Electrical question

[Pat]

DD, Excuse the use of your initials but I just can't get used to referring to a nice guy by your handle. I know the fault is mine but there it is...

Anyway, the answer is maybe. Not knowing all the applicable facts of the extant situation, I can't say with much certainty but it is certainly a possibility.

Dissimilar metal corrosion is a powerful destructive force. For example copper pipe and galvanized pipe in contact carrying water is essentially a battery with a short circuit to take all the current produced. And like a zinc carbon flashlight battery, over time the less noble material is consumed, the zinc cup in the case of the old style D cell.

Back when I took a sabbatical and did marine electronics field service engineering I saw lots of examples of dissimilar metal corrosion such as copper shield of coax crimped into a ring terminal to be attached to an aluminum stanchion with stainless steel nuts, bolts, and screws (not about a mass escape from an insane asylum.) Add a little salt and water (ocean going tuna boat in the $10 million category, the ones with a heliport atop the pilot house) and surprise, surprise, surprise, massive corrosion and poor antenna performance. That's OK they have a spare but what do you ask? Isn't the spare done the same way... YUP!!! Oh well the antenna isn't really important it is just the beacon the chopper uses to find the moving tuna boat in reduced visibility or the emergency radio used to summon help or...

I really hate copper pipe for water. A year or so ago two different friends had problems with leaking copper pipes that developed pinholes for no apparent reason. One run was in a buddy's attic to take water from the kitchen sink to the icemaker. He came home from an extended absence to find the sheet rock of the kitchen ceiling on the floor and 3 rooms of the house flooded, all by just a tiny tiny little fine mist coming out of an itsy bitsy pin hole.

The other friend up the road a half mile had the sheetrock in his shop bathroom wall get soggy. He had a copper water pipe running through a plastic sleeve in the slab to a location behind the stool in the bathroom. In the middle of the in-slab run a pinhole developed, the sleeve filled and overflowed at the lower end inside the wall. I replaced the copper with PEX, end of problem. No, I'm not a plumber but neither is the friend who is a DAV who I help with stuff he can't do when I have time.

To the point... frost free hydrants should not contact dissimilar metals anywhere any time period. PEX is a well proven time tested material. If procured from a source of supply that never stores the stuff in the sunlight it can last just about forever. If stored in the sunlight it is seriously degraded and I don''t know how to easily tell. The best insurance is to buy fresh stock from someone who moves it quickly and does not store it outside. I have seen large wholesalers with thousands of feet of rolls of various size PEX in outdoor fenced in compounds. Big chain link fences with razor wire on top. It doesn't get stolen but it does deteriorate. I would never mention Locke Supply by name.

There are lots of ways for a frost free hydrant to fail. Some are easily prevented. avoiding contact with any metal is one.

Pat

[Pat]

Dave, I nebber woiked around a foundary but spent some time in a foundry. [img]/forums/images/icons/wink.gif[/img] [img]/forums/images/icons/wink.gif[/img]

Learning about cope and drag came painlessly as did needing draft to pull a part core out cleanly. What came at a price was the shrink and double shrink ruler. I did not know such was in existence so when using the owners drafting table to draw up what I was trying to prototype, essentially an aluminum block with a dozen square holes to fit cuvettes (square test tubes) on one side and a large hollow volume on the other side to be filled with oil and contain an electric heating element (power resistor.) This was be used for temperature controlled incubation of samples for blood analysis.

Anyway I picked up his nice stainless steel rule and used it. Unbeknownst to me it was a tad off from being true inches by the amount melted aluminum contracts when hardened. Worse yet on the other side which I used indiscriminately intermixed with the first side, the ruler was off by twice as much. This caused no end of difficulty for me as I had never had drafting or mechanical drawing and was struggling at the limits of my abilities anyhow without having a ruler that was not in "real inches" and wasn't even off the same front or back.

ARRRGGGGHHHHHHH I was one frustrated puppy! The owner and his chief foundry man had big belly laughs at my expense. Once I found out the source of the humor I got pretty tickled too and laughed till I cried, a real catharsis! The guys with the secret foundry handshake call it a shrink ruler. It is a shrink ruler on one side and a double shrink ruler on the other side. When you cast an aluminum "plug" that is used to take up space in a sand casting of a second aluminum part the "double casting" has twice as much shrink so you draw it with a double shrink ruler.

We cast little slightly tapered (just a little draft) little square fingers to suspend in the mold when we cast the whole thing. Later you break out the sand fingers leaving your square holes behind. You moisten the sand you will make the fingers with in sodium silicate and then dose the cast parts with CO2 which hardens the sodium silicate so the fingers are pretty tough.

The square holes did not come out precise and or smooth enough to suit me so a broach had to be used to "drill out" the square holes a bit.

This foundry did trophies, props, struts, volutes for pumps and all sorts of stuff in various brass and bronzes as well as aluminums even replacement rungs for a pool ladder but I never saw them cast a fly.

Lost wax or investment casting. Been there done that. Low density foam plastic can also be used for "wax" if pore size is acceptable or you make a skin on the "wax." I have also done molding with flexible rubber molds and catalyzed polymer casting materials. No, not grapes like all the crafty ladies were making but gear wheels for a punched belt drive and all sorts of "stuff."

Pat

[DUMBDOG]

When we did replace the hydrant, we wrapped it in duct tape and then enclosed it in a pvc pipe thinking it was a reaction to the soil. This summer I will replace the connection to the inside piping with a PEX section to prevent this from happening again.

It is a real pain to dig down six feet after breaking a hole in the concrete floor and going around a bunch of drain and sewer pipes buried above the water line. [img]/forums/images/icons/tongue.gif[/img]

[CJDave]

[img]/forums/images/icons/tongue.gif[/img] Hee hee, ..... [img]/forums/images/icons/laugh.gif[/img] the "shrink stick" notches another victim! [img]/forums/images/icons/laugh.gif[/img] By the way, Pat, that would be 5/32 of an inch per foot for single shrink in aluminum. [img]/forums/images/icons/crazy.gif[/img] I can just see you battling with dimensions, not knowing that the ruler that "Choppy" had was a shrink stick. They DID call him "Choppy", right? If you make patterns, you gotta be named Choppy. [img]/forums/images/icons/crazy.gif[/img] I was lucky enough to design a part that had such acceptance that we went to an eight-cavity permanent mold; four on one side and four on the backstroke. Sand cores, yes, but the outside was cut out of Mehanite. It left us a nice part. We had to do a little fine tuning here and there as we had a boss with a tapered bore that needed to be tapped 3/4" NPT and where a web came into the side of the boss, we got a shrink pocket which interrupted our threading. Aluminum is very shrinky and pullie. I just made up those two terms. [img]/forums/images/icons/crazy.gif[/img] This foundry also cast Magnesium gear cases for Meyer-Drake, and magnesium orange juice squeezers for one of the other divisions. You don't want to be there when they pour that mag. The fumes from the mag ate the sheet metal off the building. [img]/forums/images/icons/blush.gif[/img]

[Pat]

Don't you just hate having to do stuff like that over again?

I have a place in a pasture just down hill from an acre residential lot that is surrounded by my land on three sides that is always wet to the point of leaving tracks if you drive on it. We avoid it when haying. Recently I found clear water coming out of the ground and called the DEQ. Eventually they put dye in a toilet in the house but none showed up in the flow. I thought maybe it was grey water from the laundry.

The DEQ guy (young lad on the job 7 months) told me to go ahead and dig down to see what is there and if I found a pipe to cap it off. Gee, why would he say that if he wasn't privy to some info shared with him by the residence owner? I had dumped 3 dump trailer loads of dirt on the wet place before the water broke the surface and I realized it wasn't just a damp place from ground water. I quit dumping dirt when I saw considerable surface flow.

Anyway I dug down and found a 4 inch sewer line but I accidentally hooked it with the FEL bucket and pulled out a section. So I had to dig down again to find it, more carefully and with some hand shovel work. The thin wall 4 inch PVC was oval shaped and extremely difficult to get the round cap onto the end but I managed with brute strength and awkwardness.

I then back filled and went on with my fencing work that had brought me to this location in the first place. The lady comes to the fence and motions me over. She says the line comes from a well. I ask what well and she shows me a galvanized sheet metal (looks like a stove pipe) 4 inch in diameter sticking up 2 inches above ground next to a tree a few feet over the property line on my side. (I had not noticed it over the years.)

Why would a well have a 4 inch sewer pipe connected to it. An artesian well? Needing a 4 inch line?

Oh well, I acted in good faith with the information presented me and my reward is to be led astray and it is likely that water from whatever source could pop up again and I will be having to dig up stuff again to fix the "REAL" problem, whatever it turns out to be.

I feel your pain. You do the best you can with your understanding and your reward for not having a correct picture is to do it again. I really hate having to do stuff again. I'm not all that fond of having information "managed" by folks with an agenda.

Pat

[Pat]

Dave, I still have a little laugh at myself whenever I recall the great shrink ruler debacle. When are we the most dangerous? We are the most dangerous when we don't know that we don't know.

Never heard anyone call anyone choppy at the foundry. Besides the shrink ruler my strongest recollection is probably the owner going to lunch with me at Keith's (non-chain eatery next to I-5 south of San Diego near the Seventh Day Adventist enclave.) He was Adventist but loved pea soup which came with ham in it so he picked out all the visible chunks of ham and called it good enough.

The foundry was a small place run by the owner, a full time experienced foundryman, and a helper or two who were not full time. I was just there for a few weeks doing prototyping of the new product I designed for a little medical electronic instrument corporation for whom I was VP of engineering (and the only engineer) and super visor of a few techs and assembly line ladies.

I did learn that the foundry guys drink a LOT OF MILK to combat zinc poisoning from the zinc fumes when they cast custom zincs for electrolysis protection on boats.

Pat

[CJDave]

[img]/forums/images/icons/tongue.gif[/img] Yeah, that business with the MILK is also common for guys who work in a galvanizing operation. Welders who weld on galvanized pipe also drink milk to counteract the effect of the poison fumes. [img]/forums/images/icons/tongue.gif[/img] Have you noticed the use of patterns as decor in uppity restaurants? 95% of the clientel have no idea what those things are. [img]/forums/images/icons/smile.gif[/img]