RO125 - Over heating?

[ForumMFG]

While using my RO125 the other night, by the time I was done sanding I thought my hand was on fire because of how hot the head of the sander got.  It was very uncomfortable to use by the time I was almost done with it.

Is this normal?  What are your thought?

No pressure was applied to the sander, I let the weight of the sander do the work.  No vacuum was used.

I did a search on this issue and could not find anything.

 

[rwdawson]

I own the RO 150 and have used it with grits varying from 36, with some pressure, to 180, with no pressure.  It does get warm, but never hot.  From what I have read, this is to be expected.

The biggest difference between our respective usages is that I have never used the Rotex, or my ETS 150/3 without the dust extractor.  I believe that is at least related to your problem, perhaps the cause, especially if you are using a coarse grit.

HTH,

Richard

 

[ForumMFG]

rwdawson,

The lowest grit I used was 120.  And yes, It gets extremely hot.  I am picking up a ct 22 tonight and I will see if that makes a difference.

 

[Brice Burrell]

Dave I know this is going to sound strange but it is normal for some Rotex sanders to become very hot during use. The good news is it's only temporary. What's causing the heat is the arcing in the universal motor as the carbon brushes "break in". During this break in period the brushes are wearing to take the shape of the armature (called seating) but before they seat there can be arcing between the two. The break in period lasts about 8-10 hours of use sometimes less. I know some guys have let their sanders run while hanging up for a few hours to get past this break in period. 

 

[rwdawson]

Dave I know this is going to sound strange but it is normal for some Rotex sanders to become very hot during use. The good news is it's only temporary.... 

I didn't know that they could become that hot.  Does the use of a dust collector reduce the effect any?  Maybe I was lucky, or didn't notice the heat generation during break in.  Interesting.

 

[Brice Burrell]

Dave I know this is going to sound strange but it is normal for some Rotex sanders to become very hot during use. The good news is it's only temporary....  

I didn't know that they could become that hot.  Does the use of a dust collector reduce the effect any?  Maybe I was lucky, or didn't notice the heat generation during break in.  Interesting.

Not all Rotex sanders have this issue. The heat is generated at the motor, the vac isn't going to cool it down. Like I said above, this is only a temporary problem.

 

[Frank-Jan]

My rotex 150 also had the heat issue, but I had read about it beforehand, so I wasn't surprised by it. A few years before my trion jigsaw had it too. (The first use I had for it, required it to be working a long time without "rest")

 

[Aspiring FT Owner]

Yea, if the sander is new, it needs to be broken in.  I think that hooking up a vac should help, airflow and all that...

Feel the dust hose, it has to be doing some good hooking up to a vac, the air is hot coming off a newer tool.

If you felt you needed gloves to work, that's normal till 10+ hours of use has passed.

I returned my first RO 150 thinking it was defective, but the replacement did this too till after 12 hours of sanding had passed.

 

[ForumMFG]

Brice,

So it's safe to just hang the sander and left it run for a couple hours?

You think the manual would note this so people don't end up taking it back.  I really did consider that.

 

[Brice Burrell]

Brice,

So it's safe to just hang the sander and left it run for a couple hours?

You think the manual would note this so people don't end up taking it back.  I really did consider that.

I've not done it but I know a few guys here that have with no problems. This really is something you need to use your own judgment on. I've used my sander for hours of almost continuous use on numerous occasions so I know the tools can take that kind of use. If I were to try this I'd keep an eye on things just to be sure everything was okay. Like I said you need to decide if it's something you are comfortable with. Festool's manuals are pretty minimal so I'm surprised there is no mention of this.

 

[tbellemare]

If you wanted to "hang" the sander and were concerned that something could go wrong (Murphy's Law) because of the rotating object, you could just take the pad off. It should be safer during the break-in.

Another safety addition could be to use the Boom Arm Tool Holder.

Tom

 

[WarnerConstCo.]

I had to send back my RAS 115 because it got hotter each time I used it, so hot that you needed gloves the last time I used it.

Sent it back and they replaced the armature (like most of the electric motor right?).

Now its fine, just a lot louder than before.

 

[justinmcf]

i had a festool et 150/5 for over 10 years, and i have a recently purchased ets 150/3. after using them constantly, somedays up to 10 hours per day, they get hot, very hot, i wear gloves too. i also use them with the ct-22.
i dont worry about the heat build up, i expect any tool to heat up after 10 hours use per day.

regards, justin.

 

[Neill]

I may be wrong, but it seems to me that if you put your hand over the top / front of the RO 125's housing  you are smothering some of the vents that expel heat from the motor.  In addition, you are probably putting direct pressure above the sanding pad that would result in more heat than normal.

I think it was Brice who figured out that the Rotex sanders work best if you hold them at the junction of the cord / vac hose and the tool.

Neill

 

[ForumMFG]

On the Rotex and most of the other sanders, you should let the sander do most of the work anyway and not apply any pressure.  You're right about the vent holes.  I noticed that the first time I used it, I thought they were in a bad location considering it's right where your hand should be.