354 replies to this topic

[CaptainSlug]

That is correct, Analog. Lexan is a brand of Polycarbonate that is widely available. To address the real question, though, 3/8" is WAY too thick for anything but plunger rods. The design is around specifically dimensioned components that cannot be altered without altering everything else.

I left some tolerances around the 1/4" thick parts just in case someone were to purchase sheets in metric thicknesses.
But the above posters are correct. The clearances between the two frame pieces and the catch plate are too close for all of those parts to be made from 3/8" thick sheets. You would have to make way too many changes to all of the relevant holes in the side plates and grip in order to make them fit.

[mindlord]

Alright! First the good news! Another +bow Rev. 2 has graced this world with its presence.



She's not the prettiest but she'll do.





Now on to the bad news. Despite my best efforts I have been unable to get this gun to fire past maybe half of what its range should be (50ft at best ).
I have followed CaptainSlug's instructions to the best of my ability and everything seems to be in working order. Now in hopes of getting rid of any simple mistakes I could have made, I will give you as much information as I can about My bow.

This picture, as you can tell, is the plunger head. It comes right up to the hex bushing adapter.



I have a clean seal using 2-3 layers of aluminum tape then a layer of Orange duct tape over that. I did NOT repeat NOT over tighten the Bolt there.



The gun cocked.



This is a temporary barrel I rigged up until I can make my breech barrel. It is 9/16 Brass in the front (where the stephan goes) nesseled inside of that is 17/32 Brass. Around those two is 19/32 Brass and that is all inside 1/2' PVC. To my knowledge this barrel should be more then adequate.
So that's 17/32 in 9/16 in 19/32 in 1/2' PVC.



The stephans I use are Captainslug's. Felt tip, #8 washer, and black FBR. They are roughly 2 inches Long. The lubricant I use is from Home Depot. It is Danco Inc. Silicone Grease. Is works fine in all my guns so I don't think the problem lies there.

Help guys, your my only hope. My Mav is getting better ranges!

[diamondbacknf1626]

This would generally not need to be asked, but which end are you putting the dart in? You said in the 9/16"?

[mindlord]

Yes I am putting the dart in the 9/16. The smaller 17/32 Brass is only to make sure the dart will not get sucked back up into the gun. The 19/32 brass was just laying around and cuts the space down between the PVC and the 9/16 brass.

Sorry for the confusion.

[diamondbacknf1626]

Yes I am putting the dart in the 9/16. The smaller 17/32 Brass is only to make sure the dart will not get sucked back up into the gun. The 19/32 brass was just laying around and cuts the space down between the PVC and the 9/16 brass.

Sorry for the confusion.

How long is the piece of 17/32" and the 9/16"?

Do you ram the dart all the way down the 9/16"?

What are your darts weighted with?

How much lubricant did you use?

Is the spring the [k26] like it should be?

Edited by diamondbacknf1626, 09 May 2009 - 02:19 PM.

[mindlord]

Yes I am putting the dart in the 9/16. The smaller 17/32 Brass is only to make sure the dart will not get sucked back up into the gun. The 19/32 brass was just laying around and cuts the space down between the PVC and the 9/16 brass.

Sorry for the confusion.

How long is the piece of 17/32" and the 9/16"?

Do you ram the dart all the way down the 9/16"?

What are your darts weighted with?

How much lubricant did you use?

Is the spring the [k26] like it should be?

How long is the piece of 17/32" and the 9/16"?
17/32" x.014 9/16" x.014 Same lengths as if you were to pick them up from Ace Hardware.

Do you ram the dart all the way down the 9/16"?
I have it currently about half way down the PVC. I think what I will try next is to only use 9/16 and have the dart as far down as I can

What are your darts weighted with?
These Washers. The same washers CS recommended. Also has a Felt tip.

How much lubricant did you use?
A liberal amount.

Is the spring the [k26] like it should be?
Yes. Here.

[CaptainSlug]

I've never seen anyone use a nested brass barrel with this. Most +bow users are just using a 12-inch length of one size of brass or polyester.

You don't need anything extra to prevent the dart from being sucked into the plunger tube because the bolt that holds the bushing in place does that fine.

Edited by CaptainSlug, 09 May 2009 - 09:50 PM.

[mindlord]

Alright I think i figured out my problem. I'm not sure exactly why but somehow the Nested brass barrel was giving me problems. Basically what I have setup now is a breech. I have 1/2' PVC with a 2 inch cut out. Inside that I have 19/32 brass also with a 2 inch cut out. Then I have 9/16 brass sliding into the 19/32. It works pretty well and now I am getting normal 100+ ranges.

Moral of the story. Don't overdo it.

[NerfDude1138]

Some more +bows for the thread:

The top one is my new prototype using a different material:


This is not for sale (yet) as I am still working the bugs out. Consider it a teaser.

The color is the color of the material, it has not been painted. The only paint used was on the PVC coupler at the front. The "shell" pieces are made of black Delrin which is similar to polycarbonate, one difference being that it is more expensive. Another difference is that it scratches more easily and that is the "bug" that I am trying to work out. Anyway, here it is from the front:


The internals as you see are the same, clear.



I used black foam in the pistol grip and swapped out the white nylon rod for black.

[Darken]

And so why exactly do you want to use it if it's more expensive and less durable?

[Darken]

The reduction of fumes would probably get me using it. I hate having the cut things with fumes coming out, cause it makes it hard to work with.

[cheesypiza001]

The reduction of fumes would probably get me using it. I hate having the cut things with fumes coming out, cause it makes it hard to work with.

Get one of these:



I picked one up at my local hardware store a few months ago and it makes everything much easier. Though it does cost about $40, it is well worth it. Some of the tools I use say on the side, "This product contains chemicals known to the state of California to cause cancer." (or something like that)

[NerfDude1138]

And so why exactly do you want to use it if it's more expensive and less durable?

It's generally easier to work with. It's not at all prone to shattering, for example, or even simply crazing next to where you're drilling. Also you can laser-cut it without the toxic corrosive fumes polycarbonate would emit. And surface scratches are not the be-all/end-all of durability. I would suspect that it might actually prove to be more durable when facing the typical damage threats nerf blasters mostly do - like being dropped just a few feet, or being tossed into a box with other plastic stuff.


EDIT: yeah, yeah ... I know about respirators and all sorts of stuff. But the people who own the laser that I get to use have said no polycarbonate, and that's that. They're happy to let me cut Delrin.

Thanks Bob for the assist.

Yes I have found the Delrin to be quite durable and working with it is very similar to that of polycarbonate. The reason I chose Delrin was that I wanted to experiment with new materials, new colors and to see what else could be done with the +bow design. The performance of the finished product is identical to that of a polycarbonate +bow, the only problem I have had is one of aesthetics as I said. Yes, expense is also a drawback, but I was willing to spend a few more dollars for sake of experimentation.

[CaptainSlug]

Delrin works fine and it machines beautifully. If you want an opaque black look without the added expense you can also use vinyl dye to recolor the polycarbonate parts.

Get one of these:

Won't protect you from plastic fumes. If the plastic you are cutting is producing fumes, then you're cutting it with the wrong tool/speed/coolant and you need to stop.

Edited by CaptainSlug, 13 May 2009 - 10:18 AM.

[cheesypiza001]

Get one of these:

Won't protect you from plastic fumes. If the plastic you are cutting is producing fumes, then you're cutting it with the wrong tool/speed/coolant and you need to stop.

Is it still affecting me (when I where the respirator) even though I cannot smell even the slightest presence of a usually odor-full substance? A lot of times when I am cutting with my dremel, The plastic produces fumes that smell like.....well, plastic. Does this happen to other people? (By the way, my dremel only has two speed settings, one of which is really low powered, and the other which is very high powered....nothing in between.)

[CaptainSlug]

Is it still affecting me (when I where the respirator) even though I cannot smell even the slightest presence of a usually odor-full substance? A lot of times when I am cutting with my dremel, The plastic produces fumes that smell like.....well, plastic. Does this happen to other people? (By the way, my dremel only has two speed settings, one of which is really low powered, and the other which is very high powered....nothing in between.)

You shouldn't be using a dremel to cut plastic. The most harmful components of the fumes cannot be effectively filtered out. Especially if you are cutting polycarbonate or PVC with the wrong tool.

Edited by CaptainSlug, 14 May 2009 - 12:21 AM.

[cheesypiza001]

Is it still affecting me (when I where the respirator) even though I cannot smell even the slightest presence of a usually odor-full substance? A lot of times when I am cutting with my dremel, The plastic produces fumes that smell like.....well, plastic. Does this happen to other people? (By the way, my dremel only has two speed settings, one of which is really low powered, and the other which is very high powered....nothing in between.)

You shouldn't be using a dremel to cut plastic. The most harmful components of the fumes cannot be effectively filtered out. Especially if you are cutting polycarbonate or PVC with the wrong tool.

Is it bad to be cutting PVC with a cutting bit like this?

[MoonMaster]

Yes, I believe using a bit like that is dangerous. It is an abrasive cutting bit, meaning it will heat up the plastic. There are special bits that don't heat the plastic to fuming temperatures but instead cut out little pieces bit by bit.

[Lt Stefan]

I have a question about the cuts. I have a scroll saw, but do you need some sort of fence or something? Because some of the cuts I've seen on the +bows here are perfectly straight, and to me that doesn't seem possible without a fixed guide. Unless I'm just missing something.

[CaptainSlug]

I have a question about the cuts. I have a scroll saw, but do you need some sort of fence or something? Because some of the cuts I've seen on the +bows here are perfectly straight, and to me that doesn't seem possible without a fixed guide. Unless I'm just missing something.

You simply need a steady hand and patience when feeding the parts through the scrollsaw blade.

[Lt Stefan]

Ok. And when my saw is on, the blade slightly moves side to side as well as up and down. Is this normal?


And does the above apply to cutting circles as well?

Edited by Lt. Stefan, 30 May 2009 - 11:08 AM.

[Lt Stefan]

The saw cost arround $110 and it's a Skil model. It moves about a millimeter to the side.

[A side of nerf]

I use a configuration that consists of a jig-saw, inverted and bolted to a table. It's blade wobbles about a millimeter or so as yours does. With careful precision, I can still craft a straight line.

[CaptainSlug]

Ok. And when my saw is on, the blade slightly moves side to side as well as up and down. Is this normal?


And does the above apply to cutting circles as well?

Your blade isn't tensioned enough. Pluck the blade like a guitar string as you tighten it. Once the pitch stops changing the blade is tight enough.

[Lt Stefan]

There's not really a dial to do so. There is a lever, you pull it up, and it releases. Then when you put the blade on, you push the lever down, and it automatically tightens it. I don't really know how to tighten it more so.