Wheat Paste as a Binder

[Wiley]

I have finally amassed all of the basic materials needed to construct proper Italian-American mulitbreak cylinder shells, with one major exception: dextrin. Since I only need a pound of it, and nothing else, I really don't feel like paying about $15 shipped for a chemical that's supposed to be under $5 a pound. I've read Dan Creagan's mini instruction thingie on making dextrin from corn starch, but I've also heard that this gives inconsistent and inferior results. If this is not true, please enlighten me. Corn starch is cheap ​ .

 

However, if it is a fact that the baked corn starch method doesn't work as swimmingly as the "real stuff," what about using wheat paste as a binder? I know that thinned wheat paste is used to bind many cut glitter comps, so I don't see why it couldn't be used for "regular" charcoal streamers or rough powder. If the wheat paste is prepared by boiling flour in water, what is the optimal ratio for this application? Once the wheat paste is actually made, what percentage by weight should be added to a rough powder or charcoal streamer composition?

 

 

[ollie1016]

Baked corn starch is more than adequate for shells. Wouldn't use it for firearms. The baked corn starch is not as strong as commercially made dextrin, but it's a very good substitute.

[nater]

I tried converting corn starch into dextrin by baking early in and had terrible results. The resulting binder was weak, but the smell of the starch baking was terrible. It raised a huge objection from my wife which made further attempts a bad idea. Dextrin is cheap, so next time you order chems, just don't forget it.

 

You will need wheat paste anyway for cylinder shells. I usually use some wheat starch that you can just mix with water in a blender without cooking. Dick Blick art supplies is a website where you can order wheat paste for book binding and do the same thing.

 

For making paste from wheat flour, I boil 3 cups of water. Then mix 1 cup of flour with 3 cups of cold water in a blender. Slowly add the flour mixture to the boiling water, taking care not to get any on the sides of the pan to prevent burning. Stir frequently until it gets to the desired thickness. It will get thicker as it cooks. Cool and use.

 

I make it like a thick gravy. It works well to bind charcoal stars with a high metal content, like firefly. Just add enough paste to make the comp the right consistiency to cut. I would imagine it would work in any charcoal star, I do not know about using paste in color stars.

[Wiley]

Nater, would your method of binding charcoal stars with wheat paste also work for "ricing" a ball of pulverone through a screen?

[psyco_1322]

Most times I've seen paste used to wet comp, it incorporates dextrin as well. I believe I read somewhere, by Mike Swisher, that they are both needed to bind the stars, and you can not only use the wheatpaste. I don't have any experience with paste as binder, but I would suspect that it would not make that hard of stars.

 

Making dextrin will certainly serve the purpose. It's always seemed to take around 4hrs or so in the oven for it to get to golden brown. It does smell strange and can be a bit of a mess sometimes. I cook it in an Al turkey pan, or cheapest I can get. I'm not sure if the pan shape or material affects how much/fast it browns. I could be over cooking it, but I don't feel like trusting dextrin that isn't a nice golden color.

[Wiley]

How does SGRS compare to dextrin in terms of its binding properties? http://www.ebay.com/itm/SGRS-Soluble-Glutinous-Rice-Starch-Pyrotechnic-and-Rocketry-Supplies-/281049272579?pt=Model_Kit_US&hash=item416fd79103 I haven't heard of people using this a whole lot, especially to bind pulverone.

Edited March 2, 2014 by Wiley

[Mumbles]

You generally do need dextrin in addition to wheat paste. The basic explaination is that you need dextrin for wet strength, and wheat paste for dry strength. This combination is most often used to bind comets and compositions containing stearin coated aluminum. It helps to break the surface tension of the waxy coating from the aluminum. It's also common in making firefly comets. I've only used them in combination and can confirm that it does produce exceptionally hard stars and comets. I prefer the wheat paste a little thinner for working into compositions than I did for pasting paper. I used the dry stuff you mixed with water to make the paste. For paper I'd use 6 parts water to 1 part powder. For making stars and comets I used about 8 or 10 parts water to 1 part powder. Maybe I cooked it too long, but I always found a 6:1 water:flour ratio to be thicker than a 6:1 water:powder ratio.

 

Slightly related, but liquid laundry starch makes a good wetting and binding agent for making blackmatch. It produces very stiff match that isn't as susceptible to ambient humidity.

 

SGRS works fine for most things, it just takes some getting used to. It works great for cutting stars, certain methods of rolling, and granulating compositions. It'll work great for polverone and dries very hard. It works great for all colored stars and streamers I've tried. I had some issues with glitters, but I can't be certain that was SGRS caused. The one caveat is that I've never been able to get the hang of it for pumping. I don't know if this will make sense, but SGRS is more gummy than dextrin. It sort of behaves like rubber sometimes, and can be difficult to get chunks of composition to fuse together which I think is why I've had so much trouble with pumping. It also takes longer to fully activate, so it can be easy to overwet if you're not being patient. I have a full 55lb bag of the stuff, so come hell or high water, I'm going to make it work.

 

I got my SGRS from Tim Seekon. High quality stuff. www.pyrochemsource.com/Pyro-Chem-Source-SGRS-lb/dp/B007W7P0JA?

 

Cooking dextrin can be done at home. I personally feel the product obtained isn't as good as the commercially produced acid-catalyzed stuff. I typically cooked at 350F for a few hours, and then ramped it up to 375 or 400F toward the end to finish it off and get that good golden roast color. Given that a lot of this was done by feel (and taste), the product isn't as consistent as something purchased. I never noticed much of a smell, but I might just be oblivious to that particular odor. I also always cooked in glass dishes if that makes any difference to anyone.

 

I've give cooking it a shot, and see how it works for you. Worst case scenario you waste $1 on a box of corn starch. Having a good binder will be critical to advancing in the hobby. At the very least, it'll probably hold you over until you can get some commercial stuff, if you're less than satisfied with it.

[nater]

I cooked the cornstarch on a foil lined jelly roll pan until it was a deep golden hue. A solution of it in water was sticky like you would expect. I tolerated the smell and thr burning eyes, but my wife did not. With everything else this hobby involves, it pays to keep her happy and supportive of it.

 

I have not tried it for cutting stars, but I do mix up paste with a dextrin solution when rolling tubes or rocket headers. It gives makes the paper very hard when everything is dry.

Edited March 2, 2014 by nater

[WonderBoy]

Side note on making wheat paste: Recently I have been making paste in the microwave, it works great for small quantities. I normally use 1:4 flour:water, then cook and stir until you get the desired consistency, maybe 2 min.

 

 

WB

[Col]

Making wheat starch paste in the microwave also saves the hassle of seiving it after cooking. Wheat starch is superior to normal flour as an adhesive but can be harder to find. A ratio of 10:1 water/starch is good.

Edited March 3, 2014 by Col

[nater]

The person I bought several bounds of wheat starch from is no longer selling it. I swear he said it could be found at an Asian market.

[Col]

chinese supermarkets are a good bet too. Its pretty cheap, a gallon of ws paste (4.5L) costs about £1.20.