Sanding a round mast with a belt sander belt

[Bobcat]

I have read about using an inside out belt sander belt on a spar and powering it with a drum chucked in a drill.

Tried yesterday got nowhere. The drum would not move the belt

Anyone done this? What's the trick

(Of course my mast is mostly sanded now --- by hand)

[norseman]

Glue on a piece of rubber,inner tube for example.

[Captain Intrepid]

When I've seen it done, the drum was 3 or 4 small wheels with rubber tread. Also, you need a moderately skookum drill.

[Jay Greer]

May favorite tool for sanding spars and other large items like topsides is an air file. This tool is available from Harbor Freight for around thirty bucks. It is nothing more than a long flat air powered sanding board. Really takes the curse out of an otherwise mundane time consuming job.
Jay

[Brian Palmer]

The drum needs to be covered in rubber that is glued to the drum so that the belt has more grip on the drum than on the mast.

Otherwise, you just snd the drum instead of the mast.

You don't need a particularly large drill. I did a 2 1/2 inch mast with a 3/8 inch drill and a 1 1/2 inch diameter drum.

Brian

[willmarsh3]

I have used the little sanding drums that attach to a drill - with the sand paper on them. Sand paper against sand paper has more friction than anything else I can think of so the mast will get sanded.

[Bobcat]

Thanks for the tips

[George Ray]

Go with the air file.
Unless you have a lot of practice with the tool and a rolling jig to rotate the spar as you sand with the inside out belt you will still dig and gouge the soft wood of the spar. Air file is the tool of choice of body and fender folks world wide and standard size abrasive sheets are available everywhere. Last thing you want to do is gouge the surface of the mast. Those gouges have to be taken out with a 'long block' and mechanized version is ........ => air file.

[Nanoose]

Hey Bobcat.

I built a mast for Nanoose a couple of years ago. (I was going to post the link to the post but I checked and the pics have vanished again. Ack!!)

I tried the drill and belt trick using a number of different options. I did get the belt to spin ok. Someome suggested going to a bike shop and asking for a wrecked mountain bike tire to wrap around the spindle. That did the trick and the shop gave me the tire for free.

I found that no matter how hard I tried I could never get the belt to stop from folding which put grooves in the mast lickety split. After trying to make it work for quite awhile I gave up and simply used a power plane ( to 32 side) then an RO sander.

Good luck!

Dave

[StevenBauer]

Those big rubber bands that come on heads of broccoli will work fine, too. The belts I used were way too stiff to fold over. I think they were 48" belts. Maybe just 36"



Steven

[hikingchrs]

I use a rubber sanding drum inside a peice of PVC pipe, then I use electrical tape on the outside of the pipe, I build up the center of the pipe with extra tape, I find it makes it easier to "steer". I also buy the widest, longest belts I can find. I tried 40 grit but I could never get enough traction.
Chris

[Wooden Boat Fittings]

.
I've been using this one for years with success. It has a 4" dia wooden drum with foam glued on for friction, and also flat metal cones on each side to keep the belt where it belongs. It chucks into a 1/2" electronic drill running at slowest speed, and the lazy handle at the other end lets you take the weight with both hands and also control the tilt of the belt.

I'm quite happy with it and don't expect to be using anything else in the foreseeable future.

Mike

http://www.woodenboatfittings.com.au/public/spar-sander.jpg
.

[Bruce Hooke]

Go with the air file.

But make sure you've got a compressor that is up to the task before bothering to get an air file.

[S B]

I haven't tried any of this, but wouldn't it be better to rotate the mast, rather than the sandpaper, considering you want the mast round?

[Steve Lansdowne]

You can rotate the mast and leave the sanding belt in one spot, but that adds another layer of things to rig up. If you layer the drum on the drill that the sanding belt is driven by with lengths of tire tubing wrapped around it and secured with duck tape, and if you make the center portion of this rubber section to be of a larger diameter than the ends, the sanding belt will stay on the center of the drum as the belt is turned. My technique is to suspend the spar between two tables of equal height so that I can move the rotating belt around 50% or more of the suspended part of the spar, then I rotate the spar 180 degrees and continue. Nothing to it, but it does make lots of dust!

[Peerie Maa]

The other way is to find an old wooden block plane and make one of thesehttp://i408.photobucket.com/albums/pp164/peerie_maa/SparPlane.jpg
doesn't leave any scratches across the grain either.

[davebrown]

i saw at the local harbor freight a set of rubber drum sanding attachments for a 1/2" drill--looked easier than building yourself. $19.95 and had three or four different sized rubber drums. the largest looked about 10" or so in diamater.

[leaotis]

I found it handy, use light pressure and keep it moving.

http://mackhorton.com/Sharpie%20web/images%202/drill%20rounding%20closeup.jpg

[Wooden Boat Fittings]

My technique is to suspend the spar between two tables of equal height so that I can move the rotating belt around 50% or more of the suspended part of the spar, then I rotate the spar 180 degrees and continue.!

As is mine.

Mike

[StevenBauer]

I mount the spar so it will spin. Mary wears leather gloves and lets the spar slowly rotate while I work the belt with the drill. That way it stays nice and round. My slow half inch Milwaukee is just right. I think 700 rpms. First 80 grit then 120.

Mike, those metal discs look dangerous. :eek: Be careful, man! You don't want to slice a wrist. :eek::eek:
The disc on mine is 1/4" plywood. With the edges rounded over. ;)


Steven

[Boatsmith]

Here is a fellow who spun his mast. http://www.youtube.com/watch?v=RXwiursRLAA Not how we do ours. We saw and plane and sand. rollers for the mast are handy as is the air file. David

[Wooden Boat Fittings]

Mike, those metal discs look dangerous. :eek: Be careful, man! You don't want to slice a wrist. Steven

Thanks for your concern, Steven. But they're fine, I assure you (as long as the joints are lapped the right way....) What they do is to allow me to tilt the belt sideways a bit if I need to, without it running off the drum. Handy sometimes.

Mike

[Wooden Boat Fittings]

Here is a fellow who spun his mast. Not how we do ours.

... and you can see why that bloke calls it the widow-maker....

A mate down in Western Port where I used to be has a 40' lathe set-up -- he can turn telegraph poles with it. But it's a good deal more sensible than that widow-maker, with some intermediate supports. (It takes him a half-day to set it all up properly.)

Biggest lathe I ever expect to see.

Mike

[redbopeep]

May favorite tool for sanding spars and other large items like topsides is an air file. This tool is available from Harbor Freight for around thirty bucks. It is nothing more than a long flat air powered sanding board. Really takes the curse out of an otherwise mundane time consuming job.
Jay

Jay, I wish I'd known about this nifty tool when we were stripping and sanding the masts for repainting! We're doing a couple scarf repairs on the masts and picked one of these up at Harbor Freight. David just used it to do the sanding on the scarfed repairs. Oh, so nice :)

[redbopeep]

or chuck the mast in between lathe centers with low speed motor, and run sandpaper up and down the entire length..

Where did I get that idea???
You know its pretty funny to read some of these posts when we're all talking about masts with hugely different sizes. :rolleyes: You're obviously looking at something much smaller than my 70 ft long 9-1/2" diameter mast, right?

[StevenBauer]

I think Mystic Seaport's spar lathe could handle yours, Peep. Can I come and watch? :D



Steven

[redbopeep]

That'll be entertainin' :D

Oh, my...that really must be some spar lathe!


All this reminds me of a fellow who worked on some huge columns for his 1800-era Georgian style house in central Virginia. They were huge in diameter at the bottom (as I recall at least 24") and classical in style--so...the length was pretty long. He put his van on cement blocks, took off the back wheel, made a specialty chuck to turn the wheel into a lathe base, made himself some rollers and (I'm serious here) used the van to power his home-made column lathe while he worked his glued up columns into the right shape. It worked and he's still alive to talk about it.

Well, actually, he told me about it around 1995...its possible that he's done some other Darwin-award type thing since then and is no longer with us. :rolleyes:

[Bobcat]

Use one of these:

http://farm4.static.flickr.com/3076/2855931399_eac17fd364.jpg?v=0

http://farm4.static.flickr.com/3166/2856761926_382355f0c5.jpg?v=0


Cool tool, but probably costs more than my boat did

(Okay, the boat was free...)

[floatingkiwi]

Ya see, anything's possible :)

Thats right mate. He got the idea from Arnold Schwarzenegger on that movie "Predator", you know, before they faced old"what the hell are yoooouuuuuu", alien they snuck up on that unit camping in the sticks and Old Arnie picks the rear end........Well, anyway

[Bobcat]

Yea, I think dad spent a whopping $15 on the bearings. Everything else was from scrap and the junk heap. The drum was a chuck of Eucalyptus firewood.

Sanding is pretty darn easy with this.


I am impressed. I thought it was a store bought tool. Your dad did a great job on it.

[Canoeyawl]

That is a great little rig Brian. Your dad was a clever fellow.

For sanding spars and similar I have a small collection of heavy cardboard shipping tubes .
I select a suitable diameter, cut off a length and using spray adhesive glue sanding strips for the air file on the inside surface.

I have some trepidation for the air file. As sold the working surface is rubber padded and on raw spruce and fir it can dig into the softer summer growth leaving an uneven surface. A great tool, I can't live without it, but much caution should be used. I have a small air flow control valve mounted on the file to slow it way down.