Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
Author: Subject: ETN and witness plate questions
Grantr
Hazard to Self
**




Posts: 57
Registered: 19-9-2015
Member Is Offline

Mood: No Mood

[*] posted on 1-12-2015 at 19:19
ETN and witness plate questions


I tested 1 gram ETN hand pressed with all of my weight into a 3/8 inch diameter vinyl tube with .3 grams loose on top to set it off via spark gap. Witness plate is a 1/4 inch steel finishing mower blade. To my surprise it did not dent or bend it. I am not sure if these are harden steel blades or not.

I know it detonated as it was extremely loud and the blade was flipped over. There is a darken spot where the charge was placed. Is this typical for a small charge? 40 grams of ammonal did bend the blade.

The blade goes to a king kutter 7 foot finishing mower. What type of metal and thickness is usually used as witness plates?
View user's profile View All Posts By User
greenlight
International Hazard
*****




Posts: 676
Registered: 3-11-2014
Member Is Offline

Mood: Energetic

[*] posted on 1-12-2015 at 20:29


I am sure a gram of ETN isn't going to dent a 1/4 inch steel plate.
Even though the ammonal is a less powerful explosive there is a big difference between 1 and 40 grams.

I don't know if there is a set thickness for witness plates. They are usually steel but I have heard of lead ones for detonator testing.

I use 3mm thick 15 × 15cm squares of steel. They are all exactly the same and I use a gram of explosive for each test with a detonator of the same size to compare effects.




The only use for an atomic bomb is to keep somebody else from using one.
George Wald
View user's profile View All Posts By User
Grantr
Hazard to Self
**




Posts: 57
Registered: 19-9-2015
Member Is Offline

Mood: No Mood

[*] posted on 2-12-2015 at 05:00


Thanks that is good to know. I will find some thinner material to test on.
View user's profile View All Posts By User
aga
Forum Drunkard
*****




Posts: 7030
Registered: 25-3-2014
Member Is Offline


[*] posted on 2-12-2015 at 15:22


If the 'witness plate' is not the same material each time, and common to each user, how do you EM guys compare results ?



View user's profile View All Posts By User
greenlight
International Hazard
*****




Posts: 676
Registered: 3-11-2014
Member Is Offline

Mood: Energetic

[*] posted on 2-12-2015 at 20:18


If you use the same material and thickness each time for your own tests you will get quite good results and you should be able to see noticeable differences.
The plate test is good for the home EM experimenter but quite crude and only gives you a rough idea of the power of the explosive being tested.
There are much better test's out there but unfortunately most need a specialized setup or special equipment.




The only use for an atomic bomb is to keep somebody else from using one.
George Wald
View user's profile View All Posts By User
OneEyedPyro
Hazard to Others
***




Posts: 164
Registered: 7-10-2015
Member Is Offline

Mood: No Mood

[*] posted on 2-12-2015 at 22:41


In my experience hand pressed ETN really isn't too powerful at all compared to cast or machine pressed and with spark gap initiation I would have doubts that you're getting full power dets, it might be worth a try to use a primary instead of spark gap and see what happens.
View user's profile View All Posts By User

  Go To Top