Varnish over epoxy

I must admit, I tend to be one of those that enjoys clean and cosmetically pretty spars, etc.
I also will admit, that after all the truly earnest and helpful replies, I so damn confused...lol

My thanks to all that took the time to send your opinions.. great forum !

 

The West System piece is self serving and should be taken with a grain of salt. I respect and work with the tech guys up there all the time, but asking an epoxy formulator if you need it or not, isn't the wisest place to get unbiased answers. Rebecca Wittman is probably the best yacht finisher in the country and has the same opinion as I about epoxy under varnish. Unless the epoxy serves a purpose, such as hardening, stiffening or part of an abrasion resistance thing or a full encapsulation project, you're better off without the goo under the varnish. As it is, varnished surfaces are some of the most difficult to keep looking good, so why make more work for yourself, with the addition of epoxy. Varnish (good varnish) is designed to move with moisture content changes in wood as well as resist UV.

The LPU's are less tolerant of moisture gain movement, so in this case I would recommend an epoxy coating first. The single part polyurethanes seem more than capable of handling this movement, but repair and touch up can be difficult. In the end, if your spars are epoxy encapsulated, you don't have a choice, but if they aren't you do.

 

Epoxy under varnish will help seal gaps and such and it fills grain fast so you need fewer coats to get your surface flat. I've seen too many boats where it's gone wrong. If your varnish goes wrong you can easily sand it back and start again. If your epoxy goes wrong and goes milky or yellows stripping it off is a b*tch. Safer to stay away from that. The thing to think about is that if you do varnished spars it's an ongoing maintenance item. You'll be lucky to go 2 years between recoats. Think about if you want that much maintenance

 

Depending how one looks at it... restoring an old wooden boat has a special beauty that I believe calls for clear wood spars and gunnels rails...just can't see her (Mirror-11 with a Gunter rig sail) having her spars painted...the spars are short (less then 10' each) and will be bagged when not in use.. So I'v decided to go with all Varnish..(no epoxy) If any of you wish, I will post a few pic's once the boat is completed.

Again my most sincere thanks,

soapy

To some, a dumb Hillbilly and perhaps to others a wise man..lol

 

The only real reason for using epoxy is to fill the grain quickly, that reason alone is enough for me, but then i dont varnish fiddly things that are hard to prep, ie, i will do a transom because even though its big its easy to prep for a coat each season, i wont dick around with those silly little moldings between the cabin top and side, way too much work so it wont get regular maintainance and the varnish will all burn off and look like crap, basically, if you cant cover it for the 99% of the time when you are not on the boat paint it, this goes for spars too but with little ones like the OPs that can be stored indoors it makes sense.

Steve.

 

Many Pro painters use the Epiphanes system. PP is the base layer...you apply wet on wet...three coats per day to fill grain, then cover with several coats of UV shield varnish.

Epoxy will work, but dry time is an issue. PP dries very fast

 

You can fill the grain with varnish too. Using a Scotch Brite pad and mineral spirits, scruff up the surface in prep for varnish. You'll quickly create a slurry of very fine saw dust and spirits. Use a putty knife to move this slurry around and it'll fill the grain. You also can do this with the first thinned coats of varnish, though you have to be especially careful about scraping the surface flush, as the varnish will take on a lot of color.

If you're working on an old spar, it would be foolish to use epoxy on just the outside. In fact, and as the West System piece linked above suggested, if you do this you'll accelerate rot and other issues. Again, unless you NEED the epoxy and there are several reasons you might, the spar will live a lot longer without it. Epoxy is a one way street and once you elect to travel down it, you have to travel all the way down it. Lord knows I'm a big epoxy advocate, but with non-encapsulated parts, such as old, already assembled spars like this, epoxy isn't the wisest choice. I build several wooden spars a year and repair at least as many, so I have some limited expertise in this view. Lastly I would not use a LPU over unencapsulated wood. The single part polyurethanes have enough elongation, but the two parts generally don't and need a stabilized surface, such as that brought on with encapsulation.

 

Yep, using epoxy under varnish is a bit of a lazy mans approach (which is me when it comes to varnishwork) it just takes far fewer coats of epoxy to get the grain filled than an all varnish system, on many woods, even teak one coat of a fairly viscous epoxy like west will do the job of four or more coats of spar varnish but you may go through in a few spots when you are blocking it down so i usually use two coats. After the grain is filled i go with spar varnish, as many as i have the patience for. Ive had good results for many years with Flagship varnish so dont bother with anything else. I agree that on spars i would stick with all varnish. Ive built a few masts too so have had the opportunity to inspect the old ones and am usually quite impressed with the lack of rot when there is no sealing the inside and just varnish outside, usually confined to the butt, but often delaminating at the gluelines.

Steve.

 

Spars generally don't see a lot of water, though as you've noted, the heels can get pretty wet. Built up condensation, is their biggest concern usually, so keep the limbers cleaned out. If the spar has epoxy on the inside, you probably should epoxy the outside. If the spar hasn't any epoxy on the inside, then the best choice is just varnish.

 

I have used the polyurathene clear coat method jonr suggested on hatch covers that I rebuilt. The results and finish were incredible. I wet sanded starting with 400 and then worked up to 2000 grit. The final was a buff with compound. Lots of work but to me well worth it.