SpudFiles

Ive decided a low pressure co-axil would not be satisfying enough for me so i need to build a pump (I would find a fridge compressor but there like gold here) i was going to build a pump like Gippeto's ''stirrup pump''. but than changed to more of a design of far_cry's shock pump.

http://www.spudfiles.com/forums/my-seco ... 18650.html


QUESTION.

I have decided to use 3/4 Galvanized pipe (Cheap, sting, manageable)
BUT there is a welded notch that run's along the inside length of the pipe would this be a problem.?

Has any one used Galvanized pipe for a pumps main body

The ridge is most definitely a problem. I had to deal with it in my QDV valve builds.

With sandpaper glued to a dowel and a drill, the ridge can be sanded out. Here is what a galvanized pipe looks like in my Marshmallow cannon after polishing to remove the ridge.


Here is another build with extensive sanding to deal with the ridge and rust. You can see remains of the ridge. Original piece of the pipe is on the left for comparison.


Edit, I remembered I have a video online regarding preparing a pipe for use with a psiton and o rings. I hope this helps.
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I had my dad drill out a 3/4" pipe with a 27/32" drill bit at work. That worked fairly well, but I sanded the inside afterword. It was a short length, so I simply chucked a Mandrel in a drill, wrapped it in sand paper (80 grit, we don't have anything finer), held the pipe in a vice, and...

For a pump type length, it would be harder, especially for a small diameter. Even with a lathe, boring bars can only be only so long before they flex.

After you get it close to smooth, you could try a brake cylinder hone from harbor freight in a drill on an extension rod.

See if you can get seamless steel tubing...no welding ridge.

Try an online supplier if you can't get it locally from your welding shop.

Online metals, Metal supermarket, etc. will have it.

More money...yes, but also a LOT less work.

Brake cylinder hones are made for glaze breaking. They are very slow in cutting metal. Sandpaper is much faster cutting. A hone is OK for finishing touches, but not for ridge cutting. You will want a course fast cutting grit to get the job done quickly then finished up with a fine grit for the polish. My rusty barrel was done with 80, 120, & 150 grit. 300 & 600 grit is not needed unless you are looking for a mirror finish. Most of the heavy cutting is done with large grit.

how long is your pumps shaft, at my hardware store the short 12 inch pieces and shorter have the ridge, the 18 inch and up dont

I built valves using o rings, not pumps. 18 inch is a good length for a pump.

Tech I think clemsonguy1125 was talking to Mpeddlesden, not you . Anyway, 18 inches is a little short for a good pump don't you think? I am planning a small hand pump that gets higher pressures than a normal handpump, somewhere in the 100-150 psi range, like a shock pump with bigger volume, that will probably have a galvanized steel nipple for a main body...

Personally I'd go with Gippeto's suggestion and get seamless stainless steel from a supplier, that's what I'm using for the pump cylinder on my pump- it is half the diameter though- And the finish on it is incredible. Just place the order and it ships... no work with homemade sanding wheels or the like.

I wouldn't go over 18". At the top of the stroke, that gives you 36", a little above the average person's waist.

I own and use a brake cylinder hone Ive used on my steel coaxial for the pistons stoke, the only thing that would be the best and easiest is "Technician1002"s technique.

This is the Brake Cylinder Hone i have.

i think it would be essayer to just get some copper pipe its smooth already
or alu and use compression fittings

Or do as deathbyDWV suggested to me, use a brass nipple... they're smooth on the inside and threaded....

I don't recommend copper pipe. It is too easily damaged, ether bent, dented, or fatigued. They don't like lots of mechanical stresses in the pump application. Use a stronger harder material.