Details:
I used my air compressor as an air source. TDF member DevilDoc used an aquarium pump. A little online research revealed an aquarium pump put out about 3 psi. I set my compressor regulator at 3 psi and tested it on a latex balloon to see the quantity of air delivered. It was small and slow.
I choose 25 gauge, 1 ½” hypodermic needles. Such needles are used to insert or extract liquids. Since air is much less dense than a liquid, I reasoned the smallest possible needle would deliver the air, yet make the least invasive puncture through the TPE skin. I found an online company that sold hypodermic needles by the piece (most sell them by a box of 100) and bought 10 (in case of breakage).
I used cheap aquarium air hose for the connections. The hypodermic needles have a tapered base to friction fit the nipple of a syringe. I used two pieces of brass tubing to make a connecter that would fit into the base of the needle and make a large enough fitting to which the tubing would tightly fit. The brass fitting was epoxied together and it, to the base of the needle.
I made two such needles and connected them together using a T-connector to the air source, so that both breasts could be enlarged simultaneously.
- Injector Components 01.JPG (67.58 KiB) Viewed 20088 times
- Injector Components 02.JPG (81.4 KiB) Viewed 20088 times
- Injector Components 03.JPG (84.36 KiB) Viewed 20088 times
- Injector Components 04.JPG (116.61 KiB) Viewed 20088 times
- Injector Components 05.JPG (142.45 KiB) Viewed 20088 times
My initial plan was to increase breast circumference by a conservative 10%. The WM165 K-cup doll natural breast circumference is 49cm, so my initial plan was to increase breast size to 54cm. I cut a strip of paper measured and taped to make a 54cm circle. This was used as a measuring guide to show when her breasts had increased to that size. I also made a secondary measuring guide at a 15% increase; a 56.5cm circumference.
I initially inserted the needles through her nipples, and that had no effect. I then inserted the needles at the sides of her breasts near the chest wall, similar to that shown in the factory video… and, I saw the amazing sight of her breasts growing. Since the pressure was very low, it was a slow process and I was not sure at first, but eventually I saw her breasts getting bigger.
As they enlarged, I put the paper bands around them, so I could gauge their size. They easily and conservatively met the 10% increase and looked amazing! I decided to continue to the 15% increase. By the time I finished, the 56.5cm paper measuring guides were quite tight, and her final size for each breast was a 57.5cm circumference.
The dolls initial breast shape was oval. They were wide with less projection. The enlargement made them much more round with more projection and upper pole fullness. They still have the same weight and “jiggliness;” just much more round and full. Since the final pressure is only 3 to 5 PSI, they are not like tires or sports balls. They are nearly as squeezable as they were initially.
Seeing and feeling her bobos in person at this size is amazing. I love her fashion model figure in contrast with her, now, gigantic boobs. My Rachel is a fantasy come true.
Conclusions and Observations
I measured her breasts every day. The breasts maintained their size for several days, but after a week they were down to 52cm. After two weeks, they remained that size. Still larger than the original 49cm, but obviously had lost a significant amount of air, yet they still retain their original molded shape. It is possible the air was leaking through a hole and, by spraying on soapy water, I will check for that after her next inflation.
However, I have another hypothesis. We know TPE is porous. It readily absorbs mineral oil (good) and ink from clothing (bad). In fact, saturation with oil can cause the oil to leak out the surface. Is it possible that air, being much less dense, under light pressure can pass through the porous TPE, much like air molecules pass through a latex balloon wall, causing the balloon to deflate after a few days? I don’t know the answer, but if true, this would mean the breasts could not be permanently inflated without some kind of air-tight bladder within.
There seems to be no downside to the enlargement. Should I wish, I could insert a plain needle to vacate the excess air and reduce her breasts to their original size. The TPE should return to its original molded shape.
Those of you who have dolls with hollow breasts (such as the YL150 and PD158) can also try this technique if you wish them to be bigger. If you are a boob man (why else would have purchased such a doll?), I assure you, if you do enlarge her boobs, it will blow you mind! If you do, please post your results and observations.
This is so awesome!! Nothing like watching Boobs get bigger to get the blood flowing 
