From Jim Adams:
I made a plug from balsa and finished it to a smooth finish second I used two aluminum pans (the kind that you throw away) I filled the first one with plaster took the bulb (well waxed) and placed it in the plaster half way in I used two pins through the center to hold it down. let that dry then pull out the plug next put thin saran wrap over the mold and place the plug back in the hole.
Now comes the fun part I used rubber bands to hold the plug in place (remember I had two pins that extend past the mold walls) next fill the second pan with plaster and lay the first on top it is kind of messy but it works. When the second half dries (about two hours) pull them apart. You will need to plug the holes at the ends on the sides and create small air path upward in the and a spur (looks like a funnel when you
are dune this needs to be big enough to pour in the led) at the end.
7/05/2006
Star 45 R/C model sail boat , making a keel bulb mold and Castings
From Jim Adams:
I made a plug from balsa and finished it to a smooth finish second I used two aluminum pans (the kind that you throw away) I filled the first one with plaster took the bulb (well waxed) and placed it in the plaster half way in I used two pins through the center to hold it down. let that dry then pull out the plug next put thin saran wrap over the mold and place the plug back in the hole.
Now comes the fun part I used rubber bands to hold the plug in place (remember I had two pins that extend past the mold walls) next fill the second pan with plaster and lay the first on top it is kind of messy but it works. When the second half dries (about two hours) pull them apart. You will need to plug the holes at the ends on the sides and create small air path upward in the and a spur (looks like a funnel when you
are dune this needs to be big enough to pour in the led) at the end.
Billie Geisler's comments regarding "Keel Bulbs 2006 August 1:
I advise against using tire weights for ballast bulbs, because the tire weights seem to be some sort of alloy, and not pure lead. The markings on the weights are a good indicator, as different physically sized weights have the same ounce values stamped on them. So, if you use tire weights, you will have a physically larger bulb to achieve the necessary weight, thus more wetted surface friction, resistance through the water.
I go to the plumbing supply store to buy lead. This lead is much denser than tire weights. The lead comes in various shapes, some like hocky pucks, and some like Snickers bars. The Snickers bars fit into my lead pot better.
Incidentally, fishing supply stores sometimes carry electric lead pots, along with fishing weight molds. Good use for your tire weights. I was lucky enough to find a lead pot at a garage sale, sold by a rifleman who no longer cast his own bullets.
Consider mounting the ballast bulb on the keel fin at an angle, about 1 to 3 degrees up at the front. You can find info on performance of this arrangement on some IOM sites. It makes a substantial difference in boat speed on an IOM.
I cast my bulbs in two plaster of paris molds. One mold for the outer cheeks of the bulb(split fore and aft), and one for a center peice, to go between the cheeks. The thin (about 1/8 inch thick) center peice can be easily cut for fitting the fin, and drilled for adjusting the weight. If I need filler, I mix buckshot with epoxy. I can rough sand the lead with a belt sander, with very course belt. The course belt doesn't fill with lead.
I made a plug from balsa and finished it to a smooth finish second I used two aluminum pans (the kind that you throw away) I filled the first one with plaster took the bulb (well waxed) and placed it in the plaster half way in I used two pins through the center to hold it down. let that dry then pull out the plug next put thin saran wrap over the mold and place the plug back in the hole.
Now comes the fun part I used rubber bands to hold the plug in place (remember I had two pins that extend past the mold walls) next fill the second pan with plaster and lay the first on top it is kind of messy but it works. When the second half dries (about two hours) pull them apart. You will need to plug the holes at the ends on the sides and create small air path upward in the and a spur (looks like a funnel when you
are dune this needs to be big enough to pour in the led) at the end.
Billie Geisler's comments regarding "Keel Bulbs 2006 August 1:
I advise against using tire weights for ballast bulbs, because the tire weights seem to be some sort of alloy, and not pure lead. The markings on the weights are a good indicator, as different physically sized weights have the same ounce values stamped on them. So, if you use tire weights, you will have a physically larger bulb to achieve the necessary weight, thus more wetted surface friction, resistance through the water.
I go to the plumbing supply store to buy lead. This lead is much denser than tire weights. The lead comes in various shapes, some like hocky pucks, and some like Snickers bars. The Snickers bars fit into my lead pot better.
Incidentally, fishing supply stores sometimes carry electric lead pots, along with fishing weight molds. Good use for your tire weights. I was lucky enough to find a lead pot at a garage sale, sold by a rifleman who no longer cast his own bullets.
Consider mounting the ballast bulb on the keel fin at an angle, about 1 to 3 degrees up at the front. You can find info on performance of this arrangement on some IOM sites. It makes a substantial difference in boat speed on an IOM.
I cast my bulbs in two plaster of paris molds. One mold for the outer cheeks of the bulb(split fore and aft), and one for a center peice, to go between the cheeks. The thin (about 1/8 inch thick) center peice can be easily cut for fitting the fin, and drilled for adjusting the weight. If I need filler, I mix buckshot with epoxy. I can rough sand the lead with a belt sander, with very course belt. The course belt doesn't fill with lead.
7/04/2006
Thinning Epoxy
In a post to Yahoo Star 45 Groups Terry Forbes reveals his method for thinning epoxy so that it soaks, as a first coat, thoroughly into basswood planked decks he builds.
He adds 90% isopropyl alcohol ('rubbing" alcohol) to mixed epoxy, using an eyedropper, until the viscosity is what he wants.
Apparently, this does not adversely affect curing.
I find this fascinating and useful info.
He adds 90% isopropyl alcohol ('rubbing" alcohol) to mixed epoxy, using an eyedropper, until the viscosity is what he wants.
Apparently, this does not adversely affect curing.
I find this fascinating and useful info.
Star 45 R/C model sail boat | decks made from bass wood strips
From Terry Forbes:
"The Star 45 boats that I have built have decks made from bass wood strips that are 1/4" X 1/16". I find them easy to use and easy to bend with out fracturing. I use thick ca to bond to hull frames and to the adjoining strip. When is have it all glued down, I sand with 120 grit and then 200. I use a soft rag to wipe off deck but leave the cracks filled with the sanding dust or "wood Flower" I then give it a thinned coat of slow cure epoxy. This first coat will soak into the wood completely. I then use un-thinned epoxy for the second and third coat, wet sanding and tack ragging between coats. If you want a really glassy deck, I use a finish coat of Captians Spar varnish. I have used this finish technique on full scale boats and all of my Kayaks. Very nice and durable finish. The decks go on easy and I try to stagger the strips one dark one light. I built a full scale star in the early 60's and had a striped planked deck. I like the look and it builds light. It keeps the hull true as sometimes when you add the deck using plywood it can cause it to move around. I will post some photos of my next hull as it comes to life. I have constructed a ships-way. I used the formers that are shown on the IMYA star plans. I now only have to cut the actual hull formers. I Stack cut 4 at a time on my trusty Dremmel Moto Shop Saw. I have added some lighting holes here and there. All in all I can have a hull lofted in 1 hr. and the sides on that evening using 20-min epoxy to coat the frames and the inside of the hull side. I first made my side peaces out of poster board. This allowed me to get the fit close and have a template to trace the sides for cutting. "
"I get all of my wood from Lone Star Balsa in Texas.. It is run by Riley Wooten "
"The Star 45 boats that I have built have decks made from bass wood strips that are 1/4" X 1/16". I find them easy to use and easy to bend with out fracturing. I use thick ca to bond to hull frames and to the adjoining strip. When is have it all glued down, I sand with 120 grit and then 200. I use a soft rag to wipe off deck but leave the cracks filled with the sanding dust or "wood Flower" I then give it a thinned coat of slow cure epoxy. This first coat will soak into the wood completely. I then use un-thinned epoxy for the second and third coat, wet sanding and tack ragging between coats. If you want a really glassy deck, I use a finish coat of Captians Spar varnish. I have used this finish technique on full scale boats and all of my Kayaks. Very nice and durable finish. The decks go on easy and I try to stagger the strips one dark one light. I built a full scale star in the early 60's and had a striped planked deck. I like the look and it builds light. It keeps the hull true as sometimes when you add the deck using plywood it can cause it to move around. I will post some photos of my next hull as it comes to life. I have constructed a ships-way. I used the formers that are shown on the IMYA star plans. I now only have to cut the actual hull formers. I Stack cut 4 at a time on my trusty Dremmel Moto Shop Saw. I have added some lighting holes here and there. All in all I can have a hull lofted in 1 hr. and the sides on that evening using 20-min epoxy to coat the frames and the inside of the hull side. I first made my side peaces out of poster board. This allowed me to get the fit close and have a template to trace the sides for cutting. "
"I get all of my wood from Lone Star Balsa in Texas.. It is run by Riley Wooten "
7/02/2006
HiTec HS-725 or HS-785 Winches | SCU's
From: "Stephen Pratt" :
"On the North Coast (Ohio), are using HiTec HS-725 or HS-785 Winches. Bob Luther developed a mechanism to work an endless loop system of sail control. Fits inside the Star 45 with plenty room to spare."
how much weight/advantage can be gained by using a lighter hull?
From "Larry Ludwig"
"If you are dealing with a 16 ounce hull, how much weight/advantage can be gained by using a lighter hull?
If you will test the boats with different keels, with as much as a 3 oz difference between hulls... you will find that there is virtually no noticeable, or measureable difference... and at that weight (3oz) you are 4 times the typical amount of error that would occur from weighing the keel while attached to the boat. This method has been used at many many regattas for 30 years and works well enough."
"If you are dealing with a 16 ounce hull, how much weight/advantage can be gained by using a lighter hull?
If you will test the boats with different keels, with as much as a 3 oz difference between hulls... you will find that there is virtually no noticeable, or measureable difference... and at that weight (3oz) you are 4 times the typical amount of error that would occur from weighing the keel while attached to the boat. This method has been used at many many regattas for 30 years and works well enough."
Weighing a keel while attached to a boat
From "Larry Ludwig"
"Weighing a keel while attached to a boat can be done with a high degree of accuracy. You can test this out on a boat with a removeable keel. Lay the boat on it's side with the keelbulb on the scale with the keel parallel to the table. Then take the keel off and weight it and you will be amazed that they are nearly the same, as in within 95% or better."
"Weighing a keel while attached to a boat can be done with a high degree of accuracy. You can test this out on a boat with a removeable keel. Lay the boat on it's side with the keelbulb on the scale with the keel parallel to the table. Then take the keel off and weight it and you will be amazed that they are nearly the same, as in within 95% or better."
Subscribe to:
Posts (Atom)