what to put around plastic colimator?

Sponge · Oct 28, 2008

I have build this bike light with 3xR2 glued on heatsink.

What material can I use to glue&seal heatsink and colimator?
I am thinking about black silicone or similar, but I'm afraid about acids in silicone and will black color reduce reflection of colimators?
It must be watertight&UV stabile, because of rain or mud & sunlight:sigh:

LukeA · Oct 28, 2008

You can't use anything directly in comtact with the optic. It won't work and it will ruin the optic, which works by refraction.

You might get some aluminum tube or PVC with an ID the same as the optic and then some flat strips to cover the cresents at the back. You can seal the front edge of the optic without ruining it.

Sabrewolf · Oct 29, 2008

What he said ^^^:twothumbs
Just use some pcv pipe that is slightly
larger than the optic you have there
and file down the lower areas where the
heatsink drops off. Then seal the Pvc to
the heatsink with RTV high-temp silicone
sealant. That will allow some expansion
and make it watertight. Then use some
lexan to glue over the top with Acrylic
cement. Your optics won't be affected, and
stay protected from the elements.

Robert M.

Sponge · Oct 29, 2008

LukeA said:
You can't use anything directly in comtact with the optic. It won't work and it will ruin the optic, which works by refraction.

When I press my finger on colimator cone, beam looks same as before that. I will try to wrap it with bluetack, just to see will anything change.:thinking:

Sponge · Oct 29, 2008

Sabrewolf said:
What he said ^^^:twothumbs
Just use some pcv pipe that is slightly
larger than the optic you have there
and file down the lower areas where the
heatsink drops off. Then seal the Pvc to
the heatsink with RTV high-temp silicone
sealant. That will allow some expansion
and make it watertight. Then use some
lexan to glue over the top with Acrylic
cement. Your optics won't be affected, and
stay protected from the elements.

Robert M.

Should I try to put cylinders of thick plastic foil around every colimator and then to seal it with something?

Sabrewolf · Oct 29, 2008

You should not have to..
Just do the whole thing at once
by wrapping it in Pvc. I would
assume that the lense you have
there is about 50mm Dia? Just
match that with a Pvc tube of
a slightly larger inside dia.

Sponge · Oct 29, 2008

Sabrewolf said:
You should not have to..
Just do the whole thing at once
by wrapping it in Pvc. I would
assume that the lense you have
there is about 50mm Dia? Just
match that with a Pvc tube of
a slightly larger inside dia.

I don't know is there 50mm dia PVC tubing in place where I live.If I can, I will buy it and use it.What kind of glue should use with this colimator? can I use hot melting glue? I have only ths colimator so I can't try on spare one.

Sponge · Oct 29, 2008

Sponge said:
I don't know is there 50mm dia PVC tubing in place where I live.If I can, I will buy it and use it.What kind of glue should use with this colimator? can I use hot melting glue? I have only ths colimator so I can't try on spare one.

I have been to local hardware store and found coupler for 50mm sewer pipes. It have a rubber gasket on each end, so I use it. I cut coupler at 10mm from one end and glue it to heatsink with epoxy. Hope it will last on sunshine

LukeA · Oct 29, 2008

Sponge said:
I have been to local hardware store and found coupler for 50mm sewer pipes. It have a rubber gasket on each end, so I use it. I cut coupler at 10mm from one end and glue it to heatsink with epoxy. Hope it will last on sunshine

Looks great! I'd be a lot more worried about the optic itself, as I bet it doesn't have a UV-resistant coating.

Sabrewolf · Oct 30, 2008

If you want front protection from the elements.. Go back to your hardware store and look for U.V. protective Lexan. And also pick up some lexan/acrylic glue.
Then cut your lexan to the shape of the Pvc pipe coupler you have there by tracing it around the outside edge with a magic marker. Glue it on, and Viola!
Instant Rock/Water/Sun Protection!
Ohh, and dont use hotglue! the sun will kill it for sure!
And if you want to keep the lense looking good, Wax it with automotive wax.

Have Fun,
Robert M.

Sponge · Oct 30, 2008

Sabrewolf said:
If you want front protection from the elements.. Go back to your hardware store and look for U.V. protective Lexan. And also pick up some lexan/acrylic glue.
Then cut your lexan to the shape of the Pvc pipe coupler you have there by tracing it around the outside edge with a magic marker. Glue it on, and Viola!
Instant Rock/Water/Sun Protection!
Ohh, and dont use hotglue! the sun will kill it for sure!
And if you want to keep the lense looking good, Wax it with automotive wax.

Have Fun,
Robert M.

Since lamp is for night, sun isn't a very big problem

But, if lamp is on bike on sun, optic is not under direct sunlight. Can I use some clear foil to protect optic from UV? not for this project :naughty:

Sponge · Oct 30, 2008

Thanks everybody on advices!
Hope somebody use this for solution of his/her problem :candle:

what to put around plastic colimator?

Sponge

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