19 replies to this topic

[T da B]

Sup lady and gentlemen,

This little orange piece has been the bane of my existence since I first decided to make an Angel Breech for my Longshot. For those of you that don't know, this little orange guy is the attachment point between the bolt sled and breech--the #1 point of failure. Pretty much every brass breech mod that I've read calls for gluing this piece to your brass breech. I have tried many types of epoxy, including the one from the original breech created by ForsakenAngel24, but none of them have had enough strength to withstand my [k26] spring. In typical T da B fashion, I set out to solve this annoyance once and for all. This time, it involves fire!

This mod was actually influenced by the RC car modding community. They use K&S brass tubing to make their own homemade front bumpers, Nerf bars (hehe), etc. I did my research on soldering, brazing, and welding in addition to watching Youtube clips of people joining metals to prepare for this mod. Here is what you guys will be needing to make a bond that can withstand the [k26]:


Top left: Butane torch that can produce a flame reaching 2500 degrees Fahrenheit! This will be the heat source used to prepare the metals for joining. I went with the Blazer Stingray GB4001 and I'm very pleased with it.

Top center: Stay-Brite Silver Solder that will be used to fill in the spaces between the two metals to be joined. It is composed of a few metals, and the silver allows the joint to be stronger than the actual metals themselves!

Top right: Stay-Clean Liquid Flux--really poisonous stuff. However, it is extremely necessary for soldering since it cleans the surfaces of all oxides and causes the solder to stick.

Bottom: 3/8'' x 3/8'' x 12'' copper rod (89275K461)

You will also need a Dremel with a cylindrical grinding bit, a drill press, and cutting oil for this job.

Write-up:
Cut a 19/32'' length piece off of your square copper rod and grind down one end of it with a cylindrical grinding bit on the Dremel.


Bust out the drill press and drill a 1/8'' hole 1/8'' from the flat side of the piece. Use cutting oil to lubricate the drill bit and prevent overheating. You should also grind down the top of the nub at this point to fit the bolt sled, but I forgot and did it later.


Now build yourself some sort of jig to hold everything in place. I also ended up wrapping a rag soaked in water around the end with the plunger tube to prevent melting. Ideally you would do this before gluing on the bottom of the old breech. Make some marks to designate where you want the nub to go and then rough up both surfaces and clean them with rubbing alcohol. Apply flux to the bottom of the copper nub and carefully put it into place. If you ground it down properly, it won't fall off. Now hit it with the flame from all sides for a minute, then touch the solder to the base of the nub and solder should flow into place due to "capillary action."


Finished product--not the prettiest but it gets the job done! Clean up any solder with the Dremel.


Here are some glamor shots with the new nub in place:






So there you have it! The greatest problem with the Angel Breech has finally been solved. The fact is, metal is just too slippery to be held with epoxy, even after roughing the bejeezus out of it. After soldering things into place, my breech will never be breaking in that spot ever again. A silver solder joint is actually stronger than the metals you are joining! Pretty legit, eh? If you guys want to read the full write-up for my Longshot, check it out at my blog. I modified SgNerf's design and managed to squeeze 300 fps out of it!

I hope you guys enjoyed this original write-up.
~T da B

Edited by T da B, 14 May 2013 - 01:37 PM.

[andtheherois]

This is a pretty cool mod. Good job. I know of a few other users that did a metal welded nub, though no one actually took the time to do a write up.

However I doubt your claims of 300fps. I'd like to know exactly what you did. I know it is possible using certain setups, none of which would be war usable.

Edited by andtheherois, 11 May 2013 - 05:38 PM.

[T da B]

This is a pretty cool mod. Good job. I know of a few other users that did a metal welded nub, though no one actually took the time to do a write up.

However I doubt your claims of 300fps. I'd like to know exactly what you did. I know it is possible using certain setups, none of which would be war usable.

Thanks for the feedback! Check out the link to my blog to see exactly what I did.

[azrael]

Solder is not an adhesive. Let me know how well that works out in the long term.

[shmmee]

It surprises me a bit, but I've encountered some push back and fear when I have suggested soldering in some of the mods I've done. I had a nut soldered to a brass breech in front of a pas. As the pas was primed an attached bar would also open the breech to accept a chambered round from a clip and then close it again as the handle was returned to the forward position. I eventually abandoned it due to clip stability issues, but the breech - and the soldered attachment was solid.

The only worry I see is that the smaller surface area might tend to bend or distort the brass tube as it's placed under load of the [k26]. It's still pretty early on, but after you get a few hundred rounds through it would you mind posting an update about durability? That really does look like a good long term option though. And like you said - that soldered joint is stronger than the materials it's joined to.

Another thought - copper is insanely expensive. Are brass square tubes of that size available? Perhaps a square tube can be soldered in place and then back filled with epoxy or epoxy putty? There might be some loss to durability, but it would be cheaper. A solid steel bar stock might also be more economical.

[T da B]

It surprises me a bit, but I've encountered some push back and fear when I have suggested soldering in some of the mods I've done. I had a nut soldered to a brass breech in front of a pas. As the pas was primed an attached bar would also open the breech to accept a chambered round from a clip and then close it again as the handle was returned to the forward position. I eventually abandoned it due to clip stability issues, but the breech - and the soldered attachment was solid.

The only worry I see is that the smaller surface area might tend to bend or distort the brass tube as it's placed under load of the [k26]. It's still pretty early on, but after you get a few hundred rounds through it would you mind posting an update about durability? That really does look like a good long term option though. And like you said - that soldered joint is stronger than the materials it's joined to.

Another thought - copper is insanely expensive. Are brass square tubes of that size available? Perhaps a square tube can be soldered in place and then back filled with epoxy or epoxy putty? There might be some loss to durability, but it would be cheaper. A solid steel bar stock might also be more economical.

I see what you're saying about the brass distorting--I highly doubt it will bend, but I'll post an update after warring with the LS.

As far as replacements for copper, I was unable to find anything cheaper on Mcmaster than the rod I used. Initially I wanted to just stick to brass, but K&S only makes hollow brass tubing in the desired size and I didn't want to risk the integrity of the nub. Solid steel would definitely work, but would be much harder to machine.

[koree]

I think you're kind of misrepresenting how much of an improvement your modification has over SGnerf's. You can't compare your 300 fps initial velocity to his (210 fps) considering you are using #6 slugs darts (about 0.63 grams) while he's using much much heavier 1.1 gram silicon weights. However, you can make a better comparison using the kinetic energy that is being delivered to your darts. Using KE=1/2 * mass * velocity^2 you'd see that you get about a 17% increase in kinetic energy. Assuming your LS imparts the same amount of kinetic energy into a 1.1 gram dart, your blaster would get 227 FPS, about a 8.1% increase in initial velocity. SGnerf's gun would shoot your slugs at about 277.5 fps.

Edited by koree, 11 May 2013 - 07:55 PM.

[Kronos Nerf Mods]

I assume you are using plumbing solder not solder for wires, but correct me if I am wrong.

[T da B]

@koree: Good point--I will make note of this in my write-up. I thought #6 slugs were around 1 gram but maybe not.

@Kronos: Correct. Electrical solder for wires usually has a rosin core, meaning the flux is built into the solder itself. For this application you want the flux to be separate in order to designate the area you want the solder to stick to.

Edited by T da B, 14 May 2013 - 02:40 AM.

[Zorns Lemma]

Solder is not an adhesive. Let me know how well that works out in the long term.

https://en.wikipedia.org/wiki/Brazing

[azrael]

https://en.wikipedia.org/wiki/Brazing

Which isn't soldering.
Look at all the filler metals listed, and then look at solder. It's made of lead/tin, usually. He says he's using silver solder, which usually contains maybe 3% silver.

Solder requires more of a mechanical connection/joint for it to be anything close to trustworthy for putting pressure on.

Edited by azrael, 12 May 2013 - 01:04 AM.

[T da B]

Which isn't soldering.
Look at all the filler metals listed, and then look at solder. It's made of lead/tin, usually. He says he's using silver solder, which usually contains maybe 3% silver.

Solder requires more of a mechanical connection/joint for it to be anything close to trustworthy for putting pressure on.

From the product description of the silver solder I used:
"Five times stronger than ordinary solder with tensile strength of 10,000-25,000 pounds per square inch. Will stretch under high pressure, but not break under constant stress and is vibration-resistant."

For comparison, J.B. Weld has a tensile strength of 3960 psi and polycarbonate has a tensile strength of 8,000 to 16,000 psi.

~T

[azrael]

What's the composition? I don't deny that there are legit hard solders out there, but it's important note exactly what you used if others are to use this as a guide.

[T da B]

What's the composition? I don't deny that there are legit hard solders out there, but it's important note exactly what you used if others are to use this as a guide.

Chemical Composition:
Sn - 94%
Ag - 6%

Solidus:
430°F (221°C)

Liquidus:
535°F (279°C)

Recommended Joint Clearance:
0.002"-0.007"

NSF:
51

ASTM:
B32 Grade Sn95

I went the soft solder route, since it was incredibly cheap. This type of solder is mainly used for high temperature, high reliability interconnect applications, and is more than enough for a [k26] as indicated by the tensile strength. Hard solder isn't the only solder that can handle a lot of stress!

~T

[shmmee]

See what I mean by push-back? You've probably spent more time and posts defending soldering/brazing and material choices than discussing your mod, and the unique aspects it grants - even after presenting potential tensile strengths that were almost twice as strong as polycarb.

If only long shots were still in production I would suggest a destructive test - stuff it so full of springs that it approaches the point of obscenity and see what breaks first. Maybe you could do a second sacrificial breech for an elite blaster and stack springs till the priming bar bends. My imaginary digital currency is on the bolt sled breaking before your soldered joint goes.

Edited by shmmee, 14 May 2013 - 04:13 PM.

[azrael]

Discussing the technique is discussing the mod. His details reveal a lot about what was done here. So for this application, the torch was overkill. Anyone who wants to try your technique and verify it can use a soldering iron, if they use the same materials.

I don't know how well that solder will work, it's hard to say what that tensile strength really refers to. I've used solder of similar composition for electronics, and I can't say I would trust if it didn't have more of a mechanical bond. Like a slot that a rod would fit into, if that makes sense. That's a joint I would trust mechanically, especially to hold up under stress from a different direction.

Hopefully it holds up, but you said it yourself, it's a soft solder.

[shmmee]

... the torch was overkill. Anyone who wants to try your technique and verify it can use a soldering iron, if they use the same materials...

I've done quite a bit of soldering with both an iron and a torch, and as was pointed out earlier in this thread this is brazing and not soldering. I was rolling my eyes that the distinction was being made thinking "what we call clips are actually called magazines, what we call turrets are actually called cylinders, why are we splitting hairs over the nomenclature?" but I now see the point in making the distinction between brazing and soldering. A soldering iron wouldn't have the wattage to heat the copper enough to melt and bond the solder. The torch isn't overkill, it's necessary with a heat sync as big as that piece of copper.
Feel free to try it though. I wouldn't mind being proven wrong. It would reduce the cost of tools required and open the availability to more nerfers.

Edited by shmmee, 14 May 2013 - 04:53 PM.

[Zorns Lemma]

Anyone who wants to try your technique and verify it can use a soldering iron, if they use the same materials.

A soldering iron does not have the power to deliver enough heat quickly before the energy dissipates through material conduction and surface heat loss on a joint like this.

[azrael]

Depends on what kind of iron, and if you have the right tip. I'm pretty sure mine could. Just turn it up all the way to 900 degrees Fahrenheit. I use a Hakko FX-888.

[Nerfomania]

Depends on what kind of iron, and if you have the right tip. I'm pretty sure mine could. Just turn it up all the way to 900 degrees Fahrenheit. I use a Hakko FX-888.

I doubt this greatly. Brazing is entirely different as you have to heat up the material itself to the melting point of the solder. With little to no heat dissipation. Like others have said, the breech itself becomes a huge heatsink. A HUGE heatsink.

For example. I do HVAC work a couple times a month to make some extra $$$.

We use a Oxy-acetylene torch to do our brazing for HVAC lines to the Condenser and Coil linesets. They are copper.

That flame is well over 6000 degrees Fahrenheit, and about a foot away from where we do the joint is usually only warm to the touch after brazing.

It takes about 5-10 seconds of direct heating for us to get any of the solder to flow, now granted we are using a special silver-based solder. But I think my point is made.

I simply do not believe that a soldering iron is suitable for this job. Not that it wont do it (I have no idea how powerful the irons get), it just likely wouldn't have the power capacity to allow proper flow by capillary action into the joint.