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Rule

Bob Maulucci sent a post about using UV (Black light) to quick cure varnish on wraps. Has anybody tried this and is it suitable for whole sections?  (Bill Hoy)

    I would ask the folks at Winston or the Montana division of Gibson Guitar Company.  I know Gibson flash dries their acoustic guitars -- dry in a flash.  You can imagine dust problems and assembly line problems with the body surfaces of an acoustic guitar.  The automotive industry surely does as well.  I know there is a special catalyst in the Gibson lacquer.  I do not know what you would do to a spar to make it dry in seconds.  I am sure that the Winston folks have moseyed over to Gibson and watched the process.  (Chris Lucker)

    Several of the graphite Mfg. use UV curing on both the blank coating and on guide wraps. The lamps and systems are very costly. I've built several systems for both coating blanks and golf shafts. If you can find a hand held unit like the one Dentist uses that would work for guide wraps. Epoxy Coatings Co. makes several UV curable coatings. Yes it works and fast.  (Hal Bacon)

      That seems to indicate that the wavelength is critical to the process.  Experimenting with black light couldn't hurt. It's cheap, relatively broad spectrum if I recall.  (Bill Hoy)

        The lamps used are Medium pressure mercury type that produce UV in the 200-400 nanometers range.  Lamp power  is in the range of 150-300 watts per inch. The arc length is set between 6-12 inches. The time to cure a .003" coating is less than 1 minute at 300 watts per inch. Wrap coatings take 2 minutes to cure to tack free. real  fast. You can build a graphite rod in less than 4 hours from start.  (Hal Bacon)

    I use two fluorescent fixtures (4-ft 2-tube) in my drying cabinet. This arrangement generates both warmth and UV. I get enough drying and curing to work on the sections in 24 hours. I also have a fluorescent fixture in my dip chamber and get flash drying in about 8 hours, then transfer to the drying cabinet. Maybe this is hocus-pocus, I would appreciate feedback from others.  (Steve Weiss)

    I don't know if it would work, but tropical fish supply places have UV fluorescent bulbs for tanks.  They are used for sterilizing tank/pond water and have pretty high concentrations of UV.  I imagine they are like super concentrated tanning bulbs.  Anyway, the bulbs cost $20-30.  If you want the whole fixture you would be into it for a little over $100 depending on the wattage and the brand, etc.

    Might be a neat idea to try if one has the money and the time.  A custom UV cabinet might be cool to have.  Maybe better than a lamp box.  (Jason Swan)

    I do not claim to know how or why it works, but I have a 10" black light tube and a 60W black light that I put in the cabinet. My cabinet is rather large and is insulated on the inside with silver bubble pack style insulation. (I forgot what it is called, but it sure works well). This reflects the UV pretty well.

    I let them run and a section dipped Friday night can be sanded with 1500 and olive oil, and then polished with Meguires #9 swirl remover to a perfect shine. To be honest, I do not even worry about dust specks anymore. I use ProSpar Spar Varnish. This does not work as well with Helmsmen. 

    I usually leave the normal bulb (runs 102-105 degrees) in for about 4-6 hours or whenever I am going to bed. Then I switch to the UV bulbs. The section can be sanded and polished on Sunday evening. This was John Zimny's recommendation to use UV/blacklights. He presented it at Grayrock. I may or may not have  misinterpreted it, but it sure works.  (Bob Maulucci)

    Not to be a safety nag, but lamps with output in the 200-400 nm range are capable of burning your eyes big time!!

    Ask me how I know. Do not even look at reflections from these lamps. I was lucky I didn't do permanent damage to my corneas. The DNA in your cells absorbs UV at 260 nm. Given enough exposure to this light can, in fact cause skin cancer. Used with care, however these lamps are OK.  (Doug Easton)

Rule

Isn't UV the nemesis of all finishes and what does curing it with UV do to the life of the finish? Maybe someone who has knowledge or works in the industry can enlighten us.  (Tim Doughty)

    I do not honestly know, but it does make the finish hard enough to polish in a few days of exposure.  (Bob Maulucci)

      I'm talking over my head here, but that's not unusual.  One of my customers is a specialist in Show Car finishes.  He tells me that there are some relatively new two part urethane finishes which are designed to cure very quickly (minutes?) with UV exposure.  But the UV he talks about is different wavelengths from what we get with ordinary black lights.

      When I asked him about using black lights on spar, he seemed to think that although it wouldn't hurt the finish in small doses, it would not cause it to cure significantly more quickly.

      I can't remember which company, either Merrick Tackle or Amtak I think,  but there is a new UV system for wrap finishes on graphite rods.  Apply the finish, put it in a special oven, and seconds later, viola, you have finished wraps.  Sounds interesting, but I don't think it's appropriate for the finish on an entire rod.  Trying to remember if there was a review of the product in the last Rodmaker Magazine???

      Again, I'm just repeating what I've been told, and that's dangerous.  Perhaps those of us who are really interested might consider calling the Tech Support people for the particular finishes we are using.

      Patiently waiting a few days between coats.  (Harry Boyd)

        I am not really using it to speed up the process all the time, just trying it in a pinch here and there, and it does seem to work. Maybe it is my inexperience with spar, but I had always thought you needed to wait weeks to polish. The finish I am using (ProSpar) cures in a matter of 24-48 hours in the black light. It polishes up so nicely, I don't worry about much anymore. (Bob Maulucci)

    During the bright summer months I hang the freshly dipped sections on the clothes line.  The combination of air, natural ultraviolet light and warmth hardens the finish in one day.  (Ted Knott)

Rule

I know we've been through this once or twice over the last year, but I'm wondering if any of you have had any further thoughts about curing varnish with UV lamps.  My real question is, how much of the curing process is a function of air and temperature, and how much a function of UV exposure? Anyone have some data here they'd care to share?  (Bill Harms)

    I've been using uv light for a number of years to cure varnishes first on instruments and now on rods. As far as I now it is only effective on reactive type finishes which tend to include long carbon chain molecules or polymers which are contained in the drying oils present in the varnishes we use. Linseed oils and tung oils etc. are driven more quickly toward a semi solid state by the addition of UV light. Of course the over exposure of varnish to UV light of a period of years tends to deteriorate the varnish film but for the speeding up of the varnish drying process my a few days with UV exposure I would worry about a 18 to 24 hour exposure on standard spar varnish. Its also important to note that the polymerization process creates a film that is pretty durable or cross linked and will not really be softened by additional layers of varnish to improve adhesion. That is why is important to mechanically rough up the finish aka sand between coats for maximum adhesion. If you switch to a UV bulb system during the drying phase it does cut out quite a bit of waiting to finish the rod.

    I use either of the following GE UV bulbs. F20T12/BL, 20W, 24" long, rated average life 9000 hours or F40BL, 40W, 48" long, rated average life 20,000 hours.  (David Rinker)

    I was thinking about this a few weeks ago while under the dentist's lamp.  I had a filling put in and he hit it with a UV gun to cure it. At least I think that is what he did...  It was not a hot light, so if this is indeed what he was doing, it wasn't temperature based (for which I am thankful).  Not much in the way of data, but I just cared to share anyway.  (Carl DiNardo)

    It is not uncommon to cure violin varnish under UV light.  I understand that the effect accelerate polymerization of the oils. Temperatures are supposed to be kept below 110 F and ventilation is often required.  The drying time is generally considered to be cut in half, but in some cases a more complete cure than any amount of drying is said to be accomplished.  I will be putting one of my own together soon (If you are interested in what parts I plan to use let me know.)  Maybe one of the luthiers in the list can add more information since I have not actually done it yet.  (Jim Utzerath)

Rule

I remember seeing that someone was messing with using UV light of some flavor to fast-cure varnish or something else.  What ever happened to this?  Any reports?  (Joe West)

    I'm one of 'em.  It's gonna be several more months before I get started.  I'm planning to use the 345 nm (Short UVA) type, called 350 BL by the fluorescent tube manufacturers.  (Jim Utzerath)

      Are these wavelengths unkind to humans?  WIll you mount them in a box or something?  (Joe West)

        That wavelength is not as nasty as the shorter waves, but I understand it can tan skin and is not good for eyeballs.  I will be mounting 4 tubes in an opaque drying cabinet.  The tubes I intend to use are 30W each, so I intend to vent the top and bottom of the cabinet and filter the inlet and outlet with some kind of fine furnace filter material.  (Jim Utzerath)

          I don't know anything about UV Curing but noticed you were looking for a filter. You may want to consider the "Hockey Puck" shaped filters used in breathing mask. They are available in a wide range of filter types/sizes. Just cut a round hole/holes in the top and bottom of your curing/drying box and place a filter in each hole.  (Don Schneider)

Rule

Several years ago at the Corbett Lake rodmakers gathering there was talk about curing the finish using UV rays. When I am done with a rod I "do" take it and hang it up outside in the sun (weather permitting) but I would like to use a lamp if I knew exactly what to get. I don't want to pay $200.00 bucks for some professional UV lamp if that's what it takes, but I would like to know if there’s something I can go down to a lighting store or Home Depot to pickup. Black Light maybe? Also just so th definition of curing is understood, My interpretation (non scientific explanation) is that cured varnish will be a lot harder. One thing I would like to use it for is to make it easier to sand out tiny imperfections between coats of varnish. I dip the rod section and usually do 3 coats, touching up little imperfections on the first two coats. This process has worked well and by the third coat I can get a finish that I can live with. Sanding the coats between is not easy as if there is more than the slightest sanding necessary it's hard NOT to have the varnish ball up. I have noticed some differences between MOW and Polyurethane varnish. the Poly dries a lot quicker but doesn't seem to feather in as well as the spar varnish. The Spar is soft for quite a while though. I would like to speed up that if possible. I have used Poly for most of my rods but recently when I rebuilt my dip tank, I switched back to MOW gloss for a while  (or the next several rods,  which ever comes first).

On a side note, I am still going to dip my reel seat inserts I make in the Poly though as I think it my be better for scuff resistance).  (Martin Jensen)

    UV does kick the finish greatly. Been a few times I've been a little too keen to try a new taper and should have waited longer for the varnish to cure but taken the rod fishing anyhow and by day's end it seems as if it's had the equivalent of an extra 2-3 days inside curing.  (Tony Young)

    First, the only reason I use UV at all is to obtain quicker cures for my finishes since I do a ton of repair, restoration, and preservation work (approximately 200-300 rods annually). If I was only concerned with making the 30-40 new rods annually I wouldn't bother. That being said, I currently use two UV lights in my drying cabinet ,one is long wave and one is short wave. Since installing these lights, I have noticed that my varnishes, both oil and urethane, cure much quicker (most of the time in hours, depending on humidity).

    This is where I buy wood finishing lamps from.

    TCS Tech is one one the most knowledgeable places I know of when it comes to UV lights.

    Since I'll be moving to Northeast  Arkansas this summer (from CO), I'll need to deal with the increased humidity factor. I plan on putting in a new and bigger drying cabinet in the new 600 square foot shop. I'm going to go with a short/mid/long wavelength combo light like this one here.

    I used to mix good Japan Drier in with my pure walnut oil. I was able to get DRY clear wraps after only a few days. I really don't know if the Japan Drier helped or if it was just the extremely dry Colorado winter climate. I have heard that Lavender Oil thinned with alcohol will give the same sealing/clear effect. I bet it smells better too! I would also think any oil thinned with VM&P Naphtha would cure fairly quickly. This is what I use to thin oil based varnishes, but I have to shake the heck out of it for a fairly long time (mix a gallon and take it to the paint store to let them shake it)!  (Jeff Fultz)

Rule

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