[RocketsNW] [OROC Members] Casting Tubes etc

[Marty Weiser]

The Dawg Pack uses mandrels, but the smallest diameter that we anticipate
using in that diameter size motor.  This is to eliminate some waste.  We
then drill to final size after the grains are cut to length.

It looks like we may be switching over to a spade bit with a dowel on the
front to serve as a guide down the previous mandrel hole to help keep them
centered.  Worked great the couple of times we used it for >1" cores where
we did not have twist drills.

Marty

-----Original Message-----
From: rockets-bounces at rocketsnw.com [mailto:rockets-bounces at rocketsnw.com]
On Behalf Of Fred Azinger
Sent: Wednesday, February 03, 2010 7:07 PM
To: 'Sareth Tes'; 'RocketsNW Mailing List'; 'OROC Mailing List'
Subject: Re: [RocketsNW] [OROC Members] Casting Tubes etc

Talk to John Lyngdal for tube sets......

 

Drill or mandrel -- depends on YOUR choices and needs....

 

I do both.

I ONLY use mandrels for sparkies (where you don't want to drill) or weird
cores like Moon's or Finocyls.

Otherwise I cast full or half sticks and can then cut & core tailored for
the motor configuration of the day....

If you use a mandrel, you've already determined the motor parameters to a
certain degree (you can always re-drill larger)

Using a mandrel system like TruCore also fixes your grain length...another
variable you need to choose early at casting time.

 

I choose maximum flexibility -- cutting and coring at the time I intend to
build a particular motor .

 

This how I choose to do it and why -- YMMV

FredA

 

 

From: members-bounces at oregonrocketry.org
[mailto:members-bounces at oregonrocketry.org] On Behalf Of Sareth Tes
Sent: Wednesday, February 03, 2010 6:48 PM
To: RocketsNW Mailing List; OROC Mailing List
Subject: [OROC Members] Casting Tubes etc

 

Hello EX'ers,
    I realize in the dark ages when one had to go through an apprenticeship
that anyone wanting to learn to make their own rocket motors would go
through a long process where the first five years they would haul chemicals
from the various suppliers back to the shop of the master and then spend the
next 5 rolling Casting tubes until they could do so perfectly followed by,
If the Master thought they were worthy making nozzles. Once they had become
suffucently skillful at that the Master might let them in on the secret and
arcane formula's of the art. 
 
But it is now modern times!
 
All of this is leading up to the question of what are the better companies
to buy Casting tubes from? and is the method of pouring the slug solid and
then drilling better or is the method of using a Mandrel to set the core
better?
 
Thanks
Ralph
 
TRA006672
 

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