I'm getting ready to work on finishing and I'm wondering what everyone uses to thin MOW spar varnish.  I think on the tips site Bob Nunley  talked about  thinning spar  with turps  (30% turps, 70% varnish) when working with wraps.

How do the rest of you thin the spar?  Also what are the ratios that you use for wraps & for overall rod finish?  (Todd Talsma)

I use Ace brand spar thinned 50% with mineral spirits for coating wraps. It goes on like water and dries with in 24 hours for the next coat.  So far no ill effects on its ability to adhere to the previous coat.

I have also used this mix with a foam brush (Frank Stetzer's method) with good results for finishing the rod sections after wrapping.  I keep the thinned varnish in a screw top quart jug, the one that the mineral spirits came in, and work out of a small glass jar that head cement or Flexament comes in. I have been able to complete two entire rods with less then 1 fluid oz. of thinned varnish.

I'll be doing my next rod in a drip tube as soon as I get some other jobs in the shop knocked out.  (Brad Love)

I've started using a product called Gumtine to thin my MOW.  You can get it at art supply stores.  Its primary use is to clean artists paint brushes but it can also be used to thin varnish.  It is concentrated so you don't need to add nearly as much.  I've found that the dry finish is excellent and the varnish doesn't dry out in the storage container like used to.  It smells strongly of burnt orange.  (Jim Harris)

I thin spar (Pratt & Lambert #61 spar) with Mineral Spirits to about 30%/70% for the first coat on wraps and in the dip tube. I use full strength for succeeding coats on the wraps (3 total)  (Marty DeSapio)

What is the thinking on thinning  the varnish that one uses on rods - either poly or spar.  I read some do 10% while  others suggest 50%. What is a good approach in this regard?  (Frank Paul)

For dipping? I like Minwax thinned about 15-20% with Penetrol.  For wiping? One part each of Interlux Classic Spar, Pure Tung Oil, and Pure Turps.

For wraps? I use one coat of Mike Brook's walnut varnish for clear or light colored wraps, none for darker colors. I use Interlux Classic Spar thinned about 3:1 with turps or the 211 brushing thinner from Interlux. After an initial two coats of spar, I sand and then use it near full strength for one more coat before a final dip.   (Bob Maulucci)

Found some info in the tips site - suggests 30 to 50% thinning. Is this standard for all the varnish coats?  Are more thin coats better than fewer thick coats? Oh my, lots of questions. (Frank Paul)

As a general rule, more thin coats is a better idea than a few thick ones.  (This applies to woodworking, painting your car, whatever.)  The thin coats dry faster with less chance of runs and less chance of not waiting long enough to recoat, which often causes varnish to wrinkle.  (Neil Savage)

What should I use to thin spar, turpentine?  And will mineral spirits clean up the mess when I done?    (Lee Orr)

The directions on the can will not advise you to thin spar.  That's because of EPA red tape.  The same directions will however suggest what you can use to clean up.  Whatever is suggested for cleanup is the best thinner, too.  (Harry Boyd)

Is there a difference between paint thinner and mineral spirits? What would you recommend to thin Daly's SeaFin  Super Spar?  (Tim Pembroke)

I attended a finishing seminar at the Detroit Woodworking Show two weeks ago (the old dog is still trying to learn new tricks!) The lecturer said there is indeed a difference between thinner and mineral spirits.  The thinner has the same additives as the finish product, as well as mineral spirits, whereas there are no additives in the mineral spirits.  He recommended using the manufacturer's thinner. 

He was pushing HVLP spray systems, which I can't cost justify, but what he said seems to me to be correct for any application method.  (Neil Savage)

I've seen a lot of references lately to using VM&P Naptha to thin spar varnish. I also know that some folks like turpentine while others seem to prefer mineral spirits. Other than the Pine Sol smell of turps what are the advantages and disadvantages of using these 3 different thinners?   (Larry Puckett)

For me, Naptha seems to blend with the varnish better and doesn't separate like other thinners do. I've had my dip tube filled for about 3 years and no scum or separation. All I ever do is add more. I also use gloss varnish so I don't have to worry about the settling of particles in the mix. When I dip, I dip at 80° varnish temp. @ about 1/2" per minute. No stopping at guides with thinning at 25%. To start with, I thin 2 quarts of varnish 25% with Naptha. Mix it all together in a bucket, fill the dip tube, pour the rest in one of the cans for later use.  (Don Schneider)

VM&P Naptha and mineral spirits are petroleum distillates with different boiling points.  VM&P naptha boils at 125 F while mineral spirits boils at about 175 F.  Therefore naptha dries quicker.

Turpentine is a pine sap distillate comprised mostly of terpene oils.  It boils at about 160 F so it dries about the same speed as mineral spirits. It is said that turpentine causes a varnish to flow better so "brush  strokes" would smooth out better.  It is also claimed that turpentine will chemically combine with some components of some varnishes and never fully evaporate.  I don't know if the combined product becomes a hard resin or if it acts as a plasticizer.  Good or Bad, I don' know.  (Al Baldauski)

"It is also claimed that it binds with some vanish constituents and never fully evaporates."

The important thing then is does the smell ever go away? My wife won't even let me open it in the house.  (Larry Puckett)

My rather unscientific opinion is that turps tends to slow drying time fairly noticeably. I had always considered this to be because it is a solvent rather than a drier, which is more or less what you said!  (Robin Haywood)

I have seen many times here and in the archives that some of you use a mixture of varnish + either turp or mineral spirits + Penetrol. What is the advantage of adding Penetrol?  (Will Price)

The Penetrol helps the varnish "flow."  Some varnishes, for some reason, will tend to pull from the edges.  The Penetrol helps to inhibit that little problem.  (Mark Wendt)

I thin with mineral spirits and Penetrol.  It seems to help the flow better. And like Don posted earlier, I have my dip tube set up in a lighted enclosure with a motor that pulls the rod out at a rate of 1" per minute and a half, very slow, but the finish turns out really nice.  (Scott Bahn)

What company, if any, owns the name Penetrol? I went to both of the big box stores yesterday (Lowes and Home Depot), Sherwin Williams paint store and 2 mom & pop old timey hardware stores and none of them had Penetrol on the shelf. Who makes it and where do you buy it? If I recall correctly, the one time I saw it, it was in a blue can from Crown. I just don't remember where I did see that.  (Will Price)

The Flood Company
PO Box 2535
Hudson, Ohio  44236
800-321-3444

Got my last cans at Ace and True Value.  (Mike Shay)

Penetrol is made by a company called Flood.  Here's their web site with the page on Penetrol.  There's also a store locator service on their web site.  (Mark Wendt)

Just curious -- what are the benefits of Penetrol over naptha, turps, or mineral spirits?  (Don Peet)

Penetrol is some kind of drying oil (tung? linseed? soya?) thinned with petroleum distillates, probably mineral spirits or naphtha.  The extra oil will let the varnish "flow" better but will slow drying and dilute the strength of the varnish film as a water vapor barrier. Some say it helps reduce the tendency of varnish to "pull off the corners" as it cures, but I think any high oil content varnish (exterior) will be OK in that regard.  (Rich Margiotta)

You probably know more about it than I do as I've never used it before. Wanted to try it as several on the list said that it helped the flow and also gave a smoother varnish job. That being said, are you speaking from experience as to it slowing the drying? According to the can it SPEEDS up the drying. The formula that I've seen recommended was 80% varnish to 20% turps or mineral spirits and add 1/4 cup of Penetrol to the dip tube, or around 5% of the total volume.  (Will Price)

My experiences with Penetrol have been mostly in the painting and coating end of things and it works as a lubricant in paint spraying and to a certain extent it is an extender, you can even clean oxidation off fiberglass boat hulls with it and it makes them look new, there are better products out there for varnishes, one being made by Homer Formby and another is Tru-Oil for gunstocks, experiment with the mixture with varnish and find the sweet one, it does a good job.  (Robert Olsen)

I have been using poly from Lowes in a dip tube for over a year now. I am starting my third rod and would like to have the "right" smell, look and feel. After reading some info from Mike Brooks, I called him and then purchased some Waterlox spar varnish on his recommendation. Now I am not sure how to setup my dip tube.

Is the turpentine I buy at Lowes/Home Depot "pure" enough? It reads "Turpentine Pure gum spirits" and is Crown brand if I remember correctly.

Mike talks about Xylene for penetration. Should I use some of that too?

How much should I thin?

What else should I add?

I'm not a chemist, but I know Xylene is toxic as hell. A good shot of that in your lungs and you'll know it. Oh, and you'll probably get busted for having a meth lab once the smell leaks out.  (Mike St. Clair)

I am a biochemist. You're correct in saying that  Xylene is toxic. However, safe handling procedures  aren't that   different from using spray enamel. Xylene and Toluene are the major solvents in fast drying spray varnish as well. Keep it off your hands, 4 use only in a well ventilated place where there are no sparks fire or flame. I don't know how much Mike uses but I expect not much. You might try Penetrol  (it probably contains some Xylene anyway).  (Doug Easton)

What I use to get my varnish to the right consistency is a viscosity cup, nothing fancy, I just drilled a 1/8th in hole in the bottom of a 35mm film canister I use a pair of hemostats to hold it. Submerge the canister in your varnish, start the watch and pull the canister out of the varnish, time it until it is drained completely. I like this to drain in 21 seconds. I use about 10% mineral sprits and 5% Penetrol. But when you do it this way you get the exact mix you need and can repeat your results any time you want. And it doesn't matter what you use, either in varnish or thinner.  (Joe Arguello)

Would you recommend your above viscosity test for drain and hand applications? Do you warm up the varnish before application?  (Duke Normandin)

The good thing about using a viscosity test is that it is checking how 'thick' the liquid is at whatever temperature it is. In other words the best way to do this is in the area you are going to use your dip or drip tube. This will insure that the viscosity or 'thickness' of your varnish is consistent. So to answer the question about warming up the vanish, I don't. Hope this makes sense.  (Joe Arguello)

Quick question on mixing varnish and artists turpentine. Does the combination act as a color preserver or will it allow translucent wraps?  (Wayne Kifer)

No, it doesn't act as a color preserver, only a few polyurethane's do that, Varathane 900 being the most notable. It will work as well as the varnish does, the turpentine just makes it thinner.  (John Channer)

"Most" varnishes will cause the wraps to go transparent.  Whether you use turps, mineral spirits or some other thinner won't make a difference.  (Mark Wendt)

I'm having a bit of a problem finding quality turps locally at a decent price. About $25 a pint for Winsor & Newton. Any recommendations for an acceptable substitute? (Wayne Kifer)

What's wrong with hardware store turpentine? Works fine for me.  (Jerry Drake)

At one time Chris Carlin was very high on Grumbachers Artist Grade Turpentine. I haven't heard him say anything otherwise, so I would guess he still is. Most hardware stores carry it(not the big box stores) and it's a whole lot cheaper than the W&N.  (Will Price)

Yes, there are several brands of "artist grade" turpentine that are a lot cheaper than $25/pint.  If you have an artist supply store nearby, check there.  (Rich Margiotta)

I use Grumbachers. I can't find it in hardware stores but the local artists supply store has it.

I like it but I don't ready know any better. :)  (Jim Lowe)

I have a question regarding thinning. I am currently using Minwax Spar Urethane and am wondering what the best thinning agent is that I should use. Can anyone out there who uses this product tell me what works best?  (Phil Crangi)

I've been using Minwax Spar Urethane for about five years.  The "original" formula needed to be thinned about 10%.  I used Mineral Spirits with excellent results.

The "New" formulation requires NO thinning.  It's so thin that I had to slow down my dip coating from 3 ipm to 2 ipm to prevent drips and runs.  (Al Baldauski)