Making a Bullmaster tube

[shyguy_8121]

I remember sometime on the forum "Pipefitter" and others maybe talking about using a heat gun and a spoon to convert a straight tube into a "poor man's" bullmaster. Has anyone done this successfully? I don't want to ruin one of my tubes. Given that there is only the material of the cylinder to expand outward to a pocket, how much could the pocket actually bend outward I wonder. Also wondering if there is that much advantage to pocket bullmaster type pump versus a large sun tea jar type pump.

Thanks guys!

[kuddlkat]

I wrapped a dildo and two tennis balls in cotton cloth, shoved them down a 4" tube, and put it in the oven until the plastic flexed and gave me the shape I wanted. First try was with a pasta cooker tube, but that plastic is harder to work with than regular plexiglas so it was a learning experience. The important part was shielding the top and bottom (plastic cemented bottom) from the heat to keep them from deforming. That one turned out well, and then I did a second one with just the two tennis balls inside to try to make a "ball tube." It looks good but I haven't put a fitting on it yet.

[shyguy_8121]

A few questions. How did you form the plexiglass edges together? It seems like you would need a mold for that. How do you shield the top and bottom? Post some pics maybe that will give me a better idea of how it is formed and how it looks. I like your tennis ball idea.

[pipefitterdom]

A sun tea jar is better for bulking up.

If you are going for low hanger hangers put some heat on a straight tube. The oven is a good way to do it all at once if you have something to shove inside with the shape you want.
You can expand them quite a bit without splitting them if they are thick walled. IF you use a blow dryer or heat gun eep the heat moving so as not to scorch it. Have a cool wet rag on hand to solidify the new shape. You can do it incrementally by each area. I use a spoon because it is smooth so as not to put a texture on the tube walls.

[shyguy_8121]

Good tips, pipefitter. Can you use a large plastic spoon to shape the plastic or does it need to be metal? I saw your work on a monster tube. Very cool! I was looking for photos that it can be done and it can. Thanks!

[kuddlkat]

A few questions. How did you form the plexiglass edges together? It seems like you would need a mold for that. How do you shield the top and bottom? Post some pics maybe that will give me a better idea of how it is formed and how it looks. I like your tennis ball idea.

I used an acrylic cement to glue a flat circle to the end of the tube. I sanded the 4" tube end to get rid of the cut marks, going to progressively finer grit as required for joining acrylic. Here's a video on how that is done: https://www.youtube.com/watch?v=hT6Ow_cBTps

The 4" tube was from a plastics seller on eBay, same with the end acrylic (cut from a flat piece of 1/4" acrylic).

For shielding the bottom, I sat the tube on a 5"x5"x3/4" piece of wood, after wrapping the base with cloth and then aluminum foil (extending up about 2").
For shielding the top, I took another piece of wood, same dimension, and routed a circle groove in it for the tube to fit into. This is to keep it from changing shape even if it does go soft. I made a strip of cloth and aluminum foil and wrapped it around the tube's top edge (and folding it inside), going down on the outside about an inch. The cloth is to minimize sharp marks in the softening acrylic from the aluminum foil.

Heating it in the oven isn't difficult except that it has to remain upright so it doesn't droop under it's own weight. I considered using a threaded metal rod between the pieces of wood to keep everything straight, but it didn't seem to need it. I used a cheap infrared thermometer to keep an eye on temperature. Around 240-250°F it starts to become soft and the pressure from the tennis balls (ridiculously difficult to get them in) and the dildo makes it look good. Not a perfect imitation of a bullmaster tube, but it seems to work fairly well without it costing $200+.

I don't know what a rubber or plastic dildo melts at, but I know silicone is well above the acrylic forming point.

Pasta tube photos attached. This was my first attempt and I didn't control the top's form. The plastic is more brittle (it isn't acrylic) and bubbles formed rather quickly. Sorry, I don't have pics of the current one and I'm really tired after shoveling for 5 hours.

[kuddlkat]

And I forgot it posts images in reverse order of adding them. :/

[shyguy_8121]

Very nice work! You went above and beyond to show and explain how you did it. Neat video too on gluing acrylic. Thanks for sharing, and 5 hours of snow shoveling is too much!

[pipefitterdom]

Good tips, pipefitter. Can you use a large plastic spoon to shape the plastic or does it need to be metal? I saw your work on a monster tube. Very cool! I was looking for photos that it can be done and it can. Thanks!

Thanks.
No it doesn't need to be metal. Anything with a smooth surface works.

[GinLover]

Only other possibility is to make a negative with silicone, latex or alginate molding mass from an actual bullmaster.
Then you can work out a negative that can be put apart easily in half to extract the later produkt easily. This could be made out of hard silicone, concrete, anything that will stand the heat of acrylic glass pressing against it.
Then you put in a warmed up acrylic tube (they are available for about 17€ in europe in the size we need it) and apply pressurised air into the tube, so it will press against the mold.
Wait out, take the two halves apart and you have a bullmaster copy.
I just want to Clarify that I DONT have tried it yet. It is a concept I worked out of my knowledge of acrylic glass.

And also, I lack a bullmaster to copy... But otherwise you can still make a mold of a straight tube with gipsum, and then hollow out the pockets you wish to have.

[pumpinit]

You don't need any thing but a small amunt of air pressure in the closed tube. About three to seven PSI will do.
Then move the heat gun over the area you want to expand and keep it moving in that area until it becomes soft enough to start expand.
Be sure you can remove the air pressure very fast in case you over do the heat.
Works for us.

[GinLover]

I might give it a try. Ordered acrylic glass tubes and plates so i can make my own tube... And will try to form with a heater gun and something like a corsett and pressure thebpockets. Might try some approaches, definitely will need to get somehow the pressure done.