58 replies to this topic

[starseeker]

2.23 on the comp.
If you`re unclear how to work out your hydraulic ram area it`s explained clearly on Rich`s website (Rich Wolter Tools).
You`ll need tough tubes and a sleeve of course.

I have some decent sleeves,just waiting for my perpex for the blast shield and then i can try it out.

[Mumbles]

Something made from polycarbonate would be a much better choice than an acrylic for blast shields. It's been shown to be superior.

http://www.thecalder...lastShield1.htm

[a_bab]

Here we go:
(part 1)
(part 2)


EDIT: timed reports (inspired from The Master): http://sites.google.com/site/spamento/

Edited by a_bab, 19 June 2010 - 11:38 AM.

[dave]

hi everyone,
for those of you who don't visit the apc forum, here is a link from there, to some nice CLEAR vids of
rocket making, star plates, and crossette s

http://truebluepyro.blogspot.com/

dave321

[a_bab]

Thank you so much for this post, it all makes sense now.

Just 1 small question: is this image from the same series? (http://www.pyrobin.c... crossettes.jpg)

[rocketpro]

--------

Edited by rocketpro, 06 August 2010 - 09:20 AM.

[starseeker]

Something made from polycarbonate would be a much better choice than an acrylic for blast shields. It's been shown to be superior.

http://www.thecalder...lastShield1.htm

After reading your post mumbles,i think i do have polycarb coming as before ordering it the chap assured me that you could attack with a hammer and it would stand up to it.So it should be well up to the job.

[Mumbles]

I don't know about that. Perpex, or perspex is definitely acrylic. Poly(methyl methacrylate) to be specific. Plexiglass, acrylic, lucite, the stuff you have, it's all the same stuff. I frequently see it listed as shatter resistant. It's becoming more common for plastic or "Nalgene" water bottles, as it doesn't have bisphenol-A in it, though it isn't as resilient as polycarbonate.

Shatter resistant is what I would call it, but I would NEVER trust it for a blast shield. If you want to see there is an easy experiment to do. Take an old CD (not DVD or blueray disk), and bend it in half. It will bend quite a bit, but when you get to a certain point it snaps with quite a lot of force. You can also look at any car that has been in an accident, the head and tail lights are made of PMMA. You could also go to youtube and search for "hockey glass break". Any video on there should be PMMA. They switched over at least 20 or 30 years ago. It is shatter resistant because it bends quite a bit, but when it does shatter, it releases all that stored energy.

Edited by Mumbles, 21 June 2010 - 10:28 PM.

[starseeker]

I don't know about that. Perpex, or perspex is definitely acrylic. Poly(methyl methacrylate) to be specific. Plexiglass, acrylic, lucite, the stuff you have, it's all the same stuff. I frequently see it listed as shatter resistant. It's becoming more common for plastic or "Nalgene" water bottles, as it doesn't have bisphenol-A in it, though it isn't as resilient as polycarbonate.

Shatter resistant is what I would call it, but I would NEVER trust it for a blast shield. If you want to see there is an easy experiment to do. Take an old CD (not DVD or blueray disk), and bend it in half. It will bend quite a bit, but when you get to a certain point it snaps with quite a lot of force. You can also look at any car that has been in an accident, the head and tail lights are made of PMMA. You could also go to youtube and search for "hockey glass break". Any video on there should be PMMA. They switched over at least 20 or 30 years ago. It is shatter resistant because it bends quite a bit, but when it does shatter, it releases all that stored energy.

My sheet arrived to day and it is polycarbonate so i can feel a bit safer now,but on a entirly different track,in the videos of the masters timed reports,what are the plastic caps they are using?

[Mumbles]

The caplugs are made from vinyl. I think it's the same kind of stuff that tool grips are made from. Cheap pliers, some hand weights, some clamps, maybe some wire. Thats the kind of stuff I normally see it on. I don't know if it's PVC or not, but it has other plasticizers to keep it flexible.

[karlfoxman]

Very intresting posts, I still find the inserts and effects from such a small unit amazing. I have been looking at trying to make some similar style shells. I have quite alot of info on these from various sources. I would of course use tiny beraq instead of these plastic caps. I found I could squeeze 39 beraq into a shell this size.

I will roll some small 3/8" beraq and start making a shell, I have flax twine to spike the shell. I will post some pics into the shells thread since I wont be using as rocket headers. Thanks for your posts.

[Arthur Brown]

The USA based supplier of the yellow cap plugs has recently sent several thousand to each of two EU based people to distribute, especially as small parcel airfreight is silly money from the USA.

He used the YELLOW cap plugs because it meant that he could find any inserts that failed to fire, before the neighbourhood kids did. Other than that any tube that fits, works.

[dr thrust]

heres the skinny, on how to make the "five times report rockets"
they look dam close to the real thing.

the masters rockets]

Edited by dr thrust, 01 February 2011 - 07:37 PM.

[starseeker]

heres the skinny, on how to make the "five times report rockets"
they look dam close to the real thing.

the masters rockets]

Excellent article you have found there Dr Thrust,have you tried these yet ?