Epoxy Electronic Encasing

[Sparkyflyer14]

As I recently aquired a minitimer4, It has led me to several questions about rocket electronics. One of them is if I should cover the circut board in a non cunductive epoxy to prevent anything coming loose. However, if something did go wrong, I couldn't work on it. Thoughts?

 

[heada]

Conformal coating is the term you're looking for. Some electronics don't respond well to it like baro sensors. Not saying you should or shouldn't, just research what your electronic are before doing it.

 

[Grog6]

If you use acrylic conformal coating, flux-off will remove it.
Urethanes are not removable. Look at techni-tool for humaseal.
Be sure not to block the vent on any sensor chips.

 

[G_T]

And for higher durability, mount it in an aluminum rectangular tube (not quite touching) and fill with wax. Have not done it, but know it has been done for extremely high acceleration projects. This presumes you don't have any particularly hot components on the board, obviously!

 

[GrouchoDuke]

As long as components are SMD flush-mounted stuff, loads we see (+/- ~100G) typically aren't an issue. That said, I do put a little non-conductive epoxy on the edges of big components (like GPS antennas) on my high G rockets to help spread some load. Like heada said, don't cover a baro.

If you core sample a rocket, you really should throw away all the electronics. For normal flying, let 'em rip.

For the MT4, I bet PerfectFlite would be able to give you some guidance on when to worry about it. Looking at their photos, the big cap is the only thing I would worry about for really high G flights.

 

[Steve Shannon]

As I recently aquired a minitimer4, It has led me to several questions about rocket electronics. One of them is if I should cover the circut board in a non cunductive epoxy to prevent anything coming loose. However, if something did go wrong, I couldn't work on it. Thoughts?

You have described yourself as new to the hobby and rocketry electronics. As such, there’s probably nothing to be gained by modifying a commercial design. Rocketry electronics are already designed to withstand ordinary (for Rocketry) usage and are routinely tested by other flyers. If there were a problem with “anything coming loose” in ordinary use, it would have been a subject of discussion.
I have sheared components off a PC board before. It merely requires a brief lack of attention.

 

[rocket_troy]

IIRC electronics are often potted in polyamide hot melt in the pro world, but I could be mistaken there. Gerald's suggestion of wax certainly sounds more appealing if there was a likelihood of needing to get back accessed to the populated board, but Steve's is even more appealing

TP

 

[OverTheTop]

As an electronic engineer I would suggest you don't "pot" the entire thing in epoxy or acrylic. A conformal will do sufficiently in most cases. I also recommend Humiseal, and sometimes use it on rocketry electronics. Research to see if it is suitable for what you intend.

As others have said, you need to be careful to keep it off baro sensors, switches, buzzers, connectors and anything else it might impede function.

Also consider if you need it at all.