58 replies to this topic

[KaneTheMediocre]

EDIT: Don't do this. See http://nerfhaven.com...showtopic=23349
I'm only leaving the rest of this unchanged for historical and reference purposes.

...

Original Post:

This should give you the gist of the design:


Executive Summary:
The holes are 5/16" diameter x 3/8" to 1/2" deep. The foam is the 13mm (~1/2"-ish) pink stuff that I ordered from china
The filling is silicone rubber, either the sealant type that cures with contact to moist air, or the mixed type that cures anaerobically.
The tip is 1/2" mcmaster adhesive felts with the adhesive ripped off.
Length is 32mm-36mm
Works in a conventional pvc-wye hoppers
Safer than any other hopperable darts that I know of
Comparable performance to slugs
0.8g +-.1g @ 2 sigma

Props:

Captain Slug, for putting felt bumpers on his darts and being the first person I know of to make ANY effort to pad ammo

Ryan McNumbers, for being helpful and supportive with pretty much every dart making scheme I've had.

Most of all Caffeine, for telling me that brad pointed drill bits can make good holes in foam, AND for suggesting silicone adhesive as a dart-tip material. He suggested these things to me shortly before he died a couple years ago. Efforts to resurrect him have proven futile, but I haven't give up.
The details are as follows:

Make non-adhesive, 1/2" felt pad. Die cutting non-adhesive foam is the best solution here, but I didn't (and don't) have that. So, I tore the adhesive off of some of the sticky felts that are used normally for metal weighted slugs*.

Aquire a 5/16" brad-pointed bit with a stop, and some sort of jig to guide the dart into the center of the blank. My jig was made from 5/8" x ~1/2" PEX, 1/2" x ~3/8" PEX, and 11/32" x ~5/16" brass tubing.

The outermost PEX (white) holds the dart, while the brass guides the drill.

The duct tape acts as an endstop that determines the depth of the hole

Put your blank in something to hold it while the silicone sets. This jig was precision made to do things other than this--All you need is a board of something with 1/2" holes in it to hold the foam without damaging it, position doesnt matter.


I used a 1 to 1 mixed silicone RTV at first for this, but I think for most people silicone sealant is more practical and less messy. I've used both general purpose sealant, and a low-viscosity variant (Dow Corning 734). The low viscosity variant seems to bond better with both felt and foam, but the general purpose is MUCH more controllable and less messy.

It helps to get the nozzle in the hole to reduce trapped air and better bond with the foam.



Add the 1/2" diameter felt pad



For not-a-writeup, these would be done in greater numbers than 1, but beware that the silicone forms a skin fairly quickly that will prevent the felt from sticking. I would estimate this takes 5-10 minutes, which for me was filling 30-40 darts before needing to switch to felt placement. Also beware that this type of silicone requires about 24 hours to set enough to be removed, and at least 1 week to set enough to use. During this time [internet chemist hat], the sealant cures by expelling acetate ions into the moisture in the air, forming vinegar and it's familiar caustic odor. It needs to do this a lot to cure, so it cannot be kept sealed away during the cure process, as this would saturate the air with vinegar, reaching an equilibrium with the silicone that prevents curing.
The low viscosity silicone sealant may turn out to be necessary to adhere the foam to the silicone. I don't have any real-use testing with these, but the general purpose sealant darts were very east to pull apart, separating foam from silicone. Low viscosity silicone sealant is MUCH messier, on account of not flowing controllably from the caulk gun, and also on account of not being able to bulge as much without spilling out of the dart.

Especially with mixed silicone and low-viscosity silicone, these darts are quite difficult to make well, and there are a wide variety of ways they can be flawed, resulting in a wide variety of symptoms**. However, if these type of materials are used with this basic method, no lack of quality can present as serious a safety hazard in the way that stefans and damaged / poorly made slugs can, since nothing hard is in the dart. You still, of course, don't want to get hit in the eye-Goggles, people!

*There are many ways to do this, and difficulty seems to vary from roll to roll. I ended up needing to stick the felts together, then rip the felt off the central adhesive blob one at a time with a roll of white felt for these. There are a variety of ways to do this, the best one depends on the roll of felt. In any case, I need to find a source for 1/2" non-adhesive felt pads.
**More coming on that


QA:

Great job on these, especially since they're hopperable without any wye modification. How heavy are they?

0.7g-0.9g, for the most part 0.8g. The variation in weight is mostly from the hole depth

I remember one of your design goals with the rubber-headed darts was better aerodynamic performance than slugs. Did that goal go by the wayside to meet the hopper requirement, or are these a separate evolutionary line of darts?

A bit of both. Making special hoppers for rubber tipped darts is still of-interest, but I'd also want to have vented hollow domes for better padding, and the special hoppers need to be extremely low cost/labor (at least for me) to be widely adopted. These less than revolutionary VANS work with the hoppers people already have, which are cheap and easily implemented. Since I'd like to be mass producing darts by early summer, I'll take care of these first. This method also allows me to advocate these metal free darts without directly telling them to buy MY metal free darts, so I can be a safety nazi more effectively. If I had a supplier / method for domed felts....

Do you think it would be possible to burn the hole instead of drill it?

Generally no. The silicone needs the rough surface of the drilled foam to bond.

I don't understand; why do you have to remove the adhesive? Wouldn't that help it bond to the silicone better?

Silicone is basically immune to adhesives. By using bare felt, the silicone seeps in between the threads and cures, forming a bond.

^^This.

Would a 1/4" drill bit work for this? Due to the slightly smaller diameter, I suppose you'd have to drill deeper to hold the same ammount of silicone. Also, do you have an McM number for the silicone you used?

A 1/4" drill isn't completely out of the question, and would make cleaner holes with fewer rejects. But to get the same weight, you need to drill 56% deeper, or close to 3/4". At some point, the front-heavy balance of the dart will be sufficiently disturbed that the darts will no longer fly straight. So really, the 1/4" holes are only good for lighter darts / lower powered blasters.

75825A2 for the low viscosity stuff that bonds well to the rough foam. The general purpose stuff I just got at a hardware store.

Edited by KaneTheMediocre, 27 November 2012 - 04:18 AM.

[andtheherois]

Great job on these, especially since they're hopperable without any wye modification. How heavy are they?

[snakerbot]

I remember one of your design goals with the rubber-headed darts was better aerodynamic performance than slugs. Did that goal go by the wayside to meet the hopper requirement, or are these a separate evolutionary line of darts?

[Ivan S]

Do you think it would be possible to burn the hole instead of drill it?

[cheyner]

What are you actually calling these? You have 3 different names that I have seen so far.

[KaneTheMediocre]

What are you actually calling these? You have 3 different names that I have seen so far.

They are definitely VANS

[KaptainKrazy]

I don't understand; why do you have to remove the adhesive? Wouldn't that help it bond to the silicone better?

[Ivan S]

I don't understand; why do you have to remove the adhesive? Wouldn't that help it bond to the silicone better?

Silicone is basically immune to adhesives. By using bare felt, the silicone seeps in between the threads and cures, forming a bond.

[KatanasPWN]

Would a 1/4" drill bit work for this? Due to the slightly smaller diameter, I suppose you'd have to drill deeper to hold the same ammount of silicone. Also, do you have an McM number for the silicone you used?

Edited by KatanasPWN, 26 February 2012 - 11:35 PM.

[snickers]

Very
Awesome
Non metal
Stefans

Is this what they stand for?

Edited by snickers, 27 February 2012 - 04:08 PM.

[arfink]

Very
Awesome
Non metal
Stefans

Is this what they stand for?

Not to be too much of a geek, but this is what's known as a recursive acronym. Please see https://en.wikipedia...cursive_acronym for details.

The acronym stands for

VANS
Are
Not
Slugs

EDIT: also, assuming you get the technique down, I'd be interested in buying some. Like, alot of them.

Edited by arfink, 27 February 2012 - 04:26 PM.

[KaneTheMediocre]

Not to be too much of a geek, but this is what's known as a recursive acronym. Please see https://en.wikipedia...cursive_acronym for details.

The acronym stands for

VANS
Are
Not
Slugs

EDIT: also, assuming you get the technique down, I'd be interested in buying some. Like, alot of them.

Thanks for clearing that up.

For those that haven't noticed, I've been responding to questions at the end of the original post.

I'll definitely be selling these once I get the technique down--"The Technique" being machines that do most or all of the work. As far as making these by hand, I've only done about 200, so I'm far from an expert. I don't plan to become an expert for the aforementioned reason.

[Scooter1]

Do these bounce more on impact than slugs? Do you think they are less painful to be shot by?

[Scooter1]

Sorry for the double post, Server error

Edited by Scooter1, 27 February 2012 - 07:24 PM.

[Meaker VI]

Something of a concern for determining war-legality of these - since they look identical to well-made slugs from the outside, how would you prove that all of your darts aren't slugs if slugs/metal weighted darts are illegal at a given war? Cut several open to demonstrate that they're different? Pass them through a magnet?

[mysterio]

Possible solution for the felt-sticking problem. After filling with general-purpose silicone, dust with corn starch to create an oogoo layer up top? The felt pads attached to my oogoo darts hold pretty well.

[snickers]

Something of a concern for determining war-legality of these - since they look identical to well-made slugs from the outside, how would you prove that all of your darts aren't slugs if slugs/metal weighted darts are illegal at a given war? Cut several open to demonstrate that they're different? Pass them through a magnet?

In an instance when slugs are illegal, you could just simply use a metal detector.

Edited by snickers, 27 February 2012 - 09:29 PM.

[arfink]

As another possibility for detecting the difference between VANS and slugs, you could always just squish the top. Roll the tip of a slug between your fingers and you can feel the washer. It's thin and hard and totally obvious. Roll a VANS and I bet you can tell right away that it's different. I don't know for sure, but I suspect it'll feel alot different.

[snickers]

As another possibility for detecting the difference between VANS and slugs, you could always just squish the top. Roll the tip of a slug between your fingers and you can feel the washer. It's thin and hard and totally obvious. Roll a VANS and I bet you can tell right away that it's different. I don't know for sure, but I suspect it'll feel alot different.

I don't think the host of the war wants to squish the top of everyone's slugs/VANS.

[arfink]

I don't think the host of the war wants to squish the top of everyone's slugs/VANS.

If your players aren't responsible enough to have just one dart of a batch checked, then you got other problems. Anyways, back on topic again:

Do you have plans to help automate this process? Would it be totally automatic, or more like a series of jigs/molds that makes it easier?

[KaneTheMediocre]

If your players aren't responsible enough to have just one dart of a batch checked, then you got other problems. Anyways, back on topic again:

Do you have plans to help automate this process? Would it be totally automatic, or more like a series of jigs/molds that makes it easier?

We have other problems--We have yet to successfully host (or witness) a slug-only war that didn't have a few glue domes shot around. I plan on using a magnet, which could easily be defeated by using nonmagnetic metals as weight, but it would be quick and easy. And it would work well for people who made a good faith effort to comply with the regulation, but got some old slugs mixed in.

Squeezing definitely works, but does cause mild damage to either slugs or VANS. And I don't want to squeeze 4000 darts at every war.

As far as the darts looking like slugs--This is not entirely the case. Generally, the foam is thin enough to be slightly translucent where the silicone weight is, so you can just barely make out it's outline. Furthermore, slugs that are sufficiently well made to look like VANS are not nearly the safety hazard as their poorly made or damaged bretheren, which can easily be spotted.



For automation, it will likely start out as a series of jigs and tools that I attach to my mill to automate 1 step of the process at a time. I don't have the time, money, or expertise to invest in a fully automatic dart machine at the moment.

[Langley]

We have other problems--We have yet to successfully host (or witness) a slug-only war that didn't have a few glue domes shot around.

Aside from Apoc, which is a clusterfuck no matter how you slice it, I haven't had any problems with this (although it seemed like everyone made at least a token effort to make slugs for Apoc, even if their idea of slugs was 'glue domes with a tiny dot of craft foam'. Goddamnit Pearson). 'Slugs only' means slugs only. Even when nerfing at a park that is already riddled with glue domes from previous wars, I haven't been hit with illegal ammo. If there's an issue of quality caused by people who have never made slugs, that's a separate issue. It seems like the problem in your area may be in how you handle your community dart pile.

About the curing process, is there any reason why you couldn't enclose the darts in a box with an exhaust fan and some ducting that leads to a window? Would too much air circulation cause problems?

It looks like the sealant is only in the center of the dart. Does the sealant spread out at the top and adhere the felt to the dart pretty uniformly, or does it peel up at the corners? Does this cause any problems with dart feed? How are these handling impacts with solid objects, particularly in cold weather?

Die cutting non-adhesive foam is the best solution here

Why? From the sounds of it, felt is the only thing that the sealant would adhere to without lots of help from gravity and rough cuts to open it up. If it's craft foam you're referring to, wouldn't it be way to smooth?

Would you have any interest in laser cut felt discs? I would be happy to tolerate the burning-sheep-smell for a couple of hours if it brings us any closer to that magical day when you get all the dongs out of your mouth long enough to send out some of that foam you 'put up for sale' a year ago.

[KaneTheMediocre]

Aside from Apoc, which is a clusterfuck no matter how you slice it, I haven't had any problems with this (although it seemed like everyone made at least a token effort to make slugs for Apoc, even if their idea of slugs was 'glue domes with a tiny dot of craft foam'. Goddamnit Pearson). 'Slugs only' means slugs only. Even when nerfing at a park that is already riddled with glue domes from previous wars, I haven't been hit with illegal ammo. If there's an issue of quality caused by people who have never made slugs, that's a separate issue. It seems like the problem in your area may be in how you handle your community dart pile.

There are in fact 2 issues, quality of slugs made by lazy or incompetent people, and people who use stefans at slug-only wars. Both have been an issue at every "slugs only" war I've been to, including wars in Minnesota, Wisconsin, Illinois, Ohio, and New Jersey. But I'm sure everyone's cool at your wars.

About the curing process, is there any reason why you couldn't enclose the darts in a box with an exhaust fan and some ducting that leads to a window? Would too much air circulation cause problems?

No, as long as the outside air is above freezing. Even with the mild winter we're having, that's not consistently true yet, and won't be for a while. But this is basically the plan, and I should be able to do that soon.

It looks like the sealant is only in the center of the dart. Does the sealant spread out at the top and adhere the felt to the dart pretty uniformly, or does it peel up at the corners? Does this cause any problems with dart feed? How are these handling impacts with solid objects, particularly in cold weather?

This depends on the dart. Keep in mind the process is much messier with the low viscosity silicone--which seems to hold the best. So, depending on how you you made the dart (Mostly, how much extra silicone bulges out at the top), it might peel up in the corners a lot (3/32"), or not at all. No feed problems have been witnessed, but I have been removing or cleaning up darts that have a total silicone clusterfuck, and I'm sure that the worst of the darts that I made would have caused misfires at least some of the time. This inconsistency is something I expect to fix with automation, but I'm sure practice would help. I do encourage y'all to refine the hand making of these darts, but it's not my personal focus.

I haven't fired any of these at a wall enough times to destroy one. I'm waiting for the silicone acetate to fully cure before I do that test. I would be surprised if these were less than 10 times more durable than conventional slugs in that regard--This is what Ryan and I found when we tested other dart designs that used silicone sealant.

Why? From the sounds of it, felt is the only thing that the sealant would adhere to without lots of help from gravity and rough cuts to open it up. If it's craft foam you're referring to, wouldn't it be way to smooth?

Oops, i meant felt, not foam. You are correct on all counts there.

Would you have any interest in laser cut felt discs? I would be happy to tolerate the burning-sheep-smell for a couple of hours if it brings us any closer to that magical day when you get all the dongs out of your mouth long enough to send out some of that foam you 'put up for sale' a year ago.

I think the felt we use is actually acrylic fibers, which has more of a toxic bunghole smell when burned, but I'm sure wool felt (Or any thick, fuzzy cloth) could work. I would most certainly be interested in trying out laser cut felt discs, but bear in mind that I'm used to paying about a penny each, and I don't want to go much above that if I can avoid it. If you're serious about this, PM me and I can give more details about what I'd need, because that's one of my biggest problems right now.

As far as sending out some of the foam, I'm not selling a goddamn inch of it anymore. When I can sell darts, I will, but I don't want to be responsible for some kid getting hit edgewise by a flying metal disc at 300 fps, so I'm not going to sell any more of it. For this reason, I never at any point wanted to sell foam, but I felt that it was unfair to deny the community when the darts weren't happening. Now that I have a design that I feel good about, it's a much better use of my time to work on getting dart manufacturing up and running.

I understand that's not an excuse for dragging my feet so much with foam sales, and not getting back to people promptly (Or at all in many cases). There are a lot of people who have every right to feel frustrated with me, but I think a contributing factor with you (Langley) not receiving foam is that you never ordered any.

Edited by KaneTheMediocre, 29 February 2012 - 07:12 PM.

[mysterio]

Tried VANS out, with limited success. They do better than single-bb domes out of a UMB, and hurt a lot less. Used a part of a hornet shell [the connectors to the titan] as a mold, and had trouble with molds not curing or air bubbles forming with low viscosity silicone RTV. Still need to create a better mold/felt tips for the RTV. It sticks to drilled out foam amazingly.

[KaneTheMediocre]

Tried VANS out, with limited success. They do better than single-bb domes out of a UMB, and hurt a lot less. Used a part of a hornet shell [the connectors to the titan] as a mold, and had trouble with molds not curing or air bubbles forming with low viscosity silicone RTV. Still need to create a better mold/felt tips for the RTV. It sticks to drilled out foam amazingly.

The air bubble is probably the biggest problem I've had. I'm not sure how much of it is due to air that's trapped in the hole initially and floating up, vs air seeping in from the top as the felt wicks up the silicone. I haven't lost much sleep over it, because I think that if the holes are of consistent size, and I pour exactly the same amount of silicone in every time, I can calibrate to avoid that. Or perhaps even control it--If there was enough silicone left around the rim to keep the dart strong, a void would help pad the dart substantially.

I'm not sure what the deal is with the "molds" (I assume you mean darts) not curing. Was your silicone the 2 part mixed stuff, or a single tube of silicone sealant that cures over time and contact with moist air? The former requires fairly precise mixing, the latter, just LOTS of cure time and ventilation. Let me know exactly what you're using. In any case, I appreciate that you're trying this out for yourself. As far as I know, you're the first.

Also, while I'm here I should report that the the silicone acetate darts with white felt squeaked and fired poorly out of the 2 part cpvc-sch80 "optimal barrels", but fire fine out of continuous barrels. Testing of this has been limited to the only hoppered springer with changeable barrels I have at my house ATM, which is Ryan's Aabow. Perversely, the green felted mixed silicone darts did not have this problem. In any case, I'm probably going to continue to use the silicone acetate stuff because it's easier and abandon optimal barrels because optimal barrels are more trouble than they're worth anyways.