Porter Cable 390K 5" low profile Random Orbital Sander

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Review by GeneR posted 01-12-2014 05:51 PM 8054 views 3 times favorited 22 comments Add to Favorites Watch
Porter Cable 390K 5" low profile Random Orbital Sander No-picture-s No-picture-s Click the pictures to enlarge them

First off I have used many, many different sanders before this purchase. I bought this sander to replace a porter cable 1/4 sheet finishing sander that finally gave out after many years of reliable use.

I looked at several random orbital sanders that were comparable including the Dewalt version which is more of a finishing sander where this is an all around work horse.

The most notable difference between this and other ROS’s is the fact this is very quiet compared to Dewalt, Black and decker or even previous porter cable sanders. This particular unit also has greatly reduced vibration.

If you are not aware this ROS has a unique braking feature that slows down and stops the pad when you turn it off. This is so you can fairly quickly set it down without the worry of damaging whatever you set it on due to the disc still spinning on other units.

Another incredible feature is the built in dust vacuum system. when you are sanding you can actually hear the dust being sucked up into the bag as if a shopvac was attached to the unit, thus creating very little dust in the air. I have not yet had the opportunity to connect my shop vac to it but I am sure I will be very impressed.
Note: The dust extraction definitely works better with 8 hole paper being properly lined then the Freud brand sanding discs with small universal holes.

The sand paper disc I used were by Klingspore and I highly recommend this brand very good quality paper and less expensive with a wider variety of grits then most store bought paper. I found it on ebay up to 1500 grit.

Back to the sander.

The variable speed is nice for various wood densities and also for controlling the amount of material you take off, whether you want aggressive sanding to remove a large bulk or slowed down for a little fines in smoothing.
Note: This will also be based on the quality and grit of the sand paper you use.

I did have a hard time justifying the $109.00 price tag which I got on sale at Home Depot online for $99.00 plus tax and free shipping. But after using it on my opinion is that is worth every little penny I paid for it.

This unit also came with a very nice hard plastic case for storage.

In conclusion do not waste your money on other cheaper brands or units, suck it up spend the money and you will not be disappointed.

-- Failure is always an option. :-)

View GeneR's profile


151 posts in 2706 days

22 comments so far

View DIYaholic's profile


19918 posts in 3443 days

#1 posted 01-12-2014 06:05 PM

I’m in the market for another DOS & am looking at VS….
How long have you had/used this sander???

-- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procrastination a bad thing?

View GeneR's profile


151 posts in 2706 days

#2 posted 01-12-2014 06:59 PM

Only since Christmas but a furniture builder friend of mine talked me into dropping the cash. He has had his for a year with only one problem.

The first one he bought was not in a case and got knocked off a shelve from about 6 feet and bounced across the concrete which broke something inside of it and it got replaced with no charge since it was less then a year old.

But that also was not a manufacturing issue. Other then that we have seen absolutely nothing we don’t like about them, the grip size is a little different but fine once you use it for awhile. You will not be disappointed with it.

Also watch which one you get there is the 390 (no case) and 390K (With plastic case) Same price from different places. I personally like having the case and my friend wishes his had come with the case.

-- Failure is always an option. :-)

View DIYaholic's profile


19918 posts in 3443 days

#3 posted 01-12-2014 07:09 PM

Thanks for the info!
Happy dust making!!! ;^)

-- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procrastination a bad thing?

View Vincent Nocito's profile

Vincent Nocito

485 posts in 4132 days

#4 posted 01-12-2014 08:23 PM

I have had one for over a year. I find that after a while my hand starts to cramp becasuse the top is just a bit too wide. Wish it was more like the old 333 size. Otherwise, it is a decent tool and when coupled with a dust collector, it does a nice clean job. +1 on the Klingspor.

View rodneyh's profile


147 posts in 3432 days

#5 posted 01-12-2014 08:46 PM

I’ve had this sander for about a year & have used it a lot. I would probably give it 4 stars. I love it, but have a couple issues: 1. Dust collection isn’t great (granted, I primarily use the universal discs), so I always use it on my downdraft table, and wear a mask for any large jobs. 2. Noise is about the same as my Makita 1/4 sheet sander, so you’ll want hearing protection (at least for longer jobs). 3. The pad no longer holds paper very well, so I’ll need to spend $22 on a new pad. 4. I only use it for 60-120 grit, as it’s not great for detail work like the Makita is.

View Mip's profile


454 posts in 2846 days

#6 posted 01-12-2014 09:03 PM

I have the very same sander, but not with the case. One hell of a sander. About that price: I got mine for around $70 at Woodcraft about a couple of months ago; it was on sale and I have perfect timing.

View whitebeast88's profile


4128 posts in 2959 days

#7 posted 01-12-2014 11:20 PM

i have the same sander had it for about a year now.i agree its a great sander my only complaint is the handle is to wide like vincent said and after a period of time my hand cramps.

-- Marty.Athens,AL

View ScottKaye's profile


782 posts in 2721 days

#8 posted 01-12-2014 11:57 PM

I’ve had this particular model on my radar for some time now. I would have bought it already, but SWMBO has put the kabash on any more woodshop purchases for the forseeable future. (Im sure I’ll sneak something in there !) Its good to know that you are happy with the dust collection because my 333v definetly lacks in that area. I got spoiled using my friends Festool 5” and 6”. They are some nice (but pricey) sanders and their dust extraction is second to none. But as it is, my trusy PC 333v is still going strong. Though I just burned up the belt that controls the spin-up / spin-down and random orbit funtion of the sander. Replacement belt should be here tomorrow and I ordered another as a spare. Ive had my 333v for the better part of 10+ years and its still going strong other than the belt issue. So when it finally dies, I’ll look into the 390k

-- "Nothing happens until you build it"

View TopamaxSurvivor's profile


19228 posts in 4444 days

#9 posted 01-13-2014 12:58 AM

Thanks for the review.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View Marcus's profile


1165 posts in 2788 days

#10 posted 01-13-2014 02:20 AM

My favorite ROS as well. By far the least vibration of all the ones I’ve used but can still be very aggressive. As MIP noted, woodcraft has this on sale for a very reasonable price…worth keeping an eye out for.

View lanwater's profile


3113 posts in 3702 days

#11 posted 01-13-2014 04:10 AM

Thanks for the review. I need to replace my Makita and I have been looking at the 390k.

-- Abbas, Castro Valley, CA

View Carlton Standish's profile

Carlton Standish

1 post in 2364 days

#12 posted 01-13-2014 07:11 AM

I have uses this sander for over ten years (have two) and reach for one or the other at least once a day. Extream lay dependable and have had to replace pads on each one ONCE!

-- Carlton: [email protected]

View GeneR's profile


151 posts in 2706 days

#13 posted 01-13-2014 03:33 PM

@Rodneyh I found the dust collection to be average at best with universal small hole sand paper and it wasn’t until I switched to the proper 8 hole discs that I discovered how good the dust extraction is.

I did not find this sander very loud compared to my other sanders especially my mega mouse (that thing will rattle the teeth out your head). But it is always a good idea to think safety first. (eyes, ears and Lungs keep them covered)

As far as it hurting your hand due to size comment: I don’t seem to have that problem maybe due to my fat bear paws. lol But the weight of it was noticeabley heavier then I was used to and took awhile to get comfortable with.

-- Failure is always an option. :-)

View Seed's profile


8 posts in 2763 days

#14 posted 01-13-2014 08:53 PM

I too bought this sander about 8 months ago. Just before Christmas I went out to the shop to do some sanding and pushed the switch and nothing happened. I took it to the Dewalt/Porter Cable factory store here in OKC and in about 2 weeks they repaired the sander, bad switch. I really like the sander and the support I got from Dewalt/PC.

View retfr8flyr's profile


386 posts in 2437 days

#15 posted 01-14-2014 12:49 AM

I have this sander also and I have been very happy with it. My hand is large enough that it doesn’t give me any problems. I use it hooked to my DC and dist collection is great but I only use the proper disks. I also have a 5 inch older model Makita and the PC does a much better job, with less swirl marks, then the Makita. I would recommend this to anyone looking for a quality sander.

-- Earl

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