2 Air Compressors ($125 Craigslist) for Venturi Vacuum - Good Buy?

[doctorbombei]

Hey guys,

I scored these 2 compressors off of Craigslist. I’m planning on using a venturi system from joewoodworkerto take the place of a vacuum. Since I’ll need an air compressor to run my tools for trimming & finishing, I figured this would be most economical.

I got these for $125…bought them in the dark out of a tiny shed in the countryside.
1x 60 gallon & 1x 25 gallon. They work, albeit, I don’t know for how long. They may be a little more work than I anticipated. To make things worst, I do not know the model of the 60 gallon as its label has been sprayed over

Good deal or disaster waiting to happen?

Also, what do you all think about a venturi vacuum system?

[doctorbombei]

No comments or thoughts? Not even on the venturi?

I’m in the process of partially dismantling the 26 gallon, completely disassembling the the 60 gallon, and replacing all seals. Will post pics once finished.

[herman]

Compressed air is expensive. Especially for running a venturi vacuum. I would have bought the cheapest vacuum pump on harbourfreight / pier 1 import.

[doctorbombei]

Really? Could you please elaborate? I was weighing my options between the compressor + venturi or the 5.5cfm Gast vacuum (72R645-V160-D303X) + auto cycling system…again from joewoodworker. I got these compressors for next to nothing and have not yet ordered the venturi, so I still have time to decide. Any advice is greatly appreciated as I’m on a strict budget.

Everyone says the harbor freight vacuums are garbage. I’ve never seen anyone recommend them on this forum. I don’t want to get the cheapest made thing out there. Also, very soon I hope to move up to large parts the size of automotive body panels, so I do not need something underpowered.

I see many questions here where people are very frustrated when it comes to choosing a vacuum. There is no general consensus as to which type or brand of vacuum is best and I had hoped that I found the ultimate solution. Electricity in the city where I live is brutal at $0.14 kw/hr, so heavy usage is definitely a concern of mine

Also, for those of you in search of some used equipment, I found this airtech catchpot on ebay & scored it for $80 + shipping. Apparently he has 3 more.
AIRTECH 3 GALLON PRESSURE POT PAINT / ADHESIVE 281145431958

[doctorbombei]

Everyone says the harbor freight vacuums are garbage. I’ve never seen anyone recommend them on this forum.

Also, for those of you in search of some used equipment, I found this airtech catchpot on ebay & scored it for $80 + shipping. Apparently he has 3 more.
AIRTECH 3 GALLON PRESSURE POT PAINT / ADHESIVE 281145431958

[Rotorage]

I’ve posted this pump a few times one the forum.
http://www.amazon.com/Robinair-15600-CFM-Vacuum-Pump/dp/B000JFNAJE/ref=sr_1_1?ie=UTF8&qid=1384439647&sr=8-1&keywords=robin+air+15600
It cheap, reliable (with proper care like changing oil), pulls 29" of vaccum, and can do decent size parts like car parts or multiple molds at once. Use an air compressor tank as a vacuum storage tank, set up a switch system and filter along with a manifold for multiple lines and your set.

[craj1031tx]

I’ve posted this pump a few times one the forum.
http://www.amazon.com/Robinair-15600-CFM-Vacuum-Pump/dp/B000JFNAJE/ref=sr_1_1?ie=UTF8&qid=1384439647&sr=8-1&keywords=robin+air+15600
It cheap, reliable (with proper care like changing oil), pulls 29" of vaccum, and can do decent size parts like car parts or multiple molds at once. Use an air compressor tank as a vacuum storage tank, set up a switch system and filter along with a manifold for multiple lines and your set.

You can’t really beat this for an entry level vacuum. IMO there is no reason to run a venture system when you can get a vacuum pump for 100 bucks at harbor freight, or a good quality pump such as this robinair for 150

[doctorbombei]

You can’t really beat this for an entry level vacuum. IMO there is no reason to run a venture system when you can get a vacuum pump for 100 bucks at harbor freight, or a good quality pump such as this robinair for 150

Appreciate the advice. Well the Venturi system is $159 on joewoodworker. The pump that Rotorage recommended (15600 6cfm) is $287 on Amazon.

The Robinair 15500 5 CFM is about $150

I figured I’d kill 2 birds with one stone with the compressor and the venturi, but I think I’ll go with a pump.

[herman]

If power consumption is a concern, be careful with compressed air and compressed air tools.

If you can weld or have a suitable glue (methacrylate) you can turn one of those tanks into a nice vacuum vessel, if your setup is going to need one.

Vacuum in your shop:

For infusion you need a very good vacuum (99% at least, I will use percentages, saves me from hassling with units). You also would like it adjustable.

For wet bagging you need an adjustable vacuum, between (roughly) 90% and 50%.

For getting all the air out of an oversized bag, you either need something smart in your connecting hose (limiter) or just use a vacuum cleaner, stuck in a pleat which still needs closing, which takes care of 90% of the air in the bag.

You have a couple of choices on vacuum regulation, which I will elaborate on later. First see the dentist.

[herman]

Regulation:

You can have the pump running 24/7, and thus a high vacuum. Lossless regulators can throttle down the vacuum at certain outlets. (controlled leak regulators, such as the VACREG from Airtech, I consider silly things.)

If your pump has enough capacity, and leaks in your system are taken care of, you can install a pressure switch on your vacuum pump. This makes the pump run only when needed. The Joewoodworker switch is useless, though. (I bought one out of curiosity). Hysterese is way too large, and unpredictable, just as all other microswitch/mebrane operated ones. Get a good digital or mechanical switch. (pref digital, as the hysterese is way smaller).

This essentially makes your vacuum system the same as a compressed air system, just the other way round. A larger tank makes start and stop cycles less frequent, the pump is not running 24/7, saving a lot of energy/money.

Alternatively you can rig the pump with a pressure switch, and by throttling down the switch, you can create less vacuum if desired. (50% for instance)

[doctorbombei]

Well, I may not use the venturi press, but I still refurbished the air compressor.

I completely dismantled it:

Changed all fittings that needed changing
Re taped the fittings
Painted the tank with approx 2 cans of white appliance epoxy
2 coats of clear coat
Painted the compressor, motor, wheel with black engine enamel spray paint
Disassembled compressor, degreased & scrubbed down everything
New seals
New oil
Drain valve extension
New check valve
New pressure gauge
New belt
She’s running STRONG & HAPPY!

I’m going to rework another copper pipe to run from the compressor to the tank.

[herman]

Looks nice. For security I would like to see a more sophisticated connection to the motor, and a cage or something around the belt.