1) The quick-and-dirty boat wax job, for the full-time cruiser who just wants to protect the boat's gelcoat from further degradation, prevent gelcoat stains, and make boat-cleaning jobs easier.
2) The perfectionist wax job, for the sailor who wants all of the above, plus wants the boat to look its glossy-best.
3) The in-between wax job, for the sailor who wants his boat to look good, but not at the expense of adding an extra day to his haulout or lay-days.
And certainly, the condition of the boat has a big impact on how you approach the project. If you're bringing a boat back from the dead, the quick-and-dirty wax job is not really an option (although some makers of "miracle products" would lead you to think differently). You must be prepared to put in some elbow grease.
No matter which category you are in, your waxing job will have three basic steps:
1) Cleaning: This includes getting rid of salt, dirt, grease, mold, stains. You could break this down into various stages, depending on the condition of the hull, general cleaning and stain removal.
2) Polishing: This creates the smooth glossy surface to be protected. If you have an old hull, there could be several stages to this process.
3) Waxing: This is the application of a thin polymer or natural wax coating to seal and protect your polished gelcoat.
The important thing to remember is that if your hull is not clean before you begin polishing or waxing, you might drive dirt further into the pores of the gelcoat. Not the end of the world, but you won't get the best results.
Your biggest investment will be a good polisher. We've looked at various options, ranging from el-cheapos to mid-priced powertools aimed at the automotive market, to higher-end tools geared specifically for use on boats. Lately, for polishing, waxing, and buffing, we've been using a Dewalt variable-speed polisher, the DeWalt DW849, with a 3M 3M-05705 Superbuff Polishing Pad and the 3M-05710 Superbuff Adapter (used to fit pads on any standard 5/8-inch shaft slow-speed polisher).
Two other products worth looking at:
An inexpensive variable speed from Chicago Electric:
This one rattles and and hums, but it works. Ours is still working, but it gets used only twice a year. Harbor Freight also has 7.5-inch wool buffing pads to match for much less than the 3M versions.
There is also a marine-tailored, small-diameter, dual-action polisher from Shurhold.
This one helps avoid swirl marks and is relatively lightweight. It's good for micro-finishing.
It has some nice features (like a built-in breaker, in case there is a fault in the circuit), and is sized to take the smaller 3M Finesse-It pads that 3M recommend for the Finesse It step below. Shurhold also makes its own buffing compound, Buff-Magic.
I generally apply the compound and wax by hand, using a basic microfiber round waxing pad. I then use the Dewalt to compound and remove wax. The key is to go very light at a low-RPM. I often will buff again with one of those really soft "lambswool" buffing pads, or a microfiber cloth by hand. Good polishing products will designate the RPM-range that is suitable. Start at the low end of that range.
Wash thoroughly, removing all oil and grease. We haven't tested boat soaps, but if you want to get rid of the old wax, keep in mind that many boat soaps are mildly formulated not to remove waxes. For this stage of cleaning, Nick likes Simple Green. He dilutes as needed. You could do the same with one of the recommended cleaners below in our multipurpose cleaner test, which includes some eco-friendly choices.
For serious stains, spray your chosen cleaner undiluted. Note that ALL of the spray cleaners in our last multipurpose cleaner test removed wax.
For mildew, chlorine is the ticket. Outdoor Clorox works well. You can also try some of the best products in our last mildew cleaner test, which included some more eco-friendly solutions.
If grease or exhaust soot is the big problem, then a degreaser will also work.
Serious Hull Stains
Mild acids are very effective at attacking serious stains that don't respond to the above treatments. Used incorrectly or in strong concentrations, acid cleaners can harm gelcoat, so use it sparingly and follow directions. Do a test patch first, and be sure to rinse thoroughly. Also, be sure to cover a trailer well as it will take galvanizing and even paint off. Keep away from paint and varnish. Clearly, it is better to do all of your hull cleaning before painting the bottom.
Nick liked the Davis FSR gel, here's our complete report on on 22 different hull-stain cleaners.
For a softer, more eco-friendly cleaner check out RidLyme.
The above multi-purpose cleaners should have eliminated any grease or dirt that would interfere with polishing and waxing, but some, like Don Casey, mention solvents. I personally don't do this step unless I'm painting, but there is nothing wrong with taking the extra step.
Casey recommends MEK over acetone. Interlux 202 Fiberglass Solvent Wash is another one that we've used. It seems to evaporate a little slower down here in Florida.
Also, we are looking at some "green" dewaxing solvents now from RPM technologies although these appear aimed at the industrial market.
Once you are assured you won't be driving grease and dirt deeper into the hull, you can begin polishing, or compounding. Be sure to wear goggles and a dust mask while doing this step. This process also removes any remaining old wax. Many wax manufacturers have a specific product that also includes a cleaning component (often petroleum-based) to get rid of grease and dirt. Collinite's Boat Cleaner 920 is an example.
How aggressively you want to polish your hull will depend on the hull condition. On a badly worn hull, you could wet sand with 800 grit wet-dry paper, followed by finer grits and then polishing compounds. If you've been waxing your hull regularly, and see no signs of oxidation, you might not even want to buff and skip to micro-finishing or waxing. Or, you could combine the buff and wax process into one with a one-step cleaner wax. The idea is to start with the least aggressive compound you need.
We haven't tested buffing compounds, although they all work basically the same way, they contain a mild abrasive suspended in a liquid or paste used for polishing the hull. The current trend is toward water-based products like Aqua Buff, which contain no petroleum distillates. I have had good luck with 3M Imperial Compound and Finishing Material, which does. Whatever compound you use, start with the mildest (highest # grit) that you need.
For what power tools to use, see the power tool details above. In addition to the Superbuff pad mentioned before, I have also used 3M hook-It Velcro pads for polishing. In any case, I smear polish on the hull with a foam waxing pad and go VERY LIGHTLY at a low RPM. 3M recommends 1,000-1,500 RPM for its Imperial Finish. Keep the polisher moving to avoid heat buildup or over-polishing.
Many people skip this step, but I find it produces a better gloss if you do it, particularly when trying to restore the gloss to an older boat. We have not tested this product category. Essentially, this is an even finer polish than those used for compounding. For this, I use 3M Finesse It II. Several of the automotive-oriented waxes in our liquid wax test have similar products. On a small boat, you can apply it by hand, but I do it by machine. Again, apply light pressure and use a slow RPM, being careful to follow the instructions. Do a small area at a time.
Now that your hull is shiny, it is time to protect it. We've tested dozens of liquid waxes and paste waxes. Generally, the pastes offer harder protection that lasts longer and the liquids are easier to apply and last almost as long. I generally stick with the Collinite 885 paste wax. Contributing editor Frank Lanier, who waxed his hull by hand, found it too much work and was quite happy with the Collinite. A number of readers swear by the Nu Finish.
I usually use the the same tools I used for compounding, although I change to a clean pad. I usually apply the wax by hand using a foam microfiber pad, and then buff with the machine. Working in small areas. Don't let the Collinite 885 dry too hard, or it becomes hard to buff. Also, don't lay it on too thick. If you work in cooler temperatures, this can be a tough product to apply, but you can warm up the can slightly to soften it up. Usually, I have to go over the hull twice to get the shine. Sometimes I'll switch to a very soft buffing pad for this last step.
Jamestown Distributors has a pretty good video on refinishing an old hull using the 3M system. It's pretty heavy on the 3M products ads. Often, you can do just as well with products from your local Finish Master or similar auto-refinishing place. They also have a pretty good polishing kit that has everything you need, including the polisher.