$500 Compressor Kit

[joebob24]

How many people would be interested in a $500 kit that you could assemble with basic tools that would produce a compressor capable of something like 3-4 SCFM at 3500 PSI? Motor, filtration and mounting not included. Just trying to gauge interest at this point.

 

[pauldw]

Pick any two:
Good
Fast
Cheap

 

[Ghost95]

Let me get this right. You want an oil free oil less Rix all for $500?
So a swash plate bearing being a large diameter rotating sealed bearing where the inner race is fixed to a rotating shaft at a prescribed angle offset to develop piston stroke length while the angle of approach rotates with it.
In addition while the outer race bearing is fixed from rotating by two ground thrust riders and two additional rider bearings being set between a thrust rider plate to ensure an axial direction of rotation while at every point on the bearing periphery the number of interstage stage pistons (3) being attached to the outer bearing ring each using an attached rod end bearings per piston for each stage
Not withstanding the drive shaft to ensure balance Two additional sealed bearings are used at both ends with two roller bearings.
That's a bearing count of eight, more than days in the week and your $500 is all spent. Next LOL Iain

Yeah, this sounds good!

 

[rob.mwpropane]

...and here we go

 

[Ghost95]

Actually... $350 would be a nicer number

 

[broncobowsher]

If it included a filter that would last a few hundred hours as well for that price I would forgo the motor and find my own.

 

[iain/hsm]

Actually... $350 would be a nicer number

No problem I can make it $350 an hour for the maths and the calculations if you like.
Not forgetting when the number of masses on a swash plate design do not match the number of load points some additional work will be needed to determine the distribution and optimise the dynamic behaviour of the swash plate mechanism to optimise piston rod loading and running balance

In addition the swash plate piston motion is not purely sinusoidal so additional work would be needed.
Now although it is possible to analyse the dynamic behaviour of the swash plate mechanism to optimal piston loading and running balance you really need to think quality bearing components from quality manufacturers and this will affect cost and not use Chinese crap off Ebay LOL

 

[Tracy]

If it included a filter that would last a few hundred hours as well for that price I would forgo the motor and find my own.

A filter than would last a few hundred hours would only 4-10 times his starting price.

 

[joebob24]

I think this thread has devolved to where I thought it would be within the first few hours. I think I have what I need for now. I am not sure everyone actually read the initial post, but there does seem to be enough interest that I will proceed with a prototype with the option to build a few extras for people interested. If anyone has anything constructive to add, I will check back once in a while.

It is going to take a while before I have anything to show. I am a full time engineer. Speaking of which, if all of the haters could list their professional experience along side of your input that would be helpful.

Also, here is a list of reasons I think I might be able to make it cost $500:

1. The majority of the parts would be scavenged from an off the shelf compressor. The remainder of the parts would be sourced though vendors in China that I already work with for custom machined components. It is pretty shocking how low some of them will go to get the job.

2. I am a design engineer in the automation industry. I have designed thousands of parts that do all kinds of things. This is a little outside of what I normally do, but not much. I also have access to all of the CAD and analysis software I could desire at no cost to me.

3. I wouldn't be charging for any of the design or development time. The online community has given me so much over the years, I don't really have any problem giving back.

4. This isn't some kind of high end compressor that would be expected to last a lifetime with the right care. I would expect to get a few hundred hours out of it before it needs some parts replaced. Hopefully just a valve or two, but who knows. Even if it only lasts 200 hours, that is still several hundred AL80s filed and probably enough to get me through a few years of diving and having a compressor there to just top off a tank quick would make it worth it.

5. It doesn't have interstage water removal because it actually runs off of the water that is removed from the air, just like that motorcycle that kid made that goes 90 miles on a liter of water. I just added the price of the motor to make sure the oil industry doesn't come for me.

 

[rob.mwpropane]

I think this thread has devolved to where I thought it would be within the first few hours. I think I have what I need for now. I am not sure everyone actually read the initial post, but there does seem to be enough interest that I will proceed with a prototype with the option to build a few extras for people interested. If anyone has anything constructive to add, I will check back once in a while.

It is going to take a while before I have anything to show. I am a full time engineer. Speaking of which, if all of the haters could list their professional experience along side of your input that would be helpful.

Also, here is a list of reasons I think I might be able to make it cost $500:

1. The majority of the parts would be scavenged from an off the shelf compressor. The remainder of the parts would be sourced though vendors in China that I already work with for custom machined components. It is pretty shocking how low some of them will go to get the job.

2. I am a design engineer in the automation industry. I have designed thousands of parts that do all kinds of things. This is a little outside of what I normally do, but not much. I also have access to all of the CAD and analysis software I could desire at no cost to me.

3. I wouldn't be charging for any of the design or development time. The online community has given me so much over the years, I don't really have any problem giving back.

4. This isn't some kind of high end compressor that would be expected to last a lifetime with the right care. I would expect to get a few hundred hours out of it before it needs some parts replaced. Hopefully just a valve or two, but who knows. Even if it only lasts 200 hours, that is still several hundred AL80s filed and probably enough to get me through a few years of diving and having a compressor there to just top off a tank quick would make it worth it.

5. It doesn't have interstage water removal because it actually runs off of the water that is removed from the air, just like that motorcycle that kid made that goes 90 miles on a liter of water. I just added the price of the motor to make sure the oil industry doesn't come for me.

I am excited to see what you come up with... it's just something that's never been done before. No matter what, you'll always have people that say it can't be done until it is... and then we'll all be talking about that guy that built a diy compressor for $500!

We're all critical, just push through it and please report back so we can all learn.

 

[Tracy]

It is going to take a while before I have anything to show. I am a full time engineer. Speaking of which, if all of the haters could list their professional experience along side of your input that would be helpful.

As I said before, if you think you can build it, go for it.
I'm not a hater, just a realist. $500 barely buys a bicycle at WalMart these days.
I just don't think it can be done for the price of a scuba tank.
-Tracy
Mechanical Engineer that builds and repairs breathing air systems.