UV Lamps

[Dr.Chipster]

My question is, is a battery operated uv lamp just as good as a 12 volt or a 115 volt lamp?

[GlasWeldTech]

Chipster,
If I had to GUESS I would say No. With 12 volt and 115 volt you will be getting a constant flow. With say AA batteries or such you would lose voltage sooner. Mind you this is JUST a GUESS as I am not an electrician or anything. I am getting my info from my deer feeders. When new batteries they feed great. After about 1 month they slow down.

[Brent Deines]

I would say that overall 115v or 230v are the most powerful, but assuming you have a reliable 12v power source a 12V light can be an equally effective power source, and much more convenient for mobile users. I have seen some pretty good C and D cell battery operated lights, but even the best of them will begin losing intensity fairly quickly. I have not seen any AA battery lights that were all that great so we don't recommend them for a primary UV source, but due to the low price and compact size they can be used for a backup.

The problem with battery operated lights is that as long as your surface resin is still curing within the time you allow for this purpose, you really don't know how much intensity is being produced. With 115v or 230v lights you greatly minimize this problem. If you are using a battery operated light as your primary UV source you should test it daily with a spectrometer and adjust your curing times accordingly, which is not very practical.

[toab]

WSR is kind of a side line for me so my bulbs look good.Say any of you guys useing black light.Thats what I use most of the time(got a good deal on some party lights)and they work great.Gawking people think they look cool too.

[toab]

As for battery lights I do have them on backup but I generally use an inverter powered light or a 110v if at the shop.

[ghost rider]

Since I switched to the 9W U-tube I only change every other year, but like Glasstarz, I use the sun a lot, too.

Battery lights are pretty useless up here in the cold weather, 12v lights don't even warm up enough to produce enough UV. I have always used 120v just because of the cold, and even they need extra time to warm up when it gets down to -0 F.

Toab, UVB [blacklights] work about the same as UVA bulbs, they just have a different color filter. Some think they don't cure as fast. I used one for a while, seemed to work OK. The UVA bulbs actually cost less than UVB where I buy bulbs.

[Brent Deines]

Ghost rider,

Not to be argumentative, but you are a little confused about UVA (Long Wave 320nm-400nm) vs UVB (Medium Wave 290nm-320nm). Sometimes UVB is referred to as short wave, but actually UVC is even lower on the spectrum at 100nm-290nm, and therefore considered Short Wave. You cannot cure most (99.9%) windshield repair resins using UVB or UVC, as UV curable windshield repair resins are typically formulated to cure at around 365nm. Below 320nm and above 400nm wavelengths windshield repair resin will not cure, and the closer to 365nm you get the better your results will be. Depending on the source the upper and lower end of each wavelength range may very slightly, but the above is within 10nm of most reputable sources.

UVB is what is often called "black light", so when you buy a black light you are buying a light that produces a UVB wavelength. Now, here is the fun part. You can buy filtered and unfiltered black light bulbs. The filtered bulb appears to be blue or black, and is supposed to be somewhat safer than the white unfiltered bulb, but both are capable of producing the 365nm wavelength. Some UV light manufacturers recommend the filtered bulbs for curing windshield repair resins, and some recommend the unfiltered. We sell both the filtered and unfiltered and have tested both with a Spectrometer using the same light as a power source, and the results are indistinguishable. Some of our customers swear by the unfiltered and some swear by the filtered, but I think that has more to do with the sales pitch they received when they bought their light than anything else. Either one words very will if used in a good light.

Some 115v lights perform better than others, just as some 12v or battery operated lights work better than others, but as I have said many times in the past, unless you have a way to test the output of the light it is impossible to determine exactly how powerful it is. Nearly all 12V, 115V, and 230v lights will provide a reasonably fast surface cure but that should not be the criteria used to determine the quality of the cure.

The sun puts out both UVA & UVB, but depending on the time of day, the time of year, and the part of the world you are in, the amounts can vary greatly. For this reason most windshield repair manufacturers recommend using a high quality UV light for every repair. That said, when all the conditions are right, the sun puts out far more UVA than most, if not all, UV lights used in the windshield repair industry.

I disagree that 12v lights will not warm up enough to produce enough UV in cold temperatures as we have tested this as well, but I do agree that extra time should be allowed for all lights in colder conditions, and battery operated lights suffer the most when the temperature drops.

[ChipperFixer]

Is there an affordable, portable spectrometer on the market?

[Frank EU]

Hi ChipperFixer,
It is not my business, but why would you want such a device? Like always; quality has it's price. If you need it to check the UV Bulbs' condition, why wouldn't you do the pitfill resin test -using a film tab? It shows the condition of your UV Light perfectly at a far lower cost.

[Brent Deines]

Is there an affordable, portable spectrometer on the market?

I have seen some for around $200, but have no idea if they are accurate or not. Expect to pay a couple thousand for a good one. Also called UV light meters or radiometers. There are hundreds of varieties so you need to know exactly what you are looking for to find the one best suited for this purpose, so I'm not suggesting everyone run out and buy a bunch of expensive test equipment. I really don't think that is necessary.

Just buy a high quality AC or DC (12V) UV light from a trusted source and make sure you give an adequate cure time for each repair. As far as how often to change bulbs, I agree with Screenman that changing bulbs frequently is a good idea, but Frank EU also has a good point and one that most technicians probably follow. As a simple rule of thumb if your light will cure a drop of low viscosity resin on the glass surface within 2 minutes, it will also cure the resin inside the break within 5 minutes. Using pit resin for your surface cure test is not a good idea as higher viscosity resins tend to cure a bit faster than the low viscosity resins used to fill the main body of a break. If your light doesn't pass the surface cure test you should change the bulb and test it again. If it still fails the test you should repair or replace your light. Note: Very few battery operated lights will pass this test, so if you insist on using a battery operated light, especially the AA type, you should double your cure times and change your batteries frequently.

If you are a cure under pressure guy and use a light with a circular bulb that goes around your bridge, be sure to perform the above test with your bridge in place just as you would be using the light if doing an actual repair. The UV light is much more intense right under the bulb than it is a couple of inches off to the side and if parts of the bridge are blocking some of the UV light the effectiveness of the light is even further reduced.

I know this is not a very scientific test, but I believe it is practical and sufficient for most technicians.