Thinking of buying a Bostitch oiless compressor for your ShoeBox - read this

[thwakk]

I posted this in case anyone is considering buying a Bostitch 6 gal 150psi compressor to supply air to a ShoeBox.

I bought this early Dec of 2018 to replace an older Craftsman 3 gal 100psi compressor that I initially bought to keep my car tires aired and to blow out my desktop computer. The old compressor had problems with car tires and barely made it thru one desktop blow out.

I can say the Bostitch fills those old needs nicely but I found that when using it as an air source for the ShoeBox -- it fails miserably. With the regulator set at 90-95psi and a 'duty cycle' of about 1 minute to fill the tank from 120-150psi and a little over 4 minutes to reach the starting point where the motor starts again, after about 1.5 to 1.75 hours it starts a fast 'duty cycle' (fast cycle) barely reaching 122psi before starting over. I found turning it off and on, the regular 'duty cycle' ran for several cycles but started the fast cycle again shortly afterwards.

The following day I took it to a warranty shop near by and after 1.5 weeks called for a status and they said they found nothing wrong. I picked it up and later the same day started the operation again to finish topping off my tank but once again it started that fast cycle routine at about the same time frame. Back to the warranty shop I went  and after a rather long but cordial conversation, I was told they couldn't help. It was designed for "light" work and not extended running times. They then gave me the customer support number and said they would do what the customer support folks said.

I called customer support today and they listened to my story then after inquiring with others familiar with this compressor -- said basically the same thing. It was not designed for longer run times. They were willing to give me a phone number of the main compressor technical support but if they agreed to look at it, I would need to ship it to them. I didn't keep the box and it is heavy so thats not an option for me. I would guess the shipping charges would be about 1/3 the value one way.

Bottom line -- I'm on my own. I did see what the motor looks like while at the warranty shop and the fan that cools the motor is directly connected to the motor itself. Any heat created while running that is still there once the motor shuts off has to disipate on it's own.

I don't want to let it run without my being within ear shot as it is (basiclly baby sitting) but I might try forcing air thru the intake area to see if that helps since the fan don't run without the motor. If that don't help I may look at other options or simply sell this to someone local needing air for short running times (ie: trim work).

I will post this on several forums.

[green]

Do you know what the CFM is of your compressor?

[thwakk]

" Do you know what the CFM is of your compressor? "

The manual states ( SCFM @ 90psig    2.6 * ) if that helps any..

[green]

I was curious because the manufacture of the Shoebox recommends a minimum of 2.0 CFM. 

[Loren]

Put a table top type fan next to it blowing on the motor.  That will help draw the heat of the motor and help that duty cycle a little bit.

[KnifeMaker]

Sadly, the simple truth is, the compressor is too small for the job.


I didn't' see the model of shoebox, but the F-10 for instance requires 2.o to 2.2 cfm at 125 input. With the size compressor you are using, it cannot reach the required, or desired pressure level at the needed cfm.


More importantly, running so much, generates heat. Heat will cause your compressor to literally pump water out of it. Not good. Not good at all!


I realize that now that the SB's are supplied to us at a much lower cost.. This makes it very  tempting to use a very inexpensive (small) feed compressor to keep the cost at a bare minimum.. Sadly, it is a very bad decision.
Bad on the feed compressor, bad for the desiccants, and very-very bad for both the SB and the fill bottle or AG. As the high heat generated has you pumping water thru the system. This will kill ath o rings in the compressor,  and wors, sill scar the cylinder walls and pistons. Virtually destroying the ShoeBox in short order. It cannot live is such an environment.

The repair shop cannot fix the fact that the compressor is simply too small. Only a proper sized, or larger compressor can fix that. 


Blowing a fan on the motor will do nothing to cure the water pump you have now created.

But continue to use an undersized compressor and I can guarantee that the repair shop at Shoe Box will have another compressor to repair. As will the AirGun repair shop. LOL


Your feed compressor should be rated to at least 200% grater and preferably double that to both live and give a somewhat cooler air charge. The Bostitch is not the problem. It is in this case, operator error.


I don't care how tempting it is to skimp and pinch pennies here.

Don't Do It!

 

[green]

Sadly, the simple truth is, the compressor is too small for the job.


I didn't' see the model of shoebox, but the F-10 for instance requires 2.o to 2.2 cfm at 125 input. With the size compressor you are using, it cannot reach the required, or desired pressure level at the needed cfm.


More importantly, running so much, generates heat. Heat will cause your compressor to literally pump water out of it. Not good. Not good at all!


I realize that now that the SB's are supplied to us at a much lower cost.. This makes it very  tempting to use a very inexpensive (small) feed compressor to keep the cost at a bare minimum.. Sadly, it is a very bad decision.
Bad on the feed compressor, bad for the desiccants, and very-very bad for both the SB and the fill bottle or AG. As the high heat generated has you pumping water thru the system. This will kill ath o rings in the compressor,  and wors, sill scar the cylinder walls and pistons. Virtually destroying the ShoeBox in short order. It cannot live is such an environment.

The repair shop cannot fix the fact that the compressor is simply too small. Only a proper sized, or larger compressor can fix that. 


Blowing a fan on the motor will do nothing to cure the water pump you have now created.

But continue to use an undersized compressor and I can guarantee that the repair shop at Shoe Box will have another compressor to repair. As will the AirGun repair shop. LOL


Your feed compressor should be rated to at least 200% grater and preferably double that to both live and give a somewhat cooler air charge. The Bostitch is not the problem. It is in this case, operator error.


I don't care how tempting it is to skimp and pinch pennies here.

Don't Do It!

I totally agree with KnifeMaker, but I didn't want to have to be the one to inform you that your compressor is to small! Good luck

[AlanMcD]

You stated this is compressor is rated at 2.6 cfm at 90 psi; the Shoebox is rated at 10 cubic feet per hour, thus only about 0.2 cfm.  clearly 0.2 cfm is way less than the recommended level of at least 2.0 cfm per hour on the website, but I think it has to do with the fact that what we care about in these shop compressors is actually something that the manufactures don't tell us - how well they operate at the higher pressures, and how efficiently they can fill their tanks and/or their duty cycle of continuous operation (not that we want continuous operation, but it speaks to internal cooling).

My guess would be that a 2.6 cfm compressor would need to run about 10 minutes or so to feed a Shoebox for an hour (allowing for less efficiency at the higher pressures), but this one looks like it needs 15 minutes.  That indicates to me that it is not an efficient pump at the higher pressures needed to fill the tank up to the 150 psi shut off level.  It might do better if you could lower the shut off point so that it does not have to work so hard at the top end - if stopping at 135 psi, it might only be on for about 20 seconds or so (it would come on more often, but have generated much less heat to dissipate between cycles).

Sadly, the data we need is not really published.  But I think a good surrogate is to look for an even higher flow rate at 90 psi, and of course a larger tank helps as it lets the compressor be off for a long time between cycles (yes, it runs longer to fill the larger tank, but the net cooling time improvement helps).

My 25 year old oil-less Craftsman shop compressor is rated at 6.8 cfm at 90 psi, and has a 15 gallon tank.  I always pre-fill it up to max before feeding my Shoebox, and let the air charge in it cool down for quite a while before starting things up - that insures that the most water vapor as possible has condensed out before starting, and reducing the average air charge temperature through the fill.  With the higher flow rate and larger tank, it typically only comes on about 4 times per hour, and it only needs less than a minute to fill the shop compressor tank before turning off - thus it only runs for under 4 minutes minutes per hour of Shoebox run time (although mine is a Max that puts out 6.6 cf per hour, instead of the 10 cf per hour of the new ones).

In short, I guess size does matter . . . .

[thwakk]

First off, thanks for the replies and honesty. My purchase of the Bostitch BTFP02012 does seem to be a poor decision and it's not the first one this old man had made nor will it be the last but each mistake is another life lesson (smile).

To add some clarification to the initial post, the ShoeBox I bought was a used model with upgraded pistons and belt drive. I didn't know the ShoeBox model number then and frankly -- with the upgrades don't don't know how it would fit into the air feed requirements.

The only manual I have seen for the ShoeBox that has the "clacker" spring type shutoff control is for the Max model and requirement for that indicate lower specs than the newer models (see quote below) but the Bostitch seems to meet the ShoeBox Max input specs. I'm assuming mine is the Max model since mine does have the old "clacker" spring type shut off and that rules out the F8 and F10 based on manuals I've seen. I don't see how hardened pistons could change requirements much unless the piston housing and/or capacity was changed as well (mine has the groves cut into them for cooling). I can see where the belt upgrade could if the wheels are different.

The Max manual states  (quote) "We recommend one of the small shop compressors that are oilfree and generally cost less than 100 dollars. The compressor uses less than 1 cubic foot per minute and virtually all inexpensive shop compressors can deliver that flow rate." (unquote)

I did have a fan blowing on the ShoeBox pistons while running and monitored the temperature of them using a laser type thermometer which showed temps mostly around the 85-90+/- degree mark if memory serves me.

I have tested the Bostitch without the ShoeBox connected using a controlled bleed that allowed the same basic 'duty cycle' of a little less than one minute of motor running to charge up to 150psi and a little over 4 minutes to drain the air tank pressure to the starting point of approx 120psi. If I understand the term 'duty cycle' correctly the 1minute running and 4 minutes to use air provided meets the Bostitch of "50-75% duty cycle. I got the same fast cycle results after around 2 hours of running time.

All this said, this Bostitch model doesn't meet my expectations as is and assuming this same model would provide the similar results with other ShoeBox compressors --- using the knowledge gained so far will hopefully help other ShoeBox owners regarding input compressors.

A recent post input while I was typing added more information to consider. Also, there is no way to adjust start and end pressures on the Bostitch I bought so that is not an option and it has an internal fan that is attached to the motor so when the motor is not running - neither is the fan which I think is part of the problem.

One thing for sure, if I buy another compressor I will know a whole lot more... Thanks to all for the information.

[AlanMcD]

First, I think it great that you are steering people away from this compressor, as it clearly is not the right one for our uses . . .

But I do think you can make it work for you.  Since you are not using the higher input pressure Shoebox 8 or 10, you can probably lower the cut in point, and if you get the compressor cycleing more in the 100-125 psi range it will probably do fine.

Check out this link for what I am talking about here - I don't know that it will work for yours, but most shop compressors use a variation of a this system: http://theworkshopcompressor.com/learn/air-compressor-parts/air-compressor-pressure-switch/air-compressor-pressure-switch-setting/

[Back_Roads]

 Another thought was the Shoe Box upgraded to be closer to the F-10 ratings ?

[mann]

Hmm I'm running same compressor with my shoe box  . My shoebox is a older one and I run the compressor at about 95 psi and haven't had a problem with it . I was running the shoebox on a larger compressor but it took a long time to cycle that's why I switched . At the pressure of 95 psi I've had no problems and left it running for 2 hours at a time after 2 hours I stop the shoebox and grease it . The little compressor stays on longest I've had it going is probably 6 hours

[Taso1000]

Thwakk,

Either that Bostich compressor doesn't meet the advertised ratings or there is something wrong with it, like a leak somewhere. 

I am running a California Air Tools 2050A which is rated at 1.10 CFM @ 90 PSI with my upgraded Max and a membrane air drier with a constant moisture purge.  My CAT compressor handles the load just fine and it not constantly cycling.

The Shoebox needs .2 cfm and the moisture purge is .09 cfm.  So I need to provide .29 cfm and this tiny CAT compressor does not have a problem keeping up.  Also it's is not running constantly.  It cycles between 90 and 125 psi if I remember correctly.  I haven't filled any of my tanks in a while.

Thanks,

Taso

[FuzzyGrub]

Either that Bostich compressor doesn't meet the advertised ratings or there is something wrong with it, like a leak somewhere. 

I agree.  It sounds like he has the original SB that has been upgraded to "max" level.   I ran the cheap, small, HF $50 pancake compressor, and it didn't have that kind of a duty cycle.  I went to CAT for quietness. 

A 6gal tank, filled to 150psi, should take longer before it kicks on at 120psi with a SB max.  If it is not leaking, then try to adjust the on/off pressures.   Off at 125psi, and on at 100psi, should work well with feeding the SB at 95psi.

[RichH]

Hook all of your hoses and tank up but then only turn on the Primary compressor till the high pressure switch cuts it off. Then shut it off and leave it for a few minutes and see if it all holds pressure.
If it does then check to see what the cut off and cut on pressures. Most compressors need a minimum pressure (like at least 15 to 20psi) between the 2. If the switch is set so that it cuts on at 115 and off at 125 then you will have issues. With tank empty turn compressor on and note where it cuts off. Then open the tank drain slowly and note pressure where it cuts back on. My shop compressor is set at 125 off and 90 on. Works great for all my tools.

[Taso1000]

Hook all of your hoses and tank up but then only turn on the Primary compressor till the high pressure switch cuts it off. Then shut it off and leave it for a few minutes and see if it all holds pressure.
If it does then check to see what the cut off and cut on pressures. Most compressors need a minimum pressure (like at least 15 to 20psi) between the 2. If the switch is set so that it cuts on at 115 and off at 125 then you will have issues. With tank empty turn compressor on and note where it cuts off. Then open the tank drain slowly and note pressure where it cuts back on. My shop compressor is set at 125 off and 90 on. Works great for all my tools.

I agree.  If the Bostich compressor cycles frequently with nothing connected there is definitely a leak. 

Not Shoebox related but I found a huge leak on my garage Craftsman compressor around the pressure regulator.  It's always leaked but never got into it to see from where.  I removed the pressure regulator for testing but the compressor still loses pressure from somewhere else.  I'm gonna hit all the air connections with soapy water when the weather warms up, but I think I need to see if the check valve is leaking. 

Thanks,

Taso

[thwakk]

A quick update on my attempts to use the Bostitch compressor with my upgraded Shoebox booster.

The day after my last post on the matter, I set up a contolled bleed to mimic the dury cycle seen so far but this time I had a small fan blowing into the intake grill of the Bostitch. I don't believe having the fan as part of the motor is a good design for extended run times since there is no cooling done at when the motor is not running and thought using an external fan should show improvement.  I tested temperatures off/on and didn't see any temps to be alarmed about and it ran for 4.5 hours without issues. I can make this work using an external fan.

Given one reply stating they had an older Bostitch and had no issues (same internal coolingdesign?), plus many of the replies thought leakage is causing a loss of air which in turn shortens the duty cycle, more investigation was needed. Well -- today I tested all connections before the Shoebox and did find multiple leaks (sigh). It took some time but I think I got all the leaks addressed.

I hooked up my full tank (valve closed) and fired up the Shoebox. I got to 4600psi pretty quick and once it shut down, let it sit for about 5 minutes monitoring the tank gauge during that time and pressure remained at 4600psi.

More lessons learned and I want to say thanks to those who took time to reply -- much appreciated...