
I actually don't mind the new, lighter tone and unless I have to change my registration number I guess I'm fine 😀
Sanding the Epifanes PP was a bit scary: The thin veneer left a rather uneven surface so there was quite a bit of "taking off highs" to do. I was in constant fear of accidentally sanding through but I think I got it right (in most places). Here are some intermediate stages like Dan was showing in his video. Hopefully you find this interesting: https://youtube.com/shorts/OD60HGJvjVU?feature=shared
Everything looked promising and I was getting ready for the final three coats of Epifanes PU clear coat. Around two hours after the spraying the first coat when I was in the process of mixing the second cup I noticed the one huge mistake I had made on coat number one: I had gotten the mixing ratio wrong, even though I had watched the video like 100 times... I wanted to make sure I got it right so I had another look at the cans. You may have come across the fact that the hardener says 250ml and the clear coat has 750ml written on it - next to the little added "(A+B)". Being all excited about the outcome so far I overlooked this additional piece of information so I was absolutely sure that the ratio was 3:1 instead of 2:1. In the heat of the moment I made the decision to continue and put another coat directly over the first one with the correct ratio this time. Then I was both out of time and out of varnish...
Here is the result on the next morning: https://youtube.com/shorts/ZikvMpGoXWE?feature=shared
Right now it feels bitter sweet because it looks absolutely fabulous but I don't know whether it will hold. It seemed like it was still very soft underneath surface the following day but then again nights had already started to be rather cold (down to 10C) in Germany. 3 days later the it felt hard on the outside but you could still leave marks with your fingernails. Not sure, might be normal... I now let it sit for two weeks now since I'm currently not home, will check on it next week and see. Fingers crossed... Maybe, if it does seem like it has hardened after all, putting some more layers on it to get reliable uv protection would be a good idea?!
I would love to hear your thoughts. Until then: happy boating every one, enjoy the last weeks of the season!
Cheers,
Johannes
Hey you all,
Short update after a quick check on my return home tonight: Top layer seems to have hardened nicely and it does not feel soft underneath. I haven’t check in all the places but I am a bit relieved.
Still I feel that additional layers of top coat - by roller this time - would make sense after seeing what the sun has done to the veneer in only a few weeks. What grade sanding would you guys suggest? I’m thinking 600 by hand, maybe wet?!
cheers,
Johannes
Hi Johannes
It is amazing what the sun will do to discolour things, I noticed this with my frames for Temptress that I'd built some months before, when I started sanding them I realised just how much they had discoloured and they never even went outside, this was just from sunlight coming into my workshop! I noticed the numbers on the side of your boat where you can see a significant colour difference. Some woods are also more susceptible to this than others.
If you are in fear of sanding through veneer, my advice would be to sand only with scotch bright in the early stages until you have more varnish on the surface. It is much more forgiving and essential for abrading any sharp corners.
Don't officially quote me on this but I think you will be ok with your incorrect mix ratio. A different paint supplier told me that Polyurethane can actually cope with a fluctuation of ratio between components from 2:1 to 5:1 and it will still cure but with differing physical properties. I don't know what those are and how it affects the process as a whole but that's what I was told. I would of course recommend shooting for the manufacturers recommendation. In the instance of epoxy of course thats different, your ratios must be correct in order to ensure a cure.
I am please to hear it looks ok following your return from being away. The boat looks incredible and you have a great finish on it, well done!
Regarding sanding, I wouldn't go above 400g, I have occasionally pushed to 500g but no finer. Going finer will not deliver you a better finish in the final coat but may risk a poor adhesion due to there not being enough of a key for the coat to hold on to.
Cheers
Dan
Hi Dan,
Thank you very much for your advice, this is much appreciated!
I guess my instinct told me to go finer because I don't want to risk sanding through to the layer of "questionable integrity". But it would in deed be nice if the new top layer actually stuck to it 😛 I'll go ahead with 400 then - very gently...
It may be a while until I get access to a work shop big enough but I'll share the final results here once it happens.
Thanks again and good luck with all of your endeavors,
Johannes