Flex 3401 generates a lot of heat?!

**Danube** · 01-30-2012, 05:44 AM

I've done a bonnet on a fairly big car today with 3401, 5.5 BP and 6.5" megs yellow pad.

There was some light hazing there left from UC (?!?), so I enjoyed myself working with M#205. Everything went well, but at the end (after some 30 minutes) I've noticed that the Flex was pretty hot .. especially metal housing and rating plate (see photo).

Tried to measure how hot it was by placing a finger on the housing, but had to stop as it was too hot to keep the finger there.

Btw my 3401 is brand new, with only a couple of hours of use (230 Volt environment with 230V machine, no step up/down transformers.

What are your thoughts?

Is this normal for this machine and why?!?

Thanks for the input.

**tuscarora dave** · 01-30-2012, 06:35 AM

This is normal for the machine. The design of that area of the machine was carefully thought out by the manufacturer. Aluminum (to my knowledge) dissipates heat more efficiently than any other metal.

Do you know what a "heat sink" is?

A heat sink is typically a finned piece of aluminum designed to carry heat away from a component that generates a lot of heat. Some examples of where a heat sink might be used would be on the processor inside of a computer, an AC to DC rectifier inside of a car alternator or the housing of a car stereo amplifier.

The plastic gear set that is located under the aluminum housing on the Flex 3401 generates a lot of friction. The main byproduct of friction is heat so the engineers at Flex chose aluminum for the gear set housing for it's ability to carry heat away from the gear set preventing a melt down of the plastic gears.

I'd wager a bet that if the aluminum housing was made of any material other than aluminum, the gears would heat up so hot that they would self destruct in a short period of time because of overheating.

I have run my Flex 3401 very hard, polishing metal for over 12 straight hours and the machine motor never got too hot to handle. The aluminum cover that you're concerned with however, had gotten so hot that it blistered my leg when I attempted to secure the machine between my knees in order to remove the pad from the backing plate.

I have over 200 hours on my original Flex 3401 and the original backing plate gear is showing no visible sign of wear. I'd say that the machine's ability to dissipate the heat is the reason why.

I hope this helped. TD

**shoeless89** · 01-30-2012, 10:27 AM

Wow great information Dave!

**BobbyG** · 01-30-2012, 10:42 AM

Dave's said it best so there's little that I can add.

Caution:

Some have taken the plastic guard off the front of the polisher and I personally don't recommend this as it will expose the user to metal parts that can easily burn you.

**JSMet** · 01-31-2012, 07:40 AM

I'm amazed at how knowledgeable you guys are. I was worried about my 3401 because the the tremendous amount of heat generated when I use it on my car and Dave's information has done a lot to alleviate my concerns. Thanks, Dave.

**Kaban** · 01-31-2012, 06:30 PM

Sounds right... mine gets hot too, but the rubber handle that you're supposed to hold on to stays cool, so it's never a problem.

**Danube** · 01-31-2012, 07:15 PM

Originally Posted by JSMet

I'm amazed at how knowledgeable you guys are. I was worried about my 3401 because the the tremendous amount of heat generated when I use it on my car and Dave's information has done a lot to alleviate my concerns. Thanks, Dave.

I completely agree with you. After using my 3401 for the first time I was concerned, but thanks to Dave I'm easy now.

A lot more to learn from people like Dave. Great knowledge/experience but more important - willingness to share it.

Cheers!

**Danube** · 02-02-2012, 04:42 AM

I have also contacted Flex headquarters in Germany.

Here is the answer:

the heating is not normal, but it can occur when certain negative factors come together. The factors may include: sponge larger diameter 160mm, high contact pressure at work in connection with a very low speed, viscosity of the polish. If these points are true should you try to modify it and try it again. If it appears they still have your XC 3401 VRG check whether there is a technical defect.

I hope that helps you.

Mit freundlichen Grüßen / Best regards

What to think now?

I'm awaiting on the 5.5" pads to arrive ..to see if there is any difference!?

**tuscarora dave** · 02-02-2012, 05:56 AM

I personally take that response with a grain of salt. I suspect that the person giving out that information either really didn't understand the question or he/she hasn't really used the 3401 to do more than a little in lab testing. In the real world using the tool to it's full potential, that sucker gets hot every time.

Originally Posted by Danube

I have also contacted Flex headquarters in Germany.

Here is the answer:

the heating is not normal, but it can occur when certain negative factors come together. The factors may include: sponge larger diameter 160mm, high contact pressure at work in connection with a very low speed, viscosity of the polish. If these points are true should you try to modify it and try it again. If it appears they still have your XC 3401 VRG check whether there is a technical defect.

I hope that helps you.

Mit freundlichen Grüßen / Best regards

What to think now?

I'm awaiting on the 5.5" pads to arrive ..to see if there is any difference!?

**Danube** · 02-02-2012, 06:51 AM

Looks like a lab tester to me too ..

.. he claims heating is not normal .. I even emailed the photo with the arrows pointing where it heats.

.. Or maybe all of us with 3401 should "check whether there is a technical defect".