Propellant Casting Stand

Guys, I have recently made a casting stand for my 54mm reloadable motor. What do you think could be added or improved?

I take it that you have rods that slide in the holes for the core or am I missing something?

The assembly looks nicely built, but seems to be short. Is it designed to do only one grain in each of the four locations? If so, you should know that as you go through trade offs in your motor designs there will be times that you'll vary your grain lengths, sometimes significantly. Thus having a long "stick" of propellant that can be dissected has it's advantages.

Why so much hardware? Seems like a lot to keep track of. The dividers will keep them from pulling down anyhow...would have used 2, one on either end.

+1 on the lots of hardware.

Getting the lid on 4 at once might be tricky - especially if the casting tubes fit tight.

Is the hardware stainless? I know drill bits rust up fast it not cleaned after drilling cores.

Is the thing sealed? I know I am messy went casting and drips will be everywhere. I make my bases from HDPE - cleans easily. HDPE releases easily compared to my earlier plywood bases.

Yeah, that's right Brent, I'll slide these rod in there as well.

The idea was to enclose the propellant from both sides so at the end I would get nice propellant grains.

Kevin, I am going to spray the surfaces with silicone before casting the propellant slurry into it, but you are right, that may be tricky to take the top lid off. Yes, the thing will be sealed from both sides. Currently 4x hollow acrylic rods are missing but I am going to attach it later on.

Seems ok if you want to make the same K motor over and over....
What about other geometry? More than 4 grains?

To me it would be very restrictive.

Yes, it is designed to do one grain at each location. I am going to produce several grains for my 54/1706 motor. Well, having short grains has its advantages too, after you have added your curative and the time starts ticking, you could cast your propellant with two or three people at once that will save you some time. You'll then need much shorter packing rods that help you to pack the propellant nicely inside. Taking the long grains out of rods could be tricky as well.

dixontj93060 said:

The assembly looks nicely built, but seems to be short. Is it designed to do only one grain in each of the four locations? If so, you should know that as you go through trade offs in your motor designs there will be times that you'll vary your grain lengths, sometimes significantly. Thus having a long "stick" of propellant that can be dissected has it's advantages.

Click to expand...

That was designed specifically for K motor grains. This stand has been made in 10 minutes with lazer cutting machine. So if I'll ever need other grain sizes, couple of changes in AutoCAD and I am ready to make a new one.

FredA said:

Seems ok if you want to make the same K motor over and over....
What about other geometry? More than 4 grains?

To me it would be very restrictive.

Click to expand...

thunderocketeer said:

That was designed specifically for K motor grains. This stand has been made in 10 minutes with lazer cutting machine. So if I'll ever need other grain sizes, couple of changes in AutoCAD and I am ready to make a new one.

Click to expand...

Although I like my True Core system yours look great also. I think it would be great for pourable propellants. Nice that it is laser cut.

I like the design. It would be easy to cut the wooden top along the dividers and add longer threaded rods to do grains of different lengths. You are using 4 threaded rods per grain which makes the vertical wooden dividers overkill since you can adjust the nuts on the threaded rods to get a level tight fit on the top of the grain. Overall nice work.

I like it. With Trucore going away, this is a good alternative.

Thanks mate. The idea behind the top lid with 4x threaded rods around casting tube is to press down the lid as much as possible to prevent that "cake" cap forming on the top of each grain while my HTPB propellant is being cured. Here are some better pictures of the device with the lid taken off.

amarillo_rocket said:

I like the design. It would be easy to cut the wooden top along the dividers and add longer threaded rods to do grains of different lengths. You are using 4 threaded rods per grain which makes the vertical wooden dividers overkill since you can adjust the nuts on the threaded rods to get a level tight fit on the top of the grain. Overall nice work.

Click to expand...

Can you post a pic of the bottom?

Sure. The stand is upside down on these pictures.

cwbullet said:

Can you post a pic of the bottom?

Click to expand...

Nice design.

If you lost the metal, and opened up the holes in the top so that I could slide in casting tubes from the top (and therefore have more options, say 2 grains per tube for 8 total), I would be very interested in getting one or two for 54mm and maybe 75mm.

If i bought one, i would prefer that i glued it together instead of the metal hardware. Yup, I could see one or two of those sat here..