Mystery of star solvents

[Merlin]

Please correct me if I am wrong. There are hundreds star formulas available and they are all either pumped, cut, or rolled. If a formula contains dextrin or SGRS and whatever else then the solvent must be water or water/alcohol. If it contains parlon and red gum then the solvent could be acetone or alcohol. Is this generally true? I have observed the basic formulas are usually given without reference to the wetting agent. Thanks for your comments.

[rogeryermaw]

depends on which chemical is being used as the binder. many formulae contain multiple chems that could act as binder such as some containing both red gum and parlon. if the binder is red gum, alcohol works well but the parlon won't dissolve. parlon dissolves in acetone. both of theses chems may be present in a formula with dextrin and dextrin may bind with water. just depends on the formula and the way you intend to use it. the combinations and possibilities are endless.

[Carbon796]

That is pretty much true. With SGRS you should only use water. With dextrin you can use water with up to about 30% denatured alcohol as a maximum ( less would be better 5-10% or none at all ) for cutting or pumping. With rolling you can use more alcohol when first starting cores, but thats another subject. When using water it should be distilled water.

If a formula contains enough Red Gum, Shellac, Vinsol resin, or phenolic resin it could be bound with alcohol, or possibly acetone. For formulas containing enough Parlon acetone could be used, but not alcohol.

Generally speaking if a formula contains SGRS, Dextrin, Wheat Paste, or Starpol it is meant to be water bound. Though you could use a different component of the formula to bind it with if you wanted.

If your just starting to make stars, I would recommend starting with water binding until you develop a "feel" for making stars. It seems like most formulas listed on the Internet aren't really that detailed, where as formulas found in books are a little more detailed in their correct use.

Edited August 22, 2014 by Carbon796

[nater]

Carbon, if a formula calls for wheat paste, it is to be bound with mixed wheat paste. These formulas usually include dextrin as well and both binders play a role.

[Carbon796]

Very true Nater. In hindsight I should not have included it in that limited list of binders, with out a better description of its use. The only use of wheat paste with out a secondary binder that I can think of off hand. Would be for the manufacture of Rosettes and possibly a flitter or firefly formula. . . Edited August 23, 2014 by Carbon796

[nater]

Even firefly the dextrin is better left in the formula. I have tried cut firefly stars with and without dextrin and bound with paste. With both, they cut fairly easy and fairly hard. Without the paste, I had a hard time wetting and cutting the comp. Without the dextrin the dried too soft.

 

Rosettes might be the only excpetion I can think of off the top of my head. Of course their construction would not be recommended for someone still learning about binders and solvents. I have wanted to make a rosette shell to see the effect, but have not wanted to granulate that comp.

[Carbon796]

Rosettes might be the only excpetion I can think of off the top of my head. Of course their construction would not be recommended for someone still learning about binders and solvents. I have wanted to make a rosette shell to see the effect, but have not wanted to granulate that comp.

I know what you mean, it's also on my list for later this year, or early next season.

[Arthur]

Industrially the solvent will be water for economy reasons, (kilos of water cost a LO|T less than kilos of acetone or alcohol) AND for safety reasons (Acetone and alcohol fumes will carry a long way and can flash back to the mix given an ignition source).

[Mumbles]

Rosette mix is the only composition I have left after my accident. It really does require wheat paste. I tried to use SGRS as another formula suggested. It didn't mix at all until I added a touch of alcohol, and then it turned into a soup. Classic case of over wetting. I ended up making 3x or 4x as much as I intended. When I get back to building, expect to see a lot of them.

 

Everyone basically covered the solvent stuff. The screen cut stars and everything are cute, but don't make sense when you get into bigger shells. It's basically water for everything that doesn't require NC lacquer. I am interested in phenolic though. There seem to be some applications it legitimately would make sense over water.

[Ubehage]

May I ask, what are the safety-levels of using the different solvents?

I want to make fountains and other effects, where I'd like to be able to press my mix like a dough, and let it set.

And I am under the impression, that it is generally a bad idea to mix aluminum with sulphur (BP) and water. Is this correct, and if so, would Acetone be safe to use?

 

Sorry in advance, if this is a stupid question.

[pyrokid]

The problem with pressing wet composition into tubes is that the drying time increases dramatically.

 

Acetone could be used to wet a BP and AL mixture, but there isn't any acetone-suitable binder in that composition, so the binding effect would be limited. Acetone is often used with star compositions that contain parlon, as the parlon is dissolved by the acetone.

 

In my experience with BP that is wet enough to be considered dough like, pressing it causes excess water to come to the surface of the mass of composition, which causes a big mess.

[Ubehage]

Thank you for the helpful answer.

When it comes to drying time, I have been inspired by some chinese factory videos, and I will get myself an old oven, and start experimenting with temperatures and drying times.

I will post my experiences, good or bad, later.