SpudFiles

I'm not sure if he has a lathe or not, that is probably one thing I would have to have done by a metal shop possibly. Which material would be best to make the piston out and where would you buy the material? Who would you go to to make that? A metal shop? I know I sound like a broken record but thanks again JSR.

Is there a QEV of those dimensions that can be purchased at a reasonable price?

Do you think 50 bucks is reasonable?????

Atattack wrote:I'm not sure if he has a lathe or not, that is probably one thing I would have to have done by a metal shop possibly. Which material would be best to make the piston out and where would you buy the material? Who would you go to to make that? A metal shop?

For those with limited tooling I recommend epoxy

There are other alternatives,washers on a threaded rod, PVC tube or endcaps, even wood if you're feeling organic

I know I sound like a broken record but thanks again JSR.

No worries, pleasure helping those who are enthusiastic about furthering their experience

mattyzip77 wrote:Do you think 50 bucks is reasonable?????

You could get this for $68 excluding postage, do you know of anything better?

mattyzip77 wrote:Is there a QEV of those dimensions that can be purchased at a reasonable price?

Do you think 50 bucks is reasonable?????

I searched google for 20 minutes for 1.5" qev and couldn't find one larger than 1" and it was $212. Do u have a link to one?

Never mind, found JSR's link

JSR, that tutorial on how to cast a epoxy piston is great. In the pics it looked to be a cup piston, with the piston being a 4 inch diameter should I do a cup piston or the piston that is a plain cylinder? Would epoxy be the best material? Was thinking about having foam in the middle as you mentioned because I'm a little concerned with that large of a piston flying back with 200-300 psi.

Atattack wrote:JSR, that tutorial on how to cast a epoxy piston is great. In the pics it looked to be a cup piston, with the piston being a 4 inch diameter should I do a cup piston or the piston that is a plain cylinder? Would epoxy be the best material? Was thinking about having foam in the middle as you mentioned because I'm a little concerned with that large of a piston flying back with 200-300 psi.

For a relatively large piston I would definitely make it cup shaped, to save on material and weight. Here's roughly how I would put it together:

I actually contacted a plastic specialty store today and they said they can get me a 4" diameter solid piece of PVC for about $25. I talked to a metal shop and they said they could hollow it out for about $30. So for $55 I could have a machined hollow piston. Figure this would be a good way to go and would not be too expensive.

The question is which would be the best material to make it out of. The guy at shop said he thought PVC would be the best material to make it out of. Any thoughts?

Cue Technician...
PVC is brittle Can that same machine shop make you a UMHW piston?

What happened to my 1 1/2 q e v valve idea?? Anyhow, I would think maybe a nylon material would be stronger, and $25 seems steep. Did you check McMaster online??

They can make it out of whatever material. The guys there thought PVC would be better than UMHW. I can go with nylon also, just not sure which material to use. Anybody have experience with the different materials. Nylon on McMaster looks to be $36 for a 6" section.

I would say go with UMHW, it seems to be a favorite around here.

Heres a link. http://www.mcmaster.com/#uhmw-polyethylene/=doyahs

UHMW is a ultra high molecular weight polyethylene (UHMWPE) thermoplastic. It is a very tough material with the highest impact strength of any thermoplastic. It is highly resistant to corrosive chemicals, except for oxidizing acids. UHMW has extremely low moisture absorption, very low coefficient of friction and is self lubricating. It is comparable to the properties of Teflon®, except it is more abrasion resistant.



From a plastics website, would say this would not be a bad choice.

And its sort of cheap. I bet the machine shop is going to charge more than what you paid to buy the thing.

A piece of 2 inch wide by 12 foot long of u h m w p e costs about 13 dollars online for a example!

http://www.mcmaster.com/#uhmw-polyethylene/=doydtx

Here is a link to what I believe I need, it is $18 for a 6" section. So $25 for a foot isn't to bad from the local plastic store. That way I can make atleast 2 or 3 pistons for later use. What would the best way to construct the piston be? Just drill a hole and had a rubber seal? Super glue it on?