Using 8g CO2 soda bulbs in your Tap King

[carpedaym]

It is suggested to use 2 white washers due to the offset caused by the yellow section and the fatter neck of the 8g bulbs. Doing it this way means the spike that pierces the bulb has to travel around 2-3mm further than with the stock 12g bulb.

I was starting to wonder about this. My experience with the Leland / Mr Fizz brand bulbs was causing me some headaches.

My tests:

6 x 5c pieces: no puncture.
7 x 5c: pin only just punctured and pluged its own hole. Discharged gas upon removal of bottle.
"7.5" x 5c (achieved using thicker, foreign coins): pin still plugged its own small hole. Upon removal, the gas blew the black o ring which sits around the top of the yellow bit in half. NARRG! Swapped o rings from second bottle.
8 x 5c: Almost. It seemed to puncture and after wriggling the bottle it seemed to work... but eventually lost pressure. Upon removal I found the black o-ring had rolled up over the yellow piece slightly. I've since tightened some of the screws in the tap king unit in case that was causing problem.

ANYWAY, getting to the point: How much higher does the top of the yellow piece have to sit, compared to where it would be with a 12g cartridge?

(Pics for reference)


Do I need my 8g cartridge to be higher so the top of the bulb aligns with the 12g one? I had been worried that if the yellow tip ended up stickup up too high then it would hit the silver/chrome part in the TK unit, and that as you mounted the bottle it would put excessive pressure on the system.

I thought I'd seek some advice before trying any more, as I don't want to end up blowing up my only other o-ring.

 

[AzzA68]

ANYWAY, getting to the point: How much higher does the top of the yellow piece have to sit, compared to where it would be with a 12g cartridge?

(Pics for reference)

tk-8g-differences.jpg

tk-8g-diff-naked.jpg

Do I need my 8g cartridge to be higher so the top of the bulb aligns with the 12g one? I had been worried that if the yellow tip ended up stickup up too high then it would hit the silver/chrome part in the TK unit, and that as you mounted the bottle it would put excessive pressure on the system.

I thought I'd seek some advice before trying any more, as I don't want to end up blowing up my only other o-ring.

Well, thing have been quiet in here; everyone must be brewing... or drinking.

The two must end up the same height; otherwise you will not get the seal at the dispenser and you will not get the piercing pin to travel the required distance.

The biggest issue, between the 12g and 8g bulbs, is not just the height... that's the easiest issue to overcome... the issue is that once the height is corrected the neck of the 8g bulb is still different to the 12g bulb. Of the two 8g bulb brands, I have tried, both have wider necks... one also has a slight stepping at the top (where the seal is welded on)... this can be overcome by using the Dremel (as outlined in FreeBaseBuzz's post @ #87)... or by choosing different sized seals to replace the originals. This will depend on your mechanical skill level and which bulbs you're going to use.

It is critical that:
1. the height of the yellow plastic neck be the same as original; so that the seal is made good against the dispenser and the fixed-pin and the moving piercing pin mate.
2. the height of the 8g bulb be within ~+/-0.5mm (or less) of the 12g height; so that the piercing pin will pierce the foil so that the barbed head passes fully through the foil and the gas may flow past the narrower section of the pin.

Getting #1 right is easy... getting #2 will require some measurements, guesswork, a collection of O-rings, trial and error, some modification (like FreeBaseBuzz), and always using one brand of 8g bulb (unless you really nut it out well).

 

[lael]

I think I've found out why people are having some small issues using Beerisyummy's mod described on the first page of this thread, with regards to 7 5c pieces or 8.

It is suggested to use 2 white washers due to the offset caused by the yellow section and the fatter neck of the 8g bulbs. Doing it this way means the spike that pierces the bulb has to travel around 2-3mm further than with the stock 12g bulb.

I used a Dremel with the narrow sanding drum to widen the neck on the yellow section so the head of the 8g bulb can sit up at the same height as the 12g one does. Apart from that, I followed Beerisyummy's guide exactly.

(the narrow ones of these.)

I also used the Dremel to cut off the 12g bulb at the right height to use as a spacer.
Seems to work well, but I'll be able to let you know for sure this weekend, as I won't be kegging (and kegletting) till Sunday.

Hi Freebase,

Did you use the bottles with your mod yet? How did it turn out?

 

[Brewa]

Hello everyone, I have been experimenting with a couple of brands of 8G soda chargers and had limited success. I have done both mods developed by Beerisyummy but my beer is not ready yet so have been using water only.

I have had no success with the iSi soda chargers, as they seem to have a thicker top and are difficult to pierce. I found the pin only just pierces the charger and seems to block the gas coming out until you go to take the TK bottle out then it all escapes into thin air.

I've had success with the Mosa 8g chargers but found that it did not do a full 3.2 litres of water, this could improve with a carbonated beer .

With both mods in place, when you remove the TK bottle, the charger stays in the TK unit (dispenser) does this mean if you needed to, you could top up the gas mid way through the bottle, by disengaging the TK bottle, putting in a new charger?

Also, when you first engage the bottle, does the charger expel all the gas into the bottle, or does it do it gradually until the beer runs out?

Any recent experiences people have had would be useful as you must have had more time to try out the mods.

 

[Choppy]

Hi All,

I'm using 8g "Kayser" brand soda bulbs and found 7 coins didn't pierce, 8 did but blocked the gas, 9 pushes the pin right in like the original and works perfectly.

Empties 3.2 litres of water and has some gas left afterwards.

Also discovered holding the yellow fitting against the end of a spinning 13mm drill bit works spot on to give that 45 degree edge.

I've done 4 now and they all work fine.

The Kayser bulbs are on eBay but I got mine from "House" kitchen shop.

 

[Beerisyummy]

Well, thing have been quiet in here; everyone must be brewing... or drinking.

Whoops! I must've turned off the automatic notifications settings. Both of the above reasons are correct.

I'm at the lager stage with my TK's now so I'll get back with an update soon.

The goal is to have clear beer for parties. That is where I think the TK shines.

 

[Brewa]

Merry Christmas everyone.

I managed to get my hands on the Kayser bulbs from a House store and they do pierce much easier than the iSi bulbs I had. All set, just waiting for my brew to be ready - 1-2 weeks.

Question on whether gassing is needed. I have a bottle of IPA almost ready for drinking and the tap king bottle is hard as a rock. Should I attempt to put it into the tap king without a charger first? Or should I do something else (let some gas out of the bottle and then put the charger in). I don't want to waste any of the IPA, the last lot I made was so good.

 

[Beerisyummy]

Merry Christmas everyone.

I managed to get my hands on the Kayser bulbs from a House store and they do pierce much easier than the iSi bulbs I had. All set, just waiting for my brew to be ready - 1-2 weeks.

Question on whether gassing is needed. I have a bottle of IPA almost ready for drinking and the tap king bottle is hard as a rock. Should I attempt to put it into the tap king without a charger first? Or should I do something else (let some gas out of the bottle and then put the charger in). I don't want to waste any of the IPA, the last lot I made was so good.

Just throw the charger in the bottle and attach it to the head unit. It may be overcarbed, but it should settle down once you chill it below 4c.
Do a search on co2 at different temps and you'll get the idea.

If it does turn out to be overcarbed you can warm it up, give it a shake and depress the tap while holding the bottle upside down. Co2 will come out of solution easily at room temp and the regulator won't be able to do its thing.

 

[barls]

As he mentioned rock hard while warm then a little flex when cold.
Never had a problem with the isi ones.