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Discussion Starter · #1 ·
Before even reading this post, i suggest you take a look at this thread first and read through all the pages so you understand what the J-hop is and the many possibilities available.

http://www.airsoftsociety.com/forums/f10/j-hop-34376/

Unfortunately, the thread on airsoft society has seemed to dwindle off a bit, and i haven't found much more testing done on this. If your going to take a stab at this mod, please share your results with everyone here so we can learn from each others mistakes and find a good solution. Once we find something that works, this will be a much easier method to making R/ER-hops or any type of hop for that matter.
 

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ok, im doing my KJW 1911 stock barrel right this moment, and instead of ducktape like i did for my D boys SPR, i am using saran wrap to get to the requisite thickness. we will see if that is smooth enough

Edit- that does not work, the saran wrap sticks to itself to much, i also tried aluminum foil and wax paper, neither really worked.
 

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@Solaris- If you have packing tape or teflon tape those would probably work best. Try the packing tape first because it seems less likely to get tangled.
 

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I do have Teflon tape, issue is however that it is not very wide, i think the best option would be flashing tape for fixing duct work, similar i imagine to the tin tape MilsimTech used. as for having it not stick to that tape, maybe a carefully applied layer of grease?
 

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im at work right now, but when I get back home the first one I did should be done curing, ~18 hours should be plenty. I also started a second barrel, but on this one I used a piece of wax paper to pull tight around the outside so it looks nicer, then pulled it off to just the edge of the barrel window, will see how that one cures.

The barrel i will be doing the accuracy test with will be a stock Dboys barrel from 2011 using a stock G&G green bucking, flat hopped, in a stock metal hop up unit.
 

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Ok folks, I tried this, rather scepticaly, on my scout M14 with 18mm length barrel window, shooting at 347fps w/.2.

I used some 6mm brass tube, bought from the local DIY store, as a filler piece.

I inserted the tube into the barrel, and then using a #1 size model brush painted the exposed tube in the window with silicon grease, being carefull not to get any on the barrel window edges.

As 1 of my trades is a plumber silicon sealant isn't a problem to find..... so I applied a layer of Dow Corning 781 clear silicon sealant to the window and pushed into place/shape with my finger, then with plenty of good old fashioned spit applied to a straight edge I tooled the top so that it was flat and level to the profile of the barrel.

I left this to cure over night and then the following morning I carefully removed the packing tube, to allow the inside to cure thouroughly. When this was cured I cleaned all the grease from the inside of the barrel and reassembled the hop etc.

Tonight I got round to trying it out and initial tests show good results on lift, shot consistency and accuracy. How it will stand up to repeated use and high fps I have yet to test, but given that it now only uses the rubber as a nozzle seal and to hold the silicon 'nub' in place, I see no reason as to why it shouldnt last a fair while :shrug:

1 thing I have noticed is I've lost approximately 10 fps, I can only put this down to the extra drag being created by the slightly softer and stickier surface the BB now gets dragged along :shrug:


To my mind there is only 2 things you need to get spot on, and those are internal smoothness and the external uniformaty in thickness, as they are the only things that are going to adversley affect hop performance
 

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Discussion Starter · #11 ·
Great! I'm glad this worked out for you. And I apologize to everyone since I kind of went MIA on this thread for awhile, I've been having internet issues here at home.

The brass tube was a great idea. If I can find some 6mm tube/rod locally, then I'll give it a whirl. You said you picked it up at a DIY store. Are you referring to a hobby shop? I'm wondering if any of the corporate hardware stores would carry anything 6mm.

As soon as I can get the funds together, I may order some different mold casting solutions and try some of those silicone mixes since they leave an incredible smooth and even finish.

Glad to see some success with this!


As for the Tin tape that I used, I noticed it didn't come out smooth enough, and actually seemed to stick to the silicone when removing it, which may have damaged the R-hop. I used petroleum jelly to keep it from sticking, but it looks like that wasn't the right stuff to use. Back to experimenting.
 

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I tried it using some clear silicone 1 caulk with a plastic rod as the filler. The rod was originally an unjamming rod from my well mb10 but I have since cut it up to use for other things. I wrapped packing tape around it to get it to the right diameter. I just piled the silicone up and sanded it smooth once it dried because smoothing the uncured sticky stuff is pretty hard. I took the rod out a little while ago and found the silicone mushroomed inside the barrel because it got into the small crack in between the rod and the inside of the barrel. Took me a while to clean it out. Seems I'm also back to experimenting.

There is something called oogoo which is just corn starch mixed with silicone 1 caulk. Some guy posted how to make it on instructables and all the uses. It is basically a really fast drying silicone caulk. The moisture in the corn starch activated the silicone from the inside out, instead pf waiting for the moisture to seep in from the outside which can take a while. I'm going to experiment with it to see if it can fix the problem of it being too sticky like what Vindi found out.
 

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Discussion Starter · #14 ·
There is something called oogoo which is just corn starch mixed with silicone 1 caulk. Some guy posted how to make it on instructables and all the uses. It is basically a really fast drying silicone caulk. The moisture in the corn starch activated the silicone from the inside out, instead pf waiting for the moisture to seep in from the outside which can take a while. I'm going to experiment with it to see if it can fix the problem of it being too sticky like what Vindi found out.
I've been meaning to try that oogoo method you mentioned. Just not sure when because I'm working on a couple secret project's right now. :tup: I may post them here if its something people would be interested in.

Seems like it has already been done; there was a guide on airsoft-barracks.

Also, I thought J-hop was original name for flat hop?
I didn't see the topic on airsoft barracks. A link would be great if you could provide one. I'm sure everyone here would be interested in reading about it.

I was under the presumption that the flat hop involved flipping the bucking inside out and grinding off the "bump" and "alignment lip", basically allowing you to rotate the bucking to use a smooth factory molded surface of the bucking. Then using a new hop nub of some sort (nerf dart, eraser, etc) to push the smooth surface down into the hop window. But I'm new to all this, so maybe I presumed wrong. Someone please fill me in if that's the case.
 

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@ Milsim..... a flat hop refers to the R and ER style hops or any other method that you use to create a long flat pressure pad to hop the BB.


@ all of you..... after being in the plumbig trade for the better part of 25 years I've leant that the best lube for moulding silicon is spit, but for gods sake don't put the stuff in your mouth, it tastes like sh1t and its none to healthy for you! Always wipe your finger, or tool of choice, clean before going back in for more spit, and dont be affraid to use plenty of it, the more you use the better it will not stick to the silicon.

There is an alternative, which is ''almost'' as effective, and that is a strong mix of washing-up liquid and water, which provides almost the same libricative qualities as spit, but not quite :tup:


Gona try this in my VSR in the near future to see if it will stand up to higher fps and maintain the same level of accuracy it currently possesses :yup:
 

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I didn't see the topic on airsoft barracks. A link would be great if you could provide one. I'm sure everyone here would be interested in reading about it.

I was under the presumption that the flat hop involved flipping the bucking inside out and grinding off the "bump" and "alignment lip", basically allowing you to rotate the bucking to use a smooth factory molded surface of the bucking. Then using a new hop nub of some sort (nerf dart, eraser, etc) to push the smooth surface down into the hop window. But I'm new to all this, so maybe I presumed wrong. Someone please fill me in if that's the case.
http://www.airsoft-barracks.com/forums/topic/26048-hop-up-modification/page__pid__259489#entry259489
This one just used liquid rubber/brush on electrical tape.

As far as I know that was how flat hop was; it works fine except it might have durability issues(while R-hop, on the other hand, does not).
 

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Sorry for necro but I see this pretty cool hop-mod. I will try tomorrow with my AEG first (Arma Ak haha ) then report later
 

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I am not sure what Necro means but I am using Oogoo to make a hop and it works very well.

I put a carbon rod wrapped in packing tape inside the barrel and then form the hop into the window. In order to get a nice outer to under your modded bucking put a piece of drinking straw over it to form the outside. I slit a piece of straw about an inch long.

Paul
 
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