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Have you removed 1000 grit sanding scratches from gelcoat on a boat with a Flex 3401? If so, please describe your pads in terms of material and size, your compound, and your technique. If you have an approach that includes 3M Super Duty Rubbing Compound or Menzerna FG400, both of which I currently have on hand, that would be ideal.
I haven't.
I wouldn't try either. Instead I would finish out at a much higher grit or use a rotary buffer with a wool pad.
You might be able to remove #1000 grit sanding marks out of gel-coat using a Flex 3401 but it's the wrong tool for this type of work. It will also take a LOT longer than doing it with a rotary buffer.
The way I explain the answer to questions like this one is like this,
To wetsand anything and then remove the sanding marks using a rotary buffer already takes a long time.... doing it any other way with any other tool is just going to take more time and require a lot more muscle on your end.
What are you working on?
What are you trying to accomplish?
Also, since this is your first post to our forum...
Welcome to AutogeekOnline!
:welcome:
Thanks for the response, Mike. I’m a do-it-yourselfer new to machine polishing with one just under 20 foot boat and one medium size pickup truck, so I anticipate a very low volume of work with my recently purchased Flex 3401 compared to someone trying to make money with it.
Last year, I purchased a 1994 Mastercraft ProStar 190 ski boat. I go on an internet forum for Mastercraft owners where I’ve seen boats brought to excellent shape that started out far, far worse than mine, so I’m looking to get my boat in excellent, though not showroom, condition.
This boat is trailered in my driveway in central Florida. I don’t have facilities to safely expose and access the bottom, so I will hire out any work on the bottom to a local marine dealer, further reducing my personal work volume on this little ski boat.
The boat is in pretty nice shape. Both sides of the bow were quite reflective when I bought it, almost mirror-like, for example. I do have oxidation down one side and across the transom, however, that is milky to the point there is only a very faint reflection when I look into it. The decals are in pretty good shape. Some people remove them and then leave them off permanently or replace them, but I plan to leave them as they are for now and try to work around them.
Being twenty years old, the boat has accumulated some scratches and scrapes here and there that appear to require wet sanding. There was also an image of the old registration letters/numbers and decal left in the dark teal stripe after I removed them from each side. I think they were on there 12-20 years. I’ve wet sanded that. There are also three small scraped and/or chipped areas, the largest being the size of your pinky, that I think will require additional gel coat, but dealing with that is down the road a bit for me.
Since a number of guys on the Mastercraft forum have these old ski boats and have reconditioned them, I figured I shouldn’t need to reinvent the wheel. I identified one who posted several successful buffing projects and who had others following his methods successfully. He advises a lot can be done with compounding, but if any wet sanding is necessary, 1000 grit first and, if that isn’t aggressive enough, 600 grit followed by 1000 grit. His steps are:
(1) 3M Super Duty on Lake Country twisted wool pad
(2) 3M Finesse It II on Lake Country orange foam pad
(3) Meguiar’s No. 45 Marine Polish on Lake Country white foam pad
(4) Carnauba wax of choice applied with Lake Country red pad
He does all this with a Makita B06040. I saw a post where you said you had used that machine. He invokes the forced rotation mode on his B06040 in steps (1) and (2) only. He’s repeatedly asserted he removes 1000 grit scratches with his B06040 and the Super Duty and that sanding higher is unnecessary. I set out to mimic his methods with the Flex 3401, but perhaps the machines are not as comparable as I believed.
I have the Flex 3401, 6.5 inch Lake Country twisted wool pads, 6.5 inch Lake Country CCS pads bundled with the Flex, the Lake Country adapter backing plate system and 5 inch Lake Country hybrid pads you recommend, the above compound and polishes, Collinite for wax, and other stuff.
Given the length of this, I’ve spared you the good and bad of my test results thus far.
A few questions:
(1) Do the methods outlined above look okay to you? Can they be improved?
(2) You suggest one option would be to finish out to a higher level with the wet sanding and then remove the sanding scratches with the Flex 3401. To what level, which pad, and what product on the pad?
(3) I’m not so concerned about efficiency because this is a small one-off project, but would I get any better end result by introducing a rotary polisher for some of this?
(4) At one point in your book, you suggest 15-20 pounds of downward force on the polisher. Is that appropriate for the Flex 3401? If not, what is an appropriate maximum downward force on it?
(5) What do you think is the best way for me to proceed?
Yes, if wetsanding is needed start out at a lower grit but if you want to safe your self a lot of time and grunt work using a tool that is no where near as effective as a rotary buffer for removing sanding marks then finish out at a MINIMUM of #2000 and if it were me I'd finish out at #3000 or even #5000 by machine.Quote:
Originally Posted by BrianC
The point being is that the more shallow the sanding marks the less polyester resin you'll need to abrade to remove them.
Yes, here's my article on this topic.... any tool that has the ability to abrade the surface can be used to remove sanding marks, the rotary buffer is the most effective tool for this job but a person can use whatever they want and/or have.Quote:
Originally Posted by BrianC
Makita BO6040 Removing Sanding Marks
http://www.autogeekonline.net/galler...040Test027.jpg
http://www.autogeekonline.net/galler...040Test025.jpg
I would never argue that what he states he did cannot be done. I personally don't have the time to use a dual action polisher to remove sanding marks when I know from years of experience the right tool for the job, the best tool for the job is the rotary buffer.Quote:
Originally Posted by BrianC
I don't want to keep you from following some other guy's recommendations if you think they'll work for you but again, I would not sand down an entire boat and then try to remove 100% of the sanding marks using a dual action polisher of any brand or any type.Quote:
Originally Posted by BrianC
Can it be done? You bet! Been there done that made videos on it and have plenty of articles on the topic too. I personally coached a Dad on how to fully wetsand, cut and buff a 1965 Mustang using ONLY a Porter Cable dual action polisher to remove his HAND sanding marks. A monumental task but with enough time, and he was retired, he did it.
Here's a short article where I show using the Rupes to remove sanding marks out of a 1928 Model A hotrod.
Removing #1500 Sanding Marks with Rupes Bigfoot 21 Polisher
Did the demo above but in the real world, when we actually did the complete wetsand, cut and buff on this hotrod we used wool pads on rotary buffers to remove our sanding marks.Quote:
Originally Posted by Mike Phillips
Pictures: 1928 Model A - Wetsand, Cut and Buff at Autogeek
So "yep", you can remove sanding marks using a dual action orbital polisher. Just like to be on record for that here on the old Internet.
Is it the fastest and most efficient way? "no". And you won't find me spending my time using that approach. In fact I've already documented how I approach sanding down cars and buffing them out in this 10 minute video. The first video ever to record the entire process from start to finish.
How to wet sand a car
Let your budget be your guide but here's my recommendation....Quote:
Originally Posted by BrianC
Finish out at the highest grit you can obtain. It's faster to sand and leave a shallow sanding mark to remove than it is to leave a deep sanding mark pattern and then compound, compound and compound to get your sanding marks out. Plus the more aggressive the compound the more work you'll have to do to clean up any haze by the compounding step.
Yes. Get a rotary buffer and an aggressive wool cutting pad. Get 100% wool, 4-ply twisted wool cutting pad. Autogeek carries a number of these by Lake Country, Meguiar's and Optimum.Quote:
Originally Posted by BrianC
If you don't have a steel spur to clean your wool pad, for $10.00 bucks get one. It works so much better than the caveman method of using a screwdriver.
With the Flex 3401 trying to remove sanding marks out of gel-coat or pigmented polyester resin, which is quite HARD for sure you're going to be leaning into it.Quote:
Originally Posted by BrianC
15 to 20 pounds for sure. It's really not that much even though it sounds like it. Just get a bathroom scale out, place the tool with the pad on it and you're already at around 7 pounds of downward pressure.
If you have not already, be sure to remove the backing plate off your Flex 3401 and lubricate the felt ring before you start doing all this hard work.
I cover this in my article here,
Lubricating the Felt Ring on the Flex 3401
http://www.autogeekonline.net/galler...3401Flex01.jpg
And I'm pretty sure I show it in this video that can be watched by clicking the link below....
How To Use The Flex 3401
Quote:
Originally Posted by BrianC
I would recommend trying what the other guy recommended. See if his approach works for you with your boat. If it does then go with it.
If you find it's taking a more time than you prefer, then I would recommend getting a rotary buffer and a wool pad and as high as grit sanding papers or sanding discs as you can obtain.
And just to note.... it's always easier and faster to remove machine sanding marks of the same grit level as it is to remove hand sanding marks. Machines tend to leave a very uniform depth of sanding marks while hand sanding tends to leave irregular depth sanding marks due to uneven pressure from your hand and the fact that you get tired while the machine never gets tired.
But... you can hand sand successfully and remove your sanding marks, it just comes down to the tools you can get for this type of project.
Looking forward to the before and after pictures...
:)
Mike, it seems you are thinking I’m planning on doing more sanding than I have thought necessary. Given the miscellaneous scratches and scrapes and the two areas with images of the old registration numbers/letters, I thought it might be necessary to wetsand only around five percent of the total surface area of the entire hull exterior. I’m not personally doing the bottom at all for safety reasons and don’t believe it worthwhile to remove scratches from it regardless of who works on the bottom.
The experiences I saw posted to the Mastercraft forum indicated quite a lot of gelcoat oxidation removal could be accomplished through compounding without wetsanding and that wetsanding would only be necessary for surface problems that didn’t compound out with a reasonable amount of compounding (not a lot, in my case, I’m hoping). I thought I found some confirmation of this when I saw your thread started on this forum in 2009 in which you removed oxidation from your personal boat without any mention of sanding.
1967 Starline Deville - Extreme Makeover
However, I’ve since come across a different thread in which you commented, in 2011 if memory serves, that you wetsanded the side of your boat (no make and model given). Was that your Starline Deville? What caused you to wetsand your boat? When is wetsanding gelcoat appropriate? I’ve read claims it can actually open things up and accelerate the oxidation process. Is that true?
Also, I noticed in your book you gave a ringing endorsement of Meznerna 4500 for paint. You said it could get the last bit of shine out of every paint system you’ve come across. Is there something you’ve found is especially good for getting the last bit of shine out of gelcoat? Could Menzera 4500 do this or might it not be aggressive enough given the hardness of gelcoat?
Also, the possible frequency with which de-oxidation may be necessary on my boat has me thinking, sanding scratch removal aside, that it may make sense to add a rotary to my arsenal for oxidation removal. Since posting this thread, I took a look at a photo of my boat transom taken in July of last year when I purchased the boat. The oxidation I’m dealing with now has clearly occurred since then, faster than I realized. There is a photo posted in 2011 of your personal boat showing oxidation on the bow.
Boat Gel-Coat Oxidation - Before and After
If this oxidation “before” photo is in 2011 and represents a recurrence of oxidation on the at least half-polished and shiny bow you posted in 2009, that is another indication that I may be de-oxidizing more often than I realized.
Quote:
Originally Posted by BrianC
Yes. I found that in order to remove enough dead and STAINED gel-coat in an efficient manner I had to machine sand the sides of the 1967 Starline Deville. Then I compounded the sanding marks out.
I've had good luck with Menzerna SF 4000 and SF4500 for a final polish on gel-coat.Quote:
Originally Posted by BrianC
Yes.Quote:
Originally Posted by BrianC
That boat was stored outside under a well fastened tarp but a portion of the bow was exposed and that portion oxidized.
Keep in mine that boat was build in 1966 or 1967 using polyester resin technology at that time. Things change. From what I've seen, gel-coat technology has also improved. Not to say oxidation isn't going to happen but as of today, that boat is now 47 years old and 47 year old gel-coat is not going to hold up as well as any newer boat, say built in the last decade or so.
Sad to say, I sold that boat and the guy I sold it to never takes care of it. I've been told it looks pretty much like it did when I first bought it and that's sad because I was able to get it looking pretty much show room new.
http://www.autogeekonline.net/galler...tInlet0081.jpg
http://www.autogeekonline.net/galler...thFlags031.jpg
http://www.autogeekonline.net/galler...thFlags021.jpg
http://www.marine31online.com/galler...eville_012.jpg
If you check out this thread, I put together a pretty good set of pictures showing before and after in one thread.
1967 Starline Deville - My second boat
I would definitely recommend getting a rotary buffer.
:)
Welcome to AGO Brian! I love my 3401 to death but I wouldn't waste my time trying to get 1000 grit out of gel-coat much less automotive paint with it. Instead personally I would finish out with a minimum of 3000 before trying to polish it out. At this point I would use my Flex.
Incredible advice as always Mike!