Small Workshop Air Compressor £67

[Radio Wrangler]

Pub gas Argon?

I always thought it was CO2 because you can get a lot more CO2 in the same size bottle, CO2 is a natural constituent in beer, and CO2 is an awful lot cheaper than Argon.

9.7m^3 of Argon at 300atm from BOC costs just shy of £140 when you include VAT, energy surcharge, paperwork surcharge and charge made for delivery to their distributor. They don't charge for the rotation of the plant Earth or danegeld. I bought a refil just before lockdown... oh and £150 ish per annum cylinder rental.

It doesn't make any difference to the use of an ex-pub cylinder as an air receiver, but you surprised me. Argon like CO2 is a heavier-than-air asphyxiant, but doesn't trigger some of the warning signs people might experience with co2 in a cellar. You need to take care with it.

David

[AC/HL]

The gas used in a pub can be co2 or a mixture of co2 and nitrogen, depending on it's use, but not argon. Presumably the bottle was acquired empty though.

[CambridgeWorks]

Back in the 80s I often went to Brian Bamber Anglia Industrial Auctions at Littleport near Cambridge. Some may remember him from the Leicester shows or his ads in radio mags.
He used to buy factory and surplus gear and auction it himself. He could make a subject of another thread as I am sure some on here would have seen him. A great character.
I always remember often joking with him about a cylinder similar to a pub CO2 one propped up near the doors. It never sold. Attached was a label "Return to Porton Down"!
One auction I bought a lot of 8 (I think) brand new school laboratory grade 240v diaphragm compressors that had a variable regulator, gauge and filter. Uk made (Charles Austen Pumps i think) and really nice. Ok for about 35psi and ideal for airbrushes. I kept one and took the rest to a train collectors fair at Kettering and sold the lot before the doors even opened! Well pleased. I bought a couple of locos and still went home with more cash than I took.
At a local rally about 5 years ago, there was a vanload of gear being sold from a SK estate. As he was packing up the few unsold items, I started examining a small compressor with tank, gauge and regulator that had not been sold. "Give us a tenner and its yours" he said.
I didn't hesitate. I dont think it ever had a lot of use. The pressure switch cutoff is I think 100psi. Used only occasionally, mostly for blowing dust away.
Rob

[ex 2 Base]

Thanks for the correction David and Bill it would be CO2 and the bottle was empty. Ted

[dodgy-dxer]

Quite a surprise as the compressor arrived with the correct UK mains plug from a Dutch supplier - top marks

Fred

[Pamphonica]

The compressor I bought is called a Fengda FD-186. Widely available.

I finally connected everything up (I needed some adapters) and here is an initial score-card:

Pros:

• Small size so can hide under workbench
• Low cost entry point for small compressors
• Definitely quiet enough to work next to it with motor running

Cons:

• Not much puff. 3L at 4bar max is really only enough for a bit of chassis cleaning or light paint spraying
• Not really enough for a professional desoldering tool (Metcal) which needs more like 80 (continuous) than 55psi falling rapidly.
• Tedious for car-tyre top-up, with waits for tank re-fill, but do-able.
• Output pressure setting and gauge a bit hit and miss.
• 1/8" thread outlet rather than the more usual 1/4", no quick-connector.
• Needs a kit of more bits to make it useful (hose, connectors etc).

The kit of extra bits was only £14 from Ebay and included a hose, tyre inflator, air nozzles and a reasonable selection of adapters and male/female connectors. But note that this kit uses the standard 1/4" fittings, so I had to order a couple of 1/4" to 1/8" adapters from Ebay as well.

To give you an idea, blasting out dust from a chassis, you only get a few seconds of blast before the motor kicks in to replenish the tank.

So after all that it may get put away for a bit while I explore slightly bigger compressors with 6L at 8bar at least, for my desoldering tool. I should have read the fine print a bit more carefully, and I under-estimated my needs.

An interesting introduction to pressurised air and its uses, though.

Hopefully this will help those who follow in this path.

-Jeremy

[Radio Wrangler]

Oh, well, at least it's done the job of giving you an idea of how much pressure and capacity you need.

I bought my dad a little 1HP direct-drive compressor with a view to driving his air brush and inflating tyres. Weight wise, I can pick it up with one hand by its handle and walk with it. We tried it out last year when I took all my welding stuff down to Yorkshire and it ran my plasma cutter! I think it's marked Clarke but also the same thing appears in other liveries.

David

[Pamphonica]

I was hoping to have a tiny, quiet compressor that would sit under the workbench. But now I know it needs to be a bit larger, as soon as I go up in size (even to 6L, or 8, or 10) the noise seems to rise dramatically (from a pleasant 45dBA to 80, or even 90dBA+ - ouch!). And if you do seek out larger but low noise versions (pancake etc) the price goes stratospheric.

This one does do a reasonable job on dust removal and even tyres at a pinch. And I might be able to use it for a bit of spray painting. And I console myself with the thought that I may not need any more cans of air duster for a bit! So it will get some use whatever happens.

But I just I don't have space inside for a huge, possibly secondhand monster, and don't really want to have to do desoldering in the garage.
Realistically I may abort the airline desoldering route, at least for now and retreat to my trusty Duratool desoldering iron.

Meanwhile, does anyone have any advice about oil-free vs oil-filled small compressors, or comments on what technology gives the lowest noise, especially when used indoors?

I blame all this confusion on advancing years, and far too many spare hours in lockdown, dreaming up new projects!

-Jeremy

How about a large extra tank to give you a good supply of air albeit intermittently. An old "barbecue" gas tank should do and it could be mounted remotely too, even outdoors. Remember the old adage, buy cheap, buy twice!

[Electronpusher0]

I have to sound the usual safety warning bell here, compressed air can be dangerous, 10 bar is 10 times atmospheric pressure, thats 145psi!, normal car tyres have only 2 bar and they can got with quite a bang if damaged.
Cobbling together an extra reservoir from a barbeque gas cylinder could work but you would not have any of the safety features like over pressure relief valves.
Go carefully!

Peter

[Radio Wrangler]

Go for a reasonable size compressor and build a little shed outside for it.

Older, low speed belt drive compressors are a lot quieter than modern high speed ones which roar loud enough to scare the paint onto the car. A large displacement pump running low revs is a good recipe for long life, so you're more likely to find one in good condition. Look for something older, with a 4-pole 1400-ish rpm motor and then look at the pulley ratio to get an idea of the pump revs. Arranging sound deadening for the input air filter can help a lot.

Oil-less usually means trouble or amazingly expensive.

David