A few weeks ago, there was a thread on the benefits of varnish over urethanes. I plan to use a varnish on an interior application. In shopping around, I found that old fashioned varnish is not available at the local hardware store although a product called spar urethane is, having supplanted the original. Woodworkers catalogues carry both spar varnish for marine use and resin varnish (not spar) for general uses. What is the difference between these products? What does the spar designation mean?<br>



wrj494@aol.com

What an interesting question, perhaps the spar is as in a boat spar. I looked around and couldn't find any reference to it. I do know from experiance that spar varnish will outlast the plastic finishes (urethane etc.) Better UV protection in spar varnish as well. A bonus is that if in a year the varnish needs touch up you just sand and recoat. The plastics need to be taken to bare wood and then coated as new. When using varnish make sure you thin the first coat with paint thinner about 15 to 20%. Lighlty sand the next day and recoat full strength and sand between each successive coat. I cannot tell you though about the new water born finishes however as a former boat carpenter I will stand behind spar varnishes.<br>

I echo the comments about the high quality of spar properly applied. I messed around with poly for a bit but have come back to spar as the coating of choice where appropriate. Buy the best quality finishing products you can afford since the bulk of the cost of the whole job is in preperation - you don't want to do it more often than necessary.<p>Dave<br>



lathro19@idt.net

A good place to get quailty wood finishes including all grades of varnish is West Marine Supply. Follow the link below and good luck.<p>Bruce<br>



trainhead@mymail.emcyber.com

West Marine Link



West Marine Supply
trainhead@mymail.emcyber.com

Spar varnish is NOT intended for interior use because it has a high [linseed] oil to resin ratio, which means it never quite "hardens", always remaining slightly gummy (in the parlance of the refinishing industry, spar varnish is a "long oil varnish"). This is because it was formulated for use on ship spars, out of doors, where there is constantly changing temperature and relative humidity (hence the name). The varnish needs to stay flexible enough to expand and contract with the wood of the spar, otherwise it will spilt and allow the weather to reach the bare wood underneath and start it rotting. <p>Interior varnishes, on the other hand, have a much lower oil to resin ratio so they dry "harder" and therefore are easier to sand and polish. These are called "short oil varnishes".<p>Wood finishing is a very complex field, using a vast variety of fillers, stains, oils, resins, and lacquers; and these arent' necessarily compatible with each other (nor even sometimes "themselves"). Perhaps the most common interior finishing method used in railroad passenger cars (1870-1910) is: plane, sand, dampen, sand, fill, stain, sand, shellac and sand about 4 times, varnish and sand about 4-6 times, and finally rub and polish. Whenever the exterior of a car was to be varnished, spar warnish was used. On the interior however, spar varnish was never used. Some properties used only shellac, others only varnish.<p>Having used both over the years in car restoration, I strongly advise against using spar varnish for interior work. After all, with the possilbe exceptions of the window sills and inside window stops, an interior isn't subject to constant bright ultraviolet sunlight. One additional advantage of using a short oil varnish is that ALL the dust motes can be eliminated by the rubbing and polishing processes.<p>Varnish (and paint) work should always fill the pores of the wood completely so that when a bright reflection is viewed as a reflection in the surface of the finish (called "viewing in the light"), the surface appears completely and uniformly smooth, regardless of whether its a satin or glossy finish. For a typical interior, this will take 4-8 coats of varnish, depending upon which filler and undercoating system you use. Wet sand between each coat with 220-400 wet or dry, starting with the coarser grade for the first coats and progress to the finer grades for the last few coats, and NEVER sand through to the bare wood. Then rub with pumice and water (and a felt pad) followed by rotten stone and water (and a different felt pad). Wet sanding, which makes the pumice and rottenstone steps much less tedious, wasn't used by the "old timers" (try wet sanding with 600 right before the pumice and rottenstone). Undercoats usually consist of 4-6 coats of shellac (sanded with about 220-320 grit in between but NOT with water). If you use shellac, make your own. Don't use commercial off-the-shelf varieties because these contain wax stabilizers to increase the shelf life. The waxes make sanding very difficult and have the added disadvantage of making a poor bond with the subsequent varnish coats.<p>Good interior [rubbing] varnish is available ("mail order") from Mohawk Finishing Products Inc in Amsterdam, NY. My Thomas Register is way obsolete (1985), so sorry, I don't have a phone number readily available (they also have local distributors). I bought a gallon this way, and have been more than satisfied with the results. Also ask them what solvent they recommend. <p>Divide the gallon into four quart cans. The stuff will turn into "jello" if left in a 1/2 empty can for a week or two exposed to the oxygen contained in the airspace. I found an "aerosol can" of CO2 at a wine shop to purge the air out of the can before resealing. This has a tube which can be attached to the nozzle just like a can of WD-40 (which is now junk and a waste of money, by the way). After inserting the tube into the can with the lid lightly resing in place, a three second burst will purge virtually all the oxygen out of the can. Tap the lid on firmly with a rubber mallet immediately afterwards.<p>Don't ask your local paint store for help; these days they barely know about [real] paint.<p>Refinishing a passenger car is like doing a piece of fine furntiture. If you need to ask questions find a furniture refinisher--although these guys tend to spray lacquer too much nowadays. Don't use polishes which contain silicones and dont' use lemon oil and the like because these will be incompatible with any subsequent refinishing attempts or repairs.<p>One last item: photographs always make surfaces appear to be shinier than they actually were/are.<br>

I have found some spar varnishes formulated without Linseed oil and only tung oils. How does this fit the long oil varnish you mention? Mohawk has a min. dollar amount purchase but that shouldn't be a prob if your working on an entire car.<br>

Mr. Mowbray obviously knows what he's talking about; however, I do know that for museum applications we have used spar varnish to good effect. The railroads themselves never used spar varnish on the interior of cars because it took quite a while to dry. At a museum, where there is no hard-and-fast schedule, drying time isn't a big deal. The owner of the cars we use spar varnish on originally used shellac. However, this is not a good idea for museum use. In cool, damp conditions shellac tends to "bloom," to crack and alligator. It worked okay on the railroads because they always kept the cars' heat on.<br>Spar varnish is certainly more resilient than interior varnish, an advantage which we have been unable to find a distinct disadvantage to negate. My personal endorsement is probably for McClauskey's "Man o' War" spar varnish.<p>Frank Hicks<br>

Well, I see I haven't quite yet got the hang of posting in chronologial order; sorry.<br>

Many thanks to all of you for the very complete and thorough presentation on varnishes and finishing. This is where RyPN really comes into it's own. I have the same concern expressed by some that the car in question will undergo extremes of temperature and humidity even without exposure to the elements. If the rubbing or non-spar varnishes perform well even under those circumstances, I would like to know it. It is interesting to note that the Pullman specs are no more specific than to state two coats of vernish rubbed between coats. Thanks again.<br>



wrj494@aol.com

"Rubbing" varnish should be OK for interiors even in those cars you have to keep out of doors because occasional drops of water now and then aren't a problem (I recommend keeping the window shades down or placing cardboard cut-outs in the windows too keep the sun out of the interior when the car isn't in use). For exteriors, its the nightly coating of water which condenses on all exposed surfaces when the ambient temperature drops below the dew point and the daily exposure to untraviolet light from the sun which will cause short oil varnishes to break down much faster than long oil formulae.<p>The Pullman spec refers to "short oil" rubbing varnish.<br>