Polyurethane glue

[DeepOvertone]

I purchased some gorilla glue today and I'm going to try it out. They didnt have the elmers brand. The gorilla bottle says its now Stronger-Faster. So I'm supposing they've changed the formula a bit. Here is the link to the MSDS if anyone is interested in comparing this with the elmers brand.

 

http://www.gorillaglue.com/Portals/0/pdfs/...r%20English.pdf

 

Actually I just read that MSDS and they have allot of warnings regarding burning this stuff. Maybe I wont try it after all. Anyone care to advise?

[Swede]

This is good information Syalr and confirms what I was thinking... too hot for dangerous quantities of HCN. They say cigarette smoke contains HCN, along with about 200 other products. I'll bet cigarette smoke also contains Gold, platinum, Ru106 from old nuclear blasts, maybe a dash of Pu... several hundred atoms or molecules each puff. Smokers dont get poisoned because the concentration is too low.

 

Still, I'll not downplay the need to stay safe and limit exposure when you can to airborne dusts and chemicals. Things that are new in pyrotechnics should be approached with caution along 3 basic fronts... sensitivity, reactivity, and toxicity. I wil keep all of these in mind when experimenting.

 

With each new mixture, when it is put aside to cure, I am isolating two or three tiny samples the size of a pea, which I test for sensitivity before touching the larger samples. The mixtures with sulfur, iron oxide, and now coarse flake Al can be ignited with a very sharp hammer blow; the straight mixture, not so much. The sensitivity seems on par with other perchlorate mixtures I've tried so far, (aside from FP) such as perchorate BP in the standard ratio.

 

I'll take some vids of the new test samples.

[Swede]

http://www.gorillaglue.com/Portals/0/pdfs/...r%20English.pdf

 

Actually I just read that MSDS and they have allot of warnings regarding burning this stuff. Maybe I wont try it after all. Anyone care to advise?

From the MSDS...

Polymeric MDI* 9016-87-9 50-60

*Polymeric MDI is a mixture of 4,4’-Diphenylmethane-diisocyanate, isomers and homologues.

 

The 4,4’-Diphenylmethane-diisocyanate is identical to the stuff in Elmer's poly glue. As to advising you on this, well, it's your call. It's a big boy hobby and ultimately it's not for us to say. If you'd like, wait a while, I am going to continue researching and doing practical work with the mixtures. There's no rush. if I get sick, I have no one to blame but me. Tonight, I'm going to try launching some pieces from a star gun and see how they behave in moving air.

[Mumbles]

Burning black powder makes cyanide too. With these complex mixtures about anything possible to form will form, at least in minute amounts.

[justanotherpyro]

Actually I just read that MSDS and they have allot of warnings regarding burning this stuff. Maybe I wont try it after all. Anyone care to advise?

MSDS can make things seem more scary than they are. Please don't get me wrong, we have MSDS for a reason and its good to read it and know what is toxic and harmful etc...but even water has MSDS info that says "Lab Protective Equip: GOGGLES; LAB COAT"

[Swede]

Initial test of the Sr Carbonate mix... a rich, brilliant red. I will try a comparison with Baechle System 5 red, which I have the components for. Videos to follow.

[Swede]

I launched several nuggets from a star tube with 2 gramps of BP lift and had no ignition problems, but the lift charge was not severe, so there was probably plenty of contact between the burning lift and the star. Anyway, ignition may not be a problem.

 

From the mixtures of yesterday, some burn videos. Videos suck for color, and the automatic systems tend to close the aperature under severe lighting, so it is kind of hard to tell, but these puppies are too bright to look at from 5 feet away. As expected, the Strontium Carbonate was a nice red, and a leisurely burn. The 325 mesh iron mix threw some nice sparks. The Al mix, despite the coarse mesh of added Al, simply seemed to jack up the brightness yet another notch.

 

KCLO4 : Glue : additive

 

10: 3.2 : 0.9 325 mesh iron powder 3.2 gram sample

 

7 : 2.5 : 1.6 Strontium Carbonate, 2.6 gram sample

 

7 : 2 : 1 asstd mesh Al 1.8 gram sample

 

I'll try to get some video from the star gun, but I'm a bit concerned at the dryness in this area. The other important thing, I don't have all that much experience, so my ability to say "Deep Red" vs "washed out"; take it with a grain of salt. That is why I want to try the published red organic fueled star, side by side, and get a better grip on what I'm looking at.

[TheSidewinder]

Interesting results there, Swede.

The Red was very nice.

Ground tests are often misleading, but I think you need to speed up the burn rate if you intend to use this for stars. Otherwise they'll hit the ground still going strong, I think.

[ULTRABUF]

Wow those were great. I think you've stumbled onto something that is very useful and versatile. I especially like the SrCO3 sample, like you said the color didnt really show in the flame but looking at the ground around it you can see its a very nice red. If all your testing goes well I am considering using a mixture of this in a shell or two for the fourth.

[Swede]

I think you need to speed up the burn rate if you intend to use this for stars. Otherwise they'll hit the ground still going strong, I think.

Agreed. The samples were "dough drops" about 2mm in diameter. I need to test more with a star gun to get a feel for them. Nitrates rather than carbonates should speed things up. The critical task for me is to produce some traditional stars, so I have a better basis for comparison.

 

I'm also going to try a silicone rubber mold, and see if I can't cast a batch. A rubber mold can be made by securing dozens of round dowel stubs on a poplar board, creating a cardboard dam, applying some release to the dowels + board, and pouring the silicone rubber over it. This should leave dozens of female impressions in the rubber. The thinned comp can be poured right in, and should release nicely from the rubber.

[psyco_1322]

Just keep in mind that with a lot of solvent in you mix the pour stars will shrink and could have cavities form in the middle of them from the evaporation of the solvent.

[tentacles]

I wonder about using the two part polyurethane casting mixes availible at art supply places (such as artstuf.com). Would one part of a two part mix work, or would it never cure (ala epoxy)?

 

Gorilla glue is a bit pricey for a lot of pyro applications, but the 2 part stuff is considerably cheaper pound for pound. Is the resin available in a cured form, like a powder or flake, that can be dissolved with a solvent?

[Photon_Junkie]

I did some more research but since I am at work I cannot link the web locations.

 

Basically, searching the web for combustion products of 4,4 MDI or 2,4 MDI will get you quite a bit of data.

The significant thing is that burning (even at what they consider high temps) you generate between 2,000 and 5,000 ppm of cyanide (CN). Foams are worse than adhesives gram for gram. Obviously a smoldering fire is slightly worse than a hot fire. Again, I do not think they were considering fireworks here, more what happens in a house or car fire.

 

I would agree with the earlier posts that in the presence of burning metals, and all of the reactive species of fireworks, the formation of CN is not too worrisome. I think the CN species would either get further combusted or form a complex with another exotic combustion species.

 

However, I would really like to go on record saying anyone doing "indoor fireworks" or stage stuff...just stay away from urethane binders.

There now that was said...I can sleep at night, not worrying...Again, I swear I am not being preachy or a "know-it-all"; I have nothing but respect for you folks.

[WarezWally]

Personally, why risk it?

 

Safer alternatives exist, while they may cost more is it really worth bitching about. I would rather be a bit poorer and safer.

[Swede]

Photon Junkie, I'll say thanks again for being concerned and pointing out possible dangers. I would NEVER resent someone with more experience pointing out "Hey, that could be dangerous!", I would only appreciate it.

 

I have some thoughts on testing the combustion by-products for later.

 

I am going to continue experimenting, but I will avoid flooding this board with massive numbers of posts on this topic. I wish I had more experience with pyro - then I could draw more meaningful conclusions that you guys could trust. My next step in this is comparison of color and brilliance with known formulas.

 

I will say this - I tested again another nugget of the strontium mixture, about a gram, kidney-bean sized, late last night. This mix has NO metal in it, yet I could not look at it, it was so bright. It illuminated a huge area in a deep, red glow. I made it into the house with sharp retinal afterimages. There's something going on here, worth exploring, I think.

[GalFisk]

This is interesting, theat red is gorgeous. Wonder if it would be possible to get a good green with only barium carbonate and a chlorine donor, and what effect chlorine would have on the red.

Blue probably wouldn't work because of the high temperature, but it would still be interesting to see what copper compounds do to the flame.

[psyco_1322]

Well the glue I mentioned is not polyurathane based I believe. It does have a liquid resin that can be thinned with even alcohol, the catalyst is powder. It does contain formaldehyde and according to the can is cancer causing < but hell what doesnt have that on it now days.

[DeepOvertone]

I just wanted to let everyone know. I tried this with gorilla glue and it does work and burn well. I dont think its as bright as swedes glue. I lit some last night in the dead of night and it casts a pretty good light but I've certainly seen things the same size put out wayyyy more light. It had a yellowish hue to it also. Not quite pure white. I'd guess around 4300K. I did put sulfur in there though. Did the sulfur dull the color for you swede? Do you think that the red formula is so nice because the polymer is donating chlorine? I'm going to try adding a small ammount of magnesium. I'm hoping there wont be any kind of decomposition reaction from the Mg so I'm only going to make up a gram or two to test.

[Swede]

DO, I have not tried it with gorilla glue. I suspect there may be ingredient differences between the two. I am in the middle of 3 very full days of "real" work and haven't been able to experiment more, but my next shopping will be for various Poly glue brands, including gorilla glue, to give them a try, and note any differences.

 

Was your KClO4 milled ultra fine, and did you get a really thorough mix? I found with less than optimum mixing, the burn is uneven. What ratio did you try? The color of the straight mix does have a slightly yellow cast. The only aluminum additions I have tried was with coarser flake, not superfine pyro dust, but that did whiten the burn significantly. I will eventually try added German dark Al, but when I do, I want to be extremely cautious, testing minute portions for sensitivity.

 

The dried "stars" are, I think, as unreactive as can be, in the sense that the oxidizers and additives are bound in a solid plastic matrix. They are incredibly strong, and require heavy wire cutters to cut samples, which makes me nervous and is a bad idea, so you might want to portion the blobs while still soft. Water won't touch them, and a long bath in acetone did nothing. Dried out, they behaved normally.

 

As I mentioned, I am going to try some non-metallic red star comps from passfire, and do a side by side comparison, both on the ground and from a star gun. When the star gun is set up, I'll get some more video as well, from a bit more distance, to get a better perspective.

[DeepOvertone]

My mixing was really good but it wasnt milled as fine as possible. I'd guess my kclo4 was around 400 mesh but I could definitely get it finer in a cofee mill. I might try that later. It burned very evenly and smoothly. Im going to do some more experimenting too and I'll let everyone know how it goes. I want to make some kraft tubes only a few layers thick and around 1" ID. I'm gonna find a formula that burns brighter and make a type of ground flare. I'm also interested in trying this in a tube with a nozzle. I dont think it will be powerful enough as is to be used as a rocket fuel. It will need a little bit of speeding up. BTW the formula I used was the one you posted on the first page of this topic:

 

20 grams KClO4, milled

6 Grams Elmers "Ultimate Glue", Polyurethane

0.5 grams Red iron oxide or sulfur

 

Of course I was using gorilla glue vs the elmers, and I added the sulfur instead of the iron oxide.

[Swede]

Of course I was using gorilla glue vs the elmers, and I added the sulfur instead of the iron oxide.

I used both red iron oxide and sulfur to try lowering the ignition temp a bit. Both of them seemed to do just that, but did not seem to acclerate the burn. Airfloat charcoal seemed to work really well (for ignition) but I think I added too much charcoal in an earlier test batch, and I reduced the amount of glue, basically a fuel swap. Probably 75K:15G:10C. It burned, but not as brightly as the straight mix. I'm going to try something more like 75:21:4 and see if the charcoal improves the mix.

 

As far as ignition, I'm not as worried as I was earlier. Even unprimed stars ignited in a star gun. If prime is needed, nothing could be simpler - roll the balls in meal, or simply sprinkle on some granulated BP. Since the comp is a glue ball, the BP sticks instantly, dries in place, and will not come off.

[jacob]

Swede, that red looked great! even in daylight, can you post the ratios you used? I'd like to try it with Barium carbonate.

[Swede]

Sure Jacob. The ratios in the video were

 

KClO4... 7

Glue... 2.5

Strontium Carbonate... 1.6

 

I have probably mixed 30 batches of test samples, trying to learn about this material. To compare, I also created some standard organic red stars (Bleser KP #1) from a Passfire formula, which I pumped.

 

The handling of the wet mix presents challenges and opportunities. It is left to the imagination to find the opportunities and benefits.

 

Benefits: A given mass of this mixture burns longer, and puts out more light, than the Bleser. So far it is relatively benign to work with, allows incorporation of all sorts of metallic additives, and cures, ready to fire, in a few hours. Once cured, the material is indestructible and waterproof. Even Acetone doesn't touch it.

 

Challenges: The uncured mass is almost impossible to handle. It sticks furiously to ANYTHING except waxed paper. Once cured, it is very difficult to cut the thicker chunks into smaller pieces, and a bit scary to do so.

 

Some thinning is required in the initial mixing, just a ml or 2 of MEK in a 10 gram batch. This will give an epoxy consistency. Mix with a wooden stick until uniform. It will look like a liquid "Bit 'o Honey" candy piece (I'm showing my age there!) If mixed thick, and not further thinned significantly with MEK, about all you can do is spoon it onto some waxed paper and let it cure. About 1/2 way to a cure, you can take a knife and score it into cube shapes. Once fully cured, you can separate the pieces easily, they snap apart. They expand and gas slightly, and the cubes are porous. Using MEK rather than acetone keeps them denser, and allows easier manipulation while uncured.

 

I've pondered on how to deal with this stuff. I really think there must be some unique applications; just need to figure out what they might be.

 

The mixture in the cup can be thinned to about maple syrup consistency. I've not thinned it past that, but I have yet to have a thinned mix NOT cure fully.

 

Possibilities: I've stirred in some cotton string and made a really potent match. Cut pieces of string could become stars, or falling leaves... a 1" piece burns about 4 seconds, but would have crappy aerodynamics. I've poured the thinned mix onto aluminum foil, spread it out very thin, and cut strips and pieces of that. It burns brilliantly. I'm not sure if the aluminum is burning, but there is nothing left when the burn is complete... it is definitely melting at a minimum. Kraft paper, same deal.

 

Maybe the aluminum strips could be incorporated into another comp. You could coat the aluminum foil with color-changing thinned mix, part strontium, part barium. You could pour this stuff into small spolette tubes, or larger tubes. I have not experimented with this (confined burning) yet. It could perhaps be used as some sort of super-prime with BP mixed in to promote ignition.

 

I'm curing a few more test samples with other additives, with appropriate caution. One final note, I bought three different polyurethane glues and tried them all - Gorilla glue, Gorilla Glue "quick cure white, and Elmer's "nano" glue. The Elmer's nano works best. The GG works OK, seems to expand more than the nano. The GG White DOES NOT WORK AT ALL, so don't even try it! So there does appear to be some differences in the glues.

 

Any thoughts on the application of this stuff? I'm wiling to try just about anything.

[ActionTekJackson]

This is definately very interesting, I did some tests a while back that are very similar. There is a rocket composition using AN and clear polyurethane, the kind you put on wood for a good clear coat. I was trying to substitute AN for Potassium Perchlorate. I have some nifty software that I can put in amounts by weight of chemicals and it will give me a simulated rocket performance/burn rate/ISP. The best ratio I came up with via the software was 89K:11PU it was a bit on the dry side to work with but once it dried it was like a rock. Burn rate was a little faster than what it appears yours is in your video's then again the glue may have different aspects to it to affect that. I may have to go back to testing my old formula, I'm thinking reduce the oxidizer and increase the fuel a bit and test to see if the software was really correct or not. You've really made this topic take off swede :-) I'll be keeping a close eye, very interested :-)

[bmarley5780]

Passfire members:

 

I think this could be applied in the "color to report" inserts for a cake

 

or a go-getter...?