Source for large cylinders with round ends?

[MillenniumFalsehood]

I'd like to make a space freighter in large scale, and I need a source for large cylinders that have round caps. I'd prefer spherical caps, but spheroid and "rounded" are acceptable. I'd like to stay away from kit parts to save money, but if you find something that'll work for an enormous pressure cylinder, that will be great. I'd prefer the diameter to be in the neighborhood of 3-4 inches and the length to be around 8-10 inches.

[naoto]

Perhaps not what you're looking for, but what about model rocket airframe tube (e.g. BT-101) with endcaps made from EPP spheres?
http://www.erockets.biz/semroc-body-tub ... 10-5-long/
https://www.rocketarium.com/Build/Airframes/Phenolic
https://www.amazon.com/Smooth-Foam-Ball ... B01ARZCGH2

(granted, the diameters may not match exactly, so some modification may be required ...)

[DaveVan]

Check Plastruct online catalog. Good stuff and staff.

[Rocketeer]

Check Plastruct online catalog. Good stuff and staff.

I see that Plastruct offers ABS tubing and end caps, round and elliptical, in the sizes the OP wanted. https://plastruct.com/product-category/ ... nd-tubing/

[Zubie]

Depending on the scale of what you are looking for, consider plastic test tubes. Generally cheap and in demand for college bio and chem students. Would allow for internal lighting since they are clear - just limited to no more than 2" max in diameter; generally much less. Endcaps can be spherical, or somewhat squatter than that, occasionally conical with a rounded tip.

https://www.stevespanglerscience.com/st ... -of-6.html (1.75" diam)
https://www.amazon.com/125mm-Plastic-Po ... B07JP33ZC5 (.63" diam, approx 5/8")

The trick is finding the ability to buy smaller lots (some I found only sell by packs of 100s). The other thing is to make sure it's plastic not glass, and that plastic is polystyrene, not polypropylene which is pretty hard to work with as it doesn't react with much (why it's used for this stuff in the first place). Bizarrely enough you can sometimes find homemade candy sold in them at craft fairs and such.

[Sluis Van Shipyards]

I also say Plastruct. Other than having a $20 minimum order they're great. I usually just order a bunch of random stuff to get it up to $20 because I'll use it at some point.

[ajmadison]

May also want to think outside of the box. Plastic pipe from a hardware store, comes in standard dimensions, albeit english ones. For example, I recently bought a very expensive resin kit, and the engine supports exactly fit some plastic pipe I bought at said hardware store, which gives me both a clue to how the resin masters were scratch-built and components for building a jig for assembling the model. At the same time, Michaels, et. al, often stock various kinds of styrene spheres and hemispheres (aka Christmas ornaments) in the same standard english dimensions.

[publiusr]

I would look for yard sales with old anniversary clocks.
They have nice domes.

Some of plastic, some of glass
https://www.etsy.com/listing/610009291/ ... KGlfD_BwEa

I think warhammer reactor type buildings may make a fair Malon type ship.

Also do a search for "bollards"
https://bollardcompany.com/new-dome-top ... rd-covers/
https://bollardcompany.com/dome-top-pla ... lard-caps/

[artic316]

750 ml Pepsi bottles or even 1L ??

[jpolacchi]

Try TAP Plastics and see what plastistruct has.

[Chacal]

If I was building, I'd go with plastic christmas tree ornaments (down in my neck of the woods they come in metric sizes, all the way up to 200 and some millimeters—metallized, varnish-coated, polypropylene blow-molded spheres—the coatings come off easily). in the US(?) there's bound to be those in imperial sizes. And regular PVC pipe. Drain pipe, gutter downspout pipe.

The attachment between those better be mechanic (wire, screws) because PP doesn't take kindly to glue. Nor paint, but spray adhesive and a layer of aluminum foil can take primer quite nicely.