The Abrasive Blasting Resource Thread

[larry4406]

In post 428, DKMC mentioned a pneumatically operated pulse valve in lieu of a foot pedal I assume to minimize flow restriction.

How do these valves work? Anyone configured one?

https://www.garagejournal.com/forum/showpost.php?p=7449080&postcount=428

 

[dkmc]

In post 428, DKMC mentioned a pneumatically operated pulse valve in lieu of a foot pedal I assume to minimize flow restriction.

How do these valves work? Anyone configured one?

https://www.garagejournal.com/forum/showpost.php?p=7449080&postcount=428

So, a lot of the foot pedals that come with cabinets, have 1/4" ports and even smaller passageways inside that restrict flow. If you have a big enough compressor and want to take advantage of higher flows from larger air jets on siphon (or Pressure Pot) systems, some of the 1/4" pipe fittings and foot pedals might be the limiting factor to higher CFM air flow.

The Pulse Valves have 3/4" ports! I suspect they'll easily flow in excess of 100 CFM. The way they work is, they are spring loaded CLOSED. There is a 1/8NPT Pilot port on the valve that you apply air pressure to, which overcomes the spring, and opens the valve.
So, chances are you'll still use a foot pedal to control the operation of the Pulse Valve....but the Pulse Valve only requires air pressure with very little if any flow to operate. You may need to modify your foot pedal so pressure bleeds off the pilot line when you let off the pedal......

 

[larry4406]

dkmc- thanks for the explanation of pulse valves.

 

[dkmc]

You're very welcome Larry. If you decide to implement one on your rig, let us know how it works for you.

 

[OccupantRJ]

There is also another type of valve used in blasting equipment known as a pinch valve to control flow of the actual abrasive or just to control air or other material flow. Here is a video link to how one operates. A set control air pressure can be used to produce a specific flow orifice size.

http://video.directindustry.com/vid...umatically-operated-isolation-slurry-7643.mp4

 

[dkmc]

Great animation vid RJ.
Pinch Valves are great for controlling grit flow, as they are very wear resistant.
Here's an interesting read on Pinch Valves, a Pressure Pot system, and various plumbing for a Pressure Pot system

https://www.instructables.com/id/Footswitch-Operated-Sandblasting-System/

 

[OccupantRJ]

Good info there, dkmc!

 

[OccupantRJ]

I refurbish equipment for a hobby during retirement, so prepping parts is a major part of the activities. These are pictures of a flywheel grinder I am working on that got wet during previous storage with grinding dust all over the work area. This one is a real challenge, but I’ll git ‘er done! I could not succeed with out my abrasive blasters. The round piece is for the blasting newbies to show their potential, before and after.

 

[Jvvmusme]

at what point I must change 1/4 hose to 3/8 hose in order to move media and air with a 8 mm gun ?

 

[OccupantRJ]

at what point I must change 1/4 hose to 3/8 hose in order to move media and air with a 8 mm gun ?

In my opinion, any suction style blaster needs 3/8” ID air feed hose and a 5/8” media suction hose. If by 8mm you mean the nozzle size on a suction gun, this is the size combination I use on my gun, which is 5/16”, or around 8 mm. Be aware, the air jet in a suction gun decides how much air is required, not the blast nozzle size.

 

[Jvvmusme]

In my opinion, any suction style blaster needs 3/8” ID air feed hose and a 5/8” media suction hose. If by 8mm you mean the nozzle size on a suction gun, this is the size combination I use on my gun, which is 5/16”, or around 8 mm. Be aware, the air jet in a suction gun decides how much air is required, not the blast nozzle size.

yes the air jet is 4mm. and the nozzle is 8 mm.

what size hoses I need ?

I use 1/4 hoses with 6mm gun, but when will I need 5/16 or 3/8 hoses ?




Thanks

 

[OccupantRJ]

I would use 3/8” hose anyway, due to less pressure drop in the air supply.

 

[OccupantRJ]

I found some economical sandblast cabinet gloves on Amazon this morning. i have not given them a try yet. They are half the cost of a lot of gloves.

https://www.amazon.com/dp/B004UC6O22/?tag=atomicindus08-20

 

[Jvvmusme]

I found some economical sandblast cabinet gloves on Amazon this morning. i have not given them a try yet. They are half the cost of a lot of gloves.

https://www.amazon.com/dp/B004UC6O22/?tag=atomicindus08-20

i bought them and so far they work ok.

 

[930dreamer]

It's been almost a year and I'm no closer to a filter bag solution, the person that told me he'd send the plans for a conversion to a cartridge filter hasn't. New cost for originals are $1400 and I need to sh*t or get off the pot with this cabinet.

 

[larry4406]

What mesh size screen are you using to sift your media?

I found this chart which equates grit size to sieve size but I don't fully understand all the columns.

Watched this youtube video of his automated sifter and at the 2:08 minute mark he does a screen shot of the mesh he used but I can't find it.

 

[OccupantRJ]

I don’t sift the glass beads, just replace them as needed. On the aluminum oxide cabinet, I use a kitchen sifter as a strainer on the abrasive before using it in the cabinet, or if I open the feed portion of the separator due to an issue with flow. I drain that abrasive, then strain it before reusing in the cabinet. On the large portable blast pot I use standard screen wire in the bottom of a fill funnel to screen out any stray pebbles and such.

 

[OccupantRJ]

A part I am presently blasting in the alox cabinet. Rather heavy to turn and twist it while blasting. Notice the full flow attachment of the media hose of my custom built gun. There is no hose barb there to restrict media flow. It uses a compression o ring to hold the hose into the body of the gun. There is a link to this gun in post #1.

 

[dkmc]

RJ, can you give an estimate of how long it took you to blast that part, for reference?

 

[OccupantRJ]

Dkmc, did not time it, but seemed like about 20 minutes to blow the rust off it and etch the existing paint, which was pretty solid.

 

[dkmc]

Sounds like a pretty good pace.

 

[OccupantRJ]

Question of an effective blaster option.

https://www.garagejournal.com/forum/showthread.php?t=419685#post7841141

 

[lis2323]

OccupantRJ. I know it’s been said, but thanks for compiling this thread and keeping it updated. I find it an excellent resource and refer to it regularly.


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[OccupantRJ]

You are all welcome. Feel free to input any information or experiences you have relative to blasting. I just noticed that this thread is over 5 years and going.

 

[OccupantRJ]

Fourbyford graciously donated information on a supplier of filter bags in another thread, so posting it here in general information.

https://www.garagejournal.com/forum/showpost.php?p=7842221&postcount=67

 

[930dreamer]

Super and I'll look in to it, PM received.

 

[930dreamer]

Ford 302 Porta Air compressor. $800 on CL.

 

[dkmc]

He'll take $725........you better go grab that 930!

Ford 302 Porta Air compressor. $800 on CL.

 

[930dreamer]

1265 miles away, If I was going to Oregon it will be on the way. I would rather have the complete tow away version.

 

[OccupantRJ]

The compressor head on that one is completely different than the Gordon Smith design like mine.

 

[930dreamer]

Spotted this while driving today.

 

[dkmc]

Is that half engine and half compressor as well?

 

[OccupantRJ]

That one looks like the V4 wisconsin pump. Runs on two, pumps on two. Normally around 50 cfm, best I remember from years ago.

 

[930dreamer]

Compressor is a Lindsay and i think it has three cylinders.

 

[OccupantRJ]

I went on a road trip with my BIL today and picked up a blast cabinet to get him into the game. It was the Central Pneumatic industrial cabinet with dust extractor for $375, new price was at $1150. Catalog picture below. I think he did OK.

 

[lis2323]

Yes. He did okay!


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[fwillison]

Siphon better than pressure pot for moisture issues?

I'm thinking about a siphon feed vs pressure pot blaster for outdoor use.
I've read that moisture is the most common problem with blasting, and using a typical hobbyist size compressor, this will be worse. Especially without expensive air dryers.
In this case, wouldn't a siphon feed be better?
The siphon feed doesn't put the moist air into the media, but rather adds air at the output/gun. Makes sense to me.
May be slower be less frustrating and less clogs.

 

[dkmc]

Re: Siphon better than pressure pot for moisture issues?

May be slower be less frustrating and less clogs.

It may also be so much slower it'll be equally as frustrating.
There is no free lunch with Abrasive Blasting.
If you wanna do the deed, you gotta have the tools, depending on what
$$$$ you want to invest, and how much time you want to spend.

 

[OccupantRJ]

True. Blasting can be somewhat of a go big or go home proposition. I started out with a siphon pot. It was frustrating to say the least. For small parts, even a small blast cabinet is the way to go. For anything larger, you pretty much either have to go big or pay someone.

 

[isb cornbinder]

That Central Pneumatic industrial cabinet looks exactly the same as the MODUBLAST 2448, I paid $3000 for. (tax incl) Modublast make their cabinets in Edmonton, Alberta. I wonder if they make rebranded cabinets for other sellers.