Harbour freight sand blasting cabinet

[shayan]

Hi guys! New to the group
I just fully modified my sand blasting cabinet and it’s now worst than it was !

I’m wondering if my gun is defective, when I press the trigger a ton of air comes out of the trigger pin?

It ***** the aluminum oxyde on and off
Suddenly a bunch comes out and then it stops

When I press the trigger the first 2 sec works the best?

I tried running everything from 60 to 120 psi and tried both nozzles

I’m thinking it’s the gun and I’m about to order the model with the pedal

But before I do i would be appreciated

 

[shayan]

Here is the gun setup

 

[csp]

Air should not be coming out of anywhere but the outlet of the gun. That issue needs to be resolved before any others are addressed. They may go away once you have proper airflow out of the gun.

 

[shayan]

Air should not be coming out of anywhere but the outlet of the gun. That issue needs to be resolved before any others are addressed. They may go away once you have proper airflow out of the gun.

So first thing would be to replace the gun?

 

[whateg01]

What did you do to modify the gun?

 

[LS1-IROC]

Take the gun apart, there is an oring that seals the trigger pin. Yours is probably shot.

 

[shayan]

Take the gun apart, there is an oring that seals the trigger pin. Yours is probably shot.

I did, it’s the metal pin I thing that’s pitted , it’s brand new first time I’m using it

 

[shayan]

What did you do to modify the gun?

It’s not modified

 

[shayan]

Do you guys see anything else wrong with my setup? And what psi should I be running ?

 

[alfadan]

Many replace that gun anyway. There is a company that sells one with an angle to the media inlet that is better for flow to pick up media.
Surging is due to inefficient flow or wet media.

 

[Jeff Ivers]

You should not have media coming out of the bottom of the cabinet requiring a bucket to catch it as shown in picture 2. You have changed from a siphon feed to gravity feed. You may have an obstruction or reduced flow in your gravity feed mechanism - pics and details of how you constructed it would help. Others have already addressed your gun issue. In addition, how much vacuum are you subjecting the cabinet to - too much could impact media flow. Finally have you experimented with adjusting the valve on your gravity feed mechanism?

 

[supratreo]

Many replace that gun anyway. There is a company that sells one with an angle to the media inlet that is better for flow to pick up media.
Surging is due to inefficient flow or wet media.

i think your thinking of "the tacoma company".
looking to do their mods myself.

 

[shayan]

Many replace that gun anyway. There is a company that sells one with an angle to the media inlet that is better for flow to pick up media.
Surging is due to inefficient flow or wet media.

Could you link the company, im looking for a non Chinese one

 

[shayan]

You should not have media coming out of the bottom of the cabinet requiring a bucket to catch it as shown in picture 2. You have changed from a siphon feed to gravity feed. You may have an obstruction or reduced flow in your gravity feed mechanism - pics and details of how you constructed it would help. Others have already addressed your gun issue. In addition, how much vacuum are you subjecting the cabinet to - too much could impact media flow. Finally have you experimented with adjusting the valve on your gravity feed mechanism?

Thank you for your input

the bucket was temporary, I had just finished the setup and apparently I forgot to silicone a small corner, that issue has been addressed

I’m using 3/4 inch pipe on the bottom , I don’t see any restriction issues

My vac setup is pretty strong, but I did try to fully open the vent on the side and it made no difference

 

[PoorUB]

Hi guys! New to the group
I just fully modified my sand blasting cabinet and it’s now worst than it was !

I’m wondering if my gun is defective, when I press the trigger a ton of air comes out of the trigger pin?

It ***** the aluminum oxyde on and off
Suddenly a bunch comes out and then it stops

When I press the trigger the first 2 sec works the best?

I tried running everything from 60 to 120 psi and tried both nozzles

I’m thinking it’s the gun and I’m about to order the model with the pedal

But before I do i would be appreciated

In the picture of the bottom of the hopper, put a shorter pipe ****** between tee fitting at the hopper and the air bleed valve, the ball valve pointed up. Put a close ****** in and try it again. You might try almost close off the bleed valve. You don't need much air going into that valve, just enough to add some air into the mix to keep the media flowing. Too much air and you lose suction on the media.

 

[Jeff Ivers]

Thank you for your input

the bucket was temporary, I had just finished the setup and apparently I forgot to silicone a small corner, that issue has been addressed

I’m using 3/4 inch pipe on the bottom , I don’t see any restriction issues

My vac setup is pretty strong, but I did try to fully open the vent on the side and it made no difference

What is the inside dimension of the area of your gravity feed mechanism where the flexible hose attaches? I have attached a pic of my assembly that works quite well.

 

[shayan]

In the picture of the bottom of the hopper, put a shorter pipe ****** between tee fitting at the hopper and the air bleed valve, the ball valve pointed up. Put a close ****** in and try it again. You might try almost close off the bleed valve. You don't need much air going into that valve, just enough to add some air into the mix to keep the media flowing. Too much air and you lose suction on the media.

If I understood correctly I’ll change two pieces
The one under the hopper and the one going to the ball valve

What do you mean when you say put a close ****** ?

I did try playing with the ball valve (from 0% to 100% in increments of 5% ish )

 

[shayan]

What is the inside dimension of the area of your gravity feed mechanism where the flexible hose attaches? I have attached a pic of my assembly that works quite well.

I’m using 3/4 inch galvanized pipe
And the hose is 5/8
I would have to mesure the inside dimension of the plastic fitting
But it does not look smaller than the setup
You posted

 

[alfadan]

A close ****** (as in 'gee that was close!) Is a short ****** with no non -threaded section in the middle.

 

[shayan]

Ah!! Sorry I get it now

I’ll change the setup and post back

 

[shayan]

Any recommendations on company’s that make us made blasting guns?

 

[PoorUB]

If I understood correctly I’ll change two pieces
The one under the hopper and the one going to the ball valve

What do you mean when you say put a close ****** ?

I did try playing with the ball valve (from 0% to 100% in increments of 5% ish )

Yep, I guess the tee fitting at the bottem can be a elbow. A close ****** is the shortest ****** you can find. So short the threads run into each other. There might be 1/2" between the fittings when you get it screwed back together.

 

[oldmachinenut]

Could you link the company, im looking for a non Chinese one

This is the one I used on my Harbor Freight cabinet upgrade, it works great. I have the carbide nozzle in mine. I also have the bottom hopper media pick-up, it was less than $40.00 from Grizzly.

https://www.amazon.com/dp/B01N2WB4JL/?tag=atomicindus08-20

 

[shayan]

What would you guys recommend? A trigger gun or one with a foot valve ?

I would prefer finger trigger ( if so what model cdn would be best?

I’m using a 90 gallon air compressor so I have a lot of air

 

[alfadan]

I use a trigger gun which looks like the above. I can get a little tiring to the wrist during long sessions, but I take breaks.
If you get pedal later, you can always ziptie the trigger down.

 

[shayan]

I use a trigger gun which looks like the above. I can get a little tiring to the wrist during long sessions, but I take breaks.
If you get pedal later, you can always ziptie the trigger down.

Good idea
Should I get the 4-8 cfm or 10-15?

I don’t know how to calculate that

 

[ZRX61]

That looks all fuckered up, why are you trying to draw the media from the bottom of the hopper like that?

 

[whateg01]

That looks all fuckered up, why are you trying to draw the media from the bottom of the hopper like that?

People generally have fewer feeding issues this way

 

[alfadan]

Good idea
Should I get the 4-8 cfm or 10-15?

I don’t know how to calculate that

depends on your compressor. Looking back to the OP, your pressures may be a little high. I run 45-50 psi.

 

[whateg01]

Good idea
Should I get the 4-8 cfm or 10-15?

I don’t know how to calculate that

That depends on the pump, not the tank size. You can always throttle it down. You can't get more air out of it though.

 

[shayan]

That depends on the pump, not the tank size. You can always throttle it down. You can't get more air out of it though.

Mine is a 3.7hp

So it’s better to get the small gun I guess ?

 

[oldmachinenut]

I have the S35 gun with the small carbide nozzle. The nozzles and air jets are changeable, you can go to the medium if needed.

 

[Jeff Ivers]

I’m using 3/4 inch galvanized pipe
And the hose is 5/8
I would have to mesure the inside dimension of the plastic fitting
But it does not look smaller than the setup
You posted

No way to know the inside dimension without measuring. May not be your problem, just something to check. Keep in mind what the underlying design of the gravity feed is. The media falls into the down pipe and some of it will "fall" into the horizontal pipe that goes to your gate valve intersection. Visualize how far the media will extend into that horizontal pipe on its own. From there, the air flowing through the gate valve and into the pipe to the gun creates a siphon feed to pull the media up the hose to your gun.If the media is not near your air flow, it is hard for the siphon to work properly. Notice my gravity feed is built with the "close" ****** others have referred to.

Also, many think the gate vale has to be vertical, but this is not the case. Smaller gate valves actually are more adjustable on air flow than large gate valves.

Finally, with regards to the gun, when I modified my blast cabinet, acquired used, I went with the Eastwood gun and foot control. I much prefer this to the original gun. My build, with more info, is documented at https://www.garagejournal.com/forum/threads/blast-cabinet-improvement.310730/ .

 

[rmmiller]

I installed the TP Tools upgrade kit before I ever used mine, works perfectly.

Skat Blast® USA Cabinet Gun & Pickup Tube Upgrade Kit

This is a complete made-in-USA Cabinet Gun Kit made to replace the operating system of most imported sandblasting cabinets on four legs. It gives you the benefit of USA blasting technology at an economical price. It also provides continual and immediate availability of nozzles and wear items as...

www.tptools.com

 

[csp]

That looks all fuckered up, why are you trying to draw the media from the bottom of the hopper like that?

It's a helluva lot more efficient than the POS siphon setup the HF cabinet comes with. Actually works great once you have it dialed in and you can blast at lower pressures.

 

[545_days]

3/4" pipe might be a little too large for your gun. In order to **** up the media you need velocity in the pipe and larger diameter equals less velocity. Sizing the suction line to entrain heavier than air media is a balance between pressure drop (pipe too small) and low velocity (pipe too large).

 

[jdepiero]

I also installed the TP tools upgrade kit. No issues. I also added a couple of flood lights inside the cabinet.

 

[ZRX61]

It's a helluva lot more efficient than the POS siphon setup the HF cabinet comes with. Actually works great once you have it dialed in and you can blast at lower pressures.

I had a bench top HF cabinet, I gave it away when I got my TP960.

 

[Benw455]

I am on my second TP tools **** Blast cabinet. Sell what you have and just buy one from TP tools instead of trying to fix what you have. You will be happier in the long run. JMO

 

[FredWanaker]

I don't know what changes you have made since this thread began. You cannot pull from the bottom using a gravity feed with a system that was designed for a siphon feed. You need a good quality siphon feed. Also the media you are using is VERY abrasive. Choose your media based on what you will be using it for.

This siphon feed is from Metal Finishing Supply Co in Brookfield Wis, but many media places sell similar. I got mine from Temple Associates but they have been sold to another company now so I don't know what they have. Also with most of the HF units, be sure to reseal all the joints or you will forever be cleaning up leaky media. Get some quality gloves too because the ones with the HF cabinets don't last. Also consider having a custom floor cut for it because those bend and fall apart quickly too.

The flexible hose sits above the media. The right side of the metal hose goes to the gun feed. when the gun siphons air, that air is pulled down the flexible hose and enters the steel tube near the bottom. That means the air only needs to lift the media an inch or so before it enters the air flow. The way you have yours now in your original photos, the air siphon has to lift the weight of a column of media feet long, and fight the hose resistance too.



see https://www.garagejournal.com/forum/threads/blaster-cabinet-media-flowing-like-a-wave.490525/ or https://www.jalopyjournal.com/forum/threads/hf-blast-cabinet.1052821/