Replacement MC-E LED head for Canister Divelight ...

[wquiles]

The Glow In the Dark helps locate the head in complete darkness for a couple of hours after being lit, but it is not "necessary" - just something I added to the epoxy mixture, and something that I have found practical when locating flashlights in the dark in my own house.

I have noted the same thing regarding P7 vs. MC-E. The MC-E seems to give me better/smaller focus in the various lights I have made with them. There is also some discussion in the CandlePowerForums about possibly using some aspherics to get an even better/tighter focus - I have some on order that I hope to try in the next month or so.

The LED Driver is the hipCC from TaskLED, although I don't think George (owner/designer) would like to share much of the specifics. I have been using his drivers on all of my LED projects for 4-5 years now:
hipCC Product Information

Thanks much for the link on the bonding agents for Delrin - I am sure that will come handy in other projects as I do like working with Delrin a lot, as using screws to keep Delrin parts together works great, but it is not always the best option. For this specific application, I am not after a true "bond" nor a fairly permanent joint against the Delrin. I just want a good water sealer for the joint between the cable glands and the Delrin. I wanted a sealant that had good adhesion, but not so much that would prevent servicing the cable glands in the future.

The 3M Marine Sealant 101 that I will be using will provide a great water seal against the Delrin, which will be imperious to watter, will handle loads better (since it does not truly hardens), and will provide the user (Grant) with the ability to free and exchange/service in the future if needed:
3M Marine Sealant 101

For an even stronger bond (although still not a true bond as the stuff from RELTEK), one can use the stronger 4200 and 5200 adhesives from 3M, but servicing parts might no longer be possible, which is why I decided on the Marine Sealant 101.

Will

 

[lucca brassi]

The LED Driver is the hipCC from TaskLED, although I don't think George (owner/designer) would like to share much of the specifics.

It is unnecessary to know details , because they are free accessible in the datasheets of the producers of chips on theirs websites normally they design first prototypes. Also it is a lot of LED driver chips with free tools to design switcher circuit (efficiency, thermal design...etc). More it is interesting for me what it is today ''IN'' in the LED driver branch.

I just want a good water sealer for the joint between the cable glands and the Delrin.

Aha -OK

in other projects as I do like working with Delrin a lot, as using screws to keep Delrin parts together works great, but it is not always the best option.

In that case it is possible (for example like bottom of canister ) to made fine ribs on outer side of bottom cylinder ( positive orientated ) and in inner tube of canister (negative orientated ). These ribs must be very carefully calculated and also depends from roughness of treatment (turning) of the surface both sticking parts. ( must be measured !)

With some carefully added pressure on both parts with a little bit surtension on material , they ''click'' together . Mean time if both sticking surfaces are treated with some glue/sealant during pressing it works in lubricant way and made pressing easier - not so charged for material!

After some time when the sealant/glue it is dryed up with a surtension on material it must hold parts together like hell and must be watertight ! )

 

[Randy43068]

What a fine engineering to produce this wonderful work of art!

Thank you for sharing.

 

[wquiles]

You are welcome. It certainly has been a fun and rewarding project so far, plus I am learning good things from various forum members as well

Will

 

[lucca brassi]

Press Fit Assembly

Press Fit Assembly Press-fit assembly uses the interference between male and female features to create a permanent joint. Pressure created by mating the two features results in static friction which can be sufficient to hold the joint together under modest loads. Press-fits can be executed with reasonable forces between plastic/metal and plastic/plastic components. Metal to metal press fits can also be created, but generally require much high forces and are extremely sensitive to small variations in the relative size of parts.
When designing a press fit joint, it is important to keep in mind that the plastic components will generally creep under load, and the joint pressure will drop over time. Including barbs or other retentive features often alleviates this condition. Cracking is a common problem during deployment of press-fit joints. Reducing the interference will alleviate this problem, but it may be possible to reduce the problem by increasing the insertion speed during assembly. Press fit joints may be susceptible to chemical induced cracking, depending on the stress and materials involved.

SNAP-IN (Delrin)
Handbook of Plastics Joining: A Practical Guide

 

[gwilki]

Interesting info, Lucca. I wonder what the effect on such a joint would be of the expansion and contraction of the parts caused by the heat from the heat sink and the cold of the water surrounding the parts.

 

[wquiles]

Cool links Lucca

When making threads (specially metal on metal) is not uncommon to encounter this friction-based bonding - we say that parts have seized together, which when doing threads is something to be avoided. It usually happens when the threads being cut are incomplete and there is not enough clearance between the two parts (it can be made worst when there is no oil/lubricant). Sometimes the bond is strong enough that they can't be separated without damaging one of the two parts being threaded, which means they go to the trash bin and you have to start all over

Will

 

[lucca brassi]

Yes - I agree with you.
I'm not mechanic constructor , but I see sometimes our engineers when try to get right bushing for specific shaft.
One of my friend prototype slug of headlamp in that way and becouse of design it was very small and he put two that pieces on the UWcamera. He also combine some materials with different elasticity. Lamp build in that way was unrepairable , before he set up right dimensions as you have said before

go to the trash bin and you have to start all over

but when he determined parameters he made beautiful small lamp.

 

[wquiles]

OK, so an interference fit on purpose - cool application. I personally like to try the two threaded pieces before final assembly, so I would be scared of the pieces seizing too early in the process . Still, it is a good idea to keep around for a future project - thanks.

Will

 

[wquiles]

Grant,

Finally got the sealer from 3M. I bought both the 101 and the 4000, but I will be using the 101 for this project:

As per our emails, I am making the new cord a few inches longer:

Prepping the canister side:

Applying the sealant on the cable gland:

Applying the sealant on the cable gland:

Applying the sealant on the switch (remember the last one leaked and had no sealant):

Applying the sealant on the boot (clean excess with Alcohol and Q-tips):

Now waiting for the sealant to cure until tomorrow to solder the wires in the canister side:

Will