Paint Torch Reflector Black

[dabateman]

It takes like 5 minutes to wrap the white plumbing PTFE tape in, at most. Its reversible and cheap. I think that is the best option. Just cut off a small section about 4 to 6 inches, first wrap around the top of the reflector to hold it in place and then push down carefully with a small finger as you wrap down. Not hard.

 

I am not sure what its doing, but clearly kills the hot spot without loss or heat.

 

Black paint would take longer and absorb some of the UV. Black paint is better for tubes and things in the optical path. This tape method seems best for reflectors. I wonder if this will be better in the Canon 199A reflector? I will have to think about my lights, this seems like a cheap, easy trick, to smooth out the light.

[Cadmium]

Air brush is cheap and easy.

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313.TR12.TRC2.A0.H0.Xair+brush.TRS0&_nkw=air+brush&_sacat=0

 

cough cough...

https://www.labspherestore.com/product-p/aa-005xx-000.htm

[Cadmium]

Measured with the Solarmeter SM 5.0, UVA + B, Spectral Response = 280-400nm, Peak Response = 370nm:

Stock = 148 mW/cm2

Reflector painted black = 132 mW/cm2

Reflector with Teflon tape = 141 mW/cm2

[Andy Perrin]

Air brush is cheap and easy.

https://www.ebay.com...sh&_sacat=0

 

cough cough...

https://www.labspher...a-005xx-000.htm

Haha, the price on that paint...

[dabateman]

Air brush is cheap and easy.

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313.TR12.TRC2.A0.H0.Xair+brush.TRS0&_nkw=air+brush&_sacat=0

 

cough cough...

https://www.labspherestore.com/product-p/aa-005xx-000.htm

 

I think you can buy some pipe dope or teflon paste for about $6. Just look for one with lots of PTFE particles in it.

If you need the paint on method, that may be cheaper. You can buy it at common stores.

 

Its very hard to dissolve teflon tape. But you could try gasoline and then spray that on the reflector. But I think what you find to dissolve the teflon will also dissolve the reflector.

[Cadmium]

I have used that stuff, I might even have some in the shop, but I don't think it really drys out, it kind of remains putty like and even kind of wet for a long time,

some brands may dry out more, I don't know, but there are people that know. You would want to find the type that will dry and get harder, otherwise it will be a mess.

[dabateman]

Ok quick google search says it dries only in the absence of oxygen.

So paint it, then place in zipp lock bag, then use gas to displace the air. If you don't have a nitrogen cylinder laying around get a large can of ready wip, wipping cream. Keep the can upright and carefully hit the nozzel. N2O, is commonly used, sometimes with just nitrogen and not oxygen or air.

[ulf]

Air brush is cheap and easy.

 

Yes it is, for simple painting but the practical handling of this "paint" is not.

It is not behaving as a normal paint.

 

I have tried to use it with a simple brush to improve my integrating spheres.

I can only imagine the problems that will arrive when trying to use it with a small airbrush gun.

[Andy Perrin]

Ok quick google search says it dries only in the absence of oxygen.

So paint it, then place in zipp lock bag, then use gas to displace the air. If you don't have a nitrogen cylinder laying around get a large can of ready wip, wipping cream. Keep the can upright and carefully hit the nozzel. N2O, is commonly used, sometimes with just nitrogen and not oxygen or air.

 

Now I'm imagining trying this maneuver and misjudging the angle somehow, followed by the bag and the reflector being coated in whipped cream...

[dabateman]

An upright can usually will not expell any oil or whipping cream. Thats why they have been a problem with some people. There is no oxygen in a can to preserve the cream.

 

If you do get any whipping cream on your stuff, avoid the urge to lick it off. I can't imagine the PTFE paste being good for you.

[Cadmium]

oops, never mind...

[ulf]

Just as an aside, I thought that Teflon was transparent to UV light ?

But it is probable its acting as a defusser ?

Teflon, DuPont's brand name is not only used for PTFE: https://en.wikipedia.org/wiki/Teflon_(disambiguation)

 

Most (all?) pure PTFE is white with a diffuse light transmission.

Thin layers can appear more or less transparent.

PTFE parts are sometimes made by cintering PTFE powder under pressure at elevated temperatures.

The reflectivity is rather high and constant over a wide wavelength range including UV.

[Cadmium]

Krylon Crystal Clear is not totally clear in UV, but might be OK for mixing PTFE powder with.

Unless someone knows of something more clear in UV that doesn't cost much.

 

[dabateman]

Why don't you just mix with epoxy, if you are painting and get it to stick.

[Cadmium]

1) because you need to use special epoxy for UV which is rather hard to proportion/mix, needs to be done my weight.

2) I had in mind to spray the mix. This will clean out better.

The UV transmitting epoxy would work however, so would UV curing adhesive, if you want to paint the mix.

I this clear above would be much easier and should work well with an air brush, or painted.

[dabateman]

1) because you need to use special epoxy for UV which is rather hard to proportion/mix, needs to be done my weight.

2) I had in mind to spray the mix. This will clean out better.

The UV transmitting epoxy would work however, so would UV curing adhesive, if you want to paint the mix.

I this clear above would be much easier and should work well with an air brush, or painted.

 

I don't see why you need special epoxy. This is not in the optical path. You just need something to hold and stick the PTFE so it can reflect the UV light.

[Cadmium]

Oh well, I tried it, and that is not a promising path regardless of which sticky concoction you decide to mix it with. That idea is off my list.

[Cadmium]

There is this stuff. I don't know if they have different concentrations, exactly how white it is, or how multiple coatings (dipping) would work to make the coating more white or not.

Nevertheless, this is an interesting product.

https://medical.micr...icant_coatings/