Death of a Vacuum

It was almost 4 months ago to the day, that I built a vacuum table for the CNC router.

While it worked well, I was sure the lack of overall airflow would result in the vacuum carking it very quickly.  Job after job, and it kept going.  It was encased in a rubbish bin with noise absorbing material stuffed around it to drop it’s horrendous noise down to bearable levels (it was a ShopVac, and it always was a screamer). It ran warm- the exhaust was always hotter than was healthy.

Went out to the shed tonight to check on a job, and although the CNC has indeed finished, it was a lot more silent than usual.

Instead of the muffled sound of the vacuum, there was a familiar smell of burnt plastic and ozone.

Carefully switching it off then unplugging it from the wall, I went on dealing with the job at hand, and then went over to the garbage bin, and started unpacking.  Partway down, and the normally white insulation material started coming out black.  Desite being some time, the vacuum itself was still very warm.  A complete meltdown.

Not as bad as the last vacuum though.  Years ago, I had a household vac for dust extraction, and it also failed in spectacular fashion, actually melting until it literally fell apart, and the motor fell out of the housing.

So the machining tonight has stopped, slightly prematurely.  I haven’t added up the hours the vac did in those 4 months, but it would legitimately be into the hundreds of hours.  Hundreds of hours, in a MDF laden atmosphere, with poor airflow. I think it did a pretty good job in the end!  Not even sure what the designed duty cycle of the vac was, or the model’s MTBF (mean time between failure).

So now the decision is “what next”?

Another cheap vac?  A vacuum pump?  If so, which one?  There’s a bunch on eBay, all different cfm, and I have no idea what cfm I’d actually need, let alone my current table would leak like a sieve, so would never actually be able to maintain a vacuum.  And that means the vacuum pump would be running continuously, unless I make some real mods (rebuild) to the table itself.  What do commercial machines do for a vacuum table, and the pump for them?  Too many questions, not enough answers (yet).

Scaring up a Storm

I have long been absolutely sold on the benefits of cyclonic dust separation methods – the combination of the convenience of easily emptying the collection bin, combined with a negligible amount of dust getting to the vacuum itself (and filling its dust bag).

Filterless, efficient dust collection – sounds like an advert for Dyson.

The fascinating thing is the concept is incredibly simple.  Pull a vacuum in an inverted cone through a central vertical port, and have the collection hose coming in the side of the cone angled so the dust-laden air is caused to spin all around the edge.  The dust is heavy, and spins to the outside where it impacts the container wall, slowing it and causing it to drop down towards the bin at the bottom.

The air on the other hand follows a torturous path from the entrance to the cone to the central exit – a path too convoluted that the dust can’t follow the twists and turns, so the dust that wasn’t removed by hitting the wall still drops out of the air stream.

You can make your own, particularly if you can work with sheet metal, but if you don’t have the skills, or simply the time there is finally another option available.

The Oneida Dust Deputy is now available under the Carbatec banner, and I was putting one through its paces today, and it was definitely achieving what I would expect of a cyclone dust collector.

Cyclone

I fitted it to my ShopVac vacuum, and the very nice thing is the fittings are compatible. The heavy hose leading from the vac to the top of the cyclone came with the cyclone, and it plugged straight in. The hose coming out of the side of the cone leads to the collection point from the tool.

The cyclone unit came with a few variety of fittings to ensure a wide variety of vacs would work with the cyclone.  It also came with 2 collection buckets – they do fill quickly, but I didn’t think a second bucket was necessary.  No matter – bonus.

Connecting the Cyclone to the Vac

A number of different methods are documented in the user manual, and I came up with this one as being particularly suitable for the model vacuum I am currently using .  I attached a couple of metal hooks to the top, which the bucket hangs off by the handle.  A brick in the vacuum itself at the front provides a counter balance (in this case, a couple of lead dive weights).

Cyclone conical section

It is interesting that the plastic chosen is both antistatic (a cyclone can build a significant charge!), and semi-transparent, so you can see the dust swirling.

All in all, an excellent unit, and if you are not inclined to make your own, this is a ready-made commercial version. I’ll shot some video of the unit in operation in the near future.

Tag Team

GMC Vacuum tagged out, ShopVac tagged in.

Despite cleaning filters, and introducing a pre-separator (home-made cyclone), it was already too late – the GMC has partaken of too much of an MDF diet (you could smell it each time the vac was turned on), and today it finally smoked itself properly.

And I mean SMOKED!

Power suddenly failed, as a circuit breaker blew, and all was surprisingly quiet in the workshop.  A glance over to the vac was all that was needed, seeing the smoke pour out.

So getting the ShopVac was excellent timing, and immediately I noticed a dramatic increase in the amount of suction that I have available.

That is the second vacuum that I’ve now gone through.  First one was a few years ago, and it smoked itself too, but to the point that it also melted and fell apart when it failed.  Hopefully the ShopVac will do better (it has an internal collection bag, and I’m still using the pre-separator, which is working very well).

The Great Flood

The sudden rains today caught Melbourne a good one, so heavy that some streets filled with water to the extent people could (and were) actually have a swim (though why you’d want to….!)

Photo by Ellen Smith from Herald Sun website

It poured down our way as well, and I found at one point that the rubber flooring wasn’t actually sitting on the floor, but had started to float.  The amount of water getting in wasn’t particularly dramatic – the downpour exceeded the guttering’s capabilities on one corner, and it started to bubble in under the wall.  I would have ignored it, (primarily because there usually was nothing I could do about it, and also because anything in that part of the shed is either elevated on wheels, or on the rubber mat), but then a thought crossed my mind…..  That new ShopVac vacuum I got from Costco is a wet and dry.  Didn’t buy it with any intention of using its wet capability, but seeing as it could I gave it a try.

Well this sucks

It didn’t just pick up water, it sucked the floor to the point that it was damp, with no surface water apparent.

And Sucks

About 60 litres of water later (emptying the bin numerous times), and the rain subsided to a point the gutters could cope.  The shed was saved any potential problems resulting from the influx.  This shed is significantly better than the previous version for coping with downpours – only its location causes even this small amount of drama, and the ShopVac performed admirably.

A visit to Costco

Had an interesting first visit to Costco over the weekend (the place seems like a Tardis – much larger on the inside than it certainly appeared from the outside)!

Didn’t expect it to become a shed-related activity, and there was a very limited number of tools there (did spot a Lithium-Ion GMC cordless drill (guess there are still some GMC tools out there)), and a stack of ShopVacs.

ShopVac 20

Given the GMC vac I have been using occasionally is already threatening to turn into a molten lump of plastic in the middle of the floor, I thought I’d grab one of the ShopVacs (think they were about $70).  The other reason I picked one was because of comments made in the past on this site when discussing dust collection from Festool power tools.  Someone mentioned they used a ShopVac as the nozzle size was pretty suitable for Festool.

ShopVac to Festool

Ah well, it’s better than nothing.  In a perfect world…….

Festool Vac with Dust Deputy Cyclone

……I’d have a Festool Dust Collection system, and even more ideally, with a cyclonic dust separator such as this commercial one from Oneida.  That sucks 😉

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