Saturday, December 15, 2012

Goat milker - details and update

UPDATE ALERT: Please note: I've made some comments at the bottom about troubles we've encountered and how to solve them. If you have tried making a milker and it isn't working check there first.

From responses I got to the post on our new goat milker, as well as personal correspondence, it's clear that there is a real need for a low cost, low-ish tech, off-grid compatible alternative to hand milking goats. While there are a variety of options you can buy online, most are expensive - more expensive than they need to be.

Not only that, but most of us are makers and aren't looking for an off the shelf solution. We don't just want to buy, we want to build, tweak and understand. So here I am following up with my parts list, some pictures of how I assembled it, and most importantly, suggestions for things to try if you want to build up or down from my model. My husband David builds things heavy, solid and indestructible. He likes to reinvent the wheel, so he kept trying to introduce innovations like "let's build a special jar to go with this".

I'm more the quick and dirty improviser. If Mason jars work pretty well, I don't want to go looking for something better. If I already have an item or know where to buy it nearby, I'm apt to go with that instead of searching out or creating something new, even if it's substantially better. You may fall somewhere within this spectrum, or have your own design approach. I just want you to think about how this works and give it a try!

Our beginning parts list:

Everything but a jar and a goat

2 x 3/8" IDx 1/4"MIP  nylon hose barb/MIP adaptor - from the plumbing aisle of the hardware store

It might be in one of these baggies
barb/MIP adaptor

 2 x 1/2  1/4" nylon or brass nuts - also hardware store.

I could only find brass but I have to believe they have nylon ones somewhere.


Anyway it's fun to ask the guy at the shop if he has brass nuts.







4' of 1/4" ID (inner diameter) 3/8" OD tubing - elsewhere in the hardware store in a special area that sold tubing. Tubing is really cheap. Buy extra if you want to experiment. Also consider buying 1' of 3/8 ID tubing, which you can slide over the smaller tubing to help it fit onto bigger fixtures.
Two kinds of tubing and brass nuts

1 x 1/4" barbed T which I got at an aquarium supply store but also probably available at a hardware store


1 x Mason Jar lid and Screw Band
1 x mason jar (not pictured. I am just not photographer enough to try and get a good picture of one. Clear stuff!) anyway you probably know what they look like. It needs to be the same mouth size as your lid.


2 x 60 cc tapered tip syringes from a larger feed supply store (big epoxy paint supply stores may also sell these)


1 x Manual vacuum pump which we ordered online but may be available from an auto parts store as a brake bleeding pump. Ours is already hose clamped onto a length of tubing, and I left it that way for the picture.

1 x 1/4" to 1/2" hose clamp, which turned out to be overkill (it's holding the stem of this pump onto the tube. It would only be needed if you planned to be very rough with your milker. Like swing it around your head rough.)



2 x clamp on valves, from an aquarium supply store. We never actually use these. They came from an aquarium store.





Assembly: 




Drill or punch 2 x 1/4" holes in the jar lid. Insert the threaded half of the hose barb/MIP adaptors through the hole, and tighten the  nuts around them. 


You will see in the next picture that we have a wooden support which David added to the lid, thinking it was too weak to handle the pressure of milking. 

But gentle reader, he was wrong. A mason jar lid can take pressure canning, my friend. It would have been just fine without the wooden circle!




Cut two lengths of the 1/4" ID tubing - one 1' long and one 2'. You may shorten them later but I belong to the measure once, cut twice school so I always allow extra length. Dip one end of each piece in boiling water briefly, to soften it enough that is slides easily on to the barb. Work it all the way on. When it cools, it will shrink and hold on tightly.

Using the same boiling water trick, attach the center branch of your T connector to the longer tube. Now cut 2 x 6" lengths out of that last bit of 1/4" tubing and attach them to the other two branches.


Slide the clamps over the tubing. As I might have mentioned, we rarely use them, but with them in place, if you ever want to cut off flow to just one teat, you could. 




Slide the mason jar screw ring over the tubing and join it up to the jar lid, because once you do the next step it will be harder to do that.

Remove and discard the plungers from the syringes. Using the boiling water trick again, wriggle the ends of your 6" tubing onto the tips of the syringes. These are your teat cups!

You are now done except for adding suction. We hose clamped the manual pump to the end of the tube, but in hindsight we didn't have to. The suction will pull the tubing closer all on its own, you just need a tight fit. But yeah, overkill, that's our middle name.





 Now screw the lid onto a jar and go out to the barn! Clean the teat, just like always, but leave it slightly damp. Milk out one squirt on each side into a strip cup, just like always. Then set on the teat cups.The hardest part of the whole operation is holding the teat cups over the teats while you establish suction. I can do it on my own, but the first few times if you can get a buddy, do so. Hold one cup firmly but gently over each teat while pumping the hand pump. It takes me about 15 compressions before milk starts flowing, but before that happens, you should feel the teats get pulled slightly into the cups and you can let go.

Now milk is flowing. If your pump has a gauge, pump to10 and then let it coast down to 6 or 7 and then pump a bit more. If you don't, pump till milk is flowing strongly, then rest till it slows down, etc. When the flow begins to slow even at pressure, stop pumping, let the milk continue to trickle a bit, then break the suction by gently squeezing one teat to let air into the cup. The two cups will fall off. Spray the teats and you're done.



 The most important part of the whole operation is this: you need to stay in touch with the goat. You are no longer hand milking, so you need to even more involved in assessing her udder - is it lumpy? Is it tender or sore? Discolored? I have not had any problems with bruising, mastitis, or anything else really, but I examine and check every single time because I want this to be as positive for the goat as it is for me.

Now - to improvising. 


All you really need are some kind of vacuum device (to create low air pressure), tubing, a jar with a sealable lid, and teat cups. None of them have to be special purpose built items.

I experimented with a setup without the nuts and barbs. I used a large nail to punch holes in the lid of a jar, and then  just stuck two pieces of aquarium tubing into the holes so they fit tightly.  When we pumped, it created a vacuum and milked the goat. It was pretty flimsy. Eventually the lid will deform too much to form a seal but so what? A lid might cost twenty cents, so if it only lasts a few months before I need a new one, I'm still doing OK. I could probably reuse lids from canned goods, which you aren't supposed to can with a second time anyway.



I was an idiot not to use Tattler canning jar lids right from the start.

These are heavy, solid plastic lids with rubber gaskets, designed for repeated canning use. Their rigidity makes them perfect in this application. Buy a box of them and can with the rest.
I bought a battery powered food saver pump from the thrift store ($3.99, I couldn't resist). I ended up using it all the time. I like it much better than the hand pump. 
Its orifice was too big for my tubing so I bought some 3/8" ID tubing and, using the boiling water trick, I slid it over the smaller tubing on the pump end. I connect the pump orifice into it and it works great - even easier on my tendons than using the manual pump.



While at the hardware store buying nuts and barbs, I snapped pictures of two other possible pumps: a mattress inflator/deflator that might work on deflation mode, and an automotive pump designed for both filling tires and starting siphons. That would be handy to have around anyway, n'est pas? On the other hand, there is already enough stuff in the world. I encourage you to look for something simple, nearby, and useful in other respects. If you camp, get the mattress pump. Save food? Plump for a food saver pump, etc.




I'm sure there are other things you can tinker with. Today I tried using Turkey Basters as teat cups. This would eliminate one of the specialty shopping trips from the process.

The basters worked reasonably well but are too long and narrow - they made attaching the milking arrangement a bit too awkward.







If anyone wants, I will happily ship you the assembled lid and teat cup part of this system (everything but the pump, the jar and the goat) for a very reasonable fee - contact me! But as much as I'd like the business, I secretly hope you don't take me up on it. I want you to really own this system, and that means owning the process of making it.

April 28 update to this story. We have had trouble with some of our milkers and heard from others who have the same problem. 

If you did everything as directed and it's not working, try using the assembly without the barbs. Stick the ends of the tubes in hot water and squeeze them through the holes in a mason jar lid. If this works, it means you may have a bad fitting hose barb.

Apparently not all Nylon Hose Barbs are created equal. You need to find one with a 5/8" or wider hex nut. This won't be written anywhere on the package, you have to measure. I don't think it's a specification for the hardware as it wouldn't matter in most applications but the extra width is what seals it tightly to the jar. If you can only find the narrower ones you might want to experiement with silicone caulking them around the top. Choose a food grade caulk. Let it dry and wash well before use. 

We've also had better luck with Brass than with Nylon nuts but I don't know if that is because we used the narrower barbs with the nylon nuts.By the time we figured out the barb problem we had used up all the nylon nuts.

One more error, I did not fully describe the barb. I'm going to write out everything on the package:
WATTS Nylon hose barb 
Lead Free
PL-326
Adapter 3/8" ID x 1/4" MIP
10 mm x 8 mm

I found this by trial and error. If you have other products that worked I'd love you to share!!



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