Search found 1002 matches

by rocket_troy
Tue Dec 15, 2015 2:23 pm
Forum: I could use that
Topic: Another Epoxy
Replies: 63
Views: 7556

Re: Another Epoxy

West systems is a boat epoxy and yet they release results. Indeed. If they were concerned about any additional liability (and it's a fair enough point), all they needed to say was "these are the results of our tests ..." and "here are a bunch of disclaimers ..." and "in no ...
by rocket_troy
Mon Dec 14, 2015 3:58 pm
Forum: Rocketry Control Room
Topic: Elon must be smiling
Replies: 1
Views: 551

Re: Elon must be smiling

CHA-CHING!!!

I would love to be the hardware store selling rakes near Elon's house for all those SHHHHHHPONDULAAAAAASSSS :)

TP
by rocket_troy
Fri Dec 11, 2015 12:12 pm
Forum: Mid/High Powered Rocketry
Topic: 29mm Callisto build
Replies: 192
Views: 10545

Re: 29mm Callisto build

Lister wrote: I like the idea of disolving it, do different expoxies require different solvents?


maybe, but I'm not aware of them. One thing is for sure - any solvent up to the task of dissolving epoxy is likely to be a pretty nasty chem requiring careful handling and good ventilation.

TP
by rocket_troy
Fri Dec 11, 2015 10:46 am
Forum: Mid/High Powered Rocketry
Topic: 29mm Callisto build
Replies: 192
Views: 10545

Re: 29mm Callisto build

Also does anyone know any tips for removing cured epoxy from bolt threads? I forgot to tape up the bolts when I glued a part and am now in a bit of a pickle... If you're trying to unscrew a glued bolt - all you can do is heat it to say 80-100deg C to soften the epoxy and apply force. If you're tryi...
by rocket_troy
Fri Dec 11, 2015 10:39 am
Forum: I could use that
Topic: Another Epoxy
Replies: 63
Views: 7556

Re: Another Epoxy

Heard back about the Epiglue strength, they said their results are confidential. No idea why they would do that, wrote back to them but don't hold much hope of getting an answer from them. Surely you're kidding! Their *results* are confidential???? Not their formulation but their results? That's go...
by rocket_troy
Mon Dec 07, 2015 11:18 am
Forum: I could use that
Topic: Laboratory Power Supply
Replies: 52
Views: 2861

Re: Laboratory Power Supply

kopius wrote:Good thing the Chinese are all about safety...

pfff... those chinese are soooo amateurish...

Google image search "electrical wiring in delhi" to see how the pros do it:)

TP
by rocket_troy
Mon Nov 30, 2015 8:03 am
Forum: I could use that
Topic: Laboratory Power Supply
Replies: 52
Views: 2861

Re: Laboratory Power Supply

... the neutral instead of terminating in the ground floor switch board, terminated on level 7 through my right hand/arm/chest/face/head/AC Duct, witnesses reported the stair lights flickering (and my screaming), followed by me running with my hair on fire... I have worked on live bus bars many tim...
by rocket_troy
Fri Nov 27, 2015 8:38 am
Forum: I could use that
Topic: Laboratory Power Supply
Replies: 52
Views: 2861

Re: Laboratory Power Supply

A mate who's a linesman uses a hook on a bit of conduit for snagging lines.. I always thought conduit could carry a current.. seeing as it can build and store static would that mean its not going to protect you from being electrocuted? Storing charge and carrying current are 2 completely different ...
by rocket_troy
Thu Nov 19, 2015 7:48 am
Forum: Mid/High Powered Rocketry
Topic: 29mm Callisto build
Replies: 192
Views: 10545

Re: 29mm Callisto build

Gluing "chopping board" plastic (typically polypropylene) is problematic. Not much sticks well to it. Indeed, you should really try to avoid chemical bonding (or attempting to bond) to either polypropylene or in particular polyethylene. They're self lubricating plastics that excel at bein...
by rocket_troy
Mon Nov 16, 2015 7:16 am
Forum: How's the Weather..?
Topic: "post"al rocket
Replies: 8
Views: 740

Re: "post"al rocket

SpaceManMat wrote:Nah that was never going to fly, only two fins!

We had one flyer down here 10 or so years ago who only flew 2 fin rockets and they worked a treat :)

TP
by rocket_troy
Fri Nov 13, 2015 12:18 pm
Forum: Support & Recovery & Misc.
Topic: Launch Detection (almost)
Replies: 31
Views: 2800

Re: Launch Detection (almost)

On a more serious note, the RF units that you mentioned Troy are available as a cheap Chinese copy on ebay (circa $6 for both the tx & rx units). Have you had any experience with these? or should I steer clear of them? I've noticed that Adafruit & Core-Electronics are out of stock. Go for i...
by rocket_troy
Wed Nov 11, 2015 2:09 pm
Forum: I could use that
Topic: Laboratory Power Supply
Replies: 52
Views: 2861

Re: Laboratory Power Supply

I've not used a Tenma power supply, but we have a few bits of Tenma test gear at work (Differential Thermocouple Thermometers, Multimeters etc) and though no-frills, they have worked flawlessly. If you want more grunt(for Anodising or whatever), there are the B&K Precision bench supplies. I hav...
by rocket_troy
Tue Nov 10, 2015 3:04 pm
Forum: Support & Recovery & Misc.
Topic: Launch Detection (almost)
Replies: 31
Views: 2800

Re: Launch Detection (almost)

I think the RF solution is the more elegant one though. Ok, I'm just assuming you want to avoid microprocessors and intricate electronics here: one of these connected to (switching) your on board electronics: https://www.adafruit.com/products/1097 and one of these connected via relay to the igniter ...
by rocket_troy
Tue Nov 10, 2015 2:22 pm
Forum: Support & Recovery & Misc.
Topic: Launch Detection (almost)
Replies: 31
Views: 2800

Re: Launch Detection (almost)

Perhaps somehow measuring the current flow? The igniter resistance will change...increase I assume as it heats up...before it finally breaks. You only need to measure current (the presence of a current) or voltage (provided you bias the presence of high impedance voltage to zero). You're only after...
by rocket_troy
Tue Nov 10, 2015 10:27 am
Forum: Support & Recovery & Misc.
Topic: Launch Detection (almost)
Replies: 31
Views: 2800

Re: Launch Detection (almost)

Continuity testing is always done with extremely high impedance so the only thing likely to be triggered by such is either a FET or a direct digital input to a microprocessor. I should add: false (continuity) triggering of either can be very easily biased out via a suitable resistor to the opposing...

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