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pressure blast vs siphon blast

HCP

Plastic
Joined
Feb 6, 2006
Location
Northern NY
My company does a large amount of sand blasting per day (4-6 man hours). We are useing conventional siphon fed cabinets. Are their any advantages to useing pressure blast cabinets? Thanks...Herb
 
If you have feed problems (moisture, debris clumps, grease)with your siphon cabinets pressure virtually eliminates them. Pressure allows you to control amount of media in stream, siphon is usually what it sucks is what you get. Pressure can be more efficient getting the job done sooner. But you are dealing with a pressure vessel and someone has to be intelligent enough to be able to operate a pressure system adjusting it to the conditions. So operator skill is a wee bit higher with pressure than simple cabinets.
 
On the same topic,
Can someone build a small to medium size pressure blaster?And is it too hard on aluminum or can you adjust it down enough?I would be using glass instead of other media?
 
I personally wouldn't. I do not want my hand in the construction/alteration of a pressure vessel.
On the aluminum....a pressure blaster would be fine. It is the media and going plastic, walnut shells, or glass beads alleviates the aggressivenes as well you can limit the pressure. Provided you are talking castings or forgings. Try aluminum sheet or fabrications and you may end up with a washboard!
 
A lot of manufacturers have stopped making pressure blasters, due to the legal liability. Nothing wrong with the process- its just that the average joe doesnt maintain the setup, moisture inevitably gets in the tank, the tank rusts out from the inside, and BLAMMO- tank explodes.
The profit margins are too small, on a couple hundred dollar pressure blaster, to pay for the insurance.
So companies like TP tools, which used to sell thousands of em, stopped altogether.
Cabinet siphon models only, now, from TP.

Here is a small one, says its made in the USA-
http://www.sjdiscounttools.com/atd-84713.html

Then there are the chinese ones- dirt cheap- so cheap its hardly worth making your own- 80 bucks at harbor freight-
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=34202
 
Also, the pressure blaster setups are cool for small jobs but if you are blasting that much the down time associated with reloading the blast media is gonna consume some time. JRouche
 
I have done a lot of blasting and have found that the pressure blasters are the best by far. With a siphon feed the flow of abrasive is not consistant spits and sputters generally a pain to use. The pressure blaster has consistant and easy to control abrasive flow, also I have noticed the maximum volume of abrasive is much higher which makes the job go much quicker when you have some heavy stuff to do. I now do not use anything but a pressure blaster setup, and would never go back to a siphon system.
Ed
 
My experience with syphon feed sandblast guns is that on a good day ,when everything is working properly, one still only gets a pitifully small stream of sand out of it. On a bad day, I spend most of my time kicking the cabinet, rodding out, etc , trying to get it to feed. I bought a cheap tank type sandblaster from Harbor Freight. It works great! It really shoots the sand out but is somewhat inconvient and dirty to have to keep re-filling the tank with sand. If I need a more gentle blast, I can reduce the air pressure and it will still feed a heavy (as I want) stream of sand.
 
The biggest advantage pressure has over syphon is it will operate at half the cfm of air as a syphon setup with the same amount of cleaning capability.You can blast aluminum as low as 25lbs depending on the media and finish you are looking for.Fill the cabinet with garnet and you can bore a hole through aluminum with it...lol.If you buy/build a good syphon cabinet,they will work well except for the heaviest of jobs.It's all in the setup(using the correct jet and nozzle for the media),having a good gun(not a $5 HF special) and having DRY media!It takes 20 cfm to run a good med. sized syphon cabinet and half that for a pressure pot.

Syphon setup is much more sensitive to water then pressure setup is,it just blows the "slurry" through.On syphon it will collect on the pick-up tube and plug it,causing you to backflow the gun all the time.As far as grease in your cabinet...I'm not sure what cabinet you need for that!

Almost everyone I know that has had a problem with a syphon cabinet,ends up being the same problem.Media is moist,they put MORE media in it,thinking that will help.Between the weight of the media and moisture,the thing doesn't have a chance.

I have 5 cabinets,all homemade,all syphon.They're filled with plastic,walnut shells,(2)glass bead,and steel shot.They all work fine.Takes 2-3 min to glass bead a cyl head.Been working on a soda blaster the last few weeks for cleaning pistons and more delicate stuff.When that's done,the plastic media is GONE.First time I saw one it was a MUST have kind of thing.You want to see a clean carb or throttle body...

[ 10-28-2006, 06:09 PM: Message edited by: Booger ]
 








 
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