Only defending the family forum policy, all for keeping it civil and being nice to each other. Yes, we should try to stay on track. But you and I both know this place is legendary for going off topic. It’s funny when you’re just watching a thread, can be frustrating when your’e trying to get information for a build. Been there. Got frustrated. Went elsewhere for my research. Ended up getting some good stuff here too.
I’m wondering why you can’t do some of both…use the wax to keep the potting compound from going in/under the components and use your alumina oxide to gain some thermal passage. I really don’t know though, as I haven’t thought about removing something I always figured to be permanent. I have, however, totally killed a Malkoff drop-in trying to get that white stuff outta there so I could rebuild the pill. Totally killed it.
And modded a light this evening that could have used some of these pointers. Totally forgot about them! Ended up doing a lot of time-consuming work shaping copper. And re-flowed some things together that would have been much easier with JB Weld. Maybe I can do the Permatex thing and do some filling in……
Screw the aluminum oxide (BTW, you can get it at ceramics supply stores) and go with silicon carbide. Much better thermal conductivity. Search Ebay for “silicon carbide powder” and “silicon carbide media”. You can also get it at lapidary suppliers.
I dont quite get why you want it to be fully reversable. If you pry the whole thing out and let the wires attached, you can use the driver again. Maybe Fujik, cheap enough, brittle when cold, doesnt stick too tough.
Screw the aluminum oxide (BTW, you can get it at ceramics supply stores) and go with silicon carbide. Much better thermal conductivity. Search Ebay for “silicon carbide powder” and “silicon carbide media”. You can also get it at lapidary suppliers.
Thank you texaspyro. Buried up above I linked to the following thread where you have some great info on it. I was trying to is if it is time proven now. I was going to post in that thread but it was about a permanent potting. In retrospect, I should have. Actually, I will because it would be good to see that thread get followup in it. It seems to be where you originated the idea:
I dont quite get why you want it to be fully reversable. If you pry the whole thing out and let the wires attached, you can use the driver again. Maybe Fujik, cheap enough, brittle when cold, doesnt stick too tough.
Thank you NightCrawl. Here is the driver and pill I want to try this in first. Actually, I want to do a 9 amp version driving an MT-G2. I think potting will be needed to push that driver that hard. As you can imagine, It has pcb's going in 3 dimensions and is surrounded by curved walls. It would take a good amount of Fujik to pot. Maybe I should consider it more closely. My experience is that it is kind of expensive and can be hard to remove from detail, delicate areas like drivers. Am I wrong? Sounds like I might be.
My 6 year old loves flashlights, and is proving to be a very adept reader. He not only see’s the pics of lights, he can read these messages almost at a glance. We don’t all sit in a cubicle or other private/semi-private area.
That vertical board sure increases the level of difficulty doesn’t it? I looked at one like that for my own build with an MT-G2. Perhaps the wax or wax paper could be used to split the potting compound into sections? Such that it would “break away” if you wanted to remove it? Then maybe you could pull a section for an upgrade, recast only that section. Just looking at the potentiometer there and going off that.
The silicone carbide idea seams great to me. I was on ebay to get some of that 1500 grit, and it even comes from Texas, but while they say they can ship it cheap, the shipping in the cart is much higher. 1 1/2 lbs were going to cost $12, with $10 shipping. Back to square one.
Would this silicone carbide work embedded in JB Weld? If not, what would be a good carrier epoxy for it?
ImA4Wheelr I have also wanted to be able to remove the potting if necessary. So I know where you are coming from.
What I did was use the fujik glue and add a little artic silver cpu paste (non conductive) in to the mix. Should improve the thermal conductivity, I have no idea how much though. The artic silver added in makes the mixed compound a little more crumbly, easier to remove. It still doesn’t just peel right off, but it can be removed easy enough given enough patience. It does take time to get back to a clean driver, so I try not to do that no more than necessary. There are a lot of good suggestions in this thread, just giving my experience with the fujik glue.
I have used silicon carbide mixed into epoxy for a potting compound. But that is not reversible
It appears to work good.
One thing to consider, you may not need to pot the driver into its driver cavity. Considering when a driver dies, normally one component burns, you may just need to glob the compound over the driver to help spread heat. Maybe grease the inside of the pill and then pot the driver to fit inside, touch, but be removable after it dries.
Thank you DBCstm, moderator007, and bdiddle. Good info. Thanks for sharing your knowledge.
I searched for some silicon carbide too and found shipping to be a bit high in each case. I will search more later. If I find a good deal, I'll post it here. Please do the same if you find a good deal DBC. Thanks man. I'll also try to keep some of your other above advice in mind.
I ordered the first 2 listed above. Now I need to find some silicone mix that won't harm the driver. Worst case, I can get sensor-safe RTV (recommended by Comfy), but that is expensive.
I love what you are doing and want to see this light at 9 amps but just be aware that the MTG-2 turns into a mini heater that could warm a small town at that current. Good luck.
Thank you MRsDNF. I was planning on high being more of a "turbo" mode. I figured the light would not be able to handle extended high based on what you have said about your MTG2 DST. Your light has much more heat sinking than mine.
In actual usage, I tend to use low and sometimes medium. I just like having a kick ass high available. With only 3 18650's, run time on high would be pretty limited too.
Kick ass I like. I haven’t given up yet on a 9 amp MTG-2 yet. Construction is underway on a new light.
A lot would not agree but the DST would have to be the best cheapest large reflector light around. The plastic reflector will not short on the electrics and I have not managed to melt one yet with all the abuse that I have thrown at them. Looking forward to your upcoming night shots. :bigsmile:
OK, Got my Silicon Carbide. According to below, the GE Silicone II's are neutral cure silicone rubber compounds. The Silicone I's are acid cure. So a whole range of cheap products like this are available to make the potting compound.
My understanding is that Alkoxy cures are better than Oxime cures for copper and certain polycarbonate plastics. I'm guessing the above products are Oxime as Alkoxy cure compounds are more expensive. I hear Dow has a couple product lines (737 and 236) that are Alkoxy, but I haven't found a local store carrying any of this stuff yet.
I plan on trying it this weekend. My 7 amp XM-L2 DST has unsoldered the positive LED wire on the driver side twice now. Hoping this helps pull enough heat out to stop that. But more important, I hope it helps keep the resisters and such cooler.
Thanks for this info! Good to know about the GE Silicone II! That's readily available! Just wish I knew about it when I was at Home Depot on Monday! Let's see if I can add another exclamation mark! :)
Auto parts store. "Sensor-safe", "Low odor and non-corrosive formula" = no acid. Cures stronger yet easier to remove than household silicone caulk. I can't for the life of me figure out why you guys are dead set on scouring the planet looking for anything other than the Ultra Grey.
