Mast tube

[Maria CS20 104]

Had one heck of a problem with getting the mast tube materials to wrap and stay. I got instructions from Carla when we talked today. She told me of the trick to used strips of plastic the length of the pipe on top of the wrapped pipe. Using 6 mil I wrapped the pipe four times and then put strips of 6 mil length wise along the pipe, used 6 strips about 3 inches wide and used blue house project tape to secure the ends well away from the work area. Still had some sag issues but tightened up as best I could doing this alone, not a good idea, get extra hands if possible. I then cut a sheet of fiberglass 26 inch wide by 52 inch long sheet and set up a wet down table and got the sheet completely saturated, all parts completely clear and then the fun began. YUCK! Got it wrapped once, a mess, undid it and re-wrapped, bigger mess, unwrapped, went back the wet down table and let the mess start to get warm, straightened out the plastic strips and then laid on the fiberglass sheet. Much better third time around. I then took 3 inch tape and wrapped diagonally to snug up the sheet. that is when the epoxy began to move through the materials and tape and I could see obvious sag, CRAP. On a stroke of inspiration, I remembered trussing the turkey and a 5 lb. stuffed pork roast, (stuffing was garlic, 2 lbs. blanched spinach, three different cheeses, swiss, munster, and riccotta, sliced onions, a lot of them and some salt and pepper, this is for the back room cooks, Lay out this stuff across a filleted pork roast that is about an inch thick, pound a bit for tenderizing, roll up and wrap with lots of oiled cotton string. Cook for about an hour and a half to inside temp of 180). Back to the string, a had a nice big spool and wrapped the heck out of the fiberglass and it became saturated while wrapping, like the pork, I took the drippings on the plastic below and rubbed into the "tube to push out as many bubbles as possible. (do not use plastic to catch pork drippings, I'd better say or one of you folks will nail me on this point), It looks akin to a long pork sausage and is generally pretty tight in place. I will go out in about and hour or so and when it begins to really set up a bit, I will massage outer bubble and flaws to the surface. I honestly think this is gonna work, it seems to be holding together for the moment. Could be that in the morning I'll go out o to the car port and have a pile of modern art sitting on the floor under a piece of bare pipe. I'll post it on ebay for San Francisco art crowed worst comes to worst.

Still Hanging in there

Jim

[John Turpin]

Awesome description. I remember having a few challenges with that step myself, but in the end, it turned out fine. Please post photos of your creation.

[PeterP]

I have tried the longitudinal strip technique recently when making a 7ft tube for the C/B pennant for the P28. Not sure if I like it that well. For shorter tubes I still like the old way of doing it the best- namely winding 3in or 4in tape over plastic on a mast blank. Not too tight. Lap about 1/4 in. Go a bit long, stick on the ends with masking tape or whatever. Wet out with epoxy. Wind on another layer from opposite end. Wet out. Do another layer if need be and that depends on your tape weight and the strength required. End for ending the layers evens out the selvedge on the tape and gives it a nice bias/ crisscross pattern. Since the mast is the form you know it will be a perfect fit -the only question is how much plastic to wrap around it to get a decent annular clearance. Two wraps of light weight plastic or one of heavy duty greenhouse plastic work for me.PeterP

[Maria CS20 104]

I have tried the longitudinal strip technique recently when making a 7ft tube for the C/B pennant for the P28. Not sure if I like it that well. For shorter tubes I still like the old way of doing it the best- namely winding 3in or 4in tape over plastic on a mast blank. Not too tight. Lap about 1/4 in. Go a bit long, stick on the ends with masking tape or whatever. Wet out with epoxy. Wind on another layer from opposite end. Wet out. Do another layer if need be and that depends on your tape weight and the strength required. End for ending the layers evens out the selvedge on the tape and gives it a nice bias/ crisscross pattern. Since the mast is the form you know it will be a perfect fit -the only question is how much plastic to wrap around it to get a decent annular clearance. Two wraps of light weight plastic or one of heavy duty greenhouse plastic work for me.PeterP

[Maria CS20 104]

Thanks Pete, always like feedback. I did forget that the pork roast should be rolled in heavy ground pepper and sprinkled lightly with crushed rock salt.

Jim

[PAR]

I've found an air chuck with a piece of copper pipe attached, worked best for removing these types of things from the mandrel. I mashed the end of a piece of 1/8" copper pipe, then drilled a 1/16" hole. This was tapped and threaded to the end of an air chuck and the pipe wedged under the 'glass laminate at one end. A blast or air, move it around, another blast and it works free very easily and suspends the laminate on a cushion of air while you slide it off the mandrel. As far as wrapping, I've not experienced the difficulties others have described.

[Maria CS20 104]

While the fiber glass and epoxy were a bit loose we sprayed Remlube down into the primary plastic wrap and into the secondary plastic strips. We let is "drain into the gap and after about 20 minutes we, the 280 beast friend of ours and I at 210 lbs grabbed mid and bottom sections and pressed down and got movement, after a bit it slid and we stopped. We will leave it on for the night to cure out and slip it off when hardened. I plan to mix a bot of epoxy with wood fiber in the morning and lay it on the outside for effect making it look like a wood spar and giving a bit of extra strength, a bit of boost, then sand down to the right diameter to the tube hole fro installation, mud it up a bit to blend into the wood matrix for the look and feel of real wood. Got consensus and I think it will be just another thing that looks good and highlights a home made boat.

Jim

[Tom Lathrop]

Everyone had a lot of trouble removing the tubes so I came up with the idea of the narrow strips of plastic to free the FG tube from the mandrel after it sets up. The strips should be about 1" wide, not a lot wider. Put a single layer of strips on first, taped individually well beyond the working area and then wrap with plastic sheeting. The strips have nothing to do with the rest of the procedure and only allow easy removal of the finished tube. Wrapping the tube with tape like Peter suggests is the easiest and cleanest way to do it but full sheets work too. If you use sheet FG, a final layer of spiral wrapped tape will make a neater job of it. I start FG sheets dry and add resin as I wrap. Any excess resin on the inner layers squeezes up through later ones and prevents all that sagging and running resin. When finished, pull the strips out one by one and the the tube will just slide off.

If you make the tube a bit too large, just add a thin collar of FG to the mast at top and bottom. Sand to fit and add wax to allow the mast to rotate freely.

[Tom Lathrop]

Here is a photo of the strips with plastic wrap over.

[hokeyhydro]

No problems, but then I spiral wrap plastic and use many, many layers. Deal is the mast tube is not structural, as in a serious support for the mast, but merely a water catcher. While driving hard with spray pluming over the bow and you going YAHOO! water will fall into the small gap around the mast where it exits the deck. Well, unless you have created a five star seal system. If the aforementioned water was allowed to accumulate in the forward compartment, bad things will begin to happen. But! You built a mast tube which doesn't need to be kissing close to the mast itself, but just a small compartment around the mast to collect water, which will then exit at the base of the tube and into the open cockpit area, or over the side, if you remembered to install a drain tube. Even if you forgot there will only be a small quantity of water betwixt mast and tube and bad things won't happen, at least not on that cruise. Maybe a few years down the line when all that sitting water grows all sorts of nasty stuff and begins eating the boat.

[Tom Lathrop]

No problems, but then I spiral wrap plastic and use many, many layers. Deal is the mast tube is not structural, as in a serious support for the mast, but merely a water catcher.

The lower part of the mainmast tube is structural and one of the four highest loaded points on the boat. It must be made strong enough to handle the levered load of the mainsail and must be anchored securely to the hull. The deck entry part of the tube is less stressed since it is supported by the kingplank and deck that support the load. The other two highly loaded points are the aft thwart hole and the mizzen step. All these need critical attention to their strength.

[Scott Dufour]

I've found an air chuck with a piece of copper pipe attached, worked best for removing these types of things from the mandrel. I mashed the end of a piece of 1/8" copper pipe, then drilled a 1/16" hole. This was tapped and threaded to the end of an air chuck and the pipe wedged under the 'glass laminate at one end. A blast or air, move it around, another blast and it works free very easily and suspends the laminate on a cushion of air while you slide it off the mandrel. As far as wrapping, I've not experienced the difficulties others have described.

So this is brilliant! I'm definitely trying it for the next ones. Thanks.