belt sanding mast

[gaffman]

WB has run at least one article about belt sanding a mast (or in my case a boom) with an inverted sanding belt rigged on a sanding drum attached to a hand drill. Macintosh also has it noted in his book.

I made one up, but the belt kept slipping the drum. It did not even begin to hold.

Can anyone suggest the trick to make the drum actually turn the sandpaper belt and effectively sand? Thanking you in advance.

[Tom Mac]

It is all in the wrist, It is how you tilt the drum. Start with light pressure, when you get it working, increase the pressure but keep it balanced. I made 3 masts with the Macintosh setup. Tom Mac

[jimmy lee]

I made my drum with sides so the belt would not slip off and the drum was a radiator hose slip over the wooden spool. I hope this will help you.Also my sanding belt is a long belt.

[soba]

Don't forget to put a BIG stationary handle on the non-drill side of the drum. Essential for control. Works a treat, though. I did my boom that way.

[gaffman]

Tom, I tilted the drum variously without result. The drum spins and the belt stays.

[SamSam]

Spray the drum with 3M adhesive or brush on some rubber cement or contact cement or maple syrup. Make the drum not slippery somehow.

[StevenBauer]

I used those wide rubber bands that come on your brocolli on the drum. I used a 36" belt, I don't think you could go smaller, 48" might be good. It's good to have a helper to hold the mast and let it spin a little so you don't get out of round.


Steven

[willmarsh3]

I did this successfully using a sanding drum on the drill to drive the sanding belt. No slippage. As others have said it take a bit of practice. Use a variable speed drill and start slowly until you get the hang of it.

[peterAustralia]

hi

how big is your mast? If it is modest in size then you may wish to consider an alternate method. Use the inside out belt manually.

I have done this now for four oars, one ten foot mast and a couple of small spars. It has worked pretty well. Time taken to sand the mast, only 40 minutes or so. For the oars, only 20 minutes each.

After using the belt I then go lengthwise with a finer hand held piece of sandpaper. Maybe my work is a fraction more workmanlike than some higher quality boats, but the results were pretty good for me. One issue is that the sandpaper can cut into your fingers and give you scratches. By the way, spending $8 on a sanding belt is a much much better way than trying to glue a length of sandpaper into a belt!

n peter evans

[Wooden Boat Fittings]

.
I glued some 1/4" foam rubber to the drum using contact cement, and this lets the belt grip properly.

As has been said, use end-shields to help stop the belt working its way off the drum as you work, and a handle at the far end, away from the drill, to support the setup properly.

Here, the end-shields were made from thin galvanised iron cut to give a shallow cone shape (which direction the cut ends are lapped matters,) and the handle is a lazy one so that it can be held firmly while the shaft extension rotates inside it. (Use soap as a lubricant.)

Mike

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

[bloggs68]

If the mast is smaller, I find it easier to spin the mast. Below is a pic of what I use for smaller spars. Only need a cheap mini lathe, extension bed and a couple of shop made steady rests (using skateboard wheels). Biggest spar to date on this setup is just over 20'.
http://i63.photobucket.com/albums/h131/bloggs1968/Bulkheadsandcases247.jpg

Very quick to get the spars near perfectly round. I normally sand up to 320grit then sand longitudinally with 240 grit to remove any cross grain scratches.

Other advantage is you can round the ends, cut tennons etc on the lathe.

FWIW

AD

[S B]

If the mast is smaller, I find it easier to spin the mast. Below is a pic of what I use for smaller spars. Only need a cheap mini lathe, extension bed and a couple of shop made steady rests (using skateboard wheels). Biggest spar to date on this setup is just over 20'.
http://i63.photobucket.com/albums/h131/bloggs1968/Bulkheadsandcases247.jpg

Very quick to get the spars near perfectly round. I normally sand up to 320grit then sand longitudinally with 240 grit to remove any cross grain scratches.

Other advantage is you can round the ends, cut tennons etc on the lathe.

FWIW

AD
Nice setup. I like the steadys.

[Nanoose]

I tried this method when I made our mast last year as some people swear by it. I found the same problem you did with the belt not spinning. Someone suggested using an inner tube wrapped around the cylinder to provide grip and this worked. I went to a bike shop and they were more than happy to donate a popped tire to the cause. Note: Use a mountain bike tire. After I got the belt to spin I found that it would frequently fold over. When it folded it would quickly "groove" the wood. I tried a couple of different methods to keep it from doing so but, in the end, gave up.

I used a power plane to 16 side the mast and sanded with an RO from there. I used a light grit and stopped frequently to check by hand for round. It was pretty easy and came out well. The mast was fir, 32 feet long and just under 6 inches in diameter at it's widest.

YMMV,

Dave

[Paul Girouard]

Off the subject but Dave hows the checking been on the mast , and have you got any thing done with the tender?

TIA

Sorry for the drift. Maybe Dave can bump / update his other threads ??

[Michael Beckman]

I just made a gunter, planed to 8 sides with marks, then continued to aprox 32 sides by eye, then used a 40 grit belt cut so that I could hold both ends and sand by hand. Worked well.

[Bill R]

Ditto a lot of the above. On mine I used some rubber radiator hose over the spindle, a flange on each side of the belt to keep it from jumping and a free spinning handle on the end.

The key is a surface on the drum that will minimize slippage without tearing up the abrasive on the belt. The radiator hose worked nicely.

Also, I used a 48" belt.

[gaffman]

Thank you all for your thoughts. The boom is 34' and 6.5" and I'm not a doing it by hand. I did the mast by hand about five years ago and I'm done with that. I'll try the foam over the drum and/or heater hose and if I get to the market, I'll throw some broccoli elastics on too. Again, thanks.

[jlaprad]

I was struggling with the "drum" and inverted belt sander process when I thought of a possible easy solution instead of using rubber bands or inner tube to wrap the drum in. What if the drum was solid rubber? Well, I got a rubber mallet from hardware store and cut the handle off, drilled pilot hole and drilled a long lag screw in it, cut of the end and attached it to the drill. It worked perfect, no slipping once you get it going and I actually made this 19' mast in less than 2 hours from a 4 sided stock. I don't know how it will work on thicker spars, but I wouldn't be afraid to try it...http://i259.photobucket.com/albums/hh319/lapradjw/whoopdedoo/sander.jpg
http://i259.photobucket.com/albums/hh319/lapradjw/whoopdedoo/mast2.jpg

[Paul Girouard]

I was struggling with the "drum" and inverted belt sander process when I thought of a possible easy solution instead of using rubber bands or inner tube to wrap the drum in. What if the drum was solid rubber? Well, I got a rubber mallet from hardware store and cut the handle off, drilled pilot hole and drilled a long lag screw in it, cut of the end and attached it to the drill. It worked perfect, no slipping once you get it going and I actually made this 19' mast in less than 2 hours from a 4 sided stock. I don't know how it will work on thicker spars, but I wouldn't be afraid to try it...http://i259.photobucket.com/albums/hh319/lapradjw/whoopdedoo/sander.jpg
http://i259.photobucket.com/albums/hh319/lapradjw/whoopdedoo/mast2.jpg


They can't keep you inside the box can they, :cool: great idea!

Was it a tad dusty :D

[Bob Smalser]

Another alternative is not to sand your spars at all.

http://pic20.picturetrail.com/VOL12/1104763/4959362/116087813.jpg

http://www.woodenboat.com/forum/showthread.php?t=9360

[David W Pratt]

A sliced in half section of PVC pipe with sandpaper glued inside works. You could prolly figure some way to power it.
Good luck.

[jlaprad]

The "inverted belt sander drill" is VERY dusty. My wife wouldn't let me in the house till I shook off. Of course I took the 4 sided down to 16 sided before sanding it...

[gaffman]

Dave, I did the mast with a piece of pvc and course grit glued to the inside of it. As for figuring a way to power it, my wife said no, and the boy is only 7. I'm back to the power drill. Good idea though.

[Helle]

Mark Corke sanded the mast (about 23 feet long) for his Golant Gaffer in a special way: The mast was turned by using a bicycle's aft wheel attached to the mast, driven by his son. There is an article in an older watercraft issue. Brilliant!
Helle

[Jay Greer]

Sanding a mast across the length or with a drum can result in an uneven surface. Think of it as a snake swallowing oranges. The most effective approach and one that we have used for over thirty years, is a long sole body and fender sanding tool called an Air File. While a professional model can cost a hundred dollars or more, air files are available from Harbor Freight for about thirty bucks. Air driven and with grits starting at 60 progressing up to 120, a forty foot mast can be fair sanded in three to four hours from rough planed surface to varnish ready finish. This method produces a fair surface because the operator is working fore and aft rather than across the long axis of the spar.
Jay

[Don Kurylko]

Jay is right about the orange filled snake, of course. But, if you’re careful, they can be little oranges in a big snake. Steven, of pilot cutter Carlotta fame, recommended using a section of old mountain bike tire screwed to the spindle to get the bite required to make the contraption work. And work it does, in spades! A wide 4” belt helps too. I did a 7” dia 37’ mast with it and I’m more than happy with the results, same as with the other spars that make up my gaff rig. Not perfect, but perfectly acceptable - at least to my eye.

[George Schuld]

For best results, it's tough to beat a properly set up custom multi speed spar lathe with long(48") curved shaped sanding forms. We've done spars up to 50ft. long with ease. Probably 75 spars or so in all so far. It would be a bit overkill for just a spar or two though.

[bloggs68]

For best results, it's tough to beat a properly set up custom multi speed spar lathe with long(48") curved shaped sanding forms. We've done spars up to 50ft. long with ease. Probably 75 spars or so in all so far. It would be a bit overkill for just a spar or two though.

Love to see some pics of that George. Can you post some? Like you mention, you need long sanding forms to avoid the lumps. Nice analogy Jay - I made one of those when I was trying my setup!

regards,

AD

[Jay Greer]

The only problem with a lathe turned mast is that the spar ends up with a taper on all sides. Then one either must add a tapered riser for the track, tune enough aft bend in the stick to create a straight after end or have the sailmaker make expensive allowances for the reverse curved in the luff. Building a proper spar will insure a basis for a well setting sail.
Jay

[hikingchrs]

I put alot of layers of electrical tape on mine.