Blasting cabinets - siphon or pressure, dust collection

slackdaddy1 · Mar 21, 2018

I am looking at a 40" Skat cabinet for my home shop (Hobby setting), it would see "occasional use".
I am at the point in my life I don't want to buy **** and have my leisure time full of frustration.
Are those that have a quality siphon unit happy with it? or wish you had a pressure unit? Has anyone converted a siphon to pressure?
I DONT want a mess, where I have to empty the cabinet into a bucket, filter the abrasive, then funnel it into the pressure pot,, that just isn't going to cut it.

Also, I am in a rural area, I had intended just running a 4" duct to the unit and exhausting it to the outside,, thoughts on this??

Thanks, for any guidance,

Slack

cvairwerks · Mar 21, 2018

With dry air and media, a siphon unit works well. For ducting, a simple duct to the outsdie won't cut it. There isn't enough flow to keep the blast area clear. You will need a suction source.

ndnchf · Mar 21, 2018

I've had a hobby size TIP Skat blast siphon cabinet for probably 20 years. I replaced the plastic window with tempered glass, it lasts much longer. I use a carbide tip on the gun. I use a TIP vacuum system to **** out the dust. I rigged it up to a dryer type exhaust vent in the eave of the garage. After 20 years, I'm still happy with it. I just wish I had a bigger compressor to keep up with big jobs.

mikegt4 · Mar 21, 2018

Siphon only, any pressure in the cabinet (including from the gun) will force dust out of the smallest opening. I have a TP Skat Blast cabinet with a Dust Deputy and then a shop vac. When I forget the turn the vac on (which is becoming all too often) visibility in the cabinet quickly goes away.

ndnchf · Mar 21, 2018

mikegt4 said:
Siphon only, any pressure in the cabinet (including from the gun) will force dust out of the smallest opening. I have a TP Skat Blast cabinet with a Dust Deputy and then a shop vac. When I forget the turn the vac on (which is becoming all too often) visibility in the cabinet quickly goes away.

My TIP vacuum is plugged into the junction box where the blast cabinet light switch is. The vac comes on when I turn on the cabinet light. Saves me that aggravation.

slackdaddy1 · Mar 21, 2018

I was going to use a simple inline exhaust fan in the 4" duct,, or a 6" inline fan in a 6" duct?
Seams like a simpler solution than a dust collection vacuum with bags, filters, and canisters,, just duct it to the outside rear of the shop ?

Slack

cvairwerks said:
With dry air and media, a siphon unit works well. For ducting, a simple duct to the outsdie won't cut it. There isn't enough flow to keep the blast area clear. You will need a suction source.

slackdaddy1 · Mar 21, 2018

?? lost me on the response.
Both a "siphon" and "pressure" blaster introduce Air pressure into the cabinet, in fact a pressure unit uses Less air than a siphon unit.

mikegt4 said:
Siphon only, any pressure in the cabinet (including from the gun) will force dust out of the smallest opening. I have a TP Skat Blast cabinet with a Dust Deputy and then a shop vac. When I forget the turn the vac on (which is becoming all too often) visibility in the cabinet quickly goes away.

ndnchf · Mar 21, 2018

The blasting media/grit is heavy. It will just settle in your ducting. The TIP vac has a lower chamber that collects the sand/grit. I empty it maybe once a year. Not a big deal. If you are going to get a good cabinet, don't go cheap on the ventilation. Do it right and you'll be much happier with the results.

rsanter · Mar 21, 2018

I built my own cabinet and my own pressure pot system.
The pressure pot blasters work faster than the siphon ones do. Big time.
I connect a shop vac to the cabinet to try to pull the dust out but I ave also used it without the vac.
My cabinet is on wheels and it gets rolled outside for blasting. The port in the back is 3” so even without the vac the cabinet will not build up pressure.

Pressure pot means you WILL be dumping the cabinet and pouring back into the pot. No way around it.
Siphon means you can keep going but the more dirty the stuff you are blasting is means the sooner the media will be contaminated and can clog the gun up.

I used to have a clean and a dirty cabinet. The dirty cabinet only used sand as it was cheap and can be tossed.
A quick blast in the dirty cabinet to get most the thing clean and then finish up in the clean cabinet

OccupantRJ · Mar 21, 2018

Self filling pressure blast cabinets are available, but you will get sticker shock pricing them. They have an automatic valve that opens once blasting stops and drains abrasive back into the pressure pot. Once blasting starts, the valve closes and the abrasive flow continues. I have been thinking about converting my large cabinet to one of these.

alan camby · Mar 21, 2018

slackdaddy1 said:
I was going to use a simple inline exhaust fan in the 4" duct,, or a 6" inline fan in a 6" duct?
Seams like a simpler solution than a dust collection vacuum with bags, filters, and canisters,, just duct it to the outside rear of the shop ?

Slack

I don't see that working. You need a ton of air flow. The larger the cabinet the more air movement you need. A shop vac is the minimum. 100cfm is the min for a vac and or cheaper dust collector vac.

The true dust collector, that is designed for a blast cabinet, moves 300cfm and up. 600cfm would be for a extra large cabinet. These 300cfm units will run you at least a $1000.

slackdaddy1 · Mar 21, 2018

Thanks for all the details guys,
I would love a pressure cabinet,, but just cant justify the price for occasional use.
I was trying to get away from the bulk of a "dust collector" and cleans the air and dumps it back into your shop, I have the luxury of being rural, no problem dumping dusty air outside.
I can get a ~200 CFM 4" inline fan, I was going to run the 4" duct straight up (8') through the ceiling into the attic, have the inline fan in the attic, 90 straight out through the gable wall. there will only be about 2' of horizontal duct. If heaver dust/grit is going to fall out of the air stream,, I am guessing it will happen in the 8' of vert and fall back into the blast cabinet?

Slack

ndnchf · Mar 21, 2018

Pulling heavy grit 8 feet straight up is asking a lot of an in-line fan motor. Will that fan motor ingest that grit? You can try and see what happens, but I doubt it will be as effective as a proper vacuum system. The nice thing about the skat blast vacuum is that accumulates the sand and grit in its lower chamber right next to the blast cabinet. Then the exhaust exits outside the garage as you have described. The grit and sand collects in a sealed chamber, while the air vents outside so there is no chance of breathing it. It really is a well designed system. Its not too expensive either.

http://www.skatblast.com/vac-45-hepa-vacuum.html

mikegt4 · Mar 21, 2018

ndnchf said:
My TIP vacuum is plugged into the junction box where the blast cabinet light switch is. The vac comes on when I turn on the cabinet light. Saves me that aggravation.

Yeap, I think of that every time that I forget to turn it on, then I forget about it until the next time that I forget to turn the vac on. Notice all the forgets.

I even have a switched receptacle on the cabinet but I used it for plugging in an extra light.

OccupantRJ · Mar 22, 2018

An internal draft blower with an impeller, not a fan blade or squirrel cage fan, is what is needed to properly evacuate a blasting cabinet.

Retlaw 66 · Mar 22, 2018

The dust collectors for the **** cabinets are about 90 cfm. Basically, a central vacuum motor, about $90.

You can buy one similar but with an outlet like this one, nice for ducting outside:
Ametek Lamb Central Vacuum Motor 116472-13

You do need to capture the dust before it gets to the fan. I just bought a Dust Deputy clone which does collect a good bit of debris. I haven't yet verified how much gets past it.

gtr1999 · Mar 22, 2018

my 02, I also have a skatblast cab from TP Tools, about 10 years now. It is a good unit overall. I used it for years tapped off a 50-hp screw compressor so cfm was never a problem. When I first bought it I thought I would save a few bucks and use a shop vac as I was told I could. What a mistake. The shop vac is too noisy, blows dust all over and won't last as long. I bought the TP vacuum
with the hepa bag- as I should have in the first place and it would have cost less to begin with and I wouldn't have had any issues in the process.

I moved my shop back home now and still use it for steering boxes and iron parts. The larger parts like differentials I now sub out to a blasting shop as it takes too much time to blast them in my cabinet. I am now using the new Eastwood scroll 12 cfm compressor with it and that works pretty good. I am going to plumb in a 80 tank to see how that works as well.

Bottom line, if you are going to use it- even 20-30 minutes at a time, get the complete package with the vac.

Keep some mylar liners on hand. I haven't changed out the window yet but use up a lot of liners, tips, and gloves. Pay up front for the better setup and just use it.

The only thing I don't like is the lights inside, mine still uses the mini flood lamps and they get frosted over. Anyone have a better setup?

ndnchf · Mar 22, 2018

I went through similar efforts trying to save a few bucks. Just venting with a hose, shop vac etc.- none were satisfactory I finally spent a few more dollars and got the TIP vac. I should have done it in the first place. That's the point I was trying to make to the OP. Been there, done that, learned the lesson. Just trying to help others from repeating the same mistakes.

ovrrdrive · Mar 22, 2018

Built my own dust collector using a 5hp mini shop vac from HD, dust deputy and a few 5 gallon buckets. Works great.

slackdaddy1 · Mar 22, 2018

I have no problem getting the TP vac,, it just needs to go ABOVE it, as in the walk in attic,, there is no (AS in zero, none, no chance of) room to put the vac next to it.

Slack

gtr1999 · Mar 22, 2018

That a tight space then. I just built a dolly for mine out of old 1" chrome sq tubing used in office desks. Whenever we scraped out desks I would grab the legs and save them. Now I can easily slide out the cabinet from the wall to do maintenance. Over head vac may work, they are not too heavy but you will have to clean them out.
Good luck

Blasting cabinets - siphon or pressure, dust collection

Well-known member

Well-known member

Well-known member

Attachments

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Attachments

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member