When does a 1/2" hose reel make sense

[ckucia]

In the process of installing my new 2-stage 80 gallon IR compressor.

Was thinking a hose reel (or maybe a couple) would be nice to have.

I have a few air tools but my old compressor was never able to really run them so I have hardly used them. Hope to get more in the future, largest would probably a good 1/2 impact driver. Main reason for the compressor is eventually to get back into auto body and painting.

So, looking at hose reels, I see 3/8 and 1/2 are available. 1/2 is a little more money. My original thought was to get the 1/2 as my first reel and then down the line get the 3/8 as a convenience reel on the other side of the garage (my garage is 32x48) with the thought that the first one will be larger and thus capable of anything I need.

But do I actually need it? I've read that for painting, the extra weight and bulk is a hindrance, although I'm not sure I'd paint with a hose reel in any case just because of the risk of me accidentally retracting it and having the hose tension and brush against the job.

Most of the time it will just be used for filling tires. Second biggest use would be a 3/8 air ratchet and then any small air tools I acquire. Die grinder is probably first on the list. Biggest thing I currently foresee is the 1/2 impact. I'm guessing that I'll use air more and more now that I have it.

Is 1/2 overkill for a 1/2" impact? What's the "threshold" for a 1/2 hose to make sense?

I do mount my own tires (with a manual breaker) if that makes any difference.

 

[Mr_fixit]

I've found that I needed a bigger hose and fittings when I tried to operate a 3/4" IR impact gun. I haven't found any other tool that wouldn't operate with reduced air. They might operate slower, with less power, but they still operate, in my experience.

More air, more power, sometimes.

 

[bob15]

With high flow coupling, even my 3/4" impact works fine with a 3/8 hose.

For what you list for air uses, buy high flow couplers (Parker RF series or Milton V-series) and stick with the 3/8 hose; you won't see any difference switching to a 1/2 hose.

 

[240sxguy]

It depends heavily on hose length. I have a 25' 1/2 hose and a 50' 3/8. My impact is a wuss on the 3/8 hose, I always drag out the 1/2 for anything besides filling tires.

 

[sberry]

3/8 is the standard for this work. 1/2 for 3/4 airgun but I used my big gun on 3/8 the other day just fine.

 

[sberry]

It depends heavily on hose length. I have a 25' 1/2 hose and a 50' 3/8. My impact is a wuss on the 3/8 hose, I always drag out the 1/2 for anything besides filling tires.

What pressure are you set at? Ain't no way a 3/8 shouldn't work unless there is another problem.

 

[ckucia]

With high flow coupling, even my 3/4" impact works fine with a 3/8 hose.

For what you list for air uses, buy high flow couplers (Parker RF series or Milton V-series) and stick with the 3/8 hose; you won't see any difference switching to a 1/2 hose.

Just recently read about the high flow couplers. Now trying to decide which type to use since none seem to be locally available to drive the decision for me.

 

[Skin]

The OD of the hose is basically the same. There isn't much reason not to start and stay with 1/2".

 

[Hammer1963]

I use one for die grinders and 4" grinders quite often. It does make a difference

 

[bob15]

The OD of the hose is basically the same. There isn't much reason not to start and stay with 1/2".

I like the ones from Parker. I buy them through Zoro. Wait or look for a "X"% off coupon from them.

 

[sberry]

I use one for die grinders and 4" grinders quite often. It does make a difference

Are you not getting enough power with a common hose that has been used for decades in this class of tool? Is the pressure set a little low?

 

[Professional Tool User]

It depends on what you expect the 1/2 impact to do. If you are going to be fighting seized bolts all day, any bit of extra omph will make a difference.

 

[ckucia]

I've been reading about the high-flow connectors. None of them approach having a 1/2 inch hole. Doesn't the smaller hole in the connector negate a lot of the benefit of the larger hose? Seems as long as the connector hole is less than 3/8 then 3/8 vs 1/2 hose is kind moot. The Milton V for example are .28. 3/8 is .375. Granted there's less friction in a larger diameter hose, but is that enough to be a benefit at the end with all other things being equal?

Just trying to understand fully before spending $$.

 

[bob15]

Look at this graph, maybe it will help you understanding this: https://www.parker.com/Literature/Quick%20Coupling/catalog_sections/RF%20Series-Catalog%203800_SectionA.pdf

 

[ckucia]

Look at this graph, maybe it will help you understanding this: https://www.parker.com/Literature/Quick%20Coupling/catalog_sections/RF%20Series-Catalog%203800_SectionA.pdf

I understand how a larger ID on the connector is better for airflow.

But would not every connector from the compressor up to and including the tool, would have to have an ID > .375 for there to be a difference between a 3/8 and a 1/2 hose? Otherwise the hose isn't the choke point, the smallest connector in the line is.

Or is there some other factor I'm missing?

 

[bob15]

The ID of a RF or European style male end, 1/4" fitting is ~.375". The 1/4 npt hose-end fitting has an ID of ~.375".

What is the size of the plumping from the compressor tank out? That is typically 1/2npt or larger on most shops I've seen or heard of (mine is 1" black pipe). But for a 50' 3/8 hose with 1/4npt ends and 1/4" body high flow couplers, you will be fine, unless you plan on using a 1" impact. But, for a 1/2 impact or a 3/8 drive ratchet why deal with bulkiness and extra weight of a 1/2 hose when it isn't needed.

FYI: 3/8 hose is almost half the weight of 1/2 hose.

 

[bamawildcat]

Have 1/2 Goodyear reel as primary hose. That 1/2 hose becomes a beast to maneuver.

 

[Laminar]

When driving a 1/2” impact at pressures a little over a hundred PSI at the tool the flow rate is around 30 CFM.
At that flow rate a 50 foot 3/8 hose has over a 24 PSI drop.
A 50 foot 1/2” hose is about 5 PSI.
High flow couplers are totally unnecessary as long as you’re not using restrictive couplers like the common Milton M style with pull back collar.

 

[MattT]

Or is there some other factor I'm missing?

The factor you're missing is length. Sure the smaller fittings will have a higher pressure drop per foot but there's only a few inches of those vs. probably 50 feet of hose.

The graph bob15 linked shows about 5 psi drop across a high flow coupler at 30 CFM, which is what you need for a modern 1/2" impact. Using Laminars numbers for the hoses you're looking at about 30 PSI total drop for the 3/8" hose plus coupler vs. about 10 total for 1/2". With a 2 stage compressor you can use 3/8" so long as you don't have anything causing significant pressure drop prior to the hose reel.

 

[ckucia]

Thanks to all of you for your patient explanations. I understand a lot better now.