Safe & Effective Way to Strip Anodizing off Threads

scalpel_ninja

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Hey Everyone,

I've recently acquired an older Malkoff 1xAA body and realized it's anodized on the threads where the head meets the body. As seen in the photos, it's different than the current body where the threads are bare; therefore the BG head won't work on the older body.

Any tips on a safe and effective way to strip the anodizing? I was going to mask the body and brush on some oven cleaner, but wanted to ask the experts before doing so.

IMG_3495.jpeg
 

LRJ88

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I was in your exact seat with a Malkoff body and a Tactician head a while ago. I used sodium hydroxide in a water solution, masked off the rest of the body with tape, and just carefully dipped the threads and scrubbed with a toothbrush and a toothpick to remove the anodising. I recommend covering the ENTIRE body with tape, you will most likely get some of the solution in otter places too and it will start eating away at the anodising there too if not covered.
 

scalpel_ninja

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I was in your exact seat with a Malkoff body and a Tactician head a while ago. I used sodium hydroxide in a water solution, masked off the rest of the body with tape, and just carefully dipped the threads and scrubbed with a toothbrush and a toothpick to remove the anodising. I recommend covering the ENTIRE body with tape, you will most likely get some of the solution in otter places too and it will start eating away at the anodising there too if not covered.
Thanks for the tip on masking the entire body. I'll experiment with the foil solution below before jumping to chemically stripping the threads.

Have you tried covering the threads with alluminum foil? That way no altering required.
It works with the foil, but then removing the head shreds the foil off the threads. However, the remaining foil did form a pseudo-wave washer inside the head that stays in place. Not exactly a permanent solution, but I'll play around with it. Thanks!

IMG_3501.jpeg
 

bykfixer

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Thanks for the tip on masking the entire body. I'll experiment with the foil solution below before jumping to chemically stripping the threads.


It works with the foil, but then removing the head shreds the foil off the threads. However, the remaining foil did form a pseudo-wave washer inside the head that stays in place. Not exactly a permanent solution, but I'll play around with it. Thanks!

View attachment 63992
It's how I got some older streamlights to work if the tailcap was slightly loosened. Used to be some would fail to light if the tailcap was loosened even the slightest bit. The o'rings back then were not "fat" enough to put up resistance so an otherwise really useful tool was rendered useless very easily as in not reliable as they could be. A foil ring helped with conductivity and with resistance to loosening.
 

aznsx

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Do you feel that the actual point of 'poor' electrical connectivity is due to anodizing on the actual threads / threaded section of the body, or specifically anodizing on the very 'end' of the body tube where it actually 'butts up' / contacts the mating contact surface of the head? If it's the latter, I think I would simply remove the anodizing from the very end contact surface of the body using an abrasive (not chemical) method. This would remove the anodizing actually causing the poor connection point, without all the mess and risk associated with chemically stripping the anodizing from the entire threaded section of the body (which might be unnecessary). I'm trying to differentiate between the actual end of the body tube (which appears to be anodized / not bare Al), and the threads themselves (which may also be anodized, but may not be the specific point of contact issue causing the problem......if that makes sense;-) (What does the photo in post 4 look like without all the scrap Al foil on it which is obscuring the point of my interest [the part of the head actually contacted by the end surface of the body tube itself]?

Which of the two bodies in your first post is problematic? The one on the right seems to have more prominent anodizing on the threaded section of the tube, but looks more like 'bare' on the end of the tube, whereas the body on the left appears to be more 'bare Al' on the end of the tube itself. This is hard to distinguish from the photo.

It should also go without saying that any bare / raw Al surface that is critical to the electrical connection should be cleaned and protected (from oxidation) w/ DeOxit D100 (vs "Gold") as a matter of practice before testing, as if it is not, that will itself promote intermittent connection issues, with or without anodizing. That is true of any raw / bare Al surface that is used as a point of electrical connection in any situation, and just comes with the territory when attempting to use raw / bare Al as an electrical contact point, in any application. That is a fundamentally flawed / problematic situation which is unavoidable in the flashlight world specifically, which is perhaps the only application I can think of where one ever depends on raw, un-plated Al as an electrical contact point. People who design other things are generally smarter than that;-)
 

scalpel_ninja

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@aznsx

The photo with the flashlight bodies shows the more recent version on the left. It has bare threads, but you're right it's obscured by some old lubricant.

The one on the right is the older version with the threads fully anodized and only the flat top part is bare.

The body on the right does not work with the current MDC head because the bare aluminum would contact only potting material, therefore unable to conduct any electricity. The body on the left conducts via the threads and therefore works.
 

xxo

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maybe you could chase the threads with a thread cutting die? have you asked Gene Malkoff for advice?
 

aznsx

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maybe you could chase the threads with a thread cutting die? have you asked Gene Malkoff for advice?
Or perhaps a thread-dressing file, for that specific threading. I've used them in the past to try to clean up burred / damaged threads, but don't recall how that went, so I hate to recommend it.

It's like that old saying about 'cops' in a way: "Where's a good machinist when you need one"...:)
 

knucklegary

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It's like that old saying about 'cops' in a way: "Where's a good machinist when you need one"...:)
No need to clean the entire threads, just try a spot to make contact with head threads.

No disrespect intended , but don't use thread files or die nut style thread chasers. They'll take off too much material leaving a loose fit.
First I'd try a Q-tip at the top of threads dipped in oven cleaner. Then stiff nylon tooth brush.
If nylon is not effective removing the softened ano, then a stainless welders toothbrush (soft strokes) should do the trick without damage to threads..
Believe me!!!!
Screenshot_20240625-174724.png
 

scalpel_ninja

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So I've removed a spot of anodizing and it seems to work with one head, but not another. I might remove another patch at a different location to see if it'll increase reliability.

Also, has anyone used a different clip with these older bodies? I don't like the deep carry and can't seem to find a clip with similar horizontal spacing for the screws.
 

aznsx

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So I've removed a spot of anodizing and it seems to work with one head, but not another. I might remove another patch at a different location to see if it'll increase reliability.

Also, has anyone used a different clip with these older bodies? I don't like the deep carry and can't seem to find a clip with similar horizontal spacing for the screws.
I would tend to err on the side of providing more, rather than less connection / contact area where possible. This would help minimize connection resistance in the circuit, which to the extent present, would subtract directly from the light's output.

To the extent that the connection area is less than optimal, that would also make this even more important than it might otherwise be, given that the area of freshly exposed Al will be oxidizing practically before you can screw the light back together;-)

It should also go without saying that any bare / raw Al surface that is critical to the electrical connection should be cleaned and protected (from oxidation) w/ DeOxit D100 (vs "Gold") as a matter of practice before testing, as if it is not, that will itself promote intermittent connection issues, with or without anodizing.

$0.02;-)
 

scalpel_ninja

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I would tend to err on the side of providing more, rather than less connection / contact area where possible. This would help minimize connection resistance in the circuit, which to the extent present, would subtract directly from the light's output.

To the extent that the connection area is less than optimal, that would also make this even more important than it might otherwise be, given that the area of freshly exposed Al will be oxidizing practically before you can screw the light back together;-)



$0.02;-)
Thank you. I'm just being cautious about how much anodizing I remove because I'm paranoid about taking off too much and end up with a wobbly connection.
 
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