36 replies to this topic

[BrightStar]

a_bab - Thanks - too many Dans

Interesting the PVB is working for you. I've heard of its use as a superior pyro binder before. It works well but the cost is usually prohibitive.

Looking it up on Wikipedia, Vinyl Resin is the monomer that is polymerised into Polyvinyl Alcohol (PVAl) then reacted with Butyraldehyde to form PVB. I've never really fully understood whether these binders (or even simple PVAc wood glue) set by polymerisation, simple evaporation of the solvent or a mixture of both.

Edited by BrightStar, 01 December 2010 - 10:01 AM.

[a_bab]

PVA glue is an already polymerised PV acohol. It is sold in the form of an emulsion in water; once the water evaporates it sets hard. If the glue is kept in cold it will precipitate the PVA droplets in solid form. This is the same reason why it will only glue water absorbent objects and not plastics, since these won't let the water evaporate. Also the reason for it's shrinkage during drying (a problem sometimes).

[BrightStar]

Interestingly, the 'Vinyl Resin' solution sold by Firefox is advertised as:

clear sealant - self curing - 40% butyrate - thick solution - very elastomeric

I wonder if there's a UK source available...

[helix]

Interestingly, the 'Vinyl Resin' solution sold by Firefox is advertised as:

clear sealant - self curing - 40% butyrate - thick solution - very elastomeric

I wonder if there's a UK source available...

you can buy mowital from Kremer or conservation resources:

http://www.conservat...products_id=584

[pyrotechnist]

BrightStar, this is Dan Williams and not Dan Creagan. Moreover that particular compo comes from a booklet sold by Firefox as Dan clearly states in the page. I wish I could get my hands on that book since it contains many fuse formulas. Anyone?


I'm currently trying to reproduce this thermalite fuse, but since I can't order anything from Firefox I did my homework a bit. Vinyl resin is actually a solution of PVB (polyvinyl butyral, same stuff laminated between the windshield glass panels). Firefox also sells PVB granules and they recomend to dissolve 40% in toluene or MEK. Toluene unfortunately DOES NOT dissolve this stuff period. I noticed it in the product sheet from one of the manufacturers where it's trade name is Mowital after waiting more then a week with no signs of dissolving. However adding some 15% of alcohol solves the problem. But toluene is toxic and a human carcinogen so I dissolved my harvested stuff from a broken windshield in iso propanol, but anything over 10% gells up. The ideal concentration is 8%, where it looks like honey, only transparent. The beauty is that the windshield PVB sheet is already full of plasticizers, so no more dibutyl phthalate is needed. That turns the formula into a trully OTC one.

The homemade thermolite could be made to burn in different colors and it's very energetic, just like visco: pieces of it once ignited tend to rocket away. So this is homemade flying fish, only better (bright with large flame). To whatever thickness you want. Magnalium can replace magnesium. Easy to make. With a hefty coating I bet it'll burn in a very precise manner with (probably) easily reproductible results.


A tutorial is on the way in any case for this thermolite along with several recipes. It'll be done by January the latest.

Once you get your PVB solution do you then add the other ingredients, minus plasticiser in your case, to the mix? or just use as is. Could colemans fuel be used to dissolve the PVB by anychance?

[a_bab]

I haven't quite got there yet (adding the components to make the slurry). Coleman fuel may work, but I'm not sure. Absolute ethanol works great, and so does acetone.

[Deano 1]

For the people that wondered if latex was any good for a coating, the answer is no. I dipped a length of blackmatch in latex, let it dry for two days, stripped four inch of rubber off just to make sure the blackmatch was dry and burnt properly. The latex melted and extinguished the fuse.