Phil, I am thoroughly impressed with your re-furb. I wish i had the time to do my entire boat like you're doing. I'm wondering if you can give me some advice. I'm about to tackle the job of sanding and refinishing the exterior teak on my 1976 Catalina 27. Not sure where to start. How did you go about doing yours? Should I remove everything or do it attached to the boat? What products would you recommend?
Thanks in advance!
-Sasha
Hi Sasha-
Removing the exterior wood for finishing will make your job a lot easier. It will also give you a chance to clean and seal any thru-holes/ screw holes used to fasten the wood in place.
On the wood, I recommend using a stripper if there is any varnish left. Usually there isn't any left though...
More times than not you can simply fire up a sander and get busy smoothing the surface and removing the grey oxidation. I use a random orbit sander and would start with 120 grit paper, finishing with 220 or 320. The surface material you are removing will be relatively soft, so it should go relatively quick.
Depending on what you end up with after initial sanding, you may find you still have some stains. Some folks leave these as they add character, but others want their woodwork looking brand new. If you are in the new-look camp, some Oxalic Acid or TSP, (tri-sodium phosphate) cleaning solution will even thins up for you. Follow the directions on the container. After washing the wood and removing the stains, you will want to wash it thoroughly with water to get rid of the cleaner. This will raise the wood grain, so sanding with your finest, (220 or 320) sandpaper will flatten things back out.
As for the finish, I have used Cetol and like it. I have used varnish and like it. I have even used Spar Urethane and have had good results. For ease of use and future touch up the Cetol is hard to beat, as you can apply layer over layer, regardless of time passed, with only a minimal scuffing required. Much of the "bad press" associated with Cetol over the years is due mostly to the fact that the original product had an orange-ish semi translucent appearance. These days you can do a Cetol finish that to the casual eye is quite similar to varnish, as Cetol is now a line of products, instead of the single product offered originally. All that being said, everyone reading this will have their own preference based on their personal experience. Nobody is wrong; there is no real definitive answer. Stu Jackson even has a humorous flow-chart for a boat owner's decisions regarding their preferred finish. If he reads this I will ask the he respond with it.
Regardless which product you choose, make sure it has UV stabilizers and make sure it is intended for full sun and exterior use. A non-UV product will deteriorate quite quickly in the sun. Be cautious too; many marine varnishes do not contain UV stabilizers... There is at least one Cetol product that is non-UV stable, and there are some varnishes, (Interlux Jet Speed is an example) that are designed for exterior use, BUT on the condition that a UV-stable top-coat, (Interlux Schooner as an example) be applied to protect it.
I used West Marine's varnish on this boat, not out of any preference, but rather that is simply what came with the boat from the previous owner and in a large enough quantity to do all the work.
What IS universal is the need for thorough and proper prep. When you hear folks griping about a product performing poorly, you have to consider the very real possibility that their prep work was not complete prior to finish application.
As you do your sanding, you will discover that as you go deeper into fresh wood the sanding dust changes. It starts to sort of cling together in little clumps rather than just flying up into the air. The reason is that the wood is by nature quite oily. The oils in the wood are causing the sanding dust to stick together. These oils are literally right on the surface of your wood. If you don't remove the oils, any finish you apply will simply be sitting on top of the wood and ONLY on top of the wood. It is an awkward analogy but varnishing on top of this oil is a lot like varnishing the surface of a body of water.
You want your finish to get INTO your wood, forming a mechanical bond. To do this you have to remove the oils.
So...
Once you get a piece of wood stripped, sanded smooth and bleached to your liking, right before finish application you need to remove that surface oil from the wood. Acetone is your friend. My standard practice is to use white rags, liberally soaked in acetone. You want to wipe down your workpiece all around, removing dust and surface oils. When you have scrubbed all over with the first white rag, pitch it aside and get a new one soaked with acetone and keep scrubbing. The white cloths will quickly get discolored by the oils; you want to scrub with clean soaked rags until they come away from your woodwork clean without color. That is your sign that you have removed all that oily surface contamination. Let the wood part dry, it only takes a few minutes, and then IMMEDIATELY apply your first coat of finish. This first coat is often thinned to aid in penetration into the surface of the wood; check the application guide for whatever product you are using. Some finished are reduced by half, while others recommend no thinning. Go with the recommendations on the container of whatever product you are using.
For any finish system to last, you want a minimum of four coats. Any less is just not sufficient to get any build thickness. I usually will go a minimum of 10 coats... Be prepared to patiently watch paint dry.... But be prepared and ready to go with the next coat as soon as you can apply it. If you can lay a fresh coat on while the previous coat is just barely dry you can use the solvents in the fresh coat to bond to the previous coat; you get a chemical bond that is quite strong. Wait too long and you need to sand before applying the next coat, resulting in only a mechanical bond. If you can drop fresh coats on top of previous coats as part of a well-planned process, I find that you will only need to sand every 4th coat. Sanding every coat prior to the next coat as many will recommend is unnecessary work and greatly slows your ability to get a sufficient build thickness of finish material. This is another topic where everyone has their own opinion but sanding in four-coat intervals is what has worked for me on all of the boats I have done, including two wooden runabout show boats.
The level of smoothness of the final coat is directly correlated to how many coats you are willing to put on. There is no shortcut... Many folks are happy with a uniform shine, leaving some grain visible in the finish top layer. You can get this with as few as 6 or 8 coats Others will want a totally flat mirror-smooth top coat, achieved by slowly filling the low parts of the surface with finish, while sanding down the high parts until there is no level difference. This usually takes 14 coats or more. Many people end up landing somewhere in between, with a top coat of finish that is pretty close to flat, but with a little grain left. That is fine. It is totally up to you. This is usually either due to getting tired of watching finish dry, or running out of either time or finish material.
My last point, going back to UV is this, and while I have heard it from several places, I do not hear it everywhere: Many wood boat and marine refinishing folks will tell you that the UV inhibitors found in UV-stable finish products will float to the top of the finish coat as part of the curing process. As a result, these people will tell you to never sand and polish your last coat, as it will remove the UV protection found in that coat. I have no definitive proof either way, but as a practice I never sand my top coat. Look at it this way: If you can get to a level of finish you are happy looking at with your last coat, leave it. Leave it ALONE. If not, lightly sand it, (I try to always put my last sanding in just prior to what I think is my last coat) and do it again. Oh, and don't wax it either...
If you ever plan on maintenance coats...
Sorry for the long read but that is my take on the subject... Be prepared for other folks to chime in...