[TheForge] Sand blaster problem: hose blows off

[Peter Fels & Phoebe Palmer]

The siphon type blaster is cheapest and most common.
 The only commercial application i know of  for  it is recycling grit in blast cabinets and the like..
Serious , heavy blasting usually uses a pressure pot where the abrasive is fed under pressure into a stream of air
and out through the hose. I have one of each.
The abrasive hose with a pressure pot must tolerate high pressure jerks and surges, especially if everything isn't bone dry.
Heavy steel or cast iron clamps are commonly available for these applications. Mine have a 2 piece clamp bolted together
and i've never seen one come loose when tightened down. Think my nozzle hose is 1 1/4 OD or so.
The clamps that came with your rig don't work quite well enough, OK,
So make up something that squeezes harder, 
Shouldn't be difficult and way quicker than going to town.

On Jul 22, 2013, at 8:38 PM, Mike Spencer wrote:


Ries wrote:

ries> A siphon gun works the same way, its just that the T is inside
ries> the gun. The air hose comes in the back of the gun, like yours
ries> comes into the T, and the hose from the bottom of the T goes to
ries> the sand pile. The third leg of the T is the nozzle.

That's how a paint sprayer works, only it usually has a paint canister
right on the gun.  Does your sandblaster have a canister on the gun?

Seems like a hard job to get enough Bernoulli effect to pull sand
trough a hose from, say, a bucket on the floor.

ries> You could braze a pipe fitting on the gun, and another on the T
ries> and then use an air hose with threaded fittings- that would be a
ries> final fix.

Yeah.  That's the plan if one more try with clamps fails.  The gun is
already threaded -- just need to find the right fitting.  The tee is
steel so I can braze or weld a fitting on to it.


Bob Ehrenberger wrote:

be> My sand blaster doesn't have the hose come off, but if you don't
be> get the air flowing before opening up the valve to the sand it
be> fills the hose up with sand and plugs everything up.  Maybe that
be> is what is happening and then when the pressure builds up it blows
be> the hose.

Using medium-sized glass bead, if I open the valve to the media all
the way, I get a stream of powder instead of a fine blast of grit.
But that is *not* what was happening when the hose blew.  Everything
was working just right.

> It may also be that your compressor has too much pressure for the
> connections and needs to be dialed back a little.

Well, it's rated for 120 psi, I was using 100 psi and cut back to 90
after the first blow-off.


- Mike

-- 
Michael Spencer                  Nova Scotia, Canada       .~. 
                                                          /V\ 
mspencer at tallships.ca                                     /( )\
http://home.tallships.ca/mspencer/                        ^^-^^

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