In a previous post we described how our choice of wood finish was driven by our inheritance of a brand new quart of Bristol Finish two part polyurethane. After prepping the cockpit table and drink holder and reading over the instruction sheet a dozen or more times we finally psyched ourselves up enough to take the plunge and put some varnish on! Not knowing how much coverage we would get the first challenge was to decide exactly how much material to mix up for the first few coats. The table and particularly the drink holder are quite small pieces and while we didn't want to come up short we also didn't want to prepare too much goop and then waste it!
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The best case pot life of the activated varnish is about four hours, and at least an hour and a half is recommended between coats, so its easy to end up wasting material if you mix too much. Finally, we took a few measurements of the two pieces we were going to treat first, made a WAG as to their surface area, and mixed up a little over a half cup.
Looking at the mixed varnish in the pot there didn't seem to be nearly enough to do the job (the facial expression says it all!) and we almost made up a second batch but in the end it went a long way, a lot further than we expected. We elected to use disposable foam 'brushes' we got from Lowes after a lot of searching. We had seen from FOGgers posts and the comments of other people that there are variable qualities of sponge painting pads or 'brushes' and by doing a bit of comparison testing we found that all pads are definitely not created equally! The density of the foam and the angle of the edge chamfer makes a big difference. The denser the foam and the sharper the edge chamfer the better the results.
With the Lowes pads and by using the 'wet on wet' method described in the Bristol instructions, we managed to get three good coats on the table and two on the cup holder from the first half cup batch. As both the table and drink holder were now two loose pieces and not secured to anything we couldn't completely finish either of them in one shot. For the table part we taped the edges so we could do the bottom first. For the drink holder part we taped off the bottom face that screws to the table top so we had something to sit it on while applying the varnish to the rest.
When we started applying the varnish the first thing that became very clear very quickly was that filling the grain is critical to a good finish. From the pictures you can see there are some big grain flaws on the edges of the table top where repeated heavy handed sanding in the past has gone through the surface teak veneer and exposed the plies underneath! We tried to be as careful as we could with our sanding but, inevitably, we didn't help the problem! Even after very gentle sanding with 220 paper it still took three heavy coats of varnish to fully seal and fill the grain and get rid of the ripples in the finish. Fortunately, as we were working on a flat, level surface the heavy coats couldn't sag or run so we were able to slather the stuff on without a problem.
The drink holder was also difficult to coat but in that case it was because of all the repair work we had to do on it. We couldn't put heavy coats on it because there were so many places for sags to form. A further issue with the drink holder was the difficulty of getting to all the interior edges and corners.......not a good design for a piece that has to be varnished. Four light coats were needed to fill all the imperfections. There were a few smudges, some runs and a lot of profanities before we finally said "good enough"!
A bigger problem was that, even with our mid 70's warm weather, the Bristol Finish took a lot longer than the 24 hours quoted as curing time for the first three 'wet-on-wet' coats to become sandable (is that a word?). Even after 48 hours the 220 sanding pads clogged quickly when we tried to prep for the final finish coat. At first we thought that the extra heavy coats we put on the table were the cause but then realised that the drink holder with its light coats had the same issues. We double checked our mixing ratios and they were fine so the curing time in the spec sheet was definitely optimistic for indoor application. Maybe it cures a lot faster outdoors? In the end it took 3 full days before the surfaces on both pieces were hard enough for sanding without clogging. For flatting before the final coat, we used some 3M Sandblaster pads, they aren't cheap but they work great in the edges and corners and seem to hold up a bit better than the production paper.
The final result was not as good as we would have liked but, for our first attempt, it wasn't half bad. Both pieces looked 100% better than when we started. Mainly due to the pre-existing 'over sanding' problem we will never see a perfect result and, ideally, we should get a fresh piece of teak plywood and make a new table but with so many other projects in the pipeline that will have to go to the bottom of the list. This will work for now. To put this project into perspective use the link below to see a replacement table, unfinished and without the drink holder.
http://www.edsonmarine.com/marinestore/index.php?main_page=product_info&products_id=806
For our first experience the Bristol Finish gave a good result in terms of appearance, a very deep gloss. It was easy to apply and brush strokes flowed out well. As far as durability goes we shall see how it holds up over time. Our biggest complaint with it was how long it took to cure to a sandable condition for re-coating. We will do some more research before making a decision on what to use for our next varnishing projects which will be the cap rail, cabin eyebrow strip and cabin top handrails.
.JPG)
The best case pot life of the activated varnish is about four hours, and at least an hour and a half is recommended between coats, so its easy to end up wasting material if you mix too much. Finally, we took a few measurements of the two pieces we were going to treat first, made a WAG as to their surface area, and mixed up a little over a half cup.
With the Lowes pads and by using the 'wet on wet' method described in the Bristol instructions, we managed to get three good coats on the table and two on the cup holder from the first half cup batch. As both the table and drink holder were now two loose pieces and not secured to anything we couldn't completely finish either of them in one shot. For the table part we taped the edges so we could do the bottom first. For the drink holder part we taped off the bottom face that screws to the table top so we had something to sit it on while applying the varnish to the rest.
The drink holder was also difficult to coat but in that case it was because of all the repair work we had to do on it. We couldn't put heavy coats on it because there were so many places for sags to form. A further issue with the drink holder was the difficulty of getting to all the interior edges and corners.......not a good design for a piece that has to be varnished. Four light coats were needed to fill all the imperfections. There were a few smudges, some runs and a lot of profanities before we finally said "good enough"!
A bigger problem was that, even with our mid 70's warm weather, the Bristol Finish took a lot longer than the 24 hours quoted as curing time for the first three 'wet-on-wet' coats to become sandable (is that a word?). Even after 48 hours the 220 sanding pads clogged quickly when we tried to prep for the final finish coat. At first we thought that the extra heavy coats we put on the table were the cause but then realised that the drink holder with its light coats had the same issues. We double checked our mixing ratios and they were fine so the curing time in the spec sheet was definitely optimistic for indoor application. Maybe it cures a lot faster outdoors? In the end it took 3 full days before the surfaces on both pieces were hard enough for sanding without clogging. For flatting before the final coat, we used some 3M Sandblaster pads, they aren't cheap but they work great in the edges and corners and seem to hold up a bit better than the production paper.
http://www.edsonmarine.com/marinestore/index.php?main_page=product_info&products_id=806
For our first experience the Bristol Finish gave a good result in terms of appearance, a very deep gloss. It was easy to apply and brush strokes flowed out well. As far as durability goes we shall see how it holds up over time. Our biggest complaint with it was how long it took to cure to a sandable condition for re-coating. We will do some more research before making a decision on what to use for our next varnishing projects which will be the cap rail, cabin eyebrow strip and cabin top handrails.
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