Sandblast Cabinet air venting.

[Jswain]

The valve looks similar to yours but it's hard to tell in the picture. 58-9989-8 @ ctire. I just went out and had a look and I'd say the orifice of the ball valve fully open is ~75% of the 1/4 npt fitting ID.

Going into the gun @ 45 degrees would be nice as it would make the gun a lot shorter. One problem with mine is blasting up near the top of the cabinet the gun will kink the suction hose because of the angle, a shorter gun should give you more height. A longer hose may work as well but could affect it in other ways(vacuum) and I don't want to redo my lines lol

 

[islandkent]

I hear you there Jswain. I did that intake manifold last weekend and the hose was kinking a little. I just had to pay attention to the orientation of the gun.

"I'd say the orifice of the ball valve fully open is ~75% of the 1/4 npt fitting ID."

Well I went to the shop and said why would I want to buy another valve when I could make it bigger/better my self. So just after about 1/2 hour of tinkering around voila bigger and better valve. Never tried it out yet but will work. If I was getting good results with it open all the way. Now with the orifices larger the only thing I might half to do is shut the valve a little. If it works better with the valve open all the way then I will have to get a bigger valve just for sh@#% and giggles.
Mine was not that large. Here are a few pictures of the process with measurements. It will make a difference...
The last picture is of the coupler from the mixing valve to the jet valve. Drilled it out as big as i dare. Can't hurt.

 

[islandkent]

Here is the before and after pictures of the valve. You can see the difference.
I hope Trooper don't mind the hi-jack??

 

[Jswain]

Nicely done you should be able to get some adjustment out of it now!

 

[trooper1954]

JSwain,
Can you just enlighten me on what valve you're referring to when you say 'out 3-4 threads"? Is this something on the gun itself, or are you referrring to the air mixing valve on the metering valve down below?
Thanks

 

[Jswain]

On the gun itself, the black jet that your air line runs into on the back of the gun that has the brass lockring. Back out the black jet & loosen the lockring, then screw the lockring in so there is 4 threads between it and the wrench flats on the black jet

If you click the last link in post #76 it shows a picture of the gun with the jet properly adjusted out, and in your photo it appears to be screwed all the way in unless it's a deceiving me

 

[trooper1954]

gotcha! will try that....should I be looking for a better flow of media when I do this?

 

[Jswain]

It should work much better. I haven't played with it much more then screwed all the way in and then doing some research and screwing it out the 4 threads because as soon as I did that the gun works flawlessly anywhere from 25psi or so up.

 

[trooper1954]

Thank you...will let you know how it fairs. I'm suprised tho that you can run your system as low as 25psi...I"m not having much success under 60psi....what could I be doing wrong?

 

[trooper1954]

oh...and will that boron nozzle fit into an Eastwood gun?

 

[Jswain]

It's probably because that jet is screwed too far in so your not creating much of a vacuum/even if you are there's not enough room for the media to flow through without clogging

To test you could pop the suction hose off the gun and run air through it with your foot pedal as is and put your finger over the fitting the suction hose was attached to, you should feel a vacuum. Then adjust the jet out 4 threads and try again and I'd bet you feel much more vacuum, plus there will be a bigger valley in the gun for the media to flow which will virtually eliminate clogs if you keep your media dry & screened.

I was bead blasting spray paint off plastic @ 25psi or so a couple weeks ago and the gun performed great. There is also a YouTuber rays garage I believe it is who did a few videos on 2 stage blasting with crushed glass then beads @ 25psi and I think 45psi.

Once these cabinets are setup correctly with the triggerless guns and metering valves they run much more efficient

You would have to measure your nozzle to know 100% but I'd damn near guarentee that it will fit your gun as I'm sure Eastwood buys from the same factory as everybody else who sells the clemco lookalikes, and as mentioned before I wouldn't veer too far from 6mm, perhaps 5-7mm at the most

 

[islandkent]

Just like using the phone fellas! lol Nice when it works like that.
Can you take the measurement to see if they will fit? I think the diameter would be the deal maker.
Seen all of Rays videos. That's where I got the idea of double/triple blasting. I never seen the need for it. But like trooper, he may want a peened look to the shoes.

 

[Jswain]

Yes you have quite a bit of room on the length with the threads on the brass cap. Even the diameter is a bit of a loose fit I just hold mine centre with the jet as I tighten it up and it's a non issue.

I believe some sellers call them 35, 35.5, and 36mm lengths and 20, 21mm diameter but I'm 99% sure they are all the same nozzles and would interchange no problems.

 

[OccupantRJ]

When I first came up with the idea of using a vacuum gauge to tune my blasting gun, it was pulling a vacuum of 5 inches. After making adjustments to the fore and aft position of the air jet, it jumped up to 14 inches of vacuum with that one adjustment. I then made several of my own air jets and played around with them. I settled on a bore diameter that used all the air that my compressor could provide during running, with maximum pressure drop maintained to 75 psi. I now have the air jet sized so that my compressor shuts down 45 seconds after releasing the air pedal. I am using a 1/4” blast nozzle. This has proved to be the most ideal setup so far running aluminum oxide through this gun with my 20 cfm compressor.

 

[Jswain]

Very impressive! I found a video on YouTube of a guy adjusting a bunch of clemco style guns to(iirc) 14 inches of vacuum that I can't find now and that was what made me search for some info on it and found the 4 threads showing that clemco recommends. If I ever buy a vacuum gauge I'll have to check mine out but from screwed all the way in to 4 threads showing is a night and day difference. What size orifice did you end up using for the jet in your gun RJ

 

[OccupantRJ]

Very impressive! I found a video on YouTube of a guy adjusting a bunch of clemco style guns to(iirc) 14 inches of vacuum that I can't find now and that was what made me search for some info on it and found the 4 threads showing that clemco recommends. If I ever buy a vacuum gauge I'll have to check mine out but from screwed all the way in to 4 threads showing is a night and day difference. What size orifice did you end up using for the jet in your gun RJ

Don’t make me lie because I made four sizes and just swapped them out until I got what I wanted out of the gun, but the number 7/64” sticks with me. I made my own gun that uses Empire blast nozzles. If you look in my Abrasive Blasting Resources thread you can find pictures of the gun, among other things.

https://www.garagejournal.com/forum/showthread.php?t=237844

 

[Jswain]

7/64 sounds about right as I believe most of these guns come with a 1/8 jet and around 80psi a ~20cfm compressor barely keeps up/pressure may slowly drop if ya really have the pedal mashed 100% of the time.

Big fan of the abrasive blasting thread I'm pretty sure I read every page when I initially picked up my cabinet lol

 

[trooper1954]

Interesting information guys...thanks. I've just received an email from Eastwood that tells me my gun is not adjustable!! Wish I had known that before buying their foot pedal/gun kit...wasn't cheap either! :-(

 

[Jswain]

I'd pretty much guarentee it is as I highly doubt Eastwood has their gun made any different than any of the other clemco clones. Put a wrench on the black air fitting on the back and try to loosen it, turn it out 4 turns then turn the inner brass locking in snug against the gun. If it wasn't adjustable it wouldn't have the brass lock ring

To them non adjustable likely means they do not sell other sized orifices & nozzles

 

[trooper1954]

Thanks jswain...I went down to the shop this afternoon and guess what
"You are right!"
I have dutyfully backed it out 4 threads, but have not had the chance to run it yet....tomorrow morning hopefully Photos attached....sorry the 'before" is not very clear.
This forum is the 'business'....it's great to be able to bounce things off those who know/have done it.
Will keep you up on how it performs.
Thanks so much

 

[trooper1954]

I have to say also, I'm finding both hoses on the gun to be quite stiff and not very manageable....anyone used that 'flexihose" and if so how is it working out?
Thx

 

[Jswain]

Yeah let us know how it works but my guess will be much better! If so can always try another turn(or more) in or out to fine tune!

I have 1/2" flexzilla rubber air hose on mine for the suction and air supply which I find quite a bit nicer & way more flexible especially when cold then the clear vinyl tubing but it will still kink at extreme angles.

 

[trooper1954]

So....have to report that at 4,3 and 2 threads out the media was hardly flowing at all. When I went back to the fully closed setting gun worked fine. What could I be doing wrong?

 

[Jswain]

I would unscrew it all the way and make sure the rubber/plastic protector hose is all the way on the jet. If it's working fine it's working fine though, whatever setting is giving you maximum vacuum = better.

Seems off that you can't blast under 65psi though

 

[trooper1954]

Hmmmm....here's a thought.....is it possible my compressor, 5HP CH @ 13cfm is not providing enough air to this setup? I'm just trying to optimize this thing, and I don't seem to be making any headway. It runs for 3-4 minutes before it kicks in.

 

[Jswain]

It should run it fine, at least until it runs for a very long time. Before upgrading my compressor I had a 3hp 12cfm Ingersoll Rand and I would blast with that thing for an hour straight then give it a break.

Can you post a couple photos of your whole setup right from the compressor to the gun

 

[trooper1954]

Will do....heading to the shop shortly

 

[Jswain]

Also not sure if mentioned in here before but make sure you are screening your media, and if you haven't been I would empty the cabinet / take the gun FULLY apart to check it and make sure you dont have a big chunk of something In there.

Now that you have a metering valve at the bottom of the cabinet you should be good to run way less media start with around 1 litre and go from there. I always drain my cabinet of media when I'm done, since it now only takes a minute, or the humidity can make it clump sitting in the cabinet and give sporadic flow.

 

[islandkent]

You said Jswain, blast for a bit then let her cool down for a while. By then it's time for a coffee anyway. lol

I'm only getting about that (3-5 minutes) with my IR with a 80 gallon tank. Once the compressor kicks in I stop blasting till she's done pumping then go at it again.
I guess I'm not pressed for time. Kind of enjoy it. Turning things all black and rusty or removing paint to a shiny new surface finish.

Oh on my own side note just finished trying out my new and improved mixing valve adjuster valve??? Eliminated any kind of surging I was experiencing. Does seem to be working better. Like I said no more surging. Not quite open all the way on the copper slag. Shut it down a shade for the glass beads.

I'm just using some heater hose for the media suction. The stuff I have is nice and pliable. I don even have any clamps on my hose. On the air yes. Media no. Find a chunk of nice soft hose and go for it. As long as it does not collapse you should be good. Yes. That Flexzilla is nice. I have a 8 foot 1/2" ID suppling my air direct to my cabinet. It would of cost me more to go to my hydraulic shop to get a short one made up. Have it for my water hose also. Not impressed with it for that. For something that is not suppose to kink, it kinks alot.

Yeah Trooper. Would love to see the whole set up. Getting many of your shoes done?

 

[islandkent]

Geez I must be lazy. I leave mine in it all the time. Moisture never a issue here at least not last summer in my cabinet. I used it quite a bit doing all my nuts and bolts and smaller stuff for the car. Yep. I leave it in till it disintegrates or I want to change up media. Maybe the glass beads don't attract the moisture?? I have never really let the copper slag lie in there for too long. I don't have a use for it really.
I saved that copper slag I played around with this morning. Put the old glass beads back in. I vacuumed all the coarser grit out before I put the finer stuff in. I'm not so worried going to a coarser stuff.
But better safe than sorry I guess if moisture is a concern. I was sifting my media but since all mine comes right from PA I seem to have no trouble with that also. You would of laughed this morning though. There must be a little piece of a yellowish tag or label going through the system. Keep seeing it blow up from time to time. So maybe sifting isn't such a bad Idea after all. lol

 

[Jswain]

That's good that it fixed the surging! I always find little sticks and paper etc. In the media as well as quite often chunks that are quite a bit larger than the grit in the bag. I have a little screen I believe it's for gold panning screening out the rocks, snaps into a 5 gal bucket which I keep me media in. I screen everything out of the bags into the bucket and I screen everything that goes in my cabinet/pressure pot.

I only use about a 1/2-1 litre of media at a time and I never know which media I'll use next so at the end of the job I empty & blow out the cabinet, I have a little blow gun plumbed in inside the cabinet so it's quick and easy/clean and depending on the job by then the media might be spent and ready to be tossed anyhow(I use mostly crushed glass & ebonygrit)

 

[trooper1954]

Boy...the jungle drums are sure beating this morning! Here's my setup...and I have to add that it's clear patience isn't one of my strong suits! After slowing down and not overthinking this thing, by playing with the air valve and the pressure this morning I managed to get good results at 25psi with the air valve fully open.....and 60psi with the valve 25% open. I'm happy.....but I'm getting about 4 minutes out of my compressor before she kicks in, then like Kent I wait....but I can't imagine having the compressor run every 4 minutes can be a good thing. I'm thinking I'll be limited to no more than 10 horseshoes a day if that's the case. Or is it okay to keep that sort of cycle rate up? As new to compressors as I am to blasting cabinets!!

 

[Jswain]

All depends on the compressor and it's duty cycle. If you run a good, synthetic oil it's probably better to let it run rather then cycle every 5 minutes.

When I had my Ingersoll Rand it could maintain pressure if I was blasting @ 60psi it would hold around 80-90 In the tank. I kept a 12" fan blowing on the head and would run it for an hour then let it cool for 30. In its original owners manual it was rated for continuous duty if you used Ingersoll all season select oil but now I think they rate them for 50-70%

I know they say the duty cycle is 50-70% but the problem with compressors is when they stop turning they stop cooling, unless you have an electric fan blowing on it.

I'd rather keep mine running, at least then it gets some cooling from the flywheel, ideally with another fan blowing on the head, and change the oil more frequently

 

[islandkent]

I have had my compressor for 20 years now and it was old when I bought it. Last summer when I was doing my stuff on my days off I would let her pound for for 2-3 hours. By then I was ready for a break anyway. Yes she was hot, but she still runs like a champ. I have mine pushed up against the side wall of my garage with a Canadian Tire heavy duty shelving unit around my entire compressor. Not the best set up for cooling. But great for space efficiency. So far so good. Hard to kill the old stuff. lol
Jswain, I should look into the cycle duty thing. See how bad I've been beating on my IR GrandPrix T-30. Like the fan Idea also. Common sense eh. Just common sense. I use to do that in the summer to my water pump when I was filling the pool and to my deep freeze when I would buy a 1/2 side of beef. Trying to cool the compressor when freezing that much meat at once.
Yeah Trooper you'd be a long time doing 3-400 shoes at that rate. Your going to have to be one with your compressor! lol Know when to hold them. Know when to fold them.
You should ask that question here. And start another thread about your model of compressor you have and the amount you could safely run it. A lot of smart doggies on here. Somebody here will be knowledgeable about that I'm sure. Won't hurt to ask.

 

[racer-john]

Trooper
The tap drill size for a 3/8 NPT thread is (Briggs Pipe Tap) 19/32
(Whitworth PT) 9/16*
* you most likely don't have this tap.
Source 14th edition of Machinerie's Handbook page 1157.
Hope this helps you out fello Canuk.

 

[trooper1954]

Thanks guys....posted a new compressor question.

 

[trooper1954]

Had a fairly good session with the blasting cabinet this afternoon and noticed that there is quite noticeable surging happening....by noticeable I mean I can actually feel it through the gun. I wonder if this could be caused by the media being damp or perhaps there's an obstruction somewhere in the system. I intend to take it all apart tomorrow and see if I can spot anything. It seems to blast okay...just the surging. I tried different settings of both psi and air valve on the metering valve but it didn't seem to prevent it.

 

[Jswain]

How much media are you running? Definitely pull everything apart blow air through it all & screen out the media. It doesn't take much to block the flow

 

[islandkent]

That's what I was getting before I opened up my metering valve adjuster. Felt it right at the gun with intermittent media flow. You must of tried the old put your gloved finger over the nozzle and step on the pedal to blow out the line eh? Yeah give everything a good cleaning. And drain your air supply in case your introducing water with your mixture. And is you media damp??? What media are you using?? Size of nozzle? Wish I was there to give you a hand. Dam covid!

 

[islandkent]

I just thought I'd repost your question here also Trooper incase someone may have missed your new thread and someone might not of read this tread from the begining . Hope you don't mind?

I have a Campbell Hausfeld 60 gal 5 hp 2 stage compressor that runs 13.5cfm @ 90psi, and has a 80/20 duty cycle. I'm using this in a sandblasting setup, and it runs for about 4 minutes before it kicks in. How long should I continue to blast after the compressor kicks in before I would be doing some damage? Is it better to run 4 mins then give it 4 mins rest, or run it for awhile after the motor kicks thereby saving the stop/start situation?
Thanks for any advice