palm sanders

What is the difference between a 1/4 sheet sander and an random orbital sander? Which is more useful? Thanks much!

 

orbital sander

 

A 1/4 sheet sander uses 1/4 of a sheet of standard
sandpaper and most of the time it is just a vibrator
type, no direct connection to the pad and motor!

A random orbit uses round paper, hook and loop or
self stick, and is geared to the motor but can also
spin on an axis.

The 1/4 sheet sanders are fine for small things and
home crafts, but not well suited for boat building as
they have little power to cut!

The RO sanders are much faster, less vibration in the
hands and are still user friendly and for the most part
forgiving of novice users!

They also cost more, but you get what you pay for!

 

I stopped using plain orbital sanders years ago. They just work too slowly.
They have one good feature however--- they are usually square so they are better at reaching into corners.
I do corners by hand anyway, so I just keep a few 5" and 6" RO sanders around.

Alan

 

Alan
Your need for fairing must be less than mine.

I use a belt sander and can do a pedal boat hull in less than an hour. You just have to take care not to provides facets on the curved surfaces. Requires very little effort if you can let the sander's weight rest on the surface. More often the weight of the sander has to be supported a little than actually applying any extra force.

Rick W

 

I think that the 1/4 sanders are normally "finishing sanders" and the ones I have met are orbital as opposed to random orbital... the later moves material more effectively and is supposed to be less prone to scoring. I think that your are probably looking at two different applications, one is better for fairing and the other for detail and finishing... but like all these things they overlap in applications... anyway on the face of it it seems to me to be an apples and oranges comparison. I have both

Cheers
MBz

 

Oh, I use a belt sander... and disc sanders as well. I said I no longer use old style orbital sanders, even though I own a very expensive older Porter Cable half sheet model. I never pick it up any more.
It's still a matter of experience, and getting the job done fast and fair requires a practiced hand.
I'll use whatever works, often rather scary looking machinary to do what might appear to be delicate jobs.
I've faired boats with 50 grit on a 6" RO when long boarding wasn't necessary.
I've heard it leaves swirl marks and I guess some folks might leave swirls. I've never seen any so maybe I know how to sweep the tool correctly.
The right hand runs across the surface and provides instant feedback every few seconds. When fairing, the eye can lie, but not the hand.
Use what works. Belt sander or long board or RO sander, or even a plane at times, as well as any combination of the above.

 

I've found that as you gain experience, you need less by way of tools and gadgets.

I too have had weird looks as I pull out a big belt sander to have at someone's hull. In a practiced hand, it can be a precise instrument.

Also working "to the job" to save effort or retain the quality of previous efforts. In other words using 400 grit on a work boat is wasting time and materials, but having 220 as the final sand on a brightly finished show boat deck, just can't do.

I also "cut to the line" rather then cut just outside of it and plane it down. I'm very experienced with a band or jig saw, so coming up to a line and following it isn't a big deal, though it has scary consequences if you scratch your butt in the middle of the cut.

To answer the original question, A random orbit sander is as the name suggests. The path taken by any point on the sander's face, will be in a random, usually circular pattern. This helps prevent swirl marks in the surface being sanded and removes material more efficiently without clogging the paper. Most 1/4 sheet palm sanders are sort of random orbit, but not truly so. They can leave little swirl makes on the surface. Some of the better version have a switch that permits the sander "action" to be changed to "in line" or orbital. I have a few that do this and they remain in the "in line" mode. Used with the grain of the wood, they can be effective at smoothing a surface and the marks flow with the grain.

There are also twists to the story, such as "duel action" (DA's) which are much better at not leaving a swirl pattern in the surface, but still can if used improperly. These style of sanders spin and shake (hence the duel action thingie).

Given a choice between all the small sanders, I'd use a DA before a regular 1/4 sheet hand shaker.

In the end, finish work, which is what these tools are designed for, is about being careful of what you're doing. It's very easy to remove much more material then necessary and unfortunately, much more difficult putting it back. Work carefully, slowly even, checking your work often, from many angles. Insure the area you're working on is what you want, before moving to the next area. Most importantly, don't practice mistakes. Use good techniques and the best tools you can afford. Constantly check you work with straight edges, battens, shadows (one of my favorite tools), what ever it takes to insure you're doing what you want and not just digging a hole with a power tool, which they'll happily do quickly, if you let them (they have a will of their own, trust me).

 

Once you have a decent Random orbital sander your old orbital square pad one will end up in the skip. I have an electric one made by Sealey (ER150) it has been superb and also an air powered version that is lighter if working overhead. I have just bought a minature 2" pad air powered random orbital sander and it is very useful for detail work.
For fairing i use an Air file which is a reciprocating longbed sander used extensively in the car trade, i have dessouter and chicago pneumatic versions, you need a powerful compressor at least 14 cfm as they eat air.
but they take the hard work out of fairing. Oh and a good respirator!

 

"(they have a will of their own, trust me)."

LOL,
Have truer words ever been written?!

 

How do you all keep the belt on a belt sander from loading up with resin? Everytime I tried using a belt sander on strip planking it lasts about 2 minutes.

My favorite sander is a Coleman disc sander (pneuamatic) with a 7" blue zircone 50 grit disc. I wear out long before the disc does. smile

 

The resin needs to be fully cured. If there is any oiliness it gums up very fast. It depends on the temperature. I find a couple of days in good sunlight helps.

Rick

 

how right you are

 

I've heard a scraper works well on resin.

 

Use a rubber eraser (not the kind on a pencil) and clean it. You can get them at a well stocked hardware store or wood crafter's supply. It's a big rubber block, which I usually contact cement to a paint stick, that you press against the belt as it's moving. It cleans it and you'll save your belts and time, if you use it regularly. I go through two or three of these a year and they cut my belt use in half. It works on all sanders that use paper and also will clean saw blades to a degree.

If you find you're getting the paper loaded up very quickly, the coating isn't completely cured or you need to remove amine or other contaminates. Scrub the surface with something relatively benign like denatured alcohol.