Workshop Blast Screen

[Arkangel]

I've always been nervous of the fact that working on a bench with any kind of energetic materials, your hands, and therefore workpiece are in the regions of your soft underbelly.

Yep, I have a leather apron and gauntlets, goggles, respirator etc. but your viscera are just to precious and fragile to risk being filled with glass and acid. I'm therefore considering building a portable blast shield on/behind which I can work in somewhat increased safety. I have in mind 6mm steel, sharply angled away from you, and welded to a baseplate. If you had the time to cut it, you could make it like the breakwater on the bow of a warship. That way any blast would be directed sideways away from you. I'd also be tempted to pad the side closest to me, so that any explosion would not drive it too painfully into me.

I also have a bulletproof vest that I plan to modify a la the LA Bank Robbers, to cover my arms, upper chest, and neck.

Am I over the top here, or does anyone have a similar rig? Suggestions would be welcome. :)

[kingspaz]

well if your main primaries are peroxides then i don't think your precautions are too over the top. they are slightly, but better over than under.
have you considered polycarbonate sheet as a blast shield?.....its clear too so you can see through it so it wouldn't hinder your work. if you were using safer primaries or atleast predictable ones then you probably wouldn't need all that. if its predictable then you will allways know what to expect and it won't explode for no apparent reason which is allways a threat with peroxides although reduced significantly if they are washed thoroughly.

[megalomania]

I have a big polycarbonate shield that I “found” in a hallway. I think they were throwing it away! A simple, and recommended, safety precaution is to use a metal screen wrapped into a cylinder around the reaction flask, and then use another clear cylinder after that. The metal screen (use fine mesh) is cheap and see-through. It stops many fragments of glass, and slows down the rest. If it gets damaged, just roll another. The plastic cylinder is of course clear and far less likely to be damaged.

[mr.evil]

TVS17 had got an Glovebox, ask him what kind of materials are used in that thing :)

[xoo1246]

I was planning on building a box where I can dream about pressing HTMD into caps(preferably somewhat remotely). Not that hard to construct one, I guess some of you allready have had dreams about this. What I wanted to know was how you did build yours. I was planing to use wood and a shield of clay blocks. The clay, in plastic bags(moms a ceramic artist), would greatly reduce the speed of the wooden fragments if anything went bad. What do you think?

[DBSP]

I have a small box that I've used when pressing smaller caps. I don't know how effective it is but together with a face shield it would probably withstand a detonation quite well. The plexi slowes/stops the shrapnell and then the face shield stops the remaining pieces.
<a href="http://w1.478.telia.com/~u47804009/E&W/DBSPs_blastshield1.JPG" target="_blank">blastshield</a>

<a href="http://w1.478.telia.com/~u47804009/E&W/DBSPs_blastshield2.JPG" target="_blank">blastshield</a>

[xoo1246]

Nice construction, you use heavy gloves and no contact with cap when pressing?

[Fallout85]

I have a 3' by 3' sheet of lexan in my garage left over from one of my previous projects. It's about 1/8" thick or a little less. Think it would be thick enough for constructing a small handheld blast shield for small amounts of primaries (2g or less) or should I even bother?

[Anthony]

It'll definitely be better than nothing, or a considerably greater thickness of a more brittle plastic like plexiglass/acyrlic.

[Zyklon_B]

Has any of you thought about putting plexiglass in such a way to diflect some of the debris in different directions instead of using a flat window? Maybe by placing it in a V shape it will send some of the small shrapnel to the sides instead of one flat sheet absorbing the complete shock :cool: .

[Fallout85]

That's what arkangel was talking about. And with something like plexiglass you'd have a weak point where you joined the pieces together. If you had metal you could weld two pieces or bend a sheet to the v-shape and it might work a bit better than plexi. But of course you wouldn't be able to see what you were doing. A viewing slot of some sort could be cut out and you could put a piece of something such as lexan put over it. It would certainly be cheaper than an all lexan shield. Lexan is pretty expensive here. edit-slight typing error

<small>[ June 13, 2002, 01:11 AM: Message edited by: Fallout85 ]</small>

[Zyklon_B]

Fallout85, thats a good idea, using a steel V shaped sheild with a small slot in it for a lexan window. You could use some nuts and bolts to hold it in and it would make it easier to change. I personaly would go for half an inch steel and I would put a non-flamable grease on it to aid the shrapnel on its way away from your face, something like vaseline.

You could also buy a cheap bullet proof vest off ebay and use it as a secondary layer just incase the metal is somehow penetrated so the Kevlar will stop it.

<small>[ June 13, 2002, 01:16 AM: Message edited by: Zyklon_B ]</small>

[Fallout85]

Do you think the addition of grease would really help? I think a flak jacket would suffice as long as you worked with small amounts. They're alot cheaper to. I was planning on getting one soon. Really, I'm more worried about my hands and face more than my torso. I've got the face protection pretty well covered (welding mask with visor up and super thick safety glasses) but I haven't really seen anything around here in the way of hand protection. Would the gauntlets be used for welding or something? I really have no idea where to look for them. If anyone has any idea as to how to obtain/to improvise a pair, I would be much obliged.

<small>[ June 13, 2002, 01:46 AM: Message edited by: Fallout85 ]</small>

[Zyklon_B]

The grease wouldnt be necessary, its just something I picked off what the did during the civil war on the first ever metal ships to diflect cannon balls. Just plain steel will do.

For your hands you can get thick leather gloves and another pair or kevlar gloves to wear underneath.

[Anthony]

I thick 1/2" steel is a bit OTT for working with blasting caps. It's be difficult to work (bend) and be awkwardly heavy. Can you imagine lifting it onto and off your workbench with it all greased up? <img border="0" title="" alt="[Eek!]" src="eek.gif" />

All this body armour, kevlar etc sounds rather expensive and a bit over complicated for a task like pressing caps.

IMO the best thing you can put between you and a device that might explode is distance, so use a press with a handle a few feet long. Then place a sandbag or a few millimetres of steel or Al between the work piece and you, even 1/4" of PLY would probably stop all shrapnel from a Al BC tube if it was at least 6" from the blast (too close and it takes the force of the blast rather than just the schrapnel).

[Zyklon_B]

Safety first! <img border="0" title="" alt="[Wink]" src="wink.gif" />

[Arkangel]

Fallout, the best gloves (but these will be expensive) can be found at abbotoirs, or any meat preparation factory. They have chainmail gloves, and sleeves (usually on the non-knife hand, but they cater for left handed people too) to protect against the inevitable slip of a knife. Put some leather gloves under these and you'd be sorted.

[Energy84]

Of course! Chain mail would be very good protection. My dad has a big (8' by 10') sheet of stainless steel chainmail :) Looks like I'm gonna have to start designing some new clothes <img border="0" title="" alt="[Wink]" src="wink.gif" />
I think that for a pair of chain mail gloves from a butcher would only cost no more than $10. At least that's what it costs here where I live.
Also, if you're very paranoid, you could use your half inch steel barrier but instead of trying to put a hole in it for a viewing slot, why not use mirrors? It would put you out of direct contact with whatever you're working with, but at the same time, it could also be more dangerous because it might take a while to get the hang of working backwards (with reflections).

[Arkangel]

Why does your dad have a huge piece of chainmail? (If it's not a personal question) :)

[Energy84]

He works at a french fry factory and they have a few hundred yards of the stuff to move the fries through the friers. It's really something to see.
They did some repairs on the conveyors though so he managed to score a nice chunk of it :)
He told me that it's worth something like $2000/ft <img border="0" title="" alt="[Eek!]" src="eek.gif" />

<small>[ June 14, 2002, 03:57 PM: Message edited by: Energy84 ]</small>

[J]

$10 for a chainmail glove? I think you'll be in for a shock; I've seen them at £90 each.

What's the verdict on kevlar gloves? I can get these for between £5 and £10 per pair. Will they provide protection against shrapnel, or are they just better than nothing?

A blast screen is something I intend to build before my next course of experiments this summer, moving up from wrapping the cap in a pair of jeans while charging <img border="0" title="" alt="[Eek!]" src="eek.gif" />

I'm thinking of building it out of mostly thick (3/4 inch) chipboard, with a viewing hole made out of several layers of 1.5mm Polycarbonate sheet. DBSP's box looks great, I think mine will be similar only smaller.

[Energy84]

Well, meatcutting must not be a very big business out there. I've seen chainmail gloves for $10. And they weren't cheap either. The rings were about 4mm round, nice and small.
As for the big sheet my dad has, I went to take a look at it today, and it's "woven" in a weird sort of pattern that allows it to flex no problem one way, but has limited flex in the other. Plus, it's really heavy shit! Our 8'x10' piece probably weighs in at over 300lbs.

[Arkangel]

The thing that worries me about a box like DBSP's is that it's enclosing to a degree. Magazines and factories have to have solid walls and light wood roofs so that any blast can escape in at least one direction. I like the idea of thick lexan or armoured glass to observe the work, but my construction is going to be completely open at the back side.

Another feature worth considering is something you will find on a grenade range, especially if you make a metal blast shield. Every surface facing the blast has a wood sheet covering. Basically that's to stop any shrapnel ricochets, since on inspection it seemed that the metel penetrated well into the wood, but didn't have the energy to rebound out.

<small>[ June 17, 2002, 01:59 PM: Message edited by: Arkangel ]</small>