That clemco blast pot...

[Dcal]

Think of it as an air relay.
It needs a signal to operate.
The "signal" is air, fed to a spring loaded deadman on the handle that is normally open, so the air just vents to the atmosphere. If you've loads of air and someone else is paying for making it, then no problem.

When you operate the deadman it sends the air through the deadman to the main valve and operates it, sending the main high flow, high pressure air to the pot to close the pop-up valve and start the blasting process.

It's a simple system and I would keep it operational however, they are really for big nossles that require a lot of air that can do serious damage if you get a burst or a medical emergency (for example)

If you only have a 3 or 5hp compressor I wouldn't worry overly.
Also, the amount of air venting out the deadman while you are trying to build up air pressure again, will get old very quickly.

A sealed system operated off a foot pedal, for example, is a lot less wasteful, but is not inherently as safe, but can be made safe enough. (In my opinion)

 

[Erie Fred]

Think of it as an air relay.
It needs a signal to operate.
The "signal" is air, fed to a spring loaded deadman on the handle that is normally open, so the air just vents to the atmosphere. If you've loads of air and someone else is paying for making it, then no problem.

When you operate the deadman it sends the air through the deadman to the main valve and operates it, sending the main high flow, high pressure air to the pot to close the pop-up valve and start the blasting process.

It's a simple system and I would keep it operational however, they are really for big nossles that require a lot of air that can do serious damage if you get a burst or a medical emergency (for example)

If you only have a 3 or 5hp compressor I wouldn't worry overly.
Also, the amount of air venting out the deadman while you are trying to build up air pressure again, will get old very quickly.

A sealed system operated off a foot pedal, for example, is a lot less wasteful, but is not inherently as safe, but can be made safe enough. (In my opinion)

Now I remember ^^^ the real deadman switch has that little leak, I wonder if you could make it smaller and still have it work properly ?
To save air consumption.

 

[julianf]

Thank you all.

It seems that, probably, what I should do is remove the control valve block and just set it all up as per one of the generic cheap units, assuming I can get the mushroom to close.


I wonder if I need to fit two valves, to close the mushroom before charging the pot, or if I can just direct air to them both at the same time and it will work.

I'll have to do some tests.

 

[brightspark]

Thank you all.

It seems that, probably, what I should do is remove the control valve block and just set it all up as per one of the generic cheap units, assuming I can get the mushroom to close.


I wonder if I need to fit two valves, to close the mushroom before charging the pot, or if I can just direct air to them both at the same time and it will work.

I'll have to do some tests.

realy the popup valve wants energising 1st to close the tank then turn on the other to fill the pot and blast hose otherwise the air will escape when filling

 

[julianf]

Is is also possible to fit a ball valve to the outlet of the grit shut off, not as a meeting device, but to simply shut off the air?

I'm thinking the grit control at the base of the pot will turn off the grit, but I'd not expect it to hold the air.

If the procedure was to turn off the grit and then turn off the valve, would the valve last, or would it die all the same?

So, to confirm, the valve would only ever have grit passing through it when it was fully open.

 

[brightspark]

Is is also possible to fit a ball valve to the outlet of the grit shut off, not as a meeting device, but to simply shut off the air?

I'm thinking the grit control at the base of the pot will turn off the grit, but I'd not expect it to hold the air.

If the procedure was to turn off the grit and then turn off the valve, would the valve last, or would it die all the same?

So, to confirm, the valve would only ever have grit passing through it when it was fully open.

dont put a ball valve past the grit valve in the line this is all you need

 

[brightspark]

heres my other

 

[julianf]

heres my other

View attachment 422170

Thank you.

The nozzle end - I was going to get one of those 3mm ace nozzles, and assumed I would just jubilee it into the end of a 10mm ID hose, it it looks like you have something more (the yellow bit)

I assume I need that - what is it?

 

[brightspark]

Thank you.

The nozzle end - I was going to get one of those 3mm ace nozzles, and assumed I would just jubilee it into the end of a 10mm ID hose, it it looks like you have something more (the yellow bit)

I assume I need that - what is it?

yes its the larger pot 90cfm with the proper fittings and a 6mm blast jet my other has the 3mm blast nozzle just in pipe with jublly clip holding it

 

[Erie Fred]

Thank you.

The nozzle end - I was going to get one of those 3mm ace nozzles, and assumed I would just jubilee it into the end of a 10mm ID hose, it it looks like you have something more (the yellow bit)

I assume I need that - what is it?

PARTS AND SUPPLIES - BLAST POTS & PARTS / SUPPLIES (CONTRACTOR) - BLAST HOSE & COUPLINGS - NOZZLE HOLDERS - STANDARD - IDS Blast

idsblast.com

 

[Erie Fred]

Pressure-Release vs Pressure-Hold: which blast pot is better? Deadman Switch | Blast Booths Spray Paint Booths Abrasives Media & Equipment

The most popular and common blast pot on jobsites is a Pressure Release System. Is this proof that the Pressure Release is better than the Pressure Hold?

www.blastone.com

 

[armalites]

the only thing you might have to watch is that the pop up valve may need a high ish pressure for it to operate and stay closed so if comp isnt up to it and drops in pressure it may fail

I would say air flow is as important as pressure for the pop up valve

 

[armalites]

Possibly, but...

Because I'll be running this on a lower air supply than most do, I'll need a smaller bore hose than is common.

I mean, I'm keen, but I can't be sure if what you have will be applicable. Although I guess the control pipes and switch would be, even if the hose itself wasn't.

Let me know when you're back and we can both see. Thank you.

The deadman valve runs on something like 6-8mm pipe so shouldn't be an issue.
There's a chap on Youtube who does blasting and often he is a reasonable distance from the compressor so air operated deadman can take a while to repsond. He converted to a 12V setup head made up after looking at the commercially available ones that cost a chunk of money, I'll try and find the video

 

[julianf]

That'll do, right?

Its just a single compressor with the tank charged (pump not running) and a skinny air line.

 

[dave h 2]

If I remember mine just blocked off both tubes so cap the two outlet pipes on the square valve and use a ball valve on the main air feed to switch it on and off. It just won't cut the grit feed so cleanly

 

[sasquar]

A little busy at the moment, so havent read the whole thread. Short answer is (saftey issues aside) yes you can connect the dead man up to a ball valve, and just close it as you need to operate the pot. it will work fine, mushroom will lift when you close the valve, thats effectively all the deam man does. Ill try and remember to get back later and have a proper read and see what else youve got going on (if anything), we run these at work, theyre actually incredible, simple bits of kit, that are pretty much indestructible....

 

[julianf]

needing a pilots licience now......

I thought that, if I left this a while, it would dawn on me what the (I hope) joke was...

And its been a while and I still don't "get" it!

 

[julianf]

No real progress, apart from acquiring a micro cabinet (below).

I think I'm going to give it a go with @Bond 's pipes, and change the dia of the main tube.

It seems that, however you set up the unit, without changing the metering valve for a solenoid one, you end up having to depressurize the pot every time you want to pause, so the existing setup appears as good as any other option, again, other than changing to a solenoid.

I need to drill out a sheered fitting on the control valve though, but not done that yet.

The micro cabinet -

shot blast cabinet Clarke | eBay

Includes extra filter for cleaner exhaust.

www.ebay.co.uk

Is one of those tiny desktop blast cabs, which I suspect may be too small for anything (inc the cfm) but it was cheap enough for a go, esp as the seller threw in a load of grit and a sack of walnut shells.

(It ended without bids, rather than the auction was cancelled on my request, hence we agreed a price a tenner less than the eBay failed sale)


I don't really have space for a large cabinet, and this one will fit in the small cast parts that I want to finish, but I'm not convinced it will be on with the air flow etc.

 

[knighty]

I hired a big blasting pot and compressor a while back, from 2 different places because the blasting pop people wanted a fortune for the compressor vs the hire place over the road from me

compressor the hire place got me wasn't big enough, and they didn't have another to hand, not enough flow/pressure to lift the mushroom thing inside the pot

needing to get it done asap I ran my 2 electric compressors in parallel with the hire one, worked ok... had to let if build up pressure now and again because the bodged up air connections I was using didn't allow enough flow

 

[julianf]

I spoke with Clemco, with regards to the availability of a new seal kit for the control valve, and a new "donut" seal thing for the top of the unit, and the prices were not shocking -

£3.75 for the dounut, and £28 for the control valve seal kit. I mean, its a lot for a couple of seals, but i assumed it would be way worse.


The chap i spoke to was enthusiastic about the unit. He seemed pleased that an old unit was being (hopefully) bought back into use.

He pointed me to this chart -

Air Consumption Chart - Hodge Clemco

Access detailed air consumption charts for blasting equipment. Ensure your operations are efficient with accurate data from Hodge Clemco.

www.hodgeclemco.co.uk

...which implies that my (aprox) 20cfm (2-off 1ph 3hp compressors) will be viable at 100psi on a 3mm nozzel (as has been said here prior) but, what im still unsure of, is how you match the pressure to the application?

The slider on the above web page lets you lower or raise the nozzle pressure. Im guessing thats relevant, but im unsure what you would want less or more pressure for?



I managed to remove the sheared fitting stub from the control valve yesterday (a task that i generally screw up) so im on coarse to getting this working.