23 replies to this topic

[Glint]

Alright, so I am a tiny step away from compleing my Doomsayer. I just have one small (well, hopefully small) problem.

When I put it together and shoot a dart, the dart comes partway out of the barrel and then just stops. I just can't figure out what it is. Here's what it can't be:
- Can't be rotoation. The turret's rotating perfectly
- Can't be dart fit. if anything, my darts are a bit loose.
- Can't be plunger head seal. I have a great plunger head seal with the E-Tape

The only thing I can think of would be plunger tube to turret seal. But that doesn't make any sense. I have a rubber washer in there that fits perfectly. Before the washer I had an O-Ring that was too thick so it pushed too hard against the turret, so I had sanded down part of the plunger tube. It still didn't work. Then when I put on the rubber washer, the plunger tube moved back and forth. So I built up the end with epoxy putty then sanded it down until the plunger tube length was practically good as new (lengthwise).

So the only thing I can think it would be would be the seal (which doesn't make any sense to me) and the plunger tube may be too long or something (but I don't want to sand down the putty too much and then have it too short again). Can someone pelase help me?

I can post internal pics if needed.

[Applefury]

How long are your barrels? What springs do you have in there? Are you sure your plunger-head seal is perfect?

[Glint]

How long are your barrels? What springs do you have in there? Are you sure your plunger-head seal is perfect?

10 inch barrels. Longshot spring + Stock Spring.

It's not absolutely perfect, but I find if I put more E-tape on there I can't fit the plunger head (the rubber washer part) into the plunger tube without haveing to squeeze it smaller and then quickly shoving it down there.

The part that I find is making the seal is the part that FA24 filled with hot glue (as I did), with the rings below the rubber part. That part's making the seal instead of the rubber washer for me. Is that normal? Does it make a difference?

Edited by Glint, 26 April 2009 - 03:39 PM.

[CaptainSlug]

How long are your barrels? What springs do you have in there? Are you sure your plunger-head seal is perfect?

Longshot spring + Stock Spring.

That's not good enough for longer barrels.

[Glint]

Longshot spring + Stock Spring.

That's not good enough for longer barrels.

Are you saying that the only reason the darts are stopping mid-barrel is because the springs aren't strong enough to push it through?

I find that kinda hard to believe, that an inch or two in barrel length difference would cause it to suddenly work or not work. But maybe you're right and I don't know anything.

Edited by Glint, 26 April 2009 - 03:46 PM.

[CaptainSlug]

Longshot spring + Stock Spring.

That's not good enough for longer barrels.

Are you saying that the only reason the darts are stopping mid-barrel is because the springs aren't strong enough to push it through?

I find that kinda hard to believe, that an inch or two in barrel length difference would cause it to suddenly work or not work. But maybe you're right and I don't know anything.

The stock spring isn't that great, and the longshot spring also is pretty marginal. You need a much stronger spring if you want to use barrels longer than 6 inches.
You're lacking the only plunger spring from FA24's write-up that really matters: the industrial strength one.

[Glint]

The stock spring isn't that great, and the longshot spring also is pretty marginal. You need a much stronger spring if you want to use barrels longer than 6 inches.
You're lacking the only plunger spring from FA24's write-up that really matters: the industrial strength one.

So the springs are the make-or-break thing here? Because I don't really have a suitable industrial spring that could go in there, and I don't want to trim down the barrels to six inches.

I'm pretty sure it's more than that, because here just a longshot and a stock spring were used, and ranges are in the 90’s.
I just dont' want to start jumping to conclusions and do things I don't have to here.

I'll post internal pics A.S.A.P.

[rokor]

CS is correct, but not totally. If you want to have only the Stock spring and LS spring in there then the friction from all that E-Tape and stuff of the plunger head will relut in a slower moving plunger, resulting in the air going places it shouldn't go due to the smaller burst of air. If you can, go back to the stock plunger head for a few shots and let me know if that's the problem, if not, try a stronger spring.

[Glint]

Alright, here are some pictures. If more in-depth ones are needed, just let me know;

If you can, go back to the stock plunger head for a few shots and let me know if that's the problem, if not, try a stronger spring.

I did as you said, and the only thing that happened has the darts traveled even shorter down the barrel.

But something you said popped an idea into my head. Maybe my plunger rod's too heavy. i used four brass bars on each corner of the + it forms, and it seems really heavy to me (for a plunger rod and compared to it stock). Do you think that might be a problem? If so, I could try and take off two of the brass bars so there's only one on each corner... It might be tough as they're held on my superglue and then brushed with Epoxy, but if it'll make a difference then I'll do it.

[Gazoo]

In my RFSG I have the stock spring, stock plunger head, stock plunger tube, stock tube-turret seal, 12" PETG barrels and I have no problem with the darts leaving the barrels. It's actually quite good, so I can just imagine what's it's gonna be like after a spring upgrade.

[DrSpaceman]

I've seen pictures of this and I've always wondered what is it? The PT part that you are supposed to hotglue? And why is yours not connected to the PT?

Also, what size brass bars are you using?

Edited by DrSpaceman, 26 April 2009 - 06:57 PM.

[Lt Stefan]

Your problem is

1. The darts. Loose is bad. You want them tight. Especially with that long of a barrel. The air gets arounf the dart and actually pushes it back. What I'm doing is putting 4"-6" stubs of 17/32" brass at the base, which will hopefully help. a lot.

2. The springs are most likely too weak. You can use 1.5 Ace #49 springs + the stock spring. That's what I did. You have to sand the plunger rod a little to make it fit though.

3. Plunger seal. Replace it with a washer sandwich.

[Glint]

Alright, I just added a trimmed down Ace #49 spring (trimmed down meaning like half an inch shorter than the stock spring). I had to re-Plumbers Goop inside the rubber washer head because I had to pop through where I had it before to her the head back on. So I'm waiting for that to dry.

In the meantime I'm Plumbers Gooping around the base of the yellow casing of the turret. Seems the outside yellow shell is a tiny bit crooked, so one half of the turret has some air leaks when I plug one end with my finger and blow down the barrel. I'm expecting it's because I didn't use enough PGoop when I forst put the base of the turret onto the yellow casing.

I also removed two of the brass bars I had on the plunger rod to decrease the weight a little bit. There are still two on opposite corners keeping it reinforced.

3. Plunger seal. Replace it with a washer sandwich.

What do you mean washer sandwich? What kind of washer sandwich?

Edited by Glint, 26 April 2009 - 07:44 PM.

[Lt Stefan]

Use proper sized fender washers and neoprene washers. Meaning like two 1 ¼” Fender Washers with a 1 ½” rubber washer in the middle. You wilol need to grind down the fender washers however.

[Glint]

I've seen pictures of this and I've always wondered what is it? The PT part that you are supposed to hotglue? And why is yours not connected to the PT?

Also, what size brass bars are you using?

You're not supposed to be gluing anything on the PT. There's a hole in the end of the PT itself which holds that thing that I'm holding in the picture. It makes sure the air goes into the barrel directly, so it kinda like minimizes and directs the air to the hole in the back of the turret.
Uhh... the tag says 1/8 x 3. They were the smallest they had at Home depot and they fit unfer the spring, so I used them.

Use proper sized fender washers and neoprene washers. Meaning like two 1 ¼” Fender Washers with a 1 ½” rubber washer in the middle. You wilol need to grind down the fender washers however.

I don't really see what that will do apart from elongating the length on the plunger tube more than it need to be. Why won't just a normal rubber washer work like I have??

Sorry I'm asking so many questions here. I just want to get facts straight and know why something will or wont work so I know what I'm actually doing if/when I do it.

Edited by Glint, 26 April 2009 - 08:00 PM.

[Applefury]

Could we get a picture of it closed from the front where the barrels are. I want to see the turrets orientation. If it is sagging downward then that could be your problem, you may have dremel'ed the shell incorrectly so the turret sags and makes for a bad seal. Try pushing up on the turret and/or backwards and firing to see if it makes any differences. From my experience Doomsayers are quite finicky and one moment will fire with a great amount of force and other times where it will just barely escape the barrel.

[Glint]

Well I did cut the shell too far down, but I built up the walls around with Epoxy Putty. I'm pretty sure it's up high and not sagging as I've checked myself a couple times, but my eye could be different.

My turret's currently drying from some PGoop applied, so I'll get that pic tommorow or Tuesday sometime.

Edited by Glint, 26 April 2009 - 08:44 PM.

[Seven7h Man]

Lube the plunger tube and head. Did wonders for me.

Edited by Seven7h Man, 26 April 2009 - 08:55 PM.

[umpshaplapa]

Lube the plunger tube and head. Did wonders for me.

He's right about that. Just make sure you get some O-ring/ Silicon lube. And not the spray stuff, get the really gooey type they sell at Ace.

[AssassinNF]

Your problem is

1. The darts. Loose is bad. You want them tight. Especially with that long of a barrel. The air gets arounf the dart and actually pushes it back. What I'm doing is putting 4"-6" stubs of 17/32" brass at the base, which will hopefully help. a lot.

2. The springs are most likely too weak. You can use 1.5 Ace #49 springs + the stock spring. That's what I did. You have to sand the plunger rod a little to make it fit though.

3. Plunger seal. Replace it with a washer sandwich.

I call bullshit.

1. I used SCH80 - which fits my darts loosely. Overly tight barrels make rear-loading a pain, too.

2. My doomsayer only has the stock spring and a Longshot spring, and it hits 80's and 90's, with foot-long barrels. There's no way that the springs are too weak.

3. My plunger head is about as close to stock as it gets.

If the springs or barrels were the problem, Glint would be experiencing sub-par ranges, not zero ranges. His problem is most likely a fucked up seal somewhere. I would double check the seal between the plunger tube and the turret, and the seal of the barrels inside the turret.

[nerkum]

If you are using OMC PETG and you are shooting a streamline (or same size as a streamline like swiftnerf's foam) then it is your dart.

I can get my Doomsayer to do this exact same thing. It is a springer, so a snug fit is best otherwise all the pressure is going to go right around your dart.

To test this, take a streamline and stuff a wendy's straw (or etape around the outside of the dart) into the hole to bulge out the foam a little. Load it up and shoot.

Two ways to fix this, one put tightening rings in the PETG, and two coat the inside of the PETG with a one or two layers of plumbers goop to get a snug fit.

Edited by nerkum, 27 April 2009 - 12:55 AM.

[Glint]

Okay, so after adding the new spring it shoots. But I still have a few kinks.

Now the turret doesn't rotate properly. The top barrel never lines up with the center of the gun. it still shoots, but the barrel isn't aligned with the plunger tube, it's off a bit when I look down the barrel. It still shoots though.

Then sometimes I'll pull it back to rotate it and it won't go the rest of the way when I push it forwrard (the advancing arm mech stops because the priming handle doesn't even go all the way forward, or at least that's what it seems like).
When it's stuck like that I can sometime fix it by pulling the priming handle abck, holding it there and pulling the trigger, then releaseing it back to forward positon. When that doesn't work I can simply fire the gun and the turret sometimes snaps back to working. Then when neither of those work after a couple tried I'll just wiggle the turret around a bit manually until it falls abck into place.

And then sometimes I'll pull it back and it'll turn and the gun'll be primed, but when I try and rotate it again it just won't, as if the advancing mech isn't there at all. Then I repeat the steps above.

So it's a step forwards, but still not in rgeat working order. I could use it, but I'd have to be careful with rotating the turretand it's not firing as far as it should (I'd guess about 40 feet with a good dart). Any suggestions now?

Edited by Glint, 28 April 2009 - 03:38 PM.

[DrSpaceman]

Try changing the amount of 1/8 pushnut fasteners you have on the rotating mech.

[Glint]

I've got two of them on there right now. Three might be too many and push against the shel where the peg goes in, but maybe not. I'll try wigglig them around and fiddling wwith them a bit; that's what FA24 recommended to do in the writeup if it wasn't rotating right.
Thanks for the suggestion.