SBS-13x Pre Stretch Instructions
Revision Date: September 26, 2023
Pre stretching the SBS-13
Please follow the instructions for pre-stretching the SBS-13 5% to 10%. Now you will have an SBS-13x that is capable of 10 grams free lift and flying 2,000 to 3,000 feet higher. Please note the SBS-13x is far less likely to burst.
Please follow the Instructions below and when finished return to the fill and launch instructions.
Please see the required equipment below to complete the pre-stretch procedure.
Lay out a soft sheet to unfold the balloon on, to complete the pre-stretch procedure. Handle the balloon with care.
This procedure can take 1 – 2 days to complete.
First you will use the mattress pump to fill the volume the SBS-13, Insert the rubber fill hose on the tip of the fill nozzle of the mattress pump. Then insert the rubber fill hose into the neck of the SBS-13 about 1 inch past the neck into the body of the balloon. Please note the following precautions: Cycle the mattress pump on and off periodically to avoid heat from the pump damaging the balloon, to avoid humidity getting into the balloon, put a cloth over the intake of the mattress pump and use a rubber band to hold it in place. Fill until the balloon is full and not under pressure. Then remove the rubber hose.
Insert the 1 inch diameter rubber hose onto the neck of the balloon, then very carefully insert the manometer rubber plug into the neck as far as it will go. Now put your two thumbs on the each side of the plug and with your fingers pull the rubber hose toward the top of the rubber plug until it snug, if you use a clamp, tighten slightly. Note over tightening will restrict air flow.
Connect the tire pump to the input.
Fill the balloon to 0.100 psi and measure the circumference around the center of the balloon.
(Note this will be the starting circumference)
Next increase the pressure to 0.150 then allow several minutes to settle and re measure the circumference.
(Note pressure will decrease as film stretches)
Then increase the pressure to 0.175 and allow several minutes to settle and re measure the circumference.
Repeat the above process until pressure settles at 0.150 or above, then re measure the circumference.
Next increase the pressure to 0.200 psi and allow several minutes to settle and re measure the circumference.
Repeat the above process until pressure settles at or 0.175 or above, then re measure the circumference.
Continue this process in increments of 0.025 psi until balloon pressure holds and is stable at 0.200 psi or above. (Note not recommended to go above 0.250 psi)
During the above process the balloon typically stretches approx. 10% (depending on humidity and temperature)
When finished, use the mattress pump to deflate the SBS-13x. Then insert the rubber fill hose into the neck of the SBS-13 about 1 inch past the neck into the body of the balloon. Connect to the suction side of the mattress pump. Lay towels on the top side of the SBS-13x keeping the air at bottom so you can vacuum out the balloon.
This should pre-stretch the balloon nicely, pressure testing is done differently
