Schedule 80 vs. Schdule 40

[Sargent80]

I'm build my ROV using the instructions found int the book Build Your Own Underwater Robot and Other Wet Projects by Harry Bohm and Vickie Jensen. I'm having a little bit of supply issues with constructions of the Seafox ROV. The instructions in the book say that I need:

-1/2 inch Schedule 40 PVC Pipe
-1/2 inch Schedule 40 PVC 90 degree elbow joints
-1/2 inch Schedule 40 PVC Tee Joints
-1/2 inch PVC Pipe Clamps

This is for all of the 1/2 inch PVC pipe. The problem is that I live in Australia and I can't get 1/2 inch PVC in stores, I have to order it off the Internet and the site that I want to get it from only has 1/2 inch Schedule 80 PVC pipe. The question that I have is: Will using Schedule 80 as a substitute for Schedule 40 mess up any of the design? I know that Schedule 80 is thicker than Schedule 40, but will that require me to rethink the design or anything?

[KR2_Diving]

Hello Sargent,
One thing that you will want to consider with this is the weight of the Schd 80. I don't have any exact figures, but because the walls of the pipe are thicker, the outer diameter of the pipe is going to be different, and the weight is going to be higher.

The added weight will affect your buoyancy, and may require you to adjust the ballast / buoyancy of the ROV.

Another alternative would be to use what ever pipe you have locally. I know one of the principles of DIY ROVs the ROVs affordable. I would like to think that using product available locally would be cheaper then trying to match the exact spec of the prints... especially for frame design.

I have loaned out my copy of the book you mentioned, but from what I recall, substituting 1/2" Schd 40 with the local mm style shouldn't be an issue...

One thing I found when shopping for parts in the States and here in the UK is to watch out for the foam core pipe. It looks as think as schd 80, but is NOT rated for any pressure. The make up of the pipe lends me to believe that at depth, the pipe will not be stable enough to withstand any pressure at all...

Just a heads up!

Good luck!

[Sargent80]

Thanks for the info. I looked online and found out that since the Sch 80 pipe has a larger overall diameter, it may not be a good substitute for the Sch 40. I am not able to find any 12mm pipe anywhere here. Do you think 10mm will be a good substitute? I built ROV frame earlier, but that one didn't end well because I didn't have any design specs on it. I used 15mm pipe on it. Do you think that would work? I'm afraid that changing the diameter of the pipe may cause some of the parts to not fit.

[KR2_Diving]

Do you think 10mm will be a good substitute?

10mm might be a bit on the small side... it may depend on how rigid the pipe is...

It it were me, I would go with the 15mm.

Ryan
"KR2_Diving"

[Sargent80]

Thanks, I know a hardware store 5 minutes from here that carries it.

Thanks for the help!

[Silver dollar]

Hello Sargent,
One thing that you will want to consider with this is the weight of the Schd 80. I don't have any exact figures, but because the walls of the pipe are thicker, the outer diameter of the pipe is going to be different, and the weight is going to be higher.

It is correct that the wall thickness is bigger on a schedule 80, but the outer diameter is the same as a sch 40. So the inner diameter will be smaller on sch 80.

[Sargent80]

I've got the frame sorted out, now I need a substitute for the floats. I think 100mm is too big and so is 90mm the book says 76mm, but I don't know if my hardware store carries anything around that. The best i can find is 80 and 65. But , if I had to chose, should I go with the 65mm or the 80mm

[RV-BETANCOURT]

SARGENT 80, could you please help me with something?, I want to use an acrylic dome on my design, but I just don´t know where to start, does your book say anything concerning the domes?., please let me know. Thanks in advance!.

[Sargent80]

I don't think it has anything on acrylic domes. The info in it is pretty basic. It just deals with basic cameras and grippers and stuff like that.