Reptile bulb for drying oil?

[Mike Novak]

Hi.

I was wondering if anyone has experimented with using a reptile UV bulb to speed drying of oil finishes.

I know some people will put things out in the sunlight to make them dry quicker. Problem is feels like I haven’t seen the sun all summer and now with winter coming, there will be even less.

I’m not sure if putting them in the sun is just baking them with Heat, or exposing them to UV, or both that speeds up the drying.

Here is an example of the bulb I was thinking about.

https://www.amazon.com/MAINENG-Bulb-Reptiles-Amphibians-Light/dp/B0BRYBQ7WD/ref=mp_s_a_1_1_sspa?crid=9P40V2WELDEG&keywords=uv%2Blight%2Bbulb%2Bfor%2Breptiles&qid=1697378193&sprefix=uv%2Blight%2Bbulb%2Bfor%2Bre%2Caps%2C177&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9waG9uZV9zZWFyY2hfYXRm&psc=1&th=1

 

[robo hippy]

No experience with reptile bulbs. I did used to put a standard 60 watt incandescent type bulb under the wire racks I had my bowls on to help speed up the curing of the walnut oils I use. That helped some. I would guess UV would help too.

robo hippy

 

[Allen Mattsen]

Does this work for finishes not specifically defined to be cured with UV light? I've seen some new finishes come out recently that do this but haven't tried myself.

 

[Tim Connell]

First off, oil finishes cure through oxidation, not exposure to sunlight. UV light, by itself, will do nothing to cure an oil finish.

When an item is put out in the sunlight, you are exposing it to more oxygen (vs sitting in a shop with no airflow) and the sunlight is warming the object ( reactions occur faster with higher temperature).

If you want to speed up the curing of an oil finish, do as Robo suggested and use a heat source to increase the temperature. A fan blowing fresh air over an object will also decrease cure time. However don't use a fan with a film finish until the surface of the film has dried or you'll have a lovely gritty finish.

 

[Leo Van Der Loo]

How fast do you want the finish to cure ??

I use Polymerized Tung Oil and have used it for a long time, I get it from Lee Valley in Canada, you could get it in the US at Sutherland Welles.

Under warm and dry conditions this will cure in 8 to 25 hours, I will give it overnight to do this in my warm shop before adding a second coat, and leave it to harden more before polishing.

 

[Dean Center]

How fast do you want the finish to cure ??
I use Polymerized Tung Oil and have used it for a long time, I get it from Lee Valley in Canada, you could get it in the US at Sutherland Welles.

Leo,
Lee Valley apparently realized that the Heathens Down South have disposable funds and have had a US based component for at least a few years now. BTW, it says the product contains driers, which are of concern to those folks who want an absolutely food safe finish.

 

[Leo Van Der Loo]

Leo,
Lee Valley apparently realized that the Heathens Down South have disposable funds and have had a US based component for at least a few years now. BTW, it says the product contains driers, which are of concern to those folks who want an absolutely food safe finish.

Dean thanks, I don't think that paragraph should be in there, looks like a safety clause, as far as I know there are no salts/heavy metals in the PTO, just thinners, as the heat treated oil is to thick to be used without that.

I saw they did add the water top up of the partially container that I had been advising for years already that users to do

And no I wasn't aware they had a place/warehouse down south, makes sense and prevents the Canadians from getting hot under the collar seeing the high cost of those products here compared to the US

OK I had to find out if I remember this right, and checked The makers of the PTO that Lee Valley sells, here is the blurb about that, and it says there is no Volatile Organic Compound, (VOC exempt)

 

[Mike Novak]

Leo

Each coat takes a couple days before handling, but I’m pretty sure the oil inside the wood takes much longer.

Allen, Tim,

I read online that it’s the UV in sunlight that speeds the cure. I don’t trust Google, that’s why I’m asking.

 

[Leo Van Der Loo]

Leo

Each coat takes a couple days before handling, but I’m pretty sure the oil inside the wood takes much longer.

Allen, Tim,

I read online that it’s the UV in sunlight that speeds the cure. I don’t trust Google, that’s why I’m asking.

Mike you do need only one or two coats of PTO, so that would be 2 days max, and the inside oil polymerizes just as fast.

I like to know who told you, that it is the UV does cure oil finish, it does change the color of wood, not cure the oil, though if in the sunlight you do get warming and that increases the speed of polymerizing, I bet that if you use just UV light and cold temps, the finish will not polymerize.

It is the oxygen in the air that reacts with the oil, and changes the oil (polymerize)

 

[Mike Zip Hamilton]

It seems reasonable to me that UV light could speed things up. Take 2 pieces of the same wood finished the same, and put one in direct sun light. See what happens.

UV light can spur on many chemical reactions. In this case, it may contribute to peroxide formation intermediate in the polymerization. Of course, you may find that the difference to be insignificant.

 

[Tim Connell]

It seems reasonable to me that UV light could speed things up. Take 2 pieces of the same wood finished the same, and put one in direct sun light. See what happens.

That would be a valid experiment only if you measure the surface temp of the object in the sun, measure the airflow and oxygen concentration and then duplicate those conditions for the control object. Then you would find that by duplicating the conditions so that UV light is the only variable, the oil finishes would cure at the same rate.

 

[Mike Zip Hamilton]

valid experiment

You are right. This would not control everything; however l would try this before investing in a reptile light. Heat would speed things up, but speeding things up might lead to undesirable results. Treating wood samples in the conditions that one can duplicate with your project save the heart ache of a bad out come.

 

[Doug Freeman]

Agree with othjers that UV will not speed the drying but heat will. I’ve enough semi- controlled experiments to verify. I use a cardboard box, sitting with the bottom flaps open (taped open) on the floor, with a wire rack for the work. Used a 150w bulb for a while, now use a 400w “personal heater” sitting on the floor. The top flaps are closed, leaving some open area for air to pass. The warm air flowing out the top draws in fresh air at the bottom. Speeds the drying process significantly.

 

[Gord Cameron]

First off, oil finishes cure through oxidation, not exposure to sunlight. UV light, by itself, will do nothing to cure an oil finish.

When an item is put out in the sunlight, you are exposing it to more oxygen (vs sitting in a shop with no airflow) and the sunlight is warming the object ( reactions occur faster with higher temperature).

If you want to speed up the curing of an oil finish, do as Robo suggested and use a heat source to increase the temperature. A fan blowing fresh air over an object will also decrease cure time. However don't use a fan with a film finish until the surface of the film has dried or you'll have a lovely gritty finish.

Tim, you speak with certainty on the assertion that since oil finishes cure through oxidation, it is the heat / airflow in outdoor exposure that helps to cure an oil finish, nothing to do with the UV light. I wonder why you reject the idea from conventional oil finish chemistry that exposure to UV light will accelerate the oxidation by creating free radicals that advance polymerization in the finish, and thereby accelerate curing. On this thinking, you expose the finish to oxygen in a warm environment, and add UV light if available. You seem confident that that is wrong, but I wonder why--has this been found to be bad science?

 

[Mike Zip Hamilton]

exposure to UV light will accelerate the oxidation by creating free radicals that advance polymerization in the finish, and thereby accelerate curing

This discussion has got me thinking. In trying to dust off my 60 year old memory of organic chemistry, I'm wondering. Do the peroxides, free radicals from all the natural oils react with wood as well as themselves? Is that why we label them as penetrating finishes? Multipal coats do combine; where as film finishes form layers. Those layers will seperate from the wood. Oil finishes can be refreshed even years later. Doctors Walnut oil with wax seems to work well. The wax won't polymerize, but will it react with the oil free radicals in the same way the wood might? Am l getting something similar to this when l combine BLO and ployurithan?

My head hurts now. I need to go get a beverage.

 

[Tim Connell]

Tim, you speak with certainty on the assertion that since oil finishes cure through oxidation, it is the heat / airflow in outdoor exposure that helps to cure an oil finish, nothing to do with the UV light. I wonder why you reject the idea from conventional oil finish chemistry that exposure to UV light will accelerate the oxidation by creating free radicals that advance polymerization in the finish, and thereby accelerate curing. On this thinking, you expose the finish to oxygen in a warm environment, and add UV light if available. You seem confident that that is wrong, but I wonder why--has this been found to be bad science?

I'm not discounting science at all. In my searching, I've yet to find a study that shows a statistically significant decrease in curing time by introducing UV light as a variable. There are lots of anecdotes by internet "scientists" and lots of companies selling UV lights making claims, but I've not seen a product label that recommends UV light for curing oil finishes nor a study that shows a benefit. Perhaps my searches have not been exhaustive enough. If you are aware of such studies, please post some links.

 

[Doug Freeman]

Drying oil finishes do indeed form layers, and do not combine (if previous layers are cured). As there isn’t a film on top, it isnt noticeable. If a film is left, it dries soft, so one soft film on top of another would be difficult to distinguish.

Its actually the lack of film on top that allows oil finishes to be renewed. I use wipe on poly the same as oil finishes, let soak in and wipe off. Those finishes can be renewed years later, just like oil.

Don’t have a clue as to free radical behavior, though, except occasionally on my motorcycle.

 

[Gord Cameron]

Reply
Sorry, Tim, I hadn’t suggested that you discounted science, I just thought that because you spoke with such certainty on this point, you might have some data. Like you, I have an interest in this issue and have tried to find good information: when I saw your categorical statement that UV light had nothing to do with curing oil finishes, I hoped you had some data.

The common view that UV helps curing appears to start with the uncontentious proposition that UV light causes oxidation / free radical polymerisation, which is what oil finish curing is about. However, to be confident that this translates into faster curing times for drying oils, we want the evidence that you and I are looking for.

Doń Należyty is a woodworker who seems to obsess about linseed oil and how to apply and cure it. There is a video on YouTube (on Lee Stoffer’s channel) of him giving a talk on this. He purports to have done a lot of testing and he insists on sunlight as one of the keys to efficient curing of linseed oil. It was that video that originally got me thinking about this several years ago.

You mention not having seen manufacturers recommending this, but this is what I have seen.

1. Mike Meredith, the “doctor” (professor of biochemistry) from Doctor’s Woodshop, states of walnut oil that “Use of a UV light will speed up the curing process, as will raising the room temperature.”
2. The chemist (who claims to have a doctorate and 35 years of formulating and testing wood finishes) at Swing Paints (maker of the Circa 1850 line of tung oil and other finishes) received the question about tung oil “I can tell you a hot day and plenty of sun will decrease the drying time. Is it the heat, sun or both?” and answered as follows: Both heat (IR radiation) and UV radiation will accelerate the polymerizion of tung oil. Heat speeds up most chemical reactions, so curing is best done in a warm environment. For polymerization reactions (curing of tung oil into polymerized tung oil), the UV radiation will accelerate the formation of free radicals, and therefore increase the rate of curing.
3. Sage, the maker of (expensive but excellent) Allback linseed oil paints, comes at the point from the other direction, advising that: “reduced exposure to full-spectrum UV light can increase drying and curing times.”
4. The UK manufacturer of linseed oil paint Brouns & Co. says on its website: “Linseed oil dries primarily by exposure to UV-light and oxygen.” and goes on to describe the testing they did with a UV light specialist to establish this. It does not look very scientific, but they seem to like the idea.

Not conclusive of anything, but at least some reputable manufacturers seem to see a benefit from UV light curing.

As for studies, I didn’t do a review of the literature, but these came up on a quick search:

1. The paper “Study on photocuring activity of tung oil under UV light” (Journal of Functional Materials) does conclude that UV light helps curing: “The main function of oxygen was to form hydroperoxides with the free radicals formed after the reaction of hydrogen extraction of tung oil under UV light, which promoted the oxidative polymerization of tung oil.”
2. The paper “Review of the kinetics and simulations of linseed oil autoxidation” in the journal “Progress in Organic Coatings” includes these statements: Drying oils are natural, bio-based oils that harden or “dry” into a solid film when exposed daylight and ambient oxygen…The reaction mechanism of triglycerides is an autoxidation process that proceeds under the influence of oxygen and light…Initiation can occur spontaneously, or with the aid of UV light.”

So, there is enough out there that, if I were wanting to expedite the curing of a drying oil, I would try a UV lamp. But like you, I would be interested to see some more testing and data on this. At this time I don’t have the certainty that you have to make a confident assertion that UV light adds nothing to curing drying oils.

Gord

 

[hughie]

No experience with reptile bulbs. I did used to put a standard 60 watt incandescent type bulb under the wire racks I had my bowls on to help speed up the curing of the walnut oils I use. That helped some. I would guess UV would help too.

robo hippy

Yup me too, had it suspended above the bulb on a rack with a cardboard box over it