Darts splitting up the middle

I apologize to the mods, admins, and thread creators as I had hijacked a few threads regarding this issue. This is what I'm talking about


I thought it only happened on my AT2K (foot long barrel, four pumps). But it started happening as I was testing my BBUMB RSCB (5 pumps). At the moment it's mostly happening to blue foam.

So put simply it comes down to high pressures. The BBUMB doesn't have as big of a tank as the Titan or the 4B, so I guess it makes sense it has high pressures for low volume of air.

Anyway share experiences and possible hypotheses for solving this issue. Someone suggested the straw mod, I need to try it out myself but we mostly drink straight out of the glass in this house so I gotta buy me some.

POSSIBLE SOLUTIONS:

• straw mod, use a straw to strengthen the hole in the dart.
  
• use FBR, or fill up the holes with cut up foam and hot glue (or this here)
  
• cutting down the length of the darts (45mm or 1.5 inch darts)
  
• don't get over-excited in your application of super glue. too much and it'll be absorbed by the foam, causing it to dry up and more prone to 'cracking'/splitting
  

This happens with most of my air blasters when the barrel is tight.

this happens too often in all my air blasters.
Solution: FBR (only thing i can think of)

Solid foam would probably not have the same problem. I wonder if informer can get some in, and how it preforms?

I have some fbr you can buy and try out to see if they split.
If you want, I can then get the items I asked about a while ago and I can give you some foam.

FBR will definately not split down the middle and how much are you selling it for Kat?

Right now, its 1.10 a meter as I only got a small amount. I was going to see if I could sell this amount before getting a larger amount as I didn't want a heap of foam lying around. I could get it a heap cheaper, but until I sell this last 30ish meters, it would be 1.10.
Go to my sales thread to see a pic of the foam.

2120: What are you using for barrels? I have had the same issue when using 17/32 brass stub barrels and short HEP20 barrels but nothing since changing to 15cm and longer PETG and 9/16 brass barrels.

so it seems that you shouldn't have a springer fit in an airgun. Makes sence.

Dietzie wrote:2120: What are you using for barrels? I have had the same issue when using 17/32 brass stub barrels and short HEP20 barrels but nothing since changing to 15cm and longer PETG and 9/16 brass barrels.

mostly PETG and really tight 16mm conduit.

mind you this has happened with PETG as well, when I singled my AT2K for testing purpose.

with the PETG, is it also happening to the loose darts? if so, im stumped.

I've had this happen to my streamlines when using my at3k with petg barrels. (very very loose fit)

I think it's just the really high pressures causing the foam to split.

There was a thread about that actually. I can't remember where it was?

@melbnerf - I have found that a 'springer' fit is much better than a slightly loose fit for air blasters. I can get more range out of it. However, yes the darts do split from time to time, but it hasn't happened to me too frequently.

I don't think inf0rm3r will be bringing any solid foam because like the '1metre length cuts', he didn't get rid of them as quickly and therefore it would be wasteful if it didn't go out as quick. Solid foam is more for the small minority of us who uses it in air blasters and short solid stefans instead.

I've found that to use blue foam in air guns, you want to cut down the size again. I've never had a problem with split darts at all, but maybe that's due to the fact I shorten them. 3/4 or 1/2 length of the pre-cuts work pretty well for me. I'm no dartsmith and I'm noob/lazy at making them but I find that 1/3-3/4 length + heavy siltip is pretty good for the ease of making them.

Clunk, myself and a few others nutted this out in inf0m3r's sales thread, but helpful admins tidied it up for us. :p It happens in the split second between when the dart tip leaves the barrel and the dart tip clears it, even for that instant the massive difference in pressure between the interior and outside of the tube causes the foam to fail, which it does without much resistance. Another potential cause is that in some darts the foam becomes brittle on contact with the adhesive if too much adhesive is used.

Possible solutions, straw mod, FBR, trying different barrel lengths, adding barrel ports, or just accepting that a percentage of your darts will fail. Another hypothetical solution could be tapering the muzzle outwards to let excess pressure leak around the dart.

Ive never had this problem either. But for my air blasters i cut the blue foam lengths to 45mm long.

On Saturday i did do some testing from my 4B full size heavy sili darts vs shortened, 5 pumps (gen 2 tank) and the shortened lengths flew further consistently.

So my tip is to cut about 28mm off the end of the heavy sili tip darts (foam end) or to shorten foam blanks to about 45mm long before making them into hot glue tipped darts. *This is a personal preference*

So my tip is to cut about 28mm off the end of the heavy sili tip darts (foam end)

I like the part where Servulus says to cut off the foam end, just in case someone was going to cut off the end with the heavy siltip on it. Sorry for hijacking but I just had to lol at this.

mister_elliott wrote:Clunk, myself and a few others nutted this out in inf0m3r's sales thread, but helpful admins tidied it up for us. :p

Indeed.
Perhaps our previous chatter on this topic should have been done on a seperate thread like this, as there was some value in it but it wasn't in the right place.

I'll just post this image again on the possible theory of dart splitting lengthways.

Servulus wrote:Ive never had this problem either. But for my air blasters i cut the blue foam lengths to 45mm long.

Hmmm...
That observation makes sense to me.

The shortened dart would clear the barrel before suffering from overpressure failure.

I have solid foam on the next few projects again, but until the community gets bigger I can't bring it in, I know the Americans are keen on solid to but there isn't enough people round to move a 7.5KM order across even a year time span.

The issue can go further, if your using super glue the wrong way to connect the heavy tips you'll split the foam to. The superglue is only ment to be applied in a tiny amount to the top of the foam and not even a ml on the stub. Any run downs from the tip to the tail or the dart will cause cracking. As you can imagine when you run superglue between a foam material and it dries it creates a solid which is cracked easily.

Try that solution and see how you go. I haven't had any issues with this except at the initial testing where we found super glue in excess created the problem mentioned above.

I would be really interested in the solid foam. What colour/colours did you have in mind?

Will be sticking to the whole blue theme if anything is done.

I'd buy a sh*t load if its pre-cut.
back on topic: that makes heaps of sence now, thanks for the diagram.

Yep I would be interested too. Seeing that it's more difficult to make stefans with the hole down the middle. (IMO)

Yup, thanks for that. I sorta forgot about that because the thread got removed.

I'll edit my first post so that future readers can find the answers a lot easier.

TooBz wrote:Yep I would be interested too. Seeing that it's more difficult to make stefans with the hole down the middle. (IMO)

Nope, I can vouch for that too. It really is that tedious, when comparing to solid foam - but it still works.
And also reiterating my interest in solid foam too :p

I don't know how you guys are making darts, but I'm pushing out 1000 heavies in just under an hour, I believe it's the fastest method, I do admit I have asian work ethics when it comes to process work.

@ 2120 did you check the super glue problemo.

Hey informer,

I believe it could have been one of the reasons. Though it has happened to a few darts straight out of the packaging box you sent me. But no biggie, I've just decided to cut it down to 45mm and cover up the hole with the excess foam and hot glue.

This happens to my streamlines out of my titan all the time, so <Censored> annoying. I'm getting some FBR soon

Yet I've never had a blue foam split out of my Titan, even with pump replacement...

Cheers,

From my experience, they only split if you fire it point blank at a completely solid surface... out of a singled air blaster (like the titan). It has yet to happen with my Longshot (the tips just break off the foam after about 5-10 point blank shots), but it happened with yeahryan's (now confiscated) unplugged titan.

Echoes wrote:From my experience, they only split if you fire it point blank at a completely solid surface... out of a singled air blaster (like the titan). It has yet to happen with my Longshot (the tips just break off the foam after about 5-10 point blank shots), but it happened with yeahryan's (now confiscated) unplugged titan.

I've split darts out of my unplugged 4b 40cm barrel just firing directly upwards.

Echoes wrote:From my experience, they only split if you fire it point blank at a completely solid surface... out of a singled air blaster (like the titan). It has yet to happen with my Longshot (the tips just break off the foam after about 5-10 point blank shots), but it happened with yeahryan's (now confiscated) unplugged titan.

Confiscated?

My titan has an epic leak at the moment, I need a new trigger section.

mister_elliott wrote:I've split darts out of my unplugged 4b 40cm barrel just firing directly upwards.

I can't quite explain that one... Maybe you had glue leak down too far and just made your foam all solid. It's probably been discussed earlier on in this thread.

bulletproofvest wrote:Confiscated?

My titan has an epic leak at the moment, I need a new trigger section.

Yeah, we had the police come and confiscate it.