How do you make a mast tube?

[JeffM]

CS20#65 progress check: Trying to grind rudder into a 0009 NACA foil, and getting ready to glue up strips for cb. Next: cb trunk. Looking ahead: I can't find anything in the plans about the fiberglass mainmast tube. Can any CS builder tell me how this is fabricated?

Thanks!

Jeff

[Ken_Potts]

If I remember correctly the mast tube directions were on one of the smaller (8.5"x11") pages...

[Kidd]

I too have yet to make my mast tubes. I was wondering if applying a lubricant to the mast before wrapping with the builders plastic would help remove it after curing. Would their be adverse effects from this?

[Tim]

You should not need lubricant because the plastic wrap makes it easy to get off. I found the bottom of my tube sagged a little as it cured making the cross section a little oblong or ellipitical. It still works fine.

[Joe Nelson CS#35]

I had a heck of a time getting my mast tube off the mast. I had to put a piece of wood on the ground, hold the tube and bang the mast on the wood...finally worked loose. I think the idea of a lubricant like WD40 might be a good idea...under the plastic. You might even want to put some wd40 on the first couple wraps of plastic. My spec sheet called for 10 oz. cloth not tape. No spiral needed if you get a piece as long as your tube needs to be.

[JeffM]

Thanks, all! I'll try to get a sheet from Graham. While I'm sort of on the subject of masts, have any of you tried to make your aluminum masts come apart for storage? I'd like to be able to put them up in the garage rafters, but at 22 feet they won't fit -- even corner to corner.

[Kidd]

Not having constructed my masts yet I am not speaking from experience, but I would think the masts could be made to come apart. This may lead to some wobbly joints down the road as the joints wear with repeated removal. On the disk I purchased with my plan set there was a picture of a CS17 which had extensions made from pvc pipe which could be inserted into the mast steps and hold the masts horizontal while stored. He would put a tarp over the masts and make a tent for boat storage. I think it was Gordy Hill's boat which is for sale now. I am sure you could probably find pictures of this boat on the forum from a long time ago. I thought this was a very clever way to store the masts and boat.

[Kidd]

I went and found the link to the pictures of "Sawdust". Here it is.

http://groups.msn.com/smallboats

It is a terriffic boat and worth a look even if you are not interested in the mast storage tent idea.

[Ken_Potts]

Jeff,

I believe the CS17 plans show masts that are in 3 sections. if I remember correctly the mast pieces come apart and can be nested inside one another for storage. The resulting package is short enough to be stored in the cockpit.

Some folks make them that way and some make one piece masts that can be set up on brackets for transport.

I'll be going with the 3 piece masts.

[JeffM]

Ray, I'm going with the sleeve luff, and reef and furl around the mast. I didn't see anything about nesting mast sections in the plans (and the only CS I've seen up close is the one you built for Bruce), but come to think of it, it isn't stated that the sections be epoxied together, either. I figure to cover my boat with the mast intact and sail wrapped during the season. The problem comes when I need to get the boat, etc. into the garage in the fall. I'm a bit worried about mast wobble; maybe a good compromise is to make the lower joint solid, since that bears more strain than the upper.

[Designer]

There is no problem with mast wobble because of the distance that the bearings are apart, even if there was wobble. The mast sections are intended to be separate so that they can be pulled apart for stowing. Having said that, after many trips and stowing the mast pieces so that they don't rattle around and ding the boat while trailing, I prefer them to be glued to make them one piece. With 2 mast crutches in place, it takes only a moment to secure them which leaves the boat interior clear and there is no risk of the masts damaging the boat.

[Kidd]

After all consideration, I think as I am going to be trailing and using either the lace luff or sleeve luff sails, I will go with the 3 piece as designed also. My concerns about wobble seem unfounded.

[JeffM]

I was quite pleased with my mast tube -- until I tried to get it off the mast. Aluminum tubing is tricky stuff to get a grip on without deforming it. When I couldn't budge it bare-handed, even with the whole family's help, I finally went out and bought a pair of these strap-type pipe wrenches. Even now, exerting my full weight on these wrenches, I can't budge it. I'm trying to avoid sawing it off like Ray did -- partly for fear of damaging the tubing. Ideas?

[Designer]

Did you wrap the mast tube with four layers of 6 mil plastic before you glassed your tube. I find that the layers of plastic slide on each other allowing you to slide the tube off of the mast.

[JeffM]

It was probably 4 mil. But I put on a little extra. I'm getting ready to clamp the tubing and tube with lumber that has 3" half-round cut-outs. If the tube really is too snug finished to fit the mast without binding, I might have to cut it anyway to open it a smidgen.

[Tom Lathrop]

Two things,

If you wrap the tube with glass tape, you could easily have used a fair amount of tension and this would cause the glass tube to be very tight on the base tube.

WD40 is not a very good lubricant for this kind of job. A heavier grease would be much better. Pre molding FG tabs that can be gripped with clamps on the end of the FG tube is a help also.

Another, and better, way to make FG tubes if you can find a PVC tube of the proper diameter is to use that. Slit the PVC lengthwise and wrap with plastic as usual. After the resin sets, drill a hole in both protruding ends and stick a metal rod through each . Now twist the ends of the PVC tubing which will cause a slight collapse in diameter and break the grip on the FG. One person should continue twisting and pulling while the other grips the FG tube. This has never failed to release any FG tube I have known.

[JeffM]

Yup, that was probably the problem: I was using 4 mil plastic. I never was able to get it off without sawing and chiseling it. Just as well, since it would have been too small. I rewrapped the mast -- this time with 6 mil plastic, put the tube back over it, and applied three staggered layers of tape longitudinally over the cut. The gap I had to close was fully 1/8" across -- the tube probably would have given trouble binding the mast in use.

Tom's ideas are worth having, though I would probably have done okay if I'd used the right plastic. I made the tube of 4 oz cloth rather than tape, but I was careful (maybe too) to wrap the plastic tightly.

[Dale Niemann]

I understand from Graham's response to use 6 mil plastic with 4 wraps but I have not seen anything that indicates how many wraps of fiberglass and what weight of glass. I was thinking either 3 or 6 oz. but would appreciate any help with how many wraps with each weight.

Thanks

[Designer]

Dale,

I like to use enough glass to have a finished thickness of around 3/32" which will take about 36" - 40" of 8-10 oz. glass. It does not make sense to use 3 oz glass as it costs a lot more to build up to the required thickness.

[Dale Niemann]

Thanks Graham, I really appreciate your quick response. I will probably be doing the mast tubes today.