Time for a V6 Gun Gas Kit, or Paging MadMax

[Danke]

Give the number of GBB rifles and SMGs coming live these days I think it's time for a new version of the gas charger.

What's needed is a new system that has an included oil chamber. The charger then senses the pressure in the tank and meters the oil added to each charge to match what you'd get in an equivalent bottle of green.

KWA USA is voiding any warranty on a GBB that's been run on propane; it seems that some folks are following the model that there can't be too much oil. They're swelling up rubber parts to the point they won't function or just clogging things up beyond belief.

I'm not to worried about sending stuff across the border to get fixed but I would prefer to see the thing run as intended and not choke to a stop.

[sushicake]

IIRC its the oil that swells the O-rings, not dry propane that just dries em out.

[MadMax]

Yeah, I once considered an auto oiling design, but I couldn't keep costs down. The usual oil chamber concept is a flawed design which shoots it's entire oil charge in one go. When the liquid propellant goes through the fill stem it dissolves the entire oil charge and runs it through. If it doesn't get into the mag the remaining liquid in the chamber flashes into gas and blows the remaining oil out the nozzle.

I just couldn't come up with any reasonable micropump designs that were economical to dose oil.

As to the oil content in green gas, I have found a significant variance in oil content between makes of green gas. In fact many brands have no detectable oil altogether. If you've got a COMPLETELY empty can of gas, try cutting the can in half and see if there was any oil film remaining in the can. If gas lubricant is intended to maintain rubber seals by leaving a thin oil film, then it stands to reason that a film of oil would also remain in an emptied can. When I was hacking cans apart years ago (propane adaptor work) I couldn't find ANY oil film in gases commonly available in Canada. That may have changed by now. I get the feeling that my product has made gas bottlers, retailers, and customers take a closer look at their propellants. In any case, I found no oil film in: Toy Jack Top Gas, Jet Green Gas, Green Power (I think it was called that) gas. These cans were bone dry when they were cut apart.

As to KWA USA having swelling issues with rubber materials, I suspect that engineers at KWA Taiwan may have made some unwise material selections in their product.

Soaking a rubber in silicone oil will only bloat the rubber if it is incompatible with the oil. There are many common elastomers which are compatible with silicone oil and exhibit no absorption of silicone oil as well as compatibility with propane:

http://www.efunda.com/designstandard...SC=Propane#mat

http://www.efunda.com/designstandard...one%20Oils#mat

I suspect that they may have chosen to use silicone rubber in some of their seals. Silicone rubber is a commonly used cast rubber, but it has silicone oil absorption problems. It is a VERY poor choice as an airsoft elastomer because we use silicone oil as our gas lubrication. Additionally, silicone rubber has very poor tear and abrasion resistance. Very nearly the worst tear and abrasion resistance of common elastomers. Urethane and nitrile are both mechanically sound and compatible with the propellants we commonly use. They are industry standard materials in the pneumatic industry so they're pretty economical materials to use.

I have heard that KWA USA looks for residues of yellow dye which is added to Coleman propane for some sort of identification purpose. If this dye is detected, they void warranty. I really don't know how they came to this decision because Coleman propane and probably all fuel grade propane gases are not dosed with colored agents. Additives can present a health risk when they are combusted (the intended purpose of most fuel grade propane). In fact, fuel grade propane needs to be very clean burning for health reasons. Additionally, burn residue is not an acceptable outcome as it could contaminate a solder wetted joint that a plumber is attempting to make. The criterion for propane purity is much more strict when used in a combustion application than our expansion-pneumatic application.

Silicone rubbers are typically used in higher temperature applications with no silicone oil exposure. It's high temperature resistance makes it a good choice for cooking and applications where sterilization is an issue (the medical sciences industry loves it). You almost never see silicone elastomers in industrial mechanical applications because of it's poor tear resistance and incompatibility with mineral oil (a typical air tool lubricant). It unfortunately shows up regularly in airsoft because it's easy cast in a two component mix fashion.

If you don't believe that there isn't a yellow dye in Coleman propane, jamming the tip of your adaptor into a wad of paper towel and shoot out a slug of liquid. Let the liquid evaporate and look for a dye. As usual, do this in a well ventilated area with no open flames. I looked for dyes by filling a clear white refillable lighter so I can see the propane in liquid form. No dye.

[Danke]

It might be worth re-visiting now that the GGB world is opening up. The players could be more open to a pump that does the mixing.

If I had to make a guess about what KWA is doing is first they'll give the gun a sniff. After used you can usually pickup the odorant clinging to your hardware. Then the next step would be to work of past experience and veto items that look suspicious. With the US market being younger and less sophisticated than Canada I'd guess they'll have more younger players abusing gear and then their parents on the phone to KWA in the best hockey parent style honking about their kid and how they never abused a thing. I suspect they're in a unique position and have had to take a hard stance to fight off the calls for replacement parts.

[m102404]

I won't comment on the specifics of the KJW mags, but the WA and WE mags are essentially oversized GBB mags. The amount of gas pumped through the system is enormous and certainly dries out things fast.

A while ago a kind soul gave me a doohicky that oiled the entire tank of propane at once and it's been a godsend. I could understand the concerns the person had about injecting different things into a tank...and I think they're well founded...but for silicone oil it works just fine.

I suppose that a different kind of injector could be made that fit the fill valve of the mag (and so relieving some of the worry about tampering with the tank). The fill valve is the same as the Madbull grenade fill valve (in fact I replace the stock WE valves with those). The process would then be to inject each mag before gassing.

The bottom line is that oiling the gas source tank is easiest and most convenient....but a pre-measured way to oil the mag would be good too.

From a manufacturer/design point....since the oring material, mag gas capacity and other factors differ between rifle to rifle to mag (i.e. prowin vs. kjw vs. we mags...WE M4 vs. PDW vs. M14 vs. SCAR vs. G&P M4, etc....) it's going to be tricky to design an injector that is "calibrated" optimally for every GBBR system out there. And having a different one volume calibrated for each would be a PITA.

[RacingManiac]

They have warranty for airsoft guns now?

[Danke]

Originally Posted by RacingManiac

They have warranty for airsoft guns now?

You bet they do (as an aside for anyone they also know if you send a gun down from Canada it won't get back across so for us it's somewhat pointless).

[MadMax]

Originally Posted by Danke

It might be worth re-visiting now that the GGB world is opening up. The players could be more open to a pump that does the mixing.

If I had to make a guess about what KWA is doing is first they'll give the gun a sniff. After used you can usually pickup the odorant clinging to your hardware. Then the next step would be to work of past experience and veto items that look suspicious. With the US market being younger and less sophisticated than Canada I'd guess they'll have more younger players abusing gear and then their parents on the phone to KWA in the best hockey parent style honking about their kid and how they never abused a thing. I suspect they're in a unique position and have had to take a hard stance to fight off the calls for replacement parts.

Like I said, I really do wish I could make an auto mix adaptor, but the difficulty of designing a cost effective dosing pump which pushes a fractional drop per fill is difficult. If one is to dose two drops of oil every 10x mag fills you'd be dosing about 16 drops of oil per entire bottle of propane (roughly 6g of gas per mag, something like 465g/can * 2 drops per 10 mags = 16 drops).

Trying to dose 0.2 drops of oil per fill isn't a simple job. Over lubrication can give your gun the drips which affects hopup performance. You need the rubber nubbin to be grippy, and goo in the barrel will also strangely affect spin and drag. Also, wet gun surfaces retain dust and dirt which combines to make a dark, possibly abrasive goo that I call gun smegma. Too little lubricant and moving rubber seals develop higher friction coefficients which contributes to seal wear and poorer performance. My dosing guideline was developed when I repetitively lifecycle tested my flow restrictor in a WA GBB. I made a rig that pulled the trigger about 10k times. The gun was powered by a remote propane connection directly to a Coleman bottle. I regularly changed bottles to power the gun so I could try out different lubricant proportions to land get a gun which ran consistently well with a very light barely visible film of oil on rubber parts.

A couple years ago I made a little high pressure syringe doohickey that was used to push a measured dose of silicone oil into a propane can. It worked very nicely as it allowed users to premix their oil right in the can. Unfortunately the risk that users might push other fluids into propane cans caused me to abandon the product. Do something stupid like push a lubricant that degraded nitrile orings and an entire can could leak out. Also, improper use can inject air into a propane can which is also potentially problematic. You'd have to shove a lot of air into a can to allow meaningful combustion inside a can, but liability is something I'm conscious of. Any accident involving a propane can with any possibility that my oil injector might be involved would expose me to a lot of liability even if my product was not at fault.

It's too bad, it was a neat little product, but one which entailed too much exposure. Please don't ask me for one. I do not sell them or give them away. The only ones out in the field were given to a small user testing group who have failed to return what I consider to be defective product.

[Amos]

I'll stick to me $30 adapters thank you very much!

I'm quite capable of reading the instructions and knowing how much oil to put in.

[Thenooblord]

Originally Posted by MadMax

It's too bad, it was a neat little product, but one which entailed too much exposure. Please don't ask me for one. I do not sell them or give them away. The only ones out in the field were given to a small user testing group who have failed to return what I consider to be defective product.

I still want one >.<
gimme

[Cilantro]

You guys want to know how much oil to put in your mags? It says so right on MadMax's page: a few drops every 8 or so mags. If you really want a "smart" propane adapter, why not go to the dollar store and duct tape a mechanical counter to your adapter :P Just click it every mag you fill, oil in every 8th (or whatever you like to do) and reset the counter.

[Danke]

A few was not a number I learned in math class. I can see you have a gas gun that's gone down for a mystery reason. Swelled seal/too dry seal, who knows right.

I'm not expecting this tomorrow, but I think it keeps perking away in folks subconscious and the demand presents itself some smart guy that makes stuff like this will figure it out. Maybe a mock cylinder of green that you preload with oil and then with propane.

[Danke]

I still think there's a market for this item. I'd call it something like the, oh I don't know "AI gas can portable filling station". But that's just me; wink wink.

[MadMax]

I'm always looking for good solutions to annoying problems. Even solutions that address multiple concerns

[Danke]

I'm going to go watch some AI videos and keep my fingers crossed!