That PVB blue.

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Pyro-Gear
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That PVB blue.

Post by Pyro-Gear »

Well here is an update on the PVB blue that has been proving very problematic.
Well I can say we now have working formulae and tests so far have proven very positive indeed.
Good clean burn, good burn rate, easy ignition and best of all its cheap!
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Re: That PVB blue.

Post by Boophoenix »

Cool Ken! You're just the energizer bunny of working one new formulas.
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Re: That PVB blue.

Post by richardh08 »

This was a joint effort between me and Ken, who has asked me to write up the results. As usual, Ken came up with the basic formulation and I just contributed the odd adjustment to the amounts.

Anyway, here it is:

KClO4 55
CuO 19
PVC 16
Sulphur 8
PVB 2

So far, we have only tested this as 10 or 11 mm diameter pumped stars, using IPA as the solvent. As is normally the case when PVB is the binder, you need to be sparing with the alcohol; add just enough so that, on thoroughly kneading the mix, it takes on a fairly dry, crumbly consistency. We don’t have a precise figure, but the required amount is around 8% of the dry weight of the mix. When ejected from a pump, the star should fall off the piston without leaving any sticky residue.

We have found PVC to be the best chlorine donor to use; replacing it with parlon gives a far poorer result. We have tried using CPVC, which also gives an initially good colour, but generates a lot of ash that rapidly disturbs the effect. We get identical results using either Mowital 30H or Mowital 60H, which suggests that any grade of PVB will be equally effective.

This formulation came about at almost the first attempt. I’ve tried one or two minor variants and found the effect on the colour to be minimal. It is possible that there is a tweak that will further improve the colour; if you find one, please let us know - we will do the same.

As with any blue, the presence of sodium as an impurity has a deleterious effect on the colour, so you need to make sure that the perchlorate is of good quality.

The stars ignite easily, so only a light prime of rough mix BP should be needed. The size of star we have tested gives a burn time of about 3.5 seconds.

Ken is a better judge of colour than me, and says he is well pleased with the result. It may not be the best ever blue, but we believe it to be at least as good as, or better than, many other published formulations. For a composition without any metal fuel, it appears to be quite bright. We suspect that to be due to the fuel qualities of PVB, even though only a small amount is present.
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Re: That PVB blue.

Post by Boophoenix »

Y'all are gonna laugh at me. I had the itch for some rollers no so started some of these rolling. It's my first experiance with rolling with PVB and so far so good. Hopefully I can a little more rolling in tomorrow and get to report back. It's hard to resist the blue's even when I'm sidetracked.

Had to give up a little of my pyro space to an associated new hobby that's had my intrest for years. From no hobbies to two in a few years where will the time come from.
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Re: That PVB blue.

Post by Pyro-Gear »

Good to see your giving it ago brad, let us know what you think.
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Re: That PVB blue.

Post by Lloyd »

I'll give you a clue, Ken.

He came to an FPAG meeting, then visited with me last month, and we did some 'joinery' metal-machining on his TLUD stack components, to make for field assembly/disassembly of the stack.

I'm around (iirc) 675 miles (1100Km) from where he lives!

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Re: That PVB blue.

Post by richardh08 »

Oh no! Surely not another deserter, distracted by the perfidious lure of machine tools :lol:
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Re: That PVB blue.

Post by Lloyd »

Hey! I resemble that perfidy!

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Re: That PVB blue.

Post by Boophoenix »

richardh08 wrote:Oh no! Surely not another deserter, distracted by the perfidious lure of machine tools :lol:
Oh, not a deserter! Just necessity so I don't have to lean on others as much for some of my crazy ideas. The recent trip to Caleb's in Missouri I got the stack to all fit together now it just needs a little fine tuning to get the sections to nest just a little more solidly. I can't find an inlet valve I like so I've slowly been pondering ideas to build one. It's part of the charcoal experiments that I've had on hold.

Poor Lloyd isn't she'd of me that easy. I still need his help for a couple of items. I wanna add temperature monitors to Brothe the TLUD and retort. The retort currently is planned to spin and cook via propane for easier regulation for beginning tests. I'm thinking about monitoring the pressure of the retort as well during the cooking cycle to see what variables that might play.

I've got to build a tap density tester since they seem kind of pricey to purchase. My first manual test gave the indication 50 to 100 taps may be necessary for accuracy with good consolidation.

Once the cooking is done I've got burn rate and gas production testing that will need items designed for.

Back on subject. I will certainly share what I find. If I can pull of quality stars from the formulas with my limited experiance then they are closer to field proven, lol. I tried my first round of cordless stars via the best idea I could come up with on the fly of some tips Lloyd's mentioned before. I think I am really liking the PVB it seems to be pretty forgiving with irregularities and recovers pretty well from them.

These are from Ken's roller. While not perfect and no sorting was done at all during the process to this stage I am very pleased with the results. There was quite a bit a variable in the cores as starting.
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Re: That PVB blue.

Post by Pyro-Gear »

Brad you will get variables in the first run and possibly the second it is just a case of screening out the good the bad and the ugly save them for another roll.
Looking at the picture what is that desiccated coconut stuff, is that a prime or a good old I phone picture, not a criticism but I am curious.
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Re: That PVB blue.

Post by Boophoenix »

Ken, that's the result of one last layer of dry comp added to the rolling process. The speckled look is the oxidizer after screening. Maybe it's a flaw in my processing of formulas, but I always end up with that. I could mill items, but commercial manufactures don't so I've been tinkering with leaving that step out.
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Re: That PVB blue.

Post by Pyro-Gear »

ok I must say you did a good job on the rolling. Using PVB you need to keep all chemicals as fine as possible perchlorate you can wiz up in a coffee grinder I suspect that’s what I am looking at, again well done on the rolling, great when no metals are involved.
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Re: That PVB blue.

Post by Boophoenix »

I liked it. The video shows a hint of green I didn't notice. Now I need some darkness to really see it.

https://youtu.be/bx232nEJqao
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Re: That PVB blue.

Post by Pyro-Gear »

Brad I can see a slight green tinge to the burn but the flame envelope comes across as being rather blue, the back ground on the test area is showing some sepia so I think it is a camera trick, get them in the air I think you will be surprised, nice job Brad.
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Re: That PVB blue.

Post by Boophoenix »

I'm "not" displeased at all with the color. May have to break the star gun in this afternoon.

Edit: Oops added Not
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Re: That PVB blue.

Post by Lloyd »

Huh? Boo... did you leave out the word 'not'? It doesn't make sense without it.

With it -- why would you 'break the star gun', when it rewarded you so well?

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Re: That PVB blue.

Post by Boophoenix »

I had some monocapa prime made up already and used it. For the first test. It destracted a little and the camera didn't do well either, but I was pleased. I pressed some stars up too, but still have to prime them. I'll try the basic BP prime on those they ignite a little easier it seems from tests with the trimmings from the plate.

https://youtu.be/kZS0g37TDzE
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Re: That PVB blue.

Post by richardh08 »

I've been thinking about the chemistry.

I believe that the green tip to the flame that you see in Bradley's ground test is real. I suspect it is caused by the production of CuOH (which has diffuse emission bands in the green, in the wavelength range of around 535 to 555 nm) as the flame interacts with the atmosphere.

I've seen this green emission in a lot of spectra of blue stars made with a wide variety of compositions and it seems to be one of the chief causes of a lack of colour purity. I suspect the only way to reduce it is to keep the oxygen balance strongly negative (which is, perhaps, why this formulation appears to work best with a fairly low percentage of perchlorate). However, if you go too far in that direction, you get problems with the burn rate.
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Re: That PVB blue.

Post by Pyro-Gear »

The air test showed that monocapa prime is way too hot or too thick, you can see that the blue ignited way before the prime had depleted, however the blue was evident and it looked rather good to me.
I would suggest a lighter coat of prime maybe some pinball would do the trick.
I have tested some of the stars with a shot tube with no prime and they still ignited, well keep up the good work guys.
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Re: That PVB blue.

Post by Boophoenix »

Maybe I'll get in from work in time to tinker some more. Without abusing the color with my prime choice, :-)
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Re: That PVB blue.

Post by Pyro-Gear »

Now we are in double figures temperature wise down south I will be testing some shot tubes with un primed blue’s should be fun!
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Re: That PVB blue.

Post by sambo »

That Blue is looking nice to me, its just the sort of baby blue I like.
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Re: That PVB blue.

Post by Pyro-Gear »

Ah yeah baby blue is a good way to describe it, I think we have a tiger by the tail here this completes our formulations, once we have the prime nailed we can move on to pastels an such like, I am going with pinball on the blue, ignition was instant straight from the tube, no prime failed 3 out of five no big deal I am working on it.
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Re: That PVB blue.

Post by Pyro-Gear »

Confirmation scratch mix works fine :D
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Re: That PVB blue.

Post by Boophoenix »

See what my follies caused, lol
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Re: That PVB blue.

Post by Boophoenix »

Got some scratch primed stars dryng to hopefully test tomorrow.
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Re: That PVB blue.

Post by richardh08 »

I took some spectra this evening. If they come out OK I should have some results tomorrow.
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Re: That PVB blue.

Post by richardh08 »

Well, here's the PVB blue spectrum that I took yesterday.

It was made with carefully recrystallised perchlorate, hence the sodium emission, at 589nm, is very weak.

I was wrong in an earlier post, when I identified the green emission as due to CuOH (which is, I suspect, the source of the three small peaks around 530 nm). The actual wavelength range is in the blue-green, from 475 to 509 nm, and I don't know what substance is emitting it.
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Re: That PVB blue.

Post by Pyro-Gear »

Excellent work as always Richard I think we have a good blue.
One thing I would like to point out is the perchlorate that was used originated in china and sure it did contain some sodium, the perchlorate was available to the EU some years back by a well-known vendor.
However things have changed the majority of perchlorate now comes from Italy so re crystallization is not necessary to obtain the true colour.
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Re: That PVB blue.

Post by richardh08 »

Here's the spectrum of the same composition, made with Ken's perchlorate, straight out of the container.

The perchlorate appears to contain less sodium contamination than the stuff I have, but there is still enough to be noticeable. The star's colour is still blue, but not quite as good as you get with really pure ingredients.

In general, all commercial perchlorate will contain sodium, left over from the manufacturing process. Except for (hugely expensive) reagent grades, it isn't cost-effective for the supplier to remove all traces.

To get a better idea of the differences, I calculated chromaticity coordinates from the measured spectra, with the following results:

For comparison, I included Cardwell's 'Photon Blue 1', (made with my purified perchlorate) which he claims to be "a stunning, bright blue that is almost equal to ammonium perchlorate blues". Compared with that, our best result appears to be a marginal improvement, both in its colour (very slightly bluer) and purity.

A word of caution: because of the unknown amount of processing carried out by the camera - with the intention of producing displayable images rather than an accurate representation of the amount of light falling on the sensor - the intensities in the measured spectra are highly suspect. Therefore, I wouldn't trust the absolute values of the calculated coordinates. However, all the measurements went through exactly the same process, so their relative positions are likely to be significant.
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Re: That PVB blue.

Post by Lloyd »

Well, then! That's a VERY narrow sodium band, so it's obviously just sodium making that peak...

I wish someone could afford to revert to the older methods of making it, rather than double-replacement from sodium salts!

On this ---
"A word of caution: because of the unknown amount of processing carried out by the camera - with the intention of producing displayable images rather than an accurate representation of the amount of light falling on the sensor - the intensities in the measured spectra are highly suspect. Therefore, I wouldn't trust the absolute values of the calculated coordinates."
-----------

Well, Richard! It looks as if it's time for you to invest in a photo spectrometer! :shock:

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Re: That PVB blue.

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Lloyd wrote:Well, Richard! It looks as if it's time for you to invest in a photo spectrometer
That's assuming I can find one that does what I want, at a price I'm prepared to pay. So far, no luck :(

At the risk of going off topic, I'm having another look at extracting data from Canon RAW (.CR2) files, which will allow me to apply as much or as little processing as I like. If that looks like it's getting anywhere, I'll start another thread somewhere more suitable.
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Re: That PVB blue.

Post by Pyro-Gear »

Hey anyone thought about using your eyes the blue is knockout, digital footage just don’t cut it, I know I shot 4 videos of the blue and there all deleted.
I have an old 35mm camera and a roll of film, these guys don’t lie so I will try that to get a still, that’s if I can find someone to develop the bloody film.
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Re: That PVB blue.

Post by Boophoenix »

I'm gonna take a few of what I have made up with me to the little gathering this weekend and hopefully talk them into trying some more along with other projects. We're going a day early to try to get some testing Inhope before the rest of the group shows up to get ready to start shooting.

I'll try to give some reports from onsite.
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Re: That PVB blue.

Post by richardh08 »

Pyro-Gear wrote:Hey anyone thought about using your eyes the blue is knockout
I totally agree.

I've had a similar problem, which is why I've concentrated on making measurements rather than relying on direct video records.
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Re: That PVB blue.

Post by Boophoenix »

I got one in the air tonight, but missed the video. It was a very nice blue much nicer than the ground test!

I've been trying to get another to record around the local traffic it's not been a fun experiance. I'm at a safe distance for the small stars but elevated out in the country. I never like distracting people driving down our dark road with any or my projects so I do them discretely.
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Re: That PVB blue.

Post by Pyro-Gear »

Well done brad it is a fantastic blue to the eyes, I agree with you on the safety issues great stuff.
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Re: That PVB blue.

Post by Boophoenix »

Couldn't get a recording before we loaded up for the road trip we're a hair over half way there. Maybe I can talk them into to rolling, rolling this afternoon.

If I can I'll see if I can Chris to share his thoughts with us since it's half his shop we're visitIng.
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Re: That PVB blue.

Post by Pyro-Gear »

Good stuff Brad hope your trip will be productive look forward to your results.
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Re: That PVB blue.

Post by Boophoenix »

People seem to like the Blue. Still need to get it in the air good but some burn tests and toss tests no one has complained.

Finished up the first part of the swimming stars and hoping to get the rest done in the morning and maybe get them in a shell by afternoon.
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Re: That PVB blue.

Post by richardh08 »

I think I have now got the extraction of data from RAW files sorted.

Interestingly, although the results are more accurate, and I can now get more meaningful values for the overall intensity, it doesn't make an ENORMOUS difference to the calculated colours. That's probably because I deliberately underexpose the spectra. The compression algorithms that cameras use have the greatest effect on high intensities, so I avoid the worst of what they do.

Anyway, the conclusion I have come to is that the results I quoted earlier in this thread are good enough, at least relative to each other.
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Re: That PVB blue.

Post by Boophoenix »

Well, not an excellent display, but some nice looking failures I thought.

This was a 5” meteor shell. The meteor comp is of multiple metal variations of Miller D1 I believe. The stars were Butter Popcorn with some mild metal alterations to a PVB core. The cores didn’t show well, but I tried. I have two more that are almost the same. The differences are just how stars are placed inside the hemis during construction.

https://youtu.be/iGzjAXXEFBs
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Re: That PVB blue.

Post by Pyro-Gear »

That was a nice shell regardless boo real nice strobe effect, I assume the PVB core was the blue?
On a side note what you think is a failure in your eyes is a success to the onlooker.
Regarding the cores did you put a changing relay over them.
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Re: That PVB blue.

Post by Boophoenix »

I wish I had gotten a better video a little lower since it looked like I planned a mine effect at lift.
Turned out better than I felt they might too.

I did not do a relay as I was gonna do smaller shell and wanted a full pattern of stars. Expecting that from such tiny stars I didn’t feel Inleft myself much wiggle room. Although a relay would have helped the blue stand out. I also had two sizes of cores I was keeping separated for a while then it became get it done time or wait and shoot them at 4F so they all went into the mix together.
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Re: That PVB blue.

Post by Adr2412 »

Good Afternoon.

Thanks for accepting me in the forum. As a thank you gift I will share here my PVB blue which works excellently I would say.

KClO4 61
CuO 8
COC 4.5
PR 7
PARLON 13
MgAl 3.5
PVB 3

MgAl is best protected with Potassium Dichromate if not using technical grade solvents. A minimum of water content is enough for the COC to attack the magnalium and the comp to start heating up.

https://www.youtube.com/watch?v=voE7vkM8MJU @ 02:04 is the blue in action.
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Re: That PVB blue.

Post by Pyro-Gear »

welcome to the forum Adrian.
I may be having a blonde day but what is COC, Copper oxychloride?
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Re: That PVB blue.

Post by Adr2412 »

Yes copper oxychloride
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Re: That PVB blue.

Post by Pyro-Gear »

Many thanks for the clarification, I will test the blue with a 20mm Crossett, I think that should look good if I get the break right.
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Re: That PVB blue.

Post by Adr2412 »

Beware the stars I give you get super hard if done properly. It might be challenging to get a symetrical crosette break. Largest I do with this is 22mm. Never done any crosettes. In here we complicate our life in other ways.
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Re: That PVB blue.

Post by Pyro-Gear »

For my Crossett super hard is what I would be looking for.
I have made a lot of Crossett’s but in 1 inch using phenolic resin.
Cross-linking the phenolic can be done at room temperature if you know what to use, if you have phenolic that has hexamine in it then I bet the PVB is doing all the work for you.
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