24 replies to this topic

[cooperman435]

I've managed to find resorcinol/paraformaldehyde 2-part resin from a uk supplier but postage is a little excessive and is the same for 1kg as it is for 100kg! Id like a few kg to experiment with myself so if anyone else would like some, it'll work out much cheaper to get 5/10kg or more sent to me, for me to distribute.

If i get 5kg it will be about £16/kg. 10kg will work out £14.60/kg. Obviously cheaper if I get more.

If anyone wants some to experiment with then please EMAIL ME not pm me, as I loose track of pms and replies to them.

Phill

Edited by cooperman435, 11 February 2008 - 01:44 PM.

[YT2095]

You probably already Know, but it`s worth a mention anyway, that quite a few resins generate considerable Heat upon curing, perhaps it would be Wise to test this out on a small scale 1`st before committing to a larger production?

[Arthur Brown]

The less viscous resins permit the use of small proportions as binders so are thermally stable during the cure exotherm. Using the usual viscous resins that come as adhesives then the exotherm is significant in large items but not in the small items I have so far tried.

The biggest problem with the viscous resins (Araldite etc) is that they are very hard to incorporate sufficient powder in. So even a highly oxidised mix is hard to light and burns incompletely.

Seems to be a lot in favour of the water thin resourcinol resins. Dry mix the compound then damp with 5 - 10% of resin and cut or pump. As large star/comets there should be no drying problem as they harden throughout the thickness rather than from the surface.

Cooperman has found a source!

[YT2095]

that`s fine, but you STILL need to establish (small scale) whether or not there will be Side reactions!

you are afterall introducing New Chems into the formula, would you not agree?

[Arthur Brown]

Agree entirely! the 1gram product was stable for the first week, so I fired it, good start but not perfect. The the 5g test piece was made -hardened in 24hours staying cool, (prob too cool!). Still sitting there no change in size shape or appearance after 5 days. In a few days I'll test fire one of these and keep the other for long term stability observation. If the 5g test is good then I;ll prob try a big piece say 25g in case there are unexpected trends on scaling up! Yes I'm looking at getting this made into some 18mm comets for 19mm tubes.

I like the idea of resin as thick sections can be cured through rather than from the outside. Also the curing produces a water-resistant product so there will be few ill effects if the thing gets damp

[cooperman435]

As far as I have been informed and read there is slight heat given out during the drying process but due to the small amount of resin needed to bind a composition it is low amounts, also it actually helps to have them slightly warm during the curing process and the heat should never get close to a point where it could be an issue.

Ive only had 2 people contact me about this so far which Im alittle suprised at. Surely someone fancies trying some new binders out and making something new? It could be the new thing?

Edited by cooperman435, 02 February 2008 - 03:27 PM.

[Arthur Brown]

Actually I think resin formulations are current practise in the pro fireworks industry - especially as the compounds in dextrin etc are much more susceptible to dampness than in resin and almost all fireworks come by sea from China -that's 10 weeks at 100% humidity. Also any insert that burns completely has an advantage over inserts that dump bits of card and clay all over the firing site.

Post 15 above actually mentioned having some devices drowned in water the propellant was black soup but the stars actually lit from a fuse -that's not dextrin or shellac!

Edited by Arthur Brown, 02 February 2008 - 04:36 PM.

[cooperman435]

Ok for those who did contact me about this I have now got some 2 part 5/1 ratioed resin. Ill have 2.4kg left after the people who asked for it have had theirs so if anyone wants some please contact me.

Price is £15.10 per 1.2kg which would be 1kg of resin and .2kg of hardener.

If anyone had had previous experience then please give me a starting place a sto the use of it for a binder or can I just replace the current binder with this?

[pyrotrev]

I tried resorcinol resin binding some Win 20 glitter comets, worked OK. The viscosity of the resin was a bit of a problem in trying to distribute it evenly through the composition, it certainly needs to be thinned (I used 1:1 EtOH, but will try acetone next time) to ensure even wetting at low concentrations when used simply as a binder, however if you were using it in larger amounts as a fuel and binder in a colour mix or propellant, you might not need to do that. Ignition (no prime) was fine, stars were hard after 12 hours cure, and it didn't seem to affect the glitter unduly: I shall try some more!

Edited by pyrotrev, 28 February 2008 - 06:58 PM.

[Bonny]

I tried resorcinol resin binding some Win 20 glitter comets, worked OK. The viscosity of the resin was a bit of a problem in trying to distribute it evenly through the composition, it certainly needs to be thinned (I used 1:1 EtOH, but will try acetone next time) to ensure even wetting at low concentrations when used simply as a binder, however if you were using it in larger amounts as a fuel and binder in a colour mix or propellant, you might not need to do that. Ingnition (no prime) was fine, stars were hard after 12 hours cure, and it didn't seem to affect the glitter unduly: I shall try some more!

There is some info on using resin binders that may help here:
http://www.apcforum....s...c=1313&st=0