Gerb Questions

[grimreefer24601]

I'm really starting to love this forum. There's so much information on pyrotechnics and fireworks. I'm not seeing a whole lot about gerbs. Maybe I'm missing it, or most people are into shells more than gerbs. I get that, I'd like to make shell too, but right now gerbs are what I'm working with, and I have a few questions along that topic.

 

How do you deal with dross? I have a couple of mixtures that buildup a lot of dross. These mixture end up being my family's favorite. Will layers of meal D blow the dross out? It's mostly my Magnalium mixes that produce a lot of dross.

 

I did have one gerb that I think the dross made a better effect. Any tips on using dross to our advantage?

 

Along the same lines, my colored mixes seem to be too hot for my tubes also, they burn out the sides. These mixes don't exhibit dross on examination. Can I add something to the tubes to prevent burnout, and would that be safe?

 

Can star formulas be converted to gerb formulas?

 

I know stars can be added to gerbs. What size of star to nozzle size? Can you ram/press stars, or will that crush them?

 

Any idea on what a loose/ non compacted gerb formula will do? Will it blow up with the added airspace? Are there some compounds that work better loose?

 

Can Dragon Eggs be used in a gerb?

 

Any answers, tips, or suggestions are greatly welcomed.

[OldMarine]

My first gerbs hand rammed with spherical Titanium in 1" tubes:

 

 

[grimreefer24601]

I don't go that big OldMarine, but one of my families favorites is the spherical titanium. I'm just running 5/8".

 

I think they like the glitter that creates a lot of dross best. Titanium sphere next. And the strontium nitrate/titanium third.

 

Does a larger tube reduce dross, or does the extra material in a larger tube equal it out?

[OldMarine]

I've found that the larger tube and orifice lead to less build-up and ejection of dross. For colored gerbs,even with metal, they do better in smaller tubes because they burn damned hot and burn through more quickly.

[grimreefer24601]

Yeah, that seems to be what my tests are showing too. Is it possible to use something like HDPE in a gerb? As the Tube?

 

Whats your favorite gerb formula OldMarine?

[grimreefer24601]

Will a Black Powder Titanium section be enough to displace nozzle dross? Big sparks and clear the nozzle?

 

More important, will my titanium mix be safe with my glitter mix? I'm going of to find out.

Edited August 21, 2016 by grimreefer24601

[OldMarine]

I love the Westech Silver Gerb formula. This is a noisy raucous comp that nobody can ignore! I press it in 1" tubes using Wolter's tooling and support and WOW!

 

Titanium doesn't react too badly with other metals or oxidizers so it's probably the only "safe" metal we deal with.

 

All that being said, take care hand ramming any metal and wear a leather glove on your cradling hand along with a face shield. Safety glasses are a placebo..... you'll feel safe until a pile of comp blows up in your face.

[grimreefer24601]

Thanks OldMarine. Can you point me to the Westech formula? Is it listed here on the site?

 

My search only shows this thread.

 

I love my tools from Wolter.

Edited August 21, 2016 by grimreefer24601

[otto]

This one OM?

 

Silver Fountain/Gerb:

 

Name: Degn, Niagara Falls

Source: Westech

 

 

Chemical - Parts by Weight

 

Potassium Perchlorate - 8

Aluminum, flake, flitters, fine 100-325 mesh - 2

Red Gum -2

Aluminum, flake, flitters, medium 16-326 mesh -1

Aluminum, flake, flitters, coarse -20 Mesh - 1

 

Notes: Use in unchoked gerb case, typically suspended above the ground from a line in a long row of gerbs pointed toward the ground.

[OldMarine]

This one OM?

 

 

Silver Fountain/Gerb:

 

Name: Degn, Niagara Falls

Source: Westech

 

 

 

 

Chemical - Parts by Weight

 

Potassium Perchlorate - 8

Aluminum, flake, flitters, fine 100-325 mesh - 2

Red Gum -2

Aluminum, flake, flitters, medium 16-326 mesh -1

Aluminum, flake, flitters, coarse -20 Mesh - 1

 

 

Notes: Use in unchoked gerb case, typically suspended above the ground from a line in a long row of gerbs pointed toward the ground.

 

No, it's a simple BP formula with the addition of a sparkling metal. Though I'm sure the formula is available elsewhere, I can only find it on FW and therefore am reluctant to post.

[grimreefer24601]

No, it's a simple BP formula with the addition of a sparkling metal. Though I'm sure the formula is available elsewhere, I can only find it on FW and therefore am reluctant to post.

I think most of us are trying different metals with BP. My main mix calls for Iron, but I've used Aluminum, titanium, and magnalium.

 

I have a lot of recipes, I'm more curious about your preference. I've read a lot of your posts.

 

I don't know what you mean by FW, is that the FireWorking website?

 

I know that's a pay site. Do what you feel is best.

[Mumbles]

Degn gives a couple of related formulas in his book. I've used both below, and they're quite nice. For what it's worth, when searching for Westech formulas, it's often attributed to the author Ralph Degn rather than the book itself.

 

KNO3 - 6

Airfloat C - 1

Sulfur - 1

Titanium - 3

 

KNO3 - 6

Airfloat C - 1

Sulfur - 1

Coarse C* - 0.5

Wax coated Steel - 2

 

* - I used -80 mesh in smaller gerbs. Larger ones may be able to handle a coarser material.

[OldMarine]

Well Mumbles hit it out of the park with the first formula. I realize it's simple as pie but it wasn't my recipe! Up the Ti to 5% and make sure it's 30-60 mesh and say Wow!

[ddewees]

Adding a "bounce" at the end makes for a great effect. Just toss in some loose 2fa and maybe a few stars.

 

[Video]

[grimreefer24601]

I was looking at Mumbles post, and that seems to be what is listed in my "Introductory Practical Pyrotechnics" as 'Iron 1'. The "Iron 2" uses quite a bit less metal powder, but seems about equal in my tests, and metal is kind of expensive.

 

KNO3 - 2

Airfloat C - 1

Sulfur - 1

Metal - 1 (I've used steel, aluminum, magnalium, and titanium)

Meal D - 6

 

That might attract attention where I live ddewees, but it looked pretty cool. Maybe on the Fourth when everyone here is going crazy.

[ExplosiveCoek]

Ddewees, how do you prevent the 2FA from not getting crushed/smashed whatever during the pressing of the gerbs? Nice effect!

[Mumbles]

This is a lot of questions, but I'll try to hit on a couple of them. There are a lot of different causes for dross. Some are easier fixes than other. Some of the simple things are to make sure your nitrate is finely ground, and that your compositions are well mixed. Adding in some meal powder to the formula can help with cleaning up the burn and preventing dross from building up. It doesn't always take a lot, 5-10% can do the trick. Along the same lines replacing some portion of the KNO3, C, and S with meal can help. I'm not sure what sort of tooling you're using (homemade is just fine for gerbs), but using a rounded rammer or a convergence on the interior of the gerb can help to funnel hot gasses, sparks, etc. out of the fountain, instead of getting stuck inside.

 

Stars inside of gerbs are fairly easy. One of the easy things to do is to make "mouse turd" stars. http://www.wichitabuggywhip.com/fireworks/mouseturds.html This are good for smaller fountains. Bigger fountains can use bigger stars of course. Adding a thicker than normal prime layer is one trick to get more out of them. That way the actual star comp doesn't start burning until it's out of the tube, instead of potentially being partly or totally consumed inside. You can ram or press them without much fear of crushing them. The rounded rammer or convergence really helps the stars to exit the fountain. I usually only make larger fountains with stars in them, but they're sized about 50% smaller than the diameter of the nozzle. 1/4" stars in gerbs containing about 3/8" chokes. Kyle Kepley on passfire.com has a wonderful microstar gerb tutorial I'd suggest checking out. Passfire isn't free, but the tutorials are fantastic.

 

As far as tight or loose, I'd compress the fountains with no less than body weight. This gets them firmly compacted. I've never really had much of an issue with them blowing up or behaving oddly. I don't know if there's anything that works better more loosely compacted. I know John Glasswick's gerb compositions are pressed with body weight in the instructions. I believe I've done some unchoked glitter gerbs hand pressed as well with good results.

[ddewees]

Ddewees, how do you prevent the 2FA from not getting crushed/smashed whatever during the pressing of the gerbs? Nice effect!

I press fountains to 2000 psi, and it has no effect on 2fa or stars in the bottom. I just put a paper liner between the comp and the clay at the end.

[OldMarine]

At the recent company picnic I lit of a couple of rows of gerbs. The first were ¾" color changing ones without a bounce. I received plenty of oooohs and aahhs on those.

The next row were 1"titanium gerbs with a healthy bounce in them. These drew cheers and foot stomping!