The Abrasive Blasting Resource Thread

[OccupantRJ]

Yowser! That IS expensive. I am not familiar with those style filter bags. Mine are like an inverted sock that fits onto a metal tube adapter and fastens with a hose clamp in an inverted position. Air is sucked out of the cabinet through the bags from the outside of the bags which inflates them in use. The nuisance dust collects in the bags as it flows through and then falls out into a lower tray when the blower is shut off. The shaker arm can be used to help shake dust from the bags when in use.

 

[930dreamer]

I guess if I could sew the bags with new material and reglue them to the frame that would work. More research on my part.

 

[OccupantRJ]

Examine the air flow through the bag house carefully until you fully understand the flow. Basic purpose is to trap contaminated air flow to hold back the nuisance dust sucked from the cabinet and still allow the blower to pull air and expell it without blowing dust into the room. Other than abrasive wear on the blower, it could be vented outside to create a neighborhood dust cloud.

Also could be vented into a water trap container. Look to see if a large bag or a few smaller bags could be adapted to the cabinet with various partitions and adapters to filter the dust. That is the main objective, other than to allow the dust to fall due to gravity into the catch pan when the machine is shut off and the bags shaken in some manner.

The nuisance dust passes through the blower on my smaller unit, right after the cyclone separator. It simply goes into a large inverted filter bag and drops into a 5 gallon bucket at the open end at the bottom, while the air enters the room.

Look at the pictures of the bag in this thread. It may give you ideas.

https://www.garagejournal.com/forum/showthread.php?t=124933

 

[OccupantRJ]

A review of the Texas Blaster.

https://www.garagejournal.com/forum/showthread.php?t=396133

 

[OccupantRJ]

Questions on minimum compressor size.

https://www.garagejournal.com/forum/showthread.php?t=396948

 

[HotRodHudson]

Trouble shooting Help Needed:

I’ve been “upgrading” my HF standing sandblast cabinet for a little over a year & a half now & the latest “upgrade” of the Eastwood Foot Pedal & Gun just isn’t working. In fact it’s worse than the original HF gun & pickup tube. The problem is basically the sand isn’t coming up & out of the gun as it should at 50-60psi. I can get enough at 100psi to not push the dang thing to the curb, but then it pulverized the glass bead into powder. Even at 100psi it still clumps towards the bottom part of the hose then surges up with most of it falling back down the tube. I’ve played around with the valve which allows air in to get the sand up the tube & its had no effect. Ideas?

Here are some pictures of the setup the pedal isn’t installed in the photo:

 

[OccupantRJ]

Take the air inlet off the feeder device and try it. Compare results with and without it. Looks like your gun is adjustable relative to the air jet. The air jet holder may be able to be adjusted in or out relative to the gun to change performance. I attach a vacuum gauge to my gun and tune it to the highest vacuum draw. If the gun is dumping abrasive in clumps, there is not enough suction air flow to properly carry the abrasive. Make sure there is no foreign debris inside the gun. 80psl should do fine with glass beads.

 

[930dreamer]

Anatomy of (1) of my Cyclo- Blast cabinet filter bags.

Two yards of new canvas.

 

[HotRodHudson]

RJ,
When you say the “Air Jet” are you referring to the white plastic piece on the aluminum feeder at the bottom of the hopper vs the jet inside the gun? I will have to try removing it completely & see what effect it has because even unscrewed for both holes to let air in didn’t improve things.

I did bypass the air regulator I have on (behind) the left front leg which did make a big difference. Additional, I was able to get things rolling well enough with the bypass that 60psi worked pretty well on the cast iron piece. So it looks like I have a restriction at the regulator. I also need to see if I can up the hose size from the foot pedal to achieve greater volume of air.

Question: Is it safe to assume taking paint & rust off of cast iron is much more difficult & take longer time, due to the porous nature of cast material than flat steel such as a pan or valve covers?

 

[OccupantRJ]

RJ,
When you say the “Air Jet” are you referring to the white plastic piece on the aluminum feeder at the bottom of the hopper vs the jet inside the gun? I will have to try removing it completely & see what effect it has because even unscrewed for both holes to let air in didn’t improve things.

I did bypass the air regulator I have on (behind) the left front leg which did make a big difference. Additional, I was able to get things rolling well enough with the bypass that 60psi worked pretty well on the cast iron piece. So it looks like I have a restriction at the regulator. I also need to see if I can up the hose size from the foot pedal to achieve greater volume of air.

Question: Is it safe to assume taking paint & rust off of cast iron is much more difficult & take longer time, due to the porous nature of cast material than flat steel such as a pan or valve covers?

Air jet is inside gun. It’s size also dictates how much air the gun uses. On a suction style gun the blast nozzle does not determine air flow. The regulator air inlet was what I was talking about removing to experiment. I have 5/8” heater hose for my suction hose, and 3/8 ID for the air supply to the gun. How large is the line feeding the general cabinet? Too small or too long will produce pressure drop.

 

[CudaChick1968]

The TPTools Upgrade Kit was the one you needed.

 

[930dreamer]

I ordered a complete manual from Vista Industries for my Cyclo-Blast cabinet and they will send instructions on converting the dust collector from dust bags to filter cartridges. I'm told the bags are good for 5 years and all of mine are shot.

 

[OccupantRJ]

I ordered a complete manual from Vista Industries for my Cyclo-Blast cabinet and they will send instructions on converting the dust collector from dust bags to filter cartridges. I'm told the bags are good for 5 years and all of mine are shot.

That sounds like the way to go if you can blow out the filters often enough that they don’t get fully loaded.

 

[930dreamer]

The kit adds a pulse purge setup to knock the media out from the inside?

 

[HotRodHudson]

In hindsight TP gun upgrade may have been the best way to go but hopefully I can get this right. This weekend I blasted a few item of steel and cast iron. The cast iron pieces definitely take much more time to clean. The system while still surging, worked well enough to get things done in reasonable time. I believe it helped to have a little bit less material in the hopper, maybe 3 cups max seemed to work better for me.

I have a 3/8” line feeding the foot pedal directly from the compressor & the line from the foot pedal to the gun is less than 3/8, I believe it’s 5/16”. I will have to look at changing that line to 3/8” to see what it does.

 

[OccupantRJ]

I would feel comfortable with the gun you have. I have been using that style for over 30 years, with a modification to the abrasive hose attachment. If the abrasive is surging, then there is an issue with the abrasive feed. The basics are that you want a continuous air flow in the suction side of the gun, then abrasive fed to it in a dribble fashion, whatever it takes.

Did you try removing the air inlet device on the feeder? The air inlet needs to be close enough to the grit intersection so that grit does not have a chance to compact at that point. Look at this post #13 from this thread. The device takes a heater hose to feed abrasive. I have this on one of my cabinets, and a shop made feeder on the other. Notice where the hole is. This works. Sometimes I feel that companies make things to sell without testing thoroughly just to get some market sales.

https://www.garagejournal.com/forum/showpost.php?p=3784056&postcount=13

 

[OccupantRJ]

This is my shop made feed regulator. Notice the term “regulator”. I made it years ago and it has worked fine. The hole is close enough to the corner to allow the intake air to **** grit along with it. If I was to make another now, I might move the air hole a bit closer to the corner to see the effect it has.

The unit is simply a piece of pipe ****** cut into at a 45, rotated and welded. The other small hole is for a thumb screw. A 5/8” heater hose is inserted and held in position with this. The hose is moved in or out to tune the air/grit ratio. A grit carburetor, in effect.
Ignore the other small fitting. That was another experiment with flow.

 

[OccupantRJ]

Looking back at your feed fitting, I personally think there is too much flow restriction with the design. Also on my gun like that one, I drilled out the grit feed fitting and epoxied in a piece of 5/8” tubing to allow me to use a 5/8” heater hose on it. Those fittings seemed too restrictive to me. I have 5/8 from the feeder to the gun, with very little restriction. These little things make or break a suction blast system. It is like hot rodding a car. You have to study how it all works together and apply the knowledge to get good results.

 

[OccupantRJ]

Here is a pic of one of my blasting guns. It got the entrance fitting removed and the hole bored to accept a piece of 5/8” metal tubing epoxied in place. This gives a full 5/8” suction flow from the bottom of the hopper through my feeder elbow up into the gun body. As mentioned before, I use a vacuum gauge adapted to the suction port of the gun to adjust the air jet relative to the blasting nozzle to give the highest vacuum. Changing air jet sizes will also change this vacuum.

Air jet sizing should be at or slightly below the output of the compressor used. I custom make my own on the lathe. In fact, one of my guns is custom made. This link contains this gun, and also has a description of how things work.

https://www.garagejournal.com/forum/showthread.php?t=91606

 

[HotRodHudson]

I can’t thank you enough for all of your insight!

Looking at my setup, there is definitely areas to improve upon. Knowing the Supply (orange hose) this “kit” came with is too small I have the goal of a larger air supply line. The orange hose is 8mm or approx 5/16 inch and a 3/8” supply hose is 9.5mm so that alone would increase things 1.5mm, about 20% air increase.

However when I dismantled the foot pedal I found greater restriction. The inlet push connector has a diameter of 5mm & the attached orange supply hose connection leaving the foot pedal is 6.6mm. These definitely don’t help air “flow”. Not too long ago I upgraded my 1/4” connections to all high flow an one an see the difference in these connectors in this photo.






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[HotRodHudson]

The foot pedal valve has 3/4” NPT ends, but looking inside of the valve I have a restriction which I may not be able to change. Looking inside the exit side of the pedal valve, I can see the hole which looks to be 8-9mm. If this or another internal part is my limiting factor for air flow, does it benefit me to increase the supply hose inside diameter & subsequent fittings as well? If I should increases these sizes what should I install 3/8, 1/2 or ?

This also got me thinking; If I increased the pressure, will I get higher cubic foot of air flow? If I would then I should probably have high pressure thru the “limiting” foot pedal valve and have the pressure regulator after the pedal & before the blast gun.

Is this thinking sound?





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[OccupantRJ]

First of all, good detective work! This is exactly how I got started pursuing the “hot rodding” of blasting. You are now on the right track. If my rough calculations are correct the airflow going from the 5/16 to the 3/8” should give about a 46% increase, as doubling the size of the hose ID would give 4 times the internal area, so this makes a noticeable difference. Feel free to check my calculations, it is still early.

I have 3/8 inch feeder hose to the gun in my cabinet, with no apparent issues. Keep in mind that fittings can be drilled out to increase flow. Keep it sensible. I have 5/8 heater hose for the suction hose on my gun by adapting the port on the gun.

Keep the hose sizes upsized even though the pedal is restrictive. You may have to go to a larger flow pedal, but get some learning from this one while you have it. Keep the hose feeding the pedal as large as practical, all the way to the compressor. Keep the regulator right before the pedal input.

 

[HotRodHudson]

RJ, It’s good to hear the improvements can be that substantial.

I started mod’n the foot pedal and thus far I have 1) drilled out the restrictive hole on the exit side of the foot pedal valve to 13/32” and 2) bent the foot pedal toward the bottom plate. This way I’m not feeling like I’m standing one one leg blasting. This lowered the end by 3/4” & it’s a much more relaxing foot position. You can see the difference of the two pedals when compressed in the photos.

Since I’ve been blasting a lot over the past week, I seem to have found the right settings to keep it from surging or it just got its act together. Either way I’ve spent so much time blasting the tip is wearing fast...









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[dkmc]

Hotrod, if you are unaware, a Pressure Pot setup is infinitely more efficient and several magnitudes more productive than a siphon setup. If you do a lot of blasting, that could be something you may want to look into.

 

[OccupantRJ]

Hotrod, if you are unaware, a Pressure Pot setup is infinitely more efficient and several magnitudes more productive than a siphon setup. If you do a lot of blasting, that could be something you may want to look into.

For sure. I keep thinking about converting my large cabinet to a pressure unit, but too many irons in the fire right now. I would be leaning toward placing the pot under the recovery cone and using a bladder type valve to allow the pot to recycle and refill.

 

[OccupantRJ]

HotRod, good going! As they say around here, “You in there now!”. Blast nozzles of various materials can be had for wear resistance. I am still searching for a cheap, good source. There are some carefully crafted ads out there that appear to be providing three nozzles for a price, but instead you really get one. Read carefully.

 

[dkmc]

For sure. I keep thinking about converting my large cabinet to a pressure unit, but too many irons in the fire right now. I would be leaning toward placing the pot under the recovery cone and using a bladder type valve to allow the pot to recycle and refill.

Same boat here, RJ. Collected the pot, and some other items, but no time to execute the conversion. Maybe some day.

 

[HotRodHudson]

dkmc & RJ: I wasn’t aware at all that the pressure pot system was better than siphon system. I guess I just assumed it was the kinda system one just used outside with frames & big objects one couldn’t fit into a cabinet to siphon blast.

I’m curious now, how does one mix the pressure pot system with an existing cabinet?


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[930dreamer]

Working on a flatbed and could use a pressure pot for outdoor use.

 

[dkmc]

dkmc & RJ: I wasn’t aware at all that the pressure pot system was better than siphon system. I guess I just assumed it was the kinda system one just used outside with frames & big objects one couldn’t fit into a cabinet to siphon blast.
I’m curious now, how does one mix the pressure pot system with an existing cabinet?
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Like most everything, there's at least 2 ways to go about.
The easiest way, is to simply use an 'outdoor' type pot, let it empty into the cabinet, then get the media out of the cabinet and place it manually back in the pot. Messy, and time consuming.

The second way is much faster, and involves 'getting' the media back on top of the pot, ready to go back it, in an automated fashion. Either the pot is placed under the cabinet, so gravity does the work, or a reclaimer is used to pull the media out of the cabinet with suction, run it thru a cyclone to remove dust and debris, then the good media drops back down on top of the pot.
When the pot is empty, it's de-pressurized, the top is opened, and the media flows back in the pot for another round of blasting.

I am certain it's less complicated than it sounds!

 

[OccupantRJ]

Working on a flatbed and could use a pressure pot for outdoor use.

Mine, before and after a restore. Got $200 in it total with all hoses needed. Bought it from a scrap yard for $75. I guess if you walk over here I could lend it to you.

 

[OccupantRJ]

Do a search with google images for “pressure blast cabinet”. Lots of pictures there.

 

[dkmc]

Mine, before and after a restore. Got $200 in it total with all hoses needed. Bought it from a scrap yard for $75. I guess if you walk over here I could lend it to you.

What brand is that one RJ? Nice job on the restore!

 

[930dreamer]

That's a nice find.
I see an Empire Pro Former pressure cabinet near me for $4500obo

http://www.sand-blasters.net/empiremodel3642proformerall-in-onepressureblastcabinet.aspx

 

[OccupantRJ]

What brand is that one RJ? Nice job on the restore!

Have no clue what brand it is. It was originally what looked to be an upflow wet blaster that I converted to a standard dry blaster by modifying the mix valve on the bottom of it. I put no-flat wheels on it to keep it from turning over if one goes flat in storage.

 

[OccupantRJ]

Here is one of the major differences in a professional level blasting pot. This is the internal abrasive mix valve that had eroded in my pot, that I had to remake part of. The handle on top of the pot is twisted to make the slots align for maximum grit flow, and conversely, narrowing the slot by rotating the control handle slows the abrasive flow.

The cheaper pots just have a hole drilled in the bottom of the pot for an abrasive outlet.

On a better pot, air enters the pot to pressurize it and at the same time air flows through the fitting on the bottom of the pot to create a flow draft to push/pull the abrasive along. Look at the piping on my tank and you can figure it out.

 

[OccupantRJ]

How a suction gun works. Take note of the air inlet hole to allow room air to mix with the abrasive.

 

[dkmc]

That's a nice find.
I see an Empire Pro Former pressure cabinet near me for $4500obo

Can I cry to you guys about the 'one that got away'?
This rig was on Pittsburg CL for a couple MONTHS last winter.
It's a Maxiblast, full-on pressure blaster with reclaimer.
The seller told me he'd let it go for $1500, and that it needed suction hoses but was otherwise in working order. Well I procrastinated. It was winter, crappy weather, woulda had to rent a truck, drive 5 hours one way.

Besides, it never came up in normal searches on CL, it was obscure.
Then it just stayed on there month, after month. I thought (foolishly) that it'd be there in spring, when the weather got better. Every couple days, I'd go have a look at the ad, drool a little,

and check back again in a day or 2.
That is, until one day it was GONE.

I called the number, "Yep, finally SOLD it, it's gone" the voice on the other end of the phone said.....
DANG!
I still kick myself about once a week on this major mess-up

 

[OccupantRJ]

You snooze, you lose!

 

[930dreamer]

That would have been a great cabinet. The two cabinets I have are taxing my shop floor space.