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Paper - 90# vs Virgin Craft


usapyro

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I'm curious, has anyone done any testing to see how much stronger virgin craft paper is vs sheets of something like 90# Xerox paper?

 

Using a standard technique like rolling with wheat paste.

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It's 'Kraft paper', not 'craft paper'.

 

Most copier paper is 30lb, not 90lb. You also never mentioned what weight virgin kraft. High-quality xerographic paper may actually be a 'virgin fiber' paper (most are not), but even if it is, the bleaching and whitening process weakens it, as compared to unbleached kraft.

 

So, basis-weight-to-basis-weight, unbleached virgin kraft will be stronger. How much, I don't know. Copier paper is normally not used for much of anything in pyro.

 

(Heck, not even for Origami...)

 

Lloyd

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It's 'Kraft paper', not 'craft paper'.

 

Most copier paper is 30lb, not 90lb. You also never mentioned what weight virgin kraft. High-quality xerographic paper may actually be a 'virgin fiber' paper (most are not), but even if it is, the bleaching and whitening process weakens it, as compared to unbleached kraft.

 

So, basis-weight-to-basis-weight, unbleached virgin kraft will be stronger. How much, I don't know. Copier paper is normally not used for much of anything in pyro.

 

(Heck, not even for Origami...)

 

Lloyd

 

I have 90# Index paper. It's Xerox brand copy paper.

 

I use to do Origami in the past... Had some special ultra-thin papers. I mean... Razor thin stuff!

Edited by usapyro
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It's no good unless you plan on making baked rocket tubes. I tried that but it was such a PITA that I went back to buying ready made tubes. The poly coated stuff won't take paste and if used on a rinfascitured shell it leaves a lot of flaming debris raining down. U-line has a pretty good price on #40 kraft. I just got me a roll of it and really like it.

https://www.uline.com/BL_1142/Virgin-Kraft-Paper?keywords=Virgin%20Kraft%20Paper

Edited by OldMarine
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"I have 90# Index paper. It's Xerox brand copy paper."

---------------------

But... have you actually "mic'd" the thickness of it? I seriously doubt that it's the 0.009" thickness of 90lb kraft.


"Roughly", the 'pound rating' on craft papers equates to their thickness. 30lb will be roughly 0.003" thick, 50lb will be 0.005", and 90lb will be 0.009".


Other 'pound bases' are 'trade references', not the actual paper weight in pounds per ream.


Lloyd

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I got myself some proper 3/4" aluminum rod today finally... Still need to sand the ends perfectly flat, then clean up the bevel. I started this hobby a decade ago and I never used anything other than hardwood tooling, lol... I never spent too much on this hobby though. Only a couple grand total.

 

post-11032-0-99649300-1497735511_thumb.jpg

 

Cut the stuff to length with a wood cutoff saw and a old blade.

 

Trying to figure out how to level the ends... I got a big drill press, the stuff may fit into it... Yea, it's a big drill press with a arbor handle for drilling. Then I can drive it down into a sanding block. Or, maybe I will just eyeball it and use a angle grinder to try to get them level enough.

Edited by usapyro
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Done... Good enough! Not bad for $14. Cheap 2' of 3/4" Al rod from the hardware store. I could take it to the machine shop and have them clean up the ends, but I have other things to spend money on right now.

 

post-11032-0-50311500-1497739260_thumb.jpg

 

So, when you hammer on Al with a metal hammer, does it flare outward over time? I don't really care, because this isn't expensive machined tooling! Just curious...

 

While good tooling would be tempting to get, I just make BP and Sugar rockets... The only thing I could really improve is performance from better nozzle shape for endburners. Wonder how much a simple base costs...

Edited by usapyro
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It will flare on the hammered end, but not on the end that is in contact with the composition... 'not enough force to do that.

 

So, just mark which end is to be hammered, and forget it.

 

L

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It will flare on the hammered end, but not on the end that is in contact with the composition... 'not enough force to do that.

 

So, just mark which end is to be hammered, and forget it.

 

L

 

Thanks! If you look at the pic, I put drill holes to mark the ends. I didn't drill all the way through because I have never had any problems pulling out dowels.

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Wow... I just rolled some tubes with 100# paper. It was a piece of cake!!! They are solid and ring like plastic when I tap them together. I used White Elmers Glue with a touch of water. About a one minute time till set.

 

post-11032-0-53847100-1497749027_thumb.jpg

 

It's now a pleasure to roll tubes! Just push down, roll forward, and pull towards yourself! Going with three sheets of paper for initial tests.

 

I coat one side of the paper evenly by running a painting roller back and forth a few times. I definitely am going to make a rolling board to make this process even better.

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100#? Really?

 

Please get out some calipers and measure the thickness of that material! Lacking that, stack up 25 layers of it (not folded, no... cut pieces), press-down hard, and measure the thickness with a good ruler.

 

If it's really 100-lb basis weight, that stack (pressed down HARD) will be a full 1/4" thick!

 

Good luck! 'Good' commercial tubes (NEPT) are wound from about 40lb paper in multiple-layer stacks equating to about 0.040" thick per stack.

 

Lloyd

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100#? Really?

 

Please get out some calipers and measure the thickness of that material! Lacking that, stack up 25 layers of it (not folded, no... cut pieces), press-down hard, and measure the thickness with a good ruler.

 

If it's really 100-lb basis weight, that stack (pressed down HARD) will be a full 1/4" thick!

 

Good luck! 'Good' commercial tubes (NEPT) are wound from about 40lb paper in multiple-layer stacks equating to about 0.040" thick per stack.

 

Lloyd

 

As for the weight... It says 100# on the label. :/ Paper company can't cheat you, can they?

 

I have been using dry rolled tubes for my rockets for years with just tape around the outside. Look at my video's... All dry rolled. This is a major step up from what I use to do. (About 8-9 sheets of normal 20# copy paper rolled up around a dowel then spiral taped around the outside.)

 

I recently realized the reason it worked for me is because I did like nine rammed increments per rocket... It pushed the inner layers outward and compacted the tube. I even had a tutorial thread where people tested the failure pressure of my dry-rolling method. It was somewhere around 2500 PSI if I remember correctly.

Edited by usapyro
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Did you measure it, or just take their word for the basis weight? SOMEBODY you know must own some calipers!

 

Lloyd

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Did you measure it, or just take their word for the basis weight? SOMEBODY you know must own some calipers!

 

Lloyd

 

I just assume that what it's labeled as is what it is. I found it today in the dept store. A pack of 250 sheets of 100# index paper for $7.99.

 

A friend of mine who is a engineer who works on race cars does, but he's a state away.

Edited by usapyro
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C'mon! Think about the possibilities. How thick is a pack of 250 sheets?

 

Actually, it's closer with virgin kraft than with xerographic paper, for which there isn't an as-exact relationship. But it's still VERY close. So, if a 250-sheet pack of that paper is 2.5" thick, then yep... I'd agree it's 100-lb paper.

 

(BTW... just ribbin' you a little, but how do you do any kind of craft work - including pyro - without measuring equipment? Go to Horrible Fright, and check out their offerings!)

 

Lloyd

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C'mon! Think about the possibilities. How thick is a pack of 250 sheets?

 

Actually, it's closer with virgin kraft than with xerographic paper, for which there isn't an as-exact relationship. But it's still VERY close. So, if a 250-sheet pack of that paper is 2.5" thick, then yep... I'd agree it's 100-lb paper.

 

(BTW... just ribbin' you a little, but how do you do any kind of craft work - including pyro - without measuring equipment? Go to Horrible Fright, and check out their offerings!)

 

Lloyd

 

The 250 pack is somewhere around 1.5 inches thick. Horrible freight, lol... I have a HF store in the city near me.

 

I got a 2' metal ruler in metric and standard, plus normal tape measures. I don't really see the point in calipering the paper. Funner to just make some rockets, drill some nozzles, and see which ones Cato... Then use or create a drill bit for the specific size.

 

Lately I have taken to making my own drill bits for precisely sizing nozzles by hammering the tips of around 3/16" steel rods flat then angle grinding them into shape. Metric drill bit sets don't do it. There such a thing as a half metric set? Eg, increments of 0.5mm.

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But, USA, you NEED TO KNOW what the weight-basis of your paper is -- most-especially if it works well for you!

 

It's not a matter of "you must do it THIS way", so much as, "would you like to reproduce it in future?"

 

LLoyd

 

(FWIW, if 250 sheets are 1.5" thick, then it's actually 60-lb paper! <grin>)

L

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The lb. or # rating has little direct correlation with most paper types, for some reason (probably coincidence), virgin kraft paper has a caliper thickness of 0.001" per pound (60lb is 0.006"):

 

Other types of papers are "weighted" based on how much a certain number of sheets, weigh. Index, tag, offset, book, etc. paper types all have different caliper thicknesses for a given "weight".

 

It would be interesting to compare the strength (and other relevant properties) of papers made with different manufacturing processes, but equal caliper thicknesses. The virgin kraft many pyros know and use may not always be available.

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Mase,

 

Normally, "Index weight" closely approximates the same weight basis as virgin kraft. It's a bit thinner at higher weights, but still close.

 

However, he's clearly indicated that the 100-lb basis weight he's been quoting is quite a lot thinner than that of virgin kraft.

 

Lloyd

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But, USA, you NEED TO KNOW what the weight-basis of your paper is -- most-especially if it works well for you!

 

It's not a matter of "you must do it THIS way", so much as, "would you like to reproduce it in future?"

 

LLoyd

 

(FWIW, if 250 sheets are 1.5" thick, then it's actually 60-lb paper! <grin>)

L

 

Well, if the paper type I am using isn't sold in the local store anymore, ill just switch to another brand. Even if it's only 250 sheets of 60# paper at $7.99... That's better than shipping for buying paper online.

 

Honestly... I don't want to hassle with slicing Kraft up. Do you guys buy a special paper cutter or something that cuts it into strips? I have a paper cutter, but it doesn't do 36".

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Uline sells a very inexpensive dispenser/cutter rack to fit rolls. I have 3 for my different weight/widths of Kraft.
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  • 3 months later...

A 36" roll of paper is a lot more versatile than individual sheets. A roll will be cheaper too, a 900mm x 220m roll is equivalent to about 3,150 A4 sheets ;).

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