insutama Posted June 13, 2015 Posted June 13, 2015 Just was wondering if you can make a glue for rolling tubes by mixing some dextrin with water in a paste and using that instead of the wood glue/water mix i have been useing. It sure would save me alot of money if this would work has anyone every tried this ?
Rocketier Posted June 13, 2015 Posted June 13, 2015 (edited) Yep it can be used as glue. Best way of using the glue effect is put it thru wheatpaste. About 50/50 flour/dextrine stir well. When the putty is cold enough you can add in some white glue for extra glueforcehardness (new word ). Best thing to add, when you want to store it for a while, is some boric acid. When you want to use dextrine by itself it's not really gone work because dextrin is glueeh only in a specific state of wetness. To wet or to dry it's not sticky. It has to reach a sort of viscosity before it works. So the wheatpast is perfect to put it thru. For the flavor( ) I put some sugar thru the mixture. This sugar makes the stickyness even better. EDIT: I just made some of this glue, the consistenty and look of it is like a nice mayonaise. And it's easy to roll tubes with. So.......... Edited June 13, 2015 by Rocketier
insutama Posted June 13, 2015 Author Posted June 13, 2015 awsome sorry so how do you make the wheatpaste you mix 50/50 dextrin/four and just add water ? or do you need to add white glue to it also? also you said when its cold enough you add glue does this mean you have to heat it up ? sorry for all the questions but this sounds super intresting
Rocketier Posted June 13, 2015 Posted June 13, 2015 (edited) Normal Wheat paste:Stir 50grams of flour thru 50gram water. Set another 50grams of water of to boil. Then when boiling add the flour water mixture thru. Stir well till it's sets and gets consistenty like pudding. Then stir two eatingspoons sugar thru. Let it cool down and then stir till it's nice paste. For the glue with dextrine do the same handling except use 25grams flour and 25grams dextrin.When you want to save it for longer then three day put some 2grams boric acid in with the boiling proces.When the paste is cool about room temperature put in white glue and stir that thru. That's about it. Edited June 13, 2015 by Rocketier 1
insutama Posted June 13, 2015 Author Posted June 13, 2015 nice thanks for sharing that. is this what you use when your rolling your tubes ?
GMetcalf Posted June 14, 2015 Posted June 14, 2015 You can also make a very similar glue in a very similar fashion using corn flour (corn starch) instead of wheat flour, requires a bit more cooking though. Corn flour is of course the starting ingredient for making dextrin. Makes great wallpaper paste and when combined with some PVA glue (white glue) it makes excellent tube rolling paste. I've heard adding some waterglass to the mix will also increase the hardness of the finished tubes, but I've never done so and never had any problems!
insutama Posted June 24, 2015 Author Posted June 24, 2015 would using dextrin and flour make it a stronger glue also i dont have boric acid so what will happen if i try and store it ? how about if i just use flour instead of dextrin do i still need boric acid ?
Mumbles Posted June 24, 2015 Posted June 24, 2015 Something like benzoate or salicylate is also commonly used in wheat paste and gum arabic solution to prevent microbial growth. Storing it in the fridge doesn't hurt either. Boric acid has some anti-fungal and anti-microbial properties of it's own, but I'm not sure how they compare.
insutama Posted June 24, 2015 Author Posted June 24, 2015 I found some borax apperently this is boric acid so I'm gonna make some wheat paste now what does the benzoate do im got some k Benz coming
Rocketier Posted June 24, 2015 Posted June 24, 2015 (edited) I did some test after my last post here. Normally when rol smaller tubes for inserts I use just white glue with some water to make it easy to apply.When this way is used for bigger tubes the glue tend to dry out before you can really roll the tube. And when you have an airpocket you are kind of f..cked. So I made glue metioned above But..Because I was not very content with the amount of water used with that glue I tryed something else. I took some warm water and desolved a good amount (didn't weigh it) dextrine in it. That nice brownnes water I used thru the with glue. I liked the result.When rolling tubes with it you can paint a fairly amount of paper and roll it easely. It does not stick like the single white glue does. And when you roll the tubes several times over a glass plate. It tides itself perfectly. When you cut it directly it has a nice straight cuttingedge. Edited June 24, 2015 by Rocketier
Mumbles Posted June 24, 2015 Posted June 24, 2015 Borax and boric acid are not the same thing. Additionally, borax will cross-link white glue and turn it into a slime. This probably would significantly affect the binding properties of the paste. I actually was writing something about this before, but decided to delete it since I'm not sure if boric acid behaves the same way. Borax certainly does though. https://en.wikipedia.org/wiki/Boraxhttps://en.wikipedia.org/wiki/Boric_acid
insutama Posted June 24, 2015 Author Posted June 24, 2015 well damn i just bought some borax because i was told it was the same as boric acid so i cant subsitute boric acid for borax ? also whats the shelf life of wheat paste ? with boric acid ?
Mumbles Posted June 25, 2015 Posted June 25, 2015 It might work. Borax also has some anti-microbial properties. No promises though. It's also not going to work to prevent reactions in Nitrate/aluminum stars since it's basic itself. Also, the paste you make wont work as well for binding stars, since it will impart sodium into the star. I normally get about 24-36hr out of wheat paste at RT. I can get close to 5-7 days in the fridge sometimes. Sometimes it's as low as 3 though. There is a very distinct sour odor when it starts to go bad. It also starts to get thin and separate. I normally use benzoates to extend the lifetime of my stuff. Gum arabic solution lasts basically indefinitely. I've had it around for months, and always use it up before it really goes bad. I use instant wheat paste, so I just make it as I need it. On the rare occasion I've cooked it, I use benzoates, so I can't speak to boric acid.
gregh Posted June 25, 2015 Posted June 25, 2015 I would personally save the borax for laundry and look for boric acid. Borax occurring naturally is a decahydrate. That's ten water water molecules for every molecule of sodium tretraborate in the crystal. I used to work for a detergent company and the industrial borax we got was partially dehydrated to a pentahydrate. I would imagine if you were using it in wheat paste that you were binding stars with, it might lead to problems with moisture or slowing burn speed with the trapped water. And I can vouch for Mumbles when he says it makes slime when mixed with PVA glue. That is a favorite of my children! Look in the pesticide dept in your local market. Boric acid is used as roach and ant killer. Here's what I got.http://www.walmart.com/ip/Enoz-Roach-Away-Boric-Acid-1-lb/19276149
insutama Posted June 25, 2015 Author Posted June 25, 2015 Okay thanks guys ya I was just using my wheat paste for pasting shells and rolling tubes not stars. I'll keep looking for boric acid locally.
nater Posted June 27, 2015 Posted June 27, 2015 I recently tried adding potassium benzoate to a batch of wheat paste with no luck at all. It was in a closed container in room air. After 3 days and it was pretty sour smelling and not in a pleasant way like sour dough bread. I have been able to store cooked paste in a refrigerator for about a week. It is cheap and quick enough to make, that I just make a batch up when I need it. I use a 1:6 ratio of flour to water. 1/4 cup of flour gets whisked into 3/4 cup of water. Meanwhile, start heating another 3/4 cup water in a small sauce pan. When the flour is well dissolved in the water, add it to the pan and bring to a boil. It will start to thicken as it boils. I pull it when it is like a gravy. Use thicker paste with thinner paper and thinner paste with thick paper. You can always thin paste with more water or cook it longer to thicken it. It will thicken as it cools. 1
insutama Posted June 27, 2015 Author Posted June 27, 2015 sounds good thanks i found boric acid at the pharmacy also
Col Posted June 27, 2015 Posted June 27, 2015 (edited) Homemade casein and dextrin will give you better results. Higher initial tack than pva and lower shrinkage than wheatpaste. The freshly rolled tube comes off the former barely damp, strong and surprisingly rigid.The low water/ high solids content gives you a fast drying tube that stays dimensionally stable. You can dry them off the former without worrying about wrinkling or bowing, overnight at room temp is plenty or 3-4 hours forced drying if you`re in a rush for tubes. Edited June 27, 2015 by Col
Col Posted June 28, 2015 Posted June 28, 2015 I use cornflour to make the dextrin and skimmed milk, vinegar and sodium bicarb to make the casein. I combine seperate casein and dextrin solutions that are modified with sodium hydroxide and sucrose. The modifications allow for increased solids content and control the rate / amount of water wicked from the glue into the paper. The high initial tack comes from the rapid increase in solids content as the glue loses a small amount of water which also serves to transport the glue into the paper. Ideally the glue should penetrate to half the paper thickness so as the tube is wound, the glue film on top will lose its remaining water penetrating halfway into the dry underside of the next turn. When you push the tube off the mandrel it will be very solid, fully glued but barely damp. 1
bumer Posted September 24, 2015 Posted September 24, 2015 Used it for the rolling shell casings of rocket engines. Cooked in boiling water sprinkled dextrin to a comfortable density.
otto Posted October 16, 2015 Posted October 16, 2015 A point of clarification: Where I am, corn flour and corn starch are not the same thing. The dextrin I've made from corn starch works great. My corn flour makes great muffins......
Col Posted October 16, 2015 Posted October 16, 2015 Its not the same here either, we just have a space between the words to differentiate the two Corn flour is milled from the whole kernel, cornflour (aka cornstarch elsewhere) is obtained from the endosperm portion of the kernel
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