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- I need a vacuum pump, soon will need it for bag-vacuum-coating various things. I’d prefer a hand-pump as it should be a lot cheaper than any electric model of comparable quality. So far I have found only two types of hand pumps: there’s a common automotive brake vacuum pump in two versions–plastic and metal. The plastic one I have found the manufacturer of, but the metal one I have not–so I dunno what a good price on it is. And there’s a cheaper lower-pressure straight pump made for classroom science demonstrations, probably not suitable. Are there any other types of hand-operated [-air-] vacuum pumps out there?
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- I need a vacuum pump, soon will need it for bag-vacuum-coating various things. I’d prefer a hand-pump as it should be a lot cheaper than any electric model of comparable quality. So far I have found only two types of hand pumps: there’s a common automotive brake vacuum pump in two versions–plastic and metal. The plastic one I have found the manufacturer of, but the metal one I have not–so I dunno what a good price on it is. And there’s a cheaper lower-pressure straight pump made for classroom science demonstrations, probably not suitable. Are there any other types of hand-operated [-air-] vacuum pumps out there?
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What sort of level of vacuum do you need? For many purposes, the rotary-vane compressor from a discarded refrigerator works very well, and you can get those free. I pulled one from a unit on a “heavy trash” day in my area, and it works well. If you need a somewhat better vacuum, the piston type often found in air conditioners works better. The piston types are a good deal taller than their rotary counterparts.
I got that backasswards. Switch all instances of rotary-vane and piston. :smack:
Lisle tools made/ might still make a ** very ** good metal hand vacuum pump. Mine has seen Twenty years of on/off hard work. Every so often it needs a drop or spray of silicone lube. Thats it.
I also own a Snap-On A/C service vacuum pump. What are you doing?
Many years back when my friend and I were making vacuum bagged model airpalce wings, we used a pump that was made for an air suspension bed in a hospital. It was electric and worked well. We used the intake side for our vacuum. We bought it at a local surplus store. I think we paid $25.
We were able to pull 25-26" of vacuum. We built a regulating system that used a syringe and some springs to control the vacuum.
Why are you asking me about hand operated vacuum pumps? I swear I don’t know anything about them! That sort of thing ain’t my bag, baby!
(ahem)
One warranty certificate for hand operated vacuum pump, signed by Little Nemo.
One instruction manual for hand operated vacuum pump, marked with “Property of Little Nemo” sticker.
One book, “Hand operated vacuum pumps ARE my bag, baby!” by Little Nemo, autographed by author Little Nemo
Thank you, sir. Have a nice day.
There’s a hand operated vacume pump on the market called mighty max. Comes in a nice gray plastic carry/storage case and comes with lots of accessorys. Dont buy it, it’s garbage.
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- Yea, I noticed that, looking around. I want it for impregnating transformers. Other um, people that use them, seem to tend towards the brake pump it seems. It’s like the time I went looking for a source of straight jackets (purely as a fasion accessory, because someone on a MTV video was wearing one). I quickly decided I never wanted to be seen wearing a straight jacket.
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- Yea, I noticed that, looking around. I want it for impregnating transformers. Other um, people that use them, seem to tend towards the brake pump it seems. It’s like the time I went looking for a source of straight jackets (purely as a fasion accessory, because someone on a MTV video was wearing one). I quickly decided I never wanted to be seen wearing a straight jacket.
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Anything that can pull 25" or better vacuum is fine for transformer impregnation. That was the level used at a previous job, where we made small transformers for military and aerospace applications. The idea is to get the air out of the way so the varnish can flow easily into the tiny spaces inside (for those who have no idea what impregnation is).
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- By the by, I have seen online Formvar, epoxy / nylon resins and wax used for impregnating. Formvar has to be cooked to cure, but I am planning on using VCR tape for the core as I am experimenting/guessing a lot basically, and can’t find any suitable info on where/how to buyor design toroidal cores… -and this way I would cut it in half, so I could hand-wind each half separately which is much easier than dealing with a toroidal core. What “varnish” specifically, and does it need to be oven cured? I dunno how hot I could get the VCR tape before it goes.
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- By the by, I have seen online Formvar, epoxy / nylon resins and wax used for impregnating. Formvar has to be cooked to cure, but I am planning on using VCR tape for the core as I am experimenting/guessing a lot basically, and can’t find any suitable info on where/how to buyor design toroidal cores… -and this way I would cut it in half, so I could hand-wind each half separately which is much easier than dealing with a toroidal core. What “varnish” specifically, and does it need to be oven cured? I dunno how hot I could get the VCR tape before it goes.
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What would the application be? For AC and many audio-frequency applications, tape-wound grain-oriented silicon-steel cores are adequate, and for RF a soft ferrite core is needed. Cores of all shapes, sizes and materials can be had from Magnetic Metals, Inc., Fair-Rite Products, and Micrometals, Inc.
As far as impregnation varnishes, Isonel is ideal for general-purpose use.
VCR tape would make a horrible core, no better than an air core. Might as well wind on wood. Let me know more about your application and I can help you with the design work.
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- I am half-heartedly attempting to put together a tube audio amp on the cheap. All the sources associated with tube audio charge rather grandly for what appears to be ordinary materials. I have found a page that shows al the calculations for a conventional 3-pole transformer, but I was interested in using toroidals but hadn’t found any info on them. At the electronics store I go to I looked through their xfmr catalog/application book, and all their specs given were for radio stuff, smaller cores and RF frequencies, 50Khz+.
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- I am half-heartedly attempting to put together a tube audio amp on the cheap. All the sources associated with tube audio charge rather grandly for what appears to be ordinary materials. I have found a page that shows al the calculations for a conventional 3-pole transformer, but I was interested in using toroidals but hadn’t found any info on them. At the electronics store I go to I looked through their xfmr catalog/application book, and all their specs given were for radio stuff, smaller cores and RF frequencies, 50Khz+.
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Ok, so basically you’re looking at a multiwinding transformer for use at 60 Hz; probably about a 6 V filament and about 100 V grid, yes? Standard 10-mil E-I, grain-oriented silicon steel laminations arranged in a 1 x 1 stack are perfect for this sort of application. I’ll need the voltages and current draws for each winding to select a lamination and stack size for you. Feel free to email me, as I have some info on obtaining the necessary lams I’d rather not reveal publicly.