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RocketMonkey

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Does anyone have any experiance with "Hot Heads" E-match heads from aerocon systems? I ordered some thinking it was a great deal but out of the 21 I prepaired NONE of them work. the instructions say check continuity but doesn't say what resistance to look for not that it matters that much because all the ones I tested showed an open. is it possable I got a batch without the nichrome bridges? It doesn't look lite there is anything running from oneside to the other on any of the heads. any help would be apprecieated.
 

WillMarchant

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The Aerocon web page implies that they should be around 2 Ohms. If you have any left you could try measuring them *before* you solder the leads. Maybe they're getting damaged when you solder the leads on?
 

RocketMonkey

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Try QuickBurst.
I used the QB pyrogen, good stuff.

The Aerocon web page implies that they should be around 2 Ohms. If you have any left you could try measuring them *before* you solder the leads. Maybe they're getting damaged when you solder the leads on?
Yea that's what I was thinking but I didnt think I got them that hot.
 
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RocketMonkey

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Well Poo...I just read over the instructions again and looks like I used the wrong solder. Calls for 60/40 which has the lowest melting point available I think I used "lead free" which puts out less fumes but melts hotter. I'll double check. I have a spool of fine 60/40 somewhere, guess I'll have to dig it out
 

JimmyL

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I have some of the same match heads and they read 1.2 to 1.3 ohms at the head. With an 18" length of wire soldered on they read 1.5 to 1.7 ohms at the end of the wire. That was using 24ga twisted pair phone wire. None of mine were open. If you get a magnifying glass you can see the bridge wire at the small end of the match. It is 50ga nichrome and it is tiny. I decided to just order the kit from Quickburst and be done with it. I will have enough pyrogen to dip all the matches in the kit plus the rest of the heads I bought. One last note, the resistance readings were taken with a Fluke digital meter. Good luck.....

JimmyL
 

bobkrech

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The instructions say check continuity but doesn't say what resistance to look for not that it matters that much because all the ones I tested showed an open. is it possible I got a batch without the nichrome bridges? It doesn't look lite there is anything running from one side to the other on any of the heads. any help would be apprecieated.
All standard commercial hobby rocket igniters use a resistive bridgewire to ignite pyrogen. If your ingiter has continuity, you have a good bridgewire or you made a solder bridge, but if you don't have continuity either you broke the bridgewire or it wasn't there to begin with.

If there was a bridgewire there, you somehow broke it in the process of holding or soldering it. The bridgewire is a very thin wire as it can easily be broken if you don't hold it as the instructions say to. If there is not a bridgewire visible under a magnifying glass, then the kit is defective and you should contact Bob Fortune at Aerocon for a replacement.

Bob
 

quickburst

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50 AWG Nickle Chromium wire is very stiff, seems to have a mind of it's own. Some failures are caused by getting the chip too hot.

Silver solder is used to build the chip (rosin core solder will not stick to NiChrome) only silver solder will work.

If the user gets the chip too hot the sliver solder lets go and the bridge wire jumps up, most of the time it breaks off. Since 50 Gage wire is so small it can be hard to see this happen. Especially with a guy that is a bit far sighted and working in less than good lighting (ask me how I know).

Always check your home made matches for continuity with a VOM before using. Do not trust the continuity checks on your avionics, these systems are easily fooled. Check for continuity then check for resistance. Both tests are invaluable. If there is no continuity, there isn't much point in testing for resistance.
 

RocketMonkey

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Well, I checked all the matches again(when I was clear headed and not tired) and they read about 2ohms until I try to fire them then squat, so I guess the bridge wire is burning but not hot enough to light the pyrogin. Now what? I'm going to order some quickburst match heads but what do I do with the 30 hotheads I have left?
 

bobkrech

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