Burr

I was wondering though does this process make the darts any denser than the original unheated dart, and does the end result leave any kind of "skin" on the dart?

The dart definitely becomes denser on the outside, but keeps its original density on the inside. There is a gradient of density. This photo should help answer your question:



However! There should be no skin on the dart if you do this process right. If the darts have a skin, then you have heated them for too long. Take a look at the photo below. The upper dart has been heated for 90 sec. The bottom dart has been heated for 40 sec. The surface of the 40sec dart is very smooth, while the surface of the 90sec dart is wrinkled. Additionally, I heated the 90sec dart with the glue tip pointing downwards, to illustrate what would happen. I neglected to add an unmodded blank for comparison.

Since you are doing this on a per-dart-length basis, given your instructions I would estimate an additional 1-2 minutes per dart. For a real war that consumes 500-1000 darts, this is an addition of 10 to 40 hours of prep time.

I don't think you would need this sort of precision in a NERF war. Again, I'm modding my darts for a specific role in HvZ games. (Which is actually a viable strategy there.) But using a rig with multiple brass tubes as hamoidar and andtheherois suggested should decrease prep time.

You might be able to do 3' at a time using a warm oven and a longer piece of metal tube. The cost of brass seems prohibitive here though.

That would not work. For one, Langley is probably right; doing so would unbalance the dart due to the way the foam would settle. But more so, it is not so much the heat from the cooktop element that molds the dart, but rather the fact that the metal of the tube heats up faster than the air pocket between the dart and the heat source. (Plus, foam is a poor conductor of heat.) This way, the dart doesn't turn into foam mush, but the heat from the metal starts working its way into the dart, melting the outside; thus the dart conforms to the diameter of the tube.

Thus, it is vital that the part of the tube that touches the heat source is as flat, broad, and uniform as can be (increasing surface area) so that the heat spreads to the metal without having to go through any tiny air pockets. Ideally, we'd put some sort of flat-topped plug onto the brass tube, and have that be the part that's touching the heatsource. However, then you'd have problems extracting the darts from the tubes, increasing manufacturing time, etc, etc. This works well enough.

Also, ideally, the tubes should be longer than 3" to increase the distance b/w the dart and the heat source, so that the foam at the end of the dart melts less. Because it does melt. As I've said, I have to trim about 0.5" off the darts - the part that gets partially melted. Unfortunately, that's foam wasted - another criticism against this method.

Take a look at this photo. From left to right: 40, 30, 20 seconds, unmodified blank. Unfortunately, I don't have my calipers here with me to confirm this, but it seems that the diameter of all four does not vary much - so 20 sec is enough to reform the darts. However, these were made to fit a 0.527" ID aluminum tube. 0.527" is not all that different from the foam's original diameter of ~0.538" ([edit]before the calibrating process[/edit] they wouldn't exit the tube, no matter how hard I blew into it). In order to test whether 20 sec is enough to reform the darts, I'd have to try a more drastic reform - from 0.538" to 0.500" for example. (Last time I tried that, I went with 40 sec, and though I had to trim more than I might have if I tried 20 sec, the darts worked very well in their new barrel.)

On topic, you mentioned that there is a hard, smooth surface formed during the heating process; how hard is the surface?

I think it's not so much that the surface gets harder (the material is the same, after all, so that property shouldn't actually change) but because the foam is denser near the surface, the dart feels harder to the touch - there is more resistance when you squeeze it or bend it. Might increase durability!


Edit: Instead of setting up vertical tubes inside an oven, consider setting them up onto a cooktop heating element instead. I think that the standard diameter for the big ones is 11" - you could fit a lot of tubes on there.

Also - I have some hypothetical plans that I might try later, when I have more money. I think that when you calibrate the darts to the barrel, it is still a little too tight a fit - too much friction, not enough acceleration. So I'm thinking of working the brass tubes to expand the inner diameter - e.g. I have a 0.527" aluminum barrel and I want 0.515" darts. So I would take a 17/32" x .014" brass tube with an ~0.504" ID and force some precision-manufactured stainless steel balls through it (probably in 0.005" increments) until the diameter is ~0.515". For instance, here is a 0.515" stainless steel ball at Bal-tec.

There's a reason why the term is "loser", and not what you wanted it to be. Mainly because there is no "losing" in nerf.

Yes, that's what I gathered while lurking. Did not notice there was a censor for it though. Anyway, there's definitely "losing" in HvZ, because there, distance matters - zombies have to get close to tag you. It's not all that different from a +Bow in principle.

Yes, you got the gist of it. I wanted the tutorial to be self-sufficient, so that if a noob like me read it, he wouldn't need much background knowledge to understand what was going on.

No, I haven't tried doing it with a row of blanks. It's crossed my mind. But I haven't started mass-producing my darts yet b/c I'll need to calibrate the weight, length, and balance of the darts first, and I'm still looking for a dart template with an ID slightly smaller than 0.527". But yes, later on, I'll make a rig.

Also, what university do you go to where stefans are allowed in HvZ?

Ah, it's not the university so much as the dorm I live at. My university is as strict about HvZ as any, but my dorm is the chillest place around. HvZ is student run and approved locally, and as long as the moderators approve each gun/dart combo, anything goes. And everything turns out pretty safe - no injuries so far afaik. It's Collins, at Indiana University. Everything around here is like that. I love this place.


Edit: Oh, and I make the darts first for a couple reasons: the way I make 'em, the glue tips tend to be over-sized, and this process makes them conform to the proper diameter. Also, I need the glue tip so that I can push on it with the blunt tool to remove the dart from the pipe. It gets a little stuck, and I don't want to damage it.