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Joe Lambert
08-15-2006, 01:53 PM
Ok, So who makes the best random orbit sander out there? We're debating between the Festool Rotex and the Fein. Anyone have a personal favorite?

Bob Perkins
08-15-2006, 02:26 PM
Rotex is by far superior to any standard Random Orbiter.. IMHO Never had to use variable speed control until Rotex scared me by removing epoxy too fast..

Bob Cleek
08-15-2006, 02:48 PM
Well, times change, I guess, but the industry standard for quarter sheet random orbital sanders was (is?) the Rockwell "Speed Bloc," now made by Porter Cable... but what do I know? Mine have run for decades now with no problem.

Joe Lambert
08-15-2006, 03:38 PM
Bob P,

How does the Rotex leave the wood when you're done? We have to strip a 35' sloop so speed of removal is important but obviously I'd rather not end up with a surface that waves hello when you walk by.

Any guidance there?

bischoffboatworks
08-15-2006, 03:42 PM
I love my Rotex 150. It does a fast job and then reset it for finishing. And the vacuum works great (I mean... dust extractor... ahem) To get around tight spots I also use the small Fein.

gary porter
08-15-2006, 04:01 PM
I have both and they are both very good sanders. I guess I'd recomend the Festool as it gives you the option of rotary vs random. It removes stock fast in rotary mode then an excellent finish in random mode. Its a bit quieter and a bit less vibration than the Fein. For stock removal on a good size hull you might look for the 8" version of the Fein rotary sander... I have the 8" random orbit but they make it in a straight rotary which would be very good for fairing a hull.
By the way if you already have a Fein with vac Festool makes an adapter. I'm using the Festool sander with the Fein vac. works great.
Gary

JimConlin
08-15-2006, 04:18 PM
I'l agree with all of the good things said about the Festool RO150.
It's being superseded by a new model. Bob P. wil know more about this.

That said, if I were stripping a 35' boat, i think i'd do the bulk of it with a torch or chemicals. You'd have a better chance of keeping a fair surface fair.

Joe Lambert
08-15-2006, 04:27 PM
Jim,

You actually bring up a debate we were having in the shop just last week.
The hull in question is epoxey'd above the waterline with cetol or something overtop, made a mess of the boat. Below the water it's glassed over. The question then is what's the best method to quickly remove the mess without damaging the wood underneath and making more work for later. I voted for random orbits but perhaps that's not right.

What's a better option? Heat? Rotary? Chemicals?

The boat in question is actually quite brilliant under all the garbage. It's a 5.5 meter which was raced we believe in the '56 Olympics in Melbourne. the hull is Mahogany on Oak and decks are Teak. Other than some unfortunate repairs below the waterline in the area of the keel it's in remarkable shape.

JimConlin
08-15-2006, 04:31 PM
You might be in luck. Most boatbuilding epoxies when heated to about 200F have the consistency of cheddar and are easily scraped off. When cooled again, what's left can be sanded.

kc8pql
08-15-2006, 04:57 PM
Well, times change, I guess, but the industry standard for quarter sheet random orbital sanders was (is?) the Rockwell "Speed Bloc," now made by Porter Cable... but what do I know? Mine have run for decades now with no problem.
The Speed Bloc is an orbital sander and does indeed use quarter sheets of sandpaper. A random orbit sander is a different animal altogether. They use disks, cut much faster and don't leave squiggly scratches like an orbital sander can.

Ken Hutchins
08-15-2006, 06:02 PM
Bob P,

How does the Rotex leave the wood when you're done? We have to strip a 35' sloop so speed of removal is important but obviously I'd rather not end up with a surface that waves hello when you walk by.

Any guidance there?

If you listen a ROS will 'talk' to you just like a lot of other tools but you have to pay attention to what it is telling you. When it is 'talking' it is telling you where the high spots are.
Hold the ROS flat, don't tip it up only cutting on the edge unless you are doing a concave surface Most of a boat is convex so keep it flat. As you are moving it around, any high spots will cause the ROS to jump around taking control of the direction of movement it will go where it wants to go, not where you want it go.
Concentrate on removing material from the high spot until the ROS behaves and you will have a fair surface. Once the pad gets worn so it's not flat replace it. Use the not flat pad for cancave surfaces.
Another item is use stiff paper backed discs for fairing and the softer flexible discs for finishing.

Bob Perkins
08-15-2006, 07:07 PM
Joe - Listen to Ken - Now his boat is a Fair boat..

Rotex mode is for quick material removal. The standard mode is like essentially a ROS - but the best one you have ever used..

FYI: The new Rotex 150-E is just coming on the market. It has a couple of new features over the classic version.

1) It has a removable "bump" guard that prevents you from side cutting into nearby items and protects the disk an pad.

2) The interface pad can now be removed w/o an allen wrench
3) Power cord is removable (an outstanding feature, almost all Festool has this now.. it is much more useful than it seems...)
I keep the vac and cord together and just plug in tools - much simpler
4) The sanding head design eliminates the diaphram that seperated the dusty side from the motor side. (The corian and bottom paint guys need this so the motor windings to not foul) the new design is still seperated - but no part to wear out..

Now the down side - Festool is very pricey - but that is their only fault..

Cecil Borel
08-15-2006, 07:09 PM
I used Fein for a long time, but have gone over to dynabride exclusively now, much, much better.

Bob Cleek
08-15-2006, 07:23 PM
"The Speed Bloc is an orbital sander and does indeed use quarter sheets of sandpaper. A random orbit sander is a different animal altogether. They use disks, cut much faster and don't leave squiggly scratches like an orbital sander can."

DUH! I should have read the question a bit more carefully. I use an old Porter Cable random orbital, actually. For fairing and topsides preparation, though, I find that a six inch disk is really tedious. I use a Makita auto polisher with a foam pad which is IIRC ten inches in diameter. I use disk adhesive and just stick the pad down on a standard sheet of sandpaper and cut around the edge of the disk with a utility knife, saving the scrap for small sanding jobs. Quite efficient and inexpensive. The disks actually cost more than the sheets, or used to. The auto polisher motor runs at 2000 RPM, slower than the sander, which looks almost the same. At 2000, the paper doesn't heat up as much and lasts longer.

Now, since we have a bit more information, I really don't think that an abrasive is what's called for to remove paint and fibreglass, particularly bottom paint, which can be deadly when reduced to dust and inhaled.

I would definitely wood the boat with a torch (5 gal propane bottle, hose and hand torch), or if you are less adventurous/skilled, a heat gun and a good scraper. The paint will come off very easily and the glass less so, but it will come off nonetheless. After the worst has been stripped with heat gun or torch, THEN use your random orbital or disk sander to clean it up and fair it out. There really shouldn't be any real fairing to do, since all you want to do is smooth the surface to prepare for the base coats.

The way to go is to scrape first and then finish sand. Sanding will, if nothing else, create tons of nasty dust everywhere and be a total mess to clean up, not to mention the cost of sandpaper, which can get significant. Hell, you'll pay for the heat gun and scraper with what you save on sandpaper stripping a hull to bare wood.

Nicholas Scheuer
08-15-2006, 08:33 PM
I suppose one can pay more. For what?

Moby Nick

David W Pratt
08-16-2006, 03:18 PM
sanding discs cost lots less than Fein.
Good luck.

pcford
08-16-2006, 03:21 PM
The best sander is attached to your arm.

slipstream
08-16-2006, 03:33 PM
Porter cable - I have used mine so much I've had to replace the pad.

Joe Lambert
08-16-2006, 04:23 PM
Wow, talk about a hot subject!

The thing that's always made me feel queasy about using heat with bottom paint is the smoke you inevitably get off the paint. I just can't imagine that it's good to be around. The other concern I've always had is the ease with which you can gouge the wood, below the waterline it's less of an issue but above it's another story.

Regarding the Festool, the concern I've had and what's really held me back from buying one is the control you have over the cut. As was mentioned earlier, a standard random orbit is generally fairly straightforward to get a good flat finish with, as someone already mentioned, they kind of "talk" to you. We use mostly 5" dewalts for general sanding and the 6" dewalt or an air DA for larger stuff to help keep a flatter surface. The thing is that when the salesman was demonstrating the Festool he was cutting so fast and furious it reminded me more of a chainsaw than a sander and it looked any way like the machine had more control of where it was going than the operator. While the Fein dosn't have the neat Rotex "move wood now" mode, it does have a bigger pad which I'm assuming not only contributes to speedy stock removal but also should help keep things flat. Is the Festool really as easy to control as a standard RO?

Rotary units have always scared me a little bit for bright work, even on the first pass, just seems too easy to gouge.

Hand sanding.. Yes, definately the best treatment for the wood but definately not the best treatment for my arm, especially upside down!

I've had good luck with pneumatic straightline sanders but the noise is so abnoxious that even through muffs I get headaches, plus it means that basically nobody else can be working in the shop while you're going at it.

I've never heard of Dynabride before, what's so much better there?

Dan McCosh
08-16-2006, 04:37 PM
My Porter Cable RO is about 25 years old, has gone through a half-dozen pads, etc. , and has kept me from much comparison shopping as a result. I also have a Bosch 6 ins. right-angle RO, which seems the best value in that class. It has a geared or friction RO drive, hence removes considerable material.

fixmyboat
08-16-2006, 05:57 PM
Second vote for dynabrade Air DA :)

JimD
08-17-2006, 04:12 PM
The best sander is attached to your arm.

You must have one helluvan arm !:D My arm is made by DeWalt