Blast Shield

[LiamPyro]

Hey everyone, it's been a while but I'm getting back into pyro and have decided it's time to build a simple press like this: https://www.skylighter.com/blogs/how-to-make-fireworks/rocket-press-arbor. However, I'm modifying the design by installing a blast shield just in front of the pressing arm, probably in such a way that it can slide up and down... I haven't figured out the details yet. It's going to be relatively small, in the realm of 12"x18". Skimming around the internet, I've found some recommendations to use 1" Lexan for the shield itself. Does this sound about right? I'm assuming acrylic shouldn't be subbed for polycarbonate, although I'm having trouble finding polycarbonate sheets thicker than 1/2". So, if anyone's built a heavy duty blast shield, what material/thickness did you use? I want to make sure I purchase what I need, as this stuff tends to be pricey. By the way, I intend to press caps as well as rockets and the like, so I'd like this thing to be TOUGH (Does this belong in HE section?). Thanks in advance, Liam.

[Mumbles]

Yes you want polycarbonate and not acrylic. You. An use multiple thinner sheets together. Some people swear by this method actually and claim it is safer.

[Arthur]

I'd fix half inch polycarbonate sheet securely and fix a thinner sheet each side of it. The second sheets to be replaceable easily when they get scratched. it's hard to see through scratched plastic sheet. I'd also fit lots of light to the hot side (say 1 - 3 watts of LEDs) so that the subject is well lit from back front and both sides.

[LiamPyro]

Thanks for the feedback guys, it didnt even cross my mind to use multiple layers of polycarbonate. LEDs are a great idea too.

[mabuse00]

Did you guys ever had an accident where the shield actually had to prove it's abilities?

 

I'm in the process getting the stuff together, 15mm Polycarbonate would be my choice.

Since the shield will hamper working with the press a little, it can only cover the possible direct fragment-flightpaths + a few degrees.

 

 

I dont have the link right now, but some +10 years ago some people tested an assembly with several plates around a whistle engine, but they used the hose clamp method.

The question is, what actually happens when some 150g whistle or even strobe fuel ignite while surrounded by one of the typical massive aluminium sleeves.

 

My experience with pipe b!!bs is rather limited, but back in the days where I could not resist these kind of experiments I found that even with hot Perchlorate flash this produced very few very large parts, indicating that DDT did most likely not occur.

Also where talking about aluminium and not cast iron, soft malleable stuff.

 

So - if my assumptions are correct, the shield would even in this case be subjected to brute but blunt force without much penentrating potential.

 

 

What brings me to another subject:

I cant help but put my press in a place where next wall is pretty close to it's back.

This might lead to parts bounce back. Do you have some material of choice to eat up as much energy as possible in the process? My first guess would be medium density fibreboard or similar stuff...

Edited February 4, 2021 by mabuse00

[pyrojig]

Maybe a cork pin board. Or acoustic board.

[Bourbon]

Yep, or, memory foam mattress topper. Coarse, not all memory foam is real. I'd make sure it's the real stuff. NASA likes it too.

[dlking59]

Maybe styrofoam will keep from bouncing back. Regular or high density ?

[pyrojig]

He may want to avoid any static retaining materials in the loading area . Cap comps depending on the priming can be touchy , no need to add to the pucker factor of loading .

[dlking59]

Yea you are right. I didn't think of the static. Every time I open a box that has styrofoam the stuff clings to me like glue.