View Full Version : 3401 for boat polishing

09-20-2018, 09:59 AM
Hi All,

I have just purchased a Flex 3401, where my thought was to have this my only polishing tool for both my cars and boat. For my car I am fairly certain that this is true, well..maybe one mini polisher would be needed. When it comes to my boat, do you think that the 3401 is up to this task? Or would I need a rotary if I don't want to spend an insane amount of time on polishing? The boats gelcoat is in ok condition, but it is 30 years old so far from new....

09-20-2018, 02:07 PM
Although I don't personally own a Flex 3401, I've been a member here long enough to say that yes, the Flex is more than up to the task.

Boats, Planes, heck, even up to and including Air Force 1!

As far as I see it, (and with regrets of not buying one up to this point) the Flex 3401 appears to be "the best of the best of the best"! (with honors sir!) :xyxthumbs:

09-20-2018, 04:40 PM
Info from a previous post hopefully this helps:. I have Cobalt 242 that is 6 years old and has moderate oxid (6/7 out of 10)Tried using my flex 3401 with compound/ wool pad test spot (result = it will take me until Christmas 2019 to get it done). Looks like I either wet sand it or get a rotary n hit with wool/compound. Will do a wet sand with 3000 grit (least aggressive) using my 3401 and see what happens. Been reading Mikes book n am leaning toward sanding

Reporting back on Cobalt mentioned above. I hit it with DA using 3000 sandpaper, then wool(marine 31 compound n polish,then light cut pad with same compound n polish,followed by wax n sealant. Don’t have pics but seemed to work very good. ( I had tried wool using rotary with heavy cut n compared to sanding , the sanding gave better results). Thanks for all advice.

Sent from my iPad

09-21-2018, 01:24 AM
Thanks! I'll try the 3401 first and then be prepared to buy a rotary if necessary...

Mike Phillips
09-21-2018, 05:47 AM
In my boat detailing book, I divide boats by category of condition.

Below are pictures of just the index. Scan down and find the section for the 4 different categories and you can see what I list for tools necessary to correct the various conditions.

Category #3 recommends a rotary buffer. Category #4 recommends sanding. Category #2 can be saved using a FLEX 3401

Paperback book - How To Detail Boats With Marine 31 by Mike Phillips (http://www.autogeekonline.net/forum/marine-31-boat-detailing-classes/97252-paperback-book-how-detail-boats-marine-31-mike-phillips.html)


It's no coincidence that car guys also tend to be boat guys!

The two hobbies go together well when it comes to having fun and also when it comes to detailing and maintaining both cars and boats.

This how to book contains more in-depth information on boat detailing than any other book ever written on this topic. This is without a doubt the most complete and information rich how-to book I've ever written. (I have 5 paperback how-to books in print and 3 ebooks available).

This paperback book on how to detail boats goes over every surface of a boat both inside and out. It also covers every conceivable condition a boat is in with specific steps for correction.

It covers all these tools,

Flex 3401
Flex PE14
RUPES BigFoot 21
RUPES BigFoot Duetto
Cyclo polisher
Porter Cable 7424XP
Makita 9237CX2
Griot's Garage 6" DA Polisher
3M Air DA Sander

Working by hand
I know most people start out working by hand so I included hand techniques for every topic.

Plus all the pads, brushes and sanding discs to use with the above tool.

Instead of typing out all the topics covered in this book I've simply taken pictures of the index which shows you just how in-depth this how to book truly is...







Many of the topics covered also apply to car detailing so it's a valuable resource even if you don't yet own a boat.

If you're familiar with my writing style in the forum world you'll find the same style of writing in all my how-to books. That is I explain in simple terms how to perform a process plus why you're performing it and it's a combination of including both types of information that helps you to do the best work possible.


09-21-2018, 06:52 AM
Matt. Yes, read Mike’s book.. As mentioned above I followed level 4 oxidation chapter. I used the flex orbital to sand (3000 grit)(next time I will follow with 4000 grit to remove shallow sanding marks) as first step then followed the steps in the book for category 3 oxidation (wool with flex rotary using Marine31 captains one step Compound n polish, then back to orbital using foam pad with same compound n polish, then wax (or ceramic coat but prep gel coat first)


Paul A.
09-21-2018, 09:34 AM
My general point of tool use demarcation is wool vs. foam pads. If i find through tests i need a wool pad i break out my rotary. While the 3401 is direct drive i still don't like beating up my Flex backing plate with overly aggressive use of a large wool pad and maybe some exerted pressure. Plus i can cut a little more and faster with my rotary. I then clean things up perfectly with foam and the 3401.

However, up to that point of needing wool, my Flex (The Beast) works perfectly.

Just my approach and as always...YMMV.

09-21-2018, 10:45 AM
Thanks everybody for the information! So it just might be that I need to have a rotary as well, well..always fun with new tools :-)

Mike: It would be good to have all of your books in e-book format for the international customers.

09-28-2018, 01:36 PM
I got a good price on a Bosch rotary so now I should be all set for some gelcoat polishing as well:
First look at the Bosch GPO 14CE (https://www.autogeekonline.net/forum/rotary-buffers/121047-first-look-bosch-gpo-14ce.html)

glen e
09-28-2018, 01:52 PM
I went through this a few years ago. I tried every pad under the sun with my DA, I got nowhere on relatively minor oxidation. Once I went to the hybrid foam wool pad, a mid compound and a flex rotary, I knocked it out in a couple hours…

FLEX L3403 VRG Lightweight Circular Polisher, FLEX rotary polisher, high speed professional buffer, car buffer, german polisher (https://www.autogeek.net/flex-l3403vrg-rotary-polisher.html?gclid=CjwKCAjworfdBRA7EiwAKX9HeLB_-ToVZQb4C9qjamL1SC3DoQkzYKWUGNlZflnj1ry2o83MAqebTRo Cnj4QAvD_BwE)