A Perfect Dedome?

how comfortable are you with light automotive work. ? If your fuel line is easy to access, you can disconnect it under the hood, put the line in a soda bottle, and turn the key to ‘run’ (NOT STSRT, DO NOT TURN IT ALL THE WAY AND CRANK THE ENGINE!!!) give it a good ten-count, then turn back to ‘off’, and go get the bottle, it will have enough gas in it to dedome, put the lid on for now, reconnect your fuel line, and close the hood, then find a jjar to put the gas and your led into.

Dunno if octane booster will work, but this is a relatively simple way to get gasoline without having to spend money on a ‘approved’ container.

Additives like octane booster are a different set of chemicals altogether as compared to gasoline. It's meant to be diluted in a full tank, and at those concentrations it's not harmful to the non-metal parts of the fuel system. But straight, undiluted? What are the odds that two completely different mixtures will give the same results? Have you bought a lottery ticket lately? :p

haha… great idea… don’t know why i didn’t think of that… access to the fuel line at the fuel rail is easy enough… :wink:

that said, i may have found another option… will know in a few hours… i have some natural orange solvent, similar to turpentine/mineral spirits/acetone that seems to be working!

will report back… this would be a much ‘safer’ alternative to something like gas or paint thinner… some of those chemicals (like toulene) have very high toxicity ratings (4 on a scale of 5,? last i checked yearssss ago) and are proven carcinogens that are harmful if inhaled and can absorb through the skin…. (i start to get paranoid about stuff like this if i think about it too long… i used to work in high end art supplies and so was referring to MSDS more often than not for certain things… ick!

dedome, yes! de-health… no…. please be careful fellow BLFers!

happy and safe dedoming! :slight_smile:

I use lighter fuel for de-doming (That stuff for zippos, I think it’s called ‘white gas’ in english). Its properties are similar enough to its heavier brothers used for cars, but is very clean.
Works fine so far.

so my dedome worked!! I used D-Limonene, a product by a company called Tri-Art. Its used as a solvent for oil painting and is made entirely from orange peels… by this morning the silicone was dissolved, no residue except a little around the emitter, not unlike some other BLFers’ results with gas…

just hooked it up to my replacement Qlite driver Rev A… love the moonlite mode!

still only getting 2.4A or so at the tail… either my MM or … I’m not sure what but I think this is definitely my brightest light yet!! (ordered a couple of the ‘underatted’ V10 drivers from FT… if my MM is indeed accurate than the underperforming drivers will still give me higher amps for my C8 and T2R P60… I want to hit 3+ amps!!)

The beam is a bit ringy… i tried a couple of reflectors that I had… the OP reflector made the beam very floody. The way it is not the hotspot is more like an XP-G2 in a P60…

Anyway, the D-Limonene does work… and should be chemically ‘safer’ though it is still labelled poisonous…

Happy dedoming everyone!

:slight_smile:

… oh great… my light just shut off and won’t turn back on… fingers crossed its just the protection circuit on my protected 18650 kicking in… or did i just fry it… :frowning:

While reflowing emitters onto sinkpads, Ive dedomed a few XML2’s and XPG2’s by accident. The domes come off completely and easily when they are at solder melting temperatures and leave no goo behind on the emitter.

There's no goo left behind after gasoline dunking either, anything remaining is dry and crumbly and comes off easily (usually just by spritzing with denatured alcohol, which needs to be done to get rid of the gasoline anyway).

That is how I did my last few dedomes: reflow them on Sinkpad boards on a heatblock, quickly move the board to the stage of a binocular microscope and when the solder is just set, lift the dome off with the edge of a knife (exacto or in my case a scalpel).

Finding solvents to remove the dome should easy.

Go here: http://www.coleparmer.com/Chemical-Resistance

Choose “Silicone” in the Material box, “All” in the Chemical box, and “D - Severe Effect” in the Rating box.

Anything that comes up on the results page will have a pretty significant effect on the dome. It’s just a matter of trying some of them and seeing what is fastest / cleanest / cheapest / whatever.

I think the fastest/cleanest/cheapest/whatever has already been found, and it might just be mentioned somewhere in this very thread, though I will admit it is hidden pretty well and it will take some expert detective work to find it....

Sure, gasoline works well, but there’s quite a few other solvents which may work better. Just trying to help.

May work better? How, exactly? Quicker? Is ~3-4 hours not quick enough? Is 'all' the silicone gone not enough silicone removed - is there another chemical that might remove not just 100%, but maybe 110%? (and would that really be 'better'?) Cheaper? Doubt it. Easier to get then gasoline? Can I drive 2 blocks from my house anytime day or night and get 5 gallons of anything on that coleparmer.com page for less than $20?

I don't get it. Why are so many trying to come up with something that 'works better' than something that just works? It works. If you don't think it will, try it first before you go looking for alternatives. That's the whole reason this thread was started. Because somebody found the answer.

Basically +1, but I know others have proven, familiar methods that are 100%, but I've found the gas method certainly the best for the average smuck (me...). I don't even wait 3-4 hours now - I'll take it out in 2 hrs if I need to, and gently flip off the dome because it always seems to be very loose then, and leaves a pretty clean footprint, as comfy says. I just give it a good soaking/shower of isopropryl alcohol when it's out, and maybe knock off loose stuff around the emitter. I'm still 100%, even after doing 1 more last night, and got another soaking now, probably 15 or so total.

Looking for a way to dedome my C8 XM-L T6 without soldering, I pulled the wires out and separated the LED/star from the pill, turned it upside down in a tiny container of gasoline with the pill sitting on top. (Tiny gas container consists of a little clear plastic cap from a bottle of throat spray!)

We’ll see how it goes from here! (do you think the gas vapors will harm any of the contents of the pill?)

Thank you!

Edit: Seems like some kind of spray contact cleaner would be good to finish up with…what do you think?

Even if you dunked the whole pill, driver and all, it wouldn't hurt anything other than the trouble it'd be to clean it well afterwards. Or if it used silicone wires... PVC or teflon should be unaffected. Epoxies or sealants could also be affected, though JBWeld I know will tolerate quite a bit of gasoline exposure before it starts to go soft. Others may be more vulnerable.

I've only ever used isopropyl in a spray bottle to clean up afterwards, I know first-hand it won't damage the newly exposed phosphor layer on the LED (that's the only part that might not be compatible). Use more aggressive stuff with caution. Might be best to test it on a 'dead' de-domed LED first.

I’m excited about maybe coming up with a way to dedome without soldering! Good point about the layer of phosphor, thanks. I’ll try finishing with alcohol like you said, I’m guessing the force of a stream shot from a bottle helps with clean-up of remaining silicone vs. just soaking in it?

Yeah, the 'silicone bits left behind' are really loose and not stuck well, and not gummy or sticky, so they come away easy. I haven't had one yet that left anything on the die itself, only around the base, but I don't trust the crumbly bits to stay there and don't want them falling off later and dancing around in the reflector. I clean off all of it (even under the bond wires - not for the faint of heart) with the tail-end of a ziptie angle cut to a very sharp point, and a good magnifier. The pointy-ziptie tool is flexible enough at the tip that you can poke at the phosphor and not damage it. The silicone bits really flake away very easily and you don't have to go near the bond wires if you want, only stuff on top of the phosphor itself will affect the beam (and the gasoline method doesn't leave bits on top of the phosphor).

But, like Tom I'm only leaving them in long enough for the dome to come off, then doing the rest by hand. I suspect if you left it in for ~24h it would all come off on its own.

Well, if you don’t own a vehicle like quite some people living in cities do these days, getting gasoline isn’t that easy and cheap. Depending on local regulations you may need to buy a proper container (=canister) to get it at the gas station.
They also may have a minimum quantity to buy (here often 2 liters). It may also be illegal to store that gas in your apartment - or at least against one’s rental agreement.
I kind of get your point, but please don’t assume that a solution is the best for all only because it works best for you.
Someone might be happy to know that he can use a bottle of acetone from the dollar store instead, even if a nice bath in ROZ95 would be (way) more effective. :wink:

Just checked on mine at the 1hr.50min. mark and the dome was barely dangling, I flung it off onto the floor with one little fling! There are still little bits of stuff on there, so I put it back in the gas ’til I decide what to do next. What to do next? I don’t have a sprayer bottle for the alcohol, maybe swish it around a bit in an alcohol bath? Do I need high pressure? Thanks again!

So someone living in your area would be familiar with all those issues, right? Are there any auto garages, motorcycle shops, small engine repair places around? Go there, explain what you're doing, ask if they can add some gasoline to the little bottle you bring in and keep it for you overnight. Don't act like this is a planet where gasoline doesn't exist.