Installing “Accuflex Bev Seal Ultra” Poly Tubing

After reading about Kal’s (of The Electric Brewery fame) post on HomebrewTalk about plastic taste in beer lines, I decided to make a purchase of the 3/16″ Accuflex Bev Seal Ultra poly beer line that he recommends.  I can officially say that getting it to fit is borderline-not-worth-it for 1/4″ MFL barbs.  It didn’t help that everyone has their own methods they used to get it to fit: I tried them all, and none of them worked as “advertised”.  In the end, I did get it to fit— after destroying about two feet of line—and now I hope that these detailed instructions can help.

Tools & supplies you will need:

Pen Tip in Poly Tubing

This depth is sufficient to flare the poly tubing (enough to proceed to the next step).

Step One: Create an opening.  Heat the metal pen tip using your heat gun (optional; or, use boiling water, though that method proved more difficult for me).

You will want the pen tip firmly resting on the floor (or other hard surface), pointed upwards; it may be easiest to hold the tip using the needlenose pliers, so that it doesn’t blow away in the heat gun airflow.  Once hot enough—and this is somewhat of a judgment call—firmly press one end of the poly tubing down on to the tip.

Pilot "Better" Pen Tip

Other metal tips from other pens or mechanical pencils may work, but the width of the metal tip of the Pilot brand “Better” model pen proved to work well.

If you have trouble here, try also heating only the bottom quarter-inch of tubing.

Continue to re-apply heat from the heat gun (in short intervals) until you can get most of the tip inside the poly tubing, stretching the opening.  This is where being able to push the tubing down onto a hard surface is so handy.

Insert the tip & tubing into your glass of cool water to “set” the stretched poly tubing.  Use the pliers to remove the pen tip, and proceed to the next step.


Step Two: Begin inserting barb.  Bring your pot filled with a couple inches of water to a boil.  While you’re waiting for it to reach a boil, screw in the 1/4″ male pipe thread (MPT) flare into your swivel nut.  You must have this, or something functionally identical, in order to be able to firmly seat the poly tube onto the barb portion of the swivel nut.

Once boiling, put on your gloves.  Then, place your MPT-flare-with-swivel-nut in the boiling water, with the barb facing upwards.  Within a few seconds, water should begin to boil up & out of the hole in the barb; once this happens, press the flared poly tubing end (from step one) directly onto the barb.  Push gently and wait; don’t try to cram it on there just yet.  Water should continue to boil up through the barb, and now through the inside of the poly tubing.  You should (or will need to) have enough water left such that boiling water is high enough to cover about a half-inch of the poly tubing.

After about 20 seconds of immersion in boiling water, begin to press firmly and strongly, directly downwards.  The tubing should now be inserted onto the barb a few millimeters.  Remove the tubing and barb from the water.  If the barb stays within the tubing, you pressed hard enough; if not, try again (you may need to return to step one).  You’re not “done” here; now we need to gain a bit of depth.


Unsuccessful Attempts

A small selection of the many, many unsuccessful attempts at installing this poly tubing. It’s inflexible at normal temperatures, so any kink or deformity is cause to cut it off & start over.

Step Three: We must go deeper.  Insert the barb & tubing back into the boiling water for 15-30 seconds, while applying firm, steady, directly downward pressure.  After 30 seconds in the water, remove the barb & tubing, and place it into your water cup to cool.  Repeat step three until you have a worm-clamp’s width of tubing (or more!) on the barb.

Be sure that the tubing is inserted into the boiling water such that the water line is above the current barb depth; you need to soften that plastic in order to push the barb deeper.  Exercise caution against leaving the hose in the boiling water for too long, lest it become too flexible too far above the barb; it may bend and kink under the pressure you’re applying, therefore requiring you to completely start over.

Also exercise caution against trying to “force it”, as the tubing is also likely to bend and kink.


Step Four: Clamp it closed.  Put your worm clamp in place, and tighten it down as far as you can go.  Based on my experience, a worm-clamp’s width of tubing on the barb is sufficient, however a tight worm clamp is necessary to avoid a slow leak.  If you’re more proficient than I and are able to get significantly more tubing on to your barb, you may not also need a clamp.

And… you’re done!  To check if your installation is successful, take a look at the following pictures.


Tips & Tricks, and Other Thoughts

  • If you don’t have the suggested pen tip handy, you can try a pair of needle-nose pliers or a nail punch.  I tried both and found the pen tip to be far-and-away the easiest.
  • Heat-resistant gloves with grip are a must-have.  I used an Ove-Glove, and its grip wasn’t nearly as good as bare hands.  So, I used my bare hands (occasionally), and I got burned, literally, several times.
  • Use caution with the heat gun; you can easily overheat.  If the opaque white tubing turns translucent or clear, you’ve destroyed it.  Cool it off, cut it off, and start over from the beginning.
  • You must heat both the tubing and the barb.  Else, your hot tubing will cool the instant it touches the (cool) barb surface, rendering the insertion process impossible.
  • This is a slow process; it is going to take you a while.  Once I had worked out some of the finesse items within steps two & three, it still took me 10-15 minutes per tubing end, or roughly two hours to complete both ends of each of four lengths of tubing.  Including multiple screw-ups, the entire process took me about 8-9 hours over three days.
  • The heat gun, by nature, will only heat one side of the tubing at any one time; it’s difficult to ensure an even heat without also over-heating.  Immersion in boiling water allows for 360-degree, even heating while naturally setting an upper-bound on the temperature.
  • Because the poly tubing is considerably more inflexible than the standard vinyl beer line—and because it will become even more inflexible when at 40 degrees inside your freezer/fridge—being able to direct the tubing downwards for better management is desirable.  Hence, the 90 degree tail pieces.  As a bonus, they’re available in 3/16″ IDs (OD is slightly larger, but still less than the OD for the 1/4″ tail piece), which makes installing the poly tubing shockingly easier.
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