BLF GT (preliminary) modding thread

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teacher
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All you have to do is put a piece of very fine grit sandpaper on a flat surface, place the black centering block on it, & rub until you remove a bit from the bottom of the block.

It should be/is very easy to do that in an even fashion. As far as causing any other blemishes, I cannot understand how that would be possible using this method.

I did it with one of mine (so far) & it was simple as well as straight forward. Seemed to tighten the hotspot a bit also.

      You never know how a horse will pull until you hook him up to a heavy load. / Paul "Bear" Bryant ~/~\~ "Slow is Smooth, Smooth is Fast"

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teacher
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@ johny723

Here are some links where people sanded their Centering Ring. JasonWW states he tightened his hotspot considerably.

Do some reading on either side of these linked posts & there is a bunch more info.

I cannot find the photo’s I mentioned by DB Custom, but I did find several by KawiBoy1428.

.
http://budgetlightforum.com/comment/1284074#comment-1284074

http://budgetlightforum.com/comment/1284516#comment-1284516

http://budgetlightforum.com/comment/1284105#comment-1284105

http://budgetlightforum.com/comment/1265552#comment-1265552

http://budgetlightforum.com/comment/1259418#comment-1259418

      You never know how a horse will pull until you hook him up to a heavy load. / Paul "Bear" Bryant ~/~\~ "Slow is Smooth, Smooth is Fast"

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johny723
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Thanks, I will read through the links.

teacher
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johny723 wrote:
Thanks, I will read through the links.
Your welcome, my pleasure. Thumbs Up

      You never know how a horse will pull until you hook him up to a heavy load. / Paul "Bear" Bryant ~/~\~ "Slow is Smooth, Smooth is Fast"

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johny723
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To make clear what I mean I took a photo of both the GT and my Boss. The first photo is the GT. It clearly is brighter, but there is a lot of light around the hotspot. IF it was possible to concentrate that light, it would improve the beam.

https://drive.google.com/open?id=1kFRRLwlCDB2OQj9aelrFFDmyvlax7aqp

This is a beamshot of my Palight Boss with a dedomed XP-L V6 1A. There is very little light around the center. If only I could make my GT throw the same.

https://drive.google.com/open?id=1UaIh6b8YzZo_9kNg5a_FxVRYQUrpQxuO

teacher
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@ johny723 ……. OK….. I think I now understand what you are saying. I do not think this is possible with the GT reflector / LED setup. It was designed to spill this amount of light so as to be a more ““useful”“ light. Sad
This is what I remember anyway.

      You never know how a horse will pull until you hook him up to a heavy load. / Paul "Bear" Bryant ~/~\~ "Slow is Smooth, Smooth is Fast"

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johny723 wrote:
To make clear what I mean I took a photo of both the GT and my Boss. The first photo is the GT. It clearly is brighter, but there is a lot of light around the hotspot. IF it was possible to concentrate that light, it would improve the beam.

https://drive.google.com/open?id=1kFRRLwlCDB2OQj9aelrFFDmyvlax7aqp

This is a beamshot of my Palight Boss with a dedomed XP-L V6 1A. There is very little light around the center. If only I could make my GT throw the same.

https://drive.google.com/open?id=1UaIh6b8YzZo_9kNg5a_FxVRYQUrpQxuO

Thanks.. i bet dedome xpl will give some green tint..

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I measured my friend’s GT too only swapping the head and his got even worse numbers than mine. The batteries were fully charged and his GT only pushed uot 894 Kcd. Mine does 980 Kcd again but interesting the different results at different distances.

Mine:
10m: 980 Kcd
15m: 969 Kcd
20m: 928 Kcd
25m: 929 Kcd

His:
10m: 894 Kcd
15m: 857 Kcd
20m: 856 Kcd
25m: 877 Kcd

I think it is mostly a focusing problem so I will try to open the head and try enderman’s focusing method

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ZozzV6 wrote:
I measured my friend’s GT too only swapping the head and his got even worse numbers than mine. The batteries were fully charged and his GT only pushed uot 894 Kcd. Mine does 980 Kcd again but interesting the different results at different distances.

Mine:
10m: 980 Kcd
15m: 969 Kcd
20m: 928 Kcd
25m: 929 Kcd

His:
10m: 894 Kcd
15m: 857 Kcd
20m: 856 Kcd
25m: 877 Kcd

I think it is mostly a focusing problem so I will try to open the head and try enderman’s focusing method

Let us know what the results are.

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Texas_Ace wrote:
Let us know what the results are.

We both got our GT in early March and they travelled together according to changes in tracking had only few minutes differences between the two lights. So I think they are same manufacturing batch got not so throwy. I need to get a strap wrench or something and then try focusing.
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I managed to open my GT head with a leather belt Smile
I printed out Enderman’s focus checking circles with the 3 square. I have still my friend’s GT too so I checked both. Mine was good for about 1m distance and then started to seem over focused. The 3 square moved to the center. At 7-8m the 3 squares almost completely overlapping each other. That is why I got the biggest numbers at 10m because it was focused around that distence. My friend’s GT was even worse. As we seen in the intensity numbers too. So I need to sand the centering plate thinner. I needed to go to work so tomorrow I will measure centering plate thickness and sand it down a little.

johny723
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could you take a beamshot before and after sanding the centering plate?

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johny723 wrote:
could you take a beamshot before and after sanding the centering plate?

you don’t see it on a beamshot. Maybe with the focusing templates you can see the squares but with naked eye I don’t think so. But I will try to make photos.
johny723
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I meant a photo that compares hotspot of a stock vs sanded centerpiece

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johny723 wrote:
I meant a photo that compares hotspot of a stock vs sanded centerpiece

I can try but you will don’t see much I think. These are not huge differences just hunting for the perfection. If I can manage to focus better and make 1100 kcd from my 980 kcd it is not what you can notice in a few meter wall beamshot.
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Just tell us if sanding down the centerpiece improves the hotspot at larger distances. Especially if it can remove the corona and make the center brighter.

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Sure I will report results Wink

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Thanks!

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I have some results! Big Smile My theory was a bit wrong. The centering plastic wasn’t too thick. It was thin. I sanded down from 2,5mm to 2,33mm and it made worse. I only got 874 kcd from the stock 980. So I started placing kapton tape stripes to the bottom and about every 0,1-0,15mm added I reassembled the head and went outside to measure lux at 10, 15, 20, 25m.
Today’s last result was 1100000 cd at 20m with 3,17mm thick centering plastic. This is not the end and I have pics and a lot of numbers. The interesting that as it was getting better the highest number moved to the bigger measuring distances which I think is good because the beam is more parallel and forming the hot spot farther is good. Tomorrow I have a lot to do but I think I will add some more tape under that centering piece and I want to find the best focus setting. And I will post all the pics and numbers when Im done.
Stay tuned!
Big Smile

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Interesting, thank you for sharing SmileBeer

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Very interesting results.

The latest batch of reflectors was made by another company (which is why there was no shipping delay this time). It is possible that the focal length has been changed slightly. It would line up well with the XHP70.2 I built.

I used a 4.25mm centering ring on the first light I built and it had no dark spot but it took almost 5mm to get the same results with the new one.

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ZozzV6 wrote:
I have some results! Big Smile My theory was a bit wrong. The centering plastic wasn’t too thick. It was thin. I sanded down from 2,5mm to 2,33mm and it made worse. I only got 874 kcd from the stock 980. So I started placing kapton tape stripes to the bottom and about every 0,1-0,15mm added I reassembled the head and went outside to measure lux at 10, 15, 20, 25m.
Today’s last result was 1100000 cd at 20m with 3,17mm thick centering plastic. This is not the end and I have pics and a lot of numbers. The interesting that as it was getting better the highest number moved to the bigger measuring distances which I think is good because the beam is more parallel and forming the hot spot farther is good. Tomorrow I have a lot to do but I think I will add some more tape under that centering piece and I want to find the best focus setting. And I will post all the pics and numbers when Im done.
Stay tuned!
Big Smile

Plastic shims for under or on top of the centering block. Mine is shimmed at 3mm thick overall, my other GT’s reflector was better so I swapped them. Dark hole in the beam 3.5-4ft. off the wall.

KB1428 “Live Life WOT”

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Enderman wrote:
Kenjii wrote:

I think the cooling is not siginificantly worse in the GT, we are talking about ~20W only Wink And I power my LED with only 5A current.

The beam is very very tight… really cool.


Lower temperature = higher output, even if the LED is very low wattage Smile
That’s why I used a CPU heatsink, cooling fan, and liquid metal, so that I could run my Black Flat up to 6A without a decrease in output.

After running about 30 Minutes on Turbo on a sunny afternoon Wink

I tweaked the focus a little bit but it is still far from perfection. Measured 1.7 Mcd-2.3Mcd.

Regards

Kenjii

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Today I went up to 3,42mm centering piece thickness and got 1174500 cd.
but the hot spot started washing out so I think the optimal thickness is between the 3,17mm and 3,42mm. Now I need to sleep so I will try the last steps a few days later when I have more time.

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Do you have a donut hole in the beam or not? I hat a visible donut hole when I placed shims under the centering plate. It was visible even at 250m distances

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ZozzV6 wrote:
Today I went up to 3,42mm centering piece thickness and got 1174500 cd. but the hot spot started washing out so I think the optimal thickness is between the 3,17mm and 3,42mm. Now I need to sleep so I will try the last steps a few days later when I have more time.

Good info, If you find a perfect thickness I will pass it onto lumintop and see if they can make some updated centering rings.

Anyone else that wants to experiment with this be sure to post your findings as well, the more the better.

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Texas_Ace wrote:
ZozzV6 wrote:
Today I went up to 3,42mm centering piece thickness and got 1174500 cd. but the hot spot started washing out so I think the optimal thickness is between the 3,17mm and 3,42mm. Now I need to sleep so I will try the last steps a few days later when I have more time.

Good info, If you find a perfect thickness I will pass it onto lumintop and see if they can make some updated centering rings.

Anyone else that wants to experiment with this be sure to post your findings as well, the more the better.

Luckily I have my friend’s GT in my hand so I will try focusing that too. That was even worse stock than mine. It only got 894000 cd. Now I have two workdays so I don’t have time for it but after that I will upload all results.

EDIT: I talked another hungarian forum member and he will send me his GT head too to measure it and focus it. So I will have 3 GT focus tests but all 3 is from the late February or early March batch because they all had same tracking movements around few minute differences.

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ZozzV6 wrote:
Texas_Ace wrote:
ZozzV6 wrote:
Today I went up to 3,42mm centering piece thickness and got 1174500 cd. but the hot spot started washing out so I think the optimal thickness is between the 3,17mm and 3,42mm. Now I need to sleep so I will try the last steps a few days later when I have more time.

Good info, If you find a perfect thickness I will pass it onto lumintop and see if they can make some updated centering rings.

Anyone else that wants to experiment with this be sure to post your findings as well, the more the better.

Luckily I have my friend’s GT in my hand so I will try focusing that too. That was even worse stock than mine. It only got 894000 cd. Now I have two workdays so I don’t have time for it but after that I will upload all results.

EDIT: I talked another hungarian forum member and he will send me his GT head too to measure it and focus it. So I will have 3 GT focus tests but all 3 is from the late February or early March batch because they all had same tracking movements around few minute differences.

Ok, so these are from the old reflectors, still good information to have.

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I spend one morning messing with the center piece of my GT, made it both thinner and thicker, but never got rid of the slight donut hole, and the throw did not get better. I may have to look more precisely, but I first have to replace the ledboard screws with version that do not have a very round head but heads with a straight side, so that the center piece can be positioned exactly and keep the led in focus. But it takes too much time already, I will first wait for a new led to arrive..

link to djozz tests 

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I have been testing with my GT using a flat plastic piece placed under the original centering disc. I have cut it with the same shape of Lumintop disk but with a bigger central hole. (Similar to those in the picture of KawiBoy1428) I started with a thickness of 1.10 mm and I have repeated readings sanding it down to 0, 90mm, 0, 70mm and 0.40 mm.

The starting point is 1.203.000Cd using a boiling thinner dedomed XHP35 E4 HD.

Lux readings were taken at 10m. I have no more available length in my house but I will try to measure in the community garage at 15 and 20m this night, when the lights can stay off, without car transit. As it is only an experiment the readings are taken at the start of the light. Therefore, No ANSI

These are my results at 10m.

- 1.10mm: Ugly spot with blurred edges and a very marked black hole up to 5m. I did not mensure. It was obvious that the result would be bad.

- 0,90mm: Nicer beam profile with a more definite spot. The black hole from 4-5m onwards was replaced by a central area that, although irregular, was more illuminated than the rest of the spot. 1.092.000Cd.

- 0,70mm: More defined spot. Illuminated area in the center of the spot is regular. 1.229.000Cd.

- 0,40mm: Perfect and well defined spot. 1.299.000Cd.

I finished the sanding because I hurt my fingertip with the sandpaper. Tired

I received my GT on February 23rd. I don’t know the date of manufacture

My luxmeter is a cheap LX1010B. I have hope that when I buy in the future a better luxmeter the results will improve.

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