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Chosen_1 03-04-2013 11:45 AM

Problem with Blast Cabinet Setup
 
So, I finally saved the funds to buy my own blasting setup (I already have parkerizing stuff). After spending the entire afternoon assembling the harbor freight blast cabinet and this

http://www.harborfreight.com/air-com...psi-67847.html
(It's the central pneumatic 21 gal 2.5 hp 125 psi model)

air compressor, something went wrong. I can only get a quick burst of pressure before its totally gone. I am using 3/8" 30 foot hose, and I had the pressure regulator all the way open, but it does not seem to be releasing the advertised 125 psi.

Help!

ExtremeX 03-04-2013 11:48 AM

Link doesn’t work...

klewan 03-04-2013 11:51 AM

Take the regulator out of the system and stick the hose right at the tank output. Try another hose if you have it. Something is blocking the air flow, be systematic to find it.

ar15barrels 03-04-2013 2:06 PM

A 20 gallon compressor is most likely not going to supply enough air volume to blast with.
Read the blaster CFM requirements.
Then read the compressor's CFM output.

Try turning the pressure down to 90psi so that your 125psi tank pressure will last a couple seconds longer.
Next, get a bigger diameter and shorter air hose.
You can't flow much air through the 1/4" air line you are probably using.

Chosen_1 03-04-2013 2:11 PM

Quote:

Originally Posted by ar15barrels (Post 10713455)
A 20 gallon compressor is most likely not going to supply enough air volume to blast with.
Read the blaster CFM requirements.
Then read the compressor's CFM output.

Try turning the pressure down to 90psi so that your 125psi tank pressure will last a couple seconds longer.
Next, get a bigger diameter and shorter air hose.
You can't flow much air through the 1/4" air line you are probably using.

By short burst, I mean less than a second. The psi on the gauge is still reading basically full. And as I said, I am using a 30 foot 3/8" hose. It would seem to me that the pressure regulator is the problem.

freonr22 03-04-2013 2:15 PM

which cabinet? my 3ph 5hp 80 gal ingersoll rand tank really had a hard time keeping up with the large hf blast cabinet

Chosen_1 03-04-2013 2:20 PM

Quote:

Originally Posted by freonr22 (Post 10713544)
which cabinet? my 3ph 5hp 80 gal ingersoll rand tank really had a hard time keeping up with the large hf blast cabinet

http://www.harborfreight.com/40-lb-c...net-68893.html

The 40 lb. capacity ~$200 one. Maximum psi 125, which is what the compressor output should be.

freonr22 03-04-2013 2:25 PM

you very well may have a restriction, but its about VOLUME and psi

here is your cabinets' air consumption:
Average air consumption 9.5 @ 90

Here is your air compressors output
Average air consumption 4.7 CFM @ 90 PSI

just sayin

Chosen_1 03-04-2013 2:27 PM

Quote:

Originally Posted by freonr22 (Post 10713645)
you very well may have a restriction, but its about VOLUME and psi

here is your cabinets' air consumption:
Average air consumption 9.5 @ 90

Here is your air compressors output
Average air consumption 4.7 CFM @ 90 PSI

just sayin

It should still be able to run it for more than one second though, right?

L4D 03-04-2013 2:33 PM

Quote:

Originally Posted by Chosen_1 (Post 10713651)
It should still be able to run it for more than one second though, right?

what happens when you run the compressor wide open without the hose attached? Does it flow freely? ( im assuming you went through the break-in process of running it this way for 30 minutes) did you?

Chosen_1 03-04-2013 2:35 PM

Quote:

Originally Posted by L4D (Post 10713732)
what happens when you run the compressor wide open without the hose attached? Does it flow freely? ( im assuming you went through the break-in process of running it this way for 30 minutes) did you?

I did, but I may have left the regulator partially closed during the break in. All I can say is now, even with the regulator totally open, it trickles out at a very slow rate. Maybe the regulator is stuck partially closed?

SMR510 03-04-2013 2:41 PM

Sounds like its the regulator, take it out and try again. Replace with another regulator if it runs good without it (you will want one on there to adjust pressure for different things).

kcstott 03-04-2013 3:04 PM

Remove the regulator and inspect the lines for little pieces of teflon tape. They can get stuck in the passages and completely shut off you air supply.
What you are doing is only using the air in the hose. 1-2 seconds worth of air. As you are reducing the pressure in the tank the obstruction (Possibly Teflon tape) is clapping shut.

I've seen this happen more then once.

ar15barrels 03-04-2013 3:07 PM

If the regulator is setup to flow 4.7 CFM, it might have a pretty small metering hole that restricts the flow so you don't run the tank down too fast.
Get another regulator that is happy flowing 20CFM or more and mount that regulator directly to the tank.
Run the regulator at 80-90 psi to make your120psi tank last a few seconds longer.
Go to a 5 or 10ft long 1/2" hose between the regulator and the blaster.

Put a smaller nozzle in the gun.
With 4.7 CFM, you want to be using about a 1/8" nozzle where the air picks up the media.

I have a 5hp 80 gallon compressor and it works my compressor pretty hard running the 1/4" carbide nozzle I have in my blast gun.
I run a 3/4" regulator right off the side of my tank that is rated for 200CFM.
I run a 5ft 1/2" hose to my foot pedal.

ar15barrels 03-04-2013 3:08 PM

Quote:

Originally Posted by Chosen_1 (Post 10713651)
It should still be able to run it for more than one second though, right?

No.

4.7 CFM will not magically grow to 9.5CFM.
Reducing your nozzle size will reduce your CFM requirement though.

valley82 03-04-2013 4:10 PM

If you are only getting a second of air thre is deffinitely a restriction in the air line either the hose or the regulator. Let the compressor build pressure and cycle off, then hit the blaster, if the air pressure falls and the compressor does not turn on it is in the regulator or the line (I've had cheap air lines collapse on themselves while the hose looks fine from the outside).

Twystd1 03-04-2013 6:02 PM

You said "with the regulator fully open" you had zip air.

Just in case you may have missed this..........

Are you aware the knob on the regulator needs to be turned CLOCKWISE to get more pressure to your blaster?

Which is the opposite of most every other valve you typically use in a normal day.

Just thinking out loud.

T

gschoelles 03-05-2013 6:18 AM

Sounds like a bad connector. Additionally, if you are using Glass Beads, they will break up at high pressure and do you no good. When you fix the flow, turn down the pressure.

ssaction 03-06-2013 8:54 PM

I have this blast cabinet: http://www.harborfreight.com/abrasiv...net-42202.html

and use this compressor: http://www.harborfreight.com/2-horse...8127-8026.html

It is barely enough.

JTecalo 03-06-2013 9:31 PM

is the shop heated? I have seen an air hose or fitting freeze and cut off air.

that said I think Randall is right about the compressor not being adequate

Jim

valley82 03-06-2013 9:52 PM

Even if the compressor will not keep up with the blast cabinet you will have air for way more than a second...the pressure will start at the desired pressure and fall off as the blast cabinet uses more air than the compressor will replenish. The problem is that you are not getting the air out of the tank quick enough because of a restriction somewhere.

ColdDeadHands1 03-06-2013 11:38 PM

Moisture from your compressor glomming up the blast media inside the suction hose (the one connectd to the nozzle in the cabinet. I have this problem with mine blasting with a hot compressor in a cold garage.

Chosen_1 03-07-2013 10:26 AM

Quote:

Originally Posted by ColdDeadHands1 (Post 10738064)
Moisture from your compressor glomming up the blast media inside the suction hose (the one connectd to the nozzle in the cabinet. I have this problem with mine blasting with a hot compressor in a cold garage.

It's brand new, and this problem occurred on the first use. I believe based on some postings here that it is due to an obstruction in the regulator, hopefully I can get it functional this weekend.

SJgunguy24 03-09-2013 2:04 AM

Quote:

Originally Posted by ColdDeadHands1 (Post 10738064)
Moisture from your compressor glomming up the blast media inside the suction hose (the one connectd to the nozzle in the cabinet. I have this problem with mine blasting with a hot compressor in a cold garage.

It doesn't even need to be in a cold room.



Quote:

Originally Posted by Chosen_1 (Post 10741151)
It's brand new, and this problem occurred on the first use. I believe based on some postings here that it is due to an obstruction in the regulator, hopefully I can get it functional this weekend.


Brand new or not, what happens when you compress something? It creates heat. Well guess what's in air? Water. I'm not saying that's your specific problem but unless you run some type of water filter set up, your going to start blowing oily water through your blast media.
When I designed the air system at Valkyrie I ran 48feet of pipe before my first take off. I had 3 and it terminated at the blast/paint outlet. I had a water filter 10feet after the tank and on every take off. I still had water coming through all the take offs except for the blaster/paint outlet. That had a 3 stage water seperator, coalesing filter, and a dessicant dehumidifier at the outlet I used for piant and blast air.
I figured the finish is what people really see and blasting oily wet media wasn't the best way to go about getting a good finish.
When you get the flow figured out, get a filter set up.

kcstott 03-09-2013 5:44 AM

SJ
you experienced what I went through at a 55K square foot plant I worked in. Air system took a dive. old compressors could not keep up with demand.
We had a great professionally installed plumbing system for the air the problem was they reused the old compressors from the old building and the old refrigerated dryer, Worked great for about two years then went south.

Solution was buy a lager compressor 30HP hydrovane, install a 250 gallon air receiver, install a cycling refrigerated air dryer with the coalesing filter and water trap. Then go in on a Saturday cut open the system in the building and drain the water out.

Once water is in your plumbing its near impossible to get out. A home system is an easy fix. Drain the tank and hose. but if you have a shop and permanently installed pipes good luck.

I still believe the OP issue in the regulator on the system. 1-2 seconds of air is the hose capacity.

ptoguy2002 03-09-2013 9:28 AM

When looking at anything with compressed gasses, keep in mind that the actual CFM (cubic feet per minute) is highly variable based on supply pressure, temperature, specific gravity, etc. There is a way of standardizing things to a standard cubic feet per minute (SCFM) at standardized conditions, but I don't thing the Chicago tools and harbor freights do this. Long story short, with compressor ratings and tool consumption ratings, it is very easy to play games with their CFM numbers, so keep this in mind if you are ever purchasing anything and trying to match up supply and demand numbers. Need a little margin in there.

Chosen_1 03-09-2013 10:25 AM

Problem solved! I removed the regulator entirely, still didn't release enough psi. I then removed the coupler and screwed the hose directly, and it would blast various AK parts at as low as 40 psi (for all the nay-sayers out there). The issue was a bad coupler.

valley82 03-09-2013 11:07 AM

Very nice...blast on...


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