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Polyester vs Epoxy resin for dinghy/kayak construction?
I am planning to build a hard dodger for my sailboat. I'm fairly mechanically skilled, and accustomed to working with my hands, but have never worked with fiberglass repair/construction. So I'm planning to make a dinghy or kayak before I make the dodger, to gain some experience. So far I like the Foamee Glen-L dinghy, it's a foam and fiberglass construction, which I like because of the fair lines (good for dodger). Search the 'net for links, I'm not promoting it.. Two questions.. What are the relative merits of polyester resin vs epoxy resin? Any recommendations on other dingy plans or kayak plans which have smooth lines instead of the hard corners seen with plywood construction? Thanks, -Koos |
Polyester vs Epoxy resin for dinghy/kayak construction?
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Polyester vs Epoxy resin for dinghy/kayak construction?
On Aug 20, 1:01 pm, Paul Oman wrote:
wrote: I am planning to build a hard dodger for my sailboat. I'm fairly mechanically skilled, and accustomed to working with my hands, but have never worked with fiberglass repair/construction. So I'm planning to make a dinghy or kayak before I make the dodger, to gain some experience. So far I like the Foamee Glen-L dinghy, it's a foam and fiberglass construction, which I like because of the fair lines (good for dodger). Search the 'net for links, I'm not promoting it.. Two questions.. What are the relative merits of polyester resin vs epoxy resin? Any recommendations on other dingy plans or kayak plans which have smooth lines instead of the hard corners seen with plywood construction? Thanks, -Koos Epoxy resins don't dissolve foam but I believe polyester resins do. Your options would seem to be a small boat or a puddle of foam goo. paul oman progressive epoxy polymers Very good! That's helps me with that question. Anyone with suggestions on alternate plans, dinghy or kayak with smooth lines? Thanks, -Koos. |
Polyester vs Epoxy resin for dinghy/kayak construction?
On Aug 20, 1:31 pm, wrote:
On Aug 20, 1:01 pm, Paul Oman wrote: wrote: I am planning to build a hard dodger for my sailboat. I'm fairly mechanically skilled, and accustomed to working with my hands, but have never worked with fiberglass repair/construction. So I'm planning to make a dinghy or kayak before I make the dodger, to gain some experience. So far I like the Foamee Glen-L dinghy, it's a foam and fiberglass construction, which I like because of the fair lines (good for dodger). Search the 'net for links, I'm not promoting it.. Two questions.. What are the relative merits of polyester resin vs epoxy resin? Any recommendations on other dingy plans or kayak plans which have smooth lines instead of the hard corners seen with plywood construction? Thanks, -Koos Epoxy resins don't dissolve foam but I believe polyester resins do. Your options would seem to be a small boat or a puddle of foam goo. paul oman progressive epoxy polymers Very good! That's helps me with that question. Anyone with suggestions on alternate plans, dinghy or kayak with smooth lines? Thanks, -Koos.- Hide quoted text - - Show quoted text - I use this site for info on constructions methods for my outrigger canoe project. He has a few plywood kayak designs. http://oneoceankayaks.com/stitchglue/stitchkayaks.htm |
Polyester vs Epoxy resin for dinghy/kayak construction?
wrote:
What are the relative merits of polyester resin vs epoxy resin? Trying to compare polyester and woven roving to epoxy and knitted glass is like trying to compare oranges and apples. Both are "fiberglass" laminates, but the similarity ends there. About the best you get is 35%glass/65%resin using woven roving, mat, and polyester. OTOH, it is quite common to get a 50%glass/50%resin using knitted glass and epoxy. This laminate does not require any mat. Bottom line.................... Polyester/roving produces a rather brittle, heavy laminate. Epoxy/knitted glass produces a more ductile, lighter weight laminate. Pound for pound, polyester and woven roving cost less per pound, but you use more pounds, so the cost differences tend to disappear. Epoxy, knitted glass and a 1/2" Airex foam core would produce a very light weight, bullet proof, dinghy or kayak. Just remember three things. 1)You will buy a commercial dinghy for less money than you will spend to build one. 2)You build one because you want to do it. 3)Once you use epoxy and knitted glass, you will never consider polyester again. Lew |
Polyester vs Epoxy resin for dinghy/kayak construction?
wrote:
What are the relative merits of polyester resin vs epoxy resin? Trying to compare polyester and woven roving to epoxy and knitted glass is like trying to compare oranges and apples. Both are "fiberglass" laminates, but the similarity ends there. About the best you get is 35%glass/65%resin using woven roving, mat, and polyester. OTOH, it is quite common to get a 50%glass/50%resin using knitted glass and epoxy. This laminate does not require any mat. Bottom line.................... Polyester/roving produces a rather brittle, heavy laminate. Epoxy/knitted glass produces a more ductile, lighter weight laminate. Pound for pound, polyester and woven roving cost less per pound, but you use more pounds, so the cost differences tend to disappear. Epoxy, knitted glass and a 1/2" Airex foam core would produce a very light weight, bullet proof, dinghy or kayak. Just remember three things. 1)You will buy a commercial dinghy for less money than you will spend to build one. 2)You build one because you want to do it. 3)Once you use epoxy and knitted glass, you will never consider polyester again. Lew |
Polyester vs Epoxy resin for dinghy/kayak construction?
Lew Hodgett wrote:
snip 3)Once you use epoxy and knitted glass, you will never consider polyester again. Lew Amen, brudder! |
Polyester vs Epoxy resin for dinghy/kayak construction?
wrote:
What are the relative merits of polyester resin vs epoxy resin? Trying to compare polyester and woven roving to epoxy and knitted glass is like trying to compare oranges and apples. Both are "fiberglass" laminates, but the similarity ends there. About the best you get is 35%glass/65%resin using woven roving, mat, and polyester. OTOH, it is quite common to get a 50%glass/50%resin using knitted glass and epoxy. This laminate does not require any mat. Bottom line.................... Polyester/roving produces a rather brittle, heavy laminate. Epoxy/knitted glass produces a more ductile, lighter weight laminate. Pound for pound, polyester and woven roving cost less per pound, but you use more pounds, so the cost differences tend to disappear. Epoxy, knitted glass and a 1/2" Airex foam core would produce a very light weight, bullet proof, dinghy or kayak. Just remember three things. 1)You will buy a commercial dinghy for less money than you will spend to build one. 2)You build one because you want to do it. 3)Once you use epoxy and knitted glass, you will never consider polyester again. Lew |
Polyester vs Epoxy resin for dinghy/kayak construction?
On Aug 20, 8:18 pm, "Lew Hodgett" wrote:
3)Once you use epoxy and knitted glass, you will never consider polyester again. Lew You got that right!! |
Polyester vs Epoxy resin for dinghy/kayak construction?
wrote in message
ups.com... Anyone with suggestions on alternate plans, dinghy or kayak with smooth lines? Ian Oughtred's Puffin? See www.customware.nl/boats And that one is entirely glued with epoxy. Meindert |
Polyester vs Epoxy resin for dinghy/kayak construction?
3)Once you use epoxy and knitted glass, you will never consider polyester again. Lew Thanks Lew, I have worked with epoxy before, rebuilding a hatch for my son's 24-foot sailboat. I don't know why I though that polyester would be an option, just ignorance I suppose.. Thus my question.. Best wishes, -Koos. |
Polyester vs Epoxy resin for dinghy/kayak construction?
On Aug 21, 1:26 am, "Meindert Sprang"
wrote: Ian Oughtred's Puffin? Seewww.customware.nl/boats And that one is entirely glued with epoxy. Meindert That's a beautiful dinghy! Perhaps I should make one like that, for the experience. I'm doing this as a prelude to making a hard dodger on my sailboat. It won't be a lapstrake dodger, but perhaps the skills will be beneficial. I don't know if I need to invest so much time into woodwork skills.. Perhaps I do? I really plan to make a fiberglass hard dodger and bimini, with smooth lines, hard windows, and some wood trim. -Koos. |
Polyester vs Epoxy resin for dinghy/kayak construction?
On Mon, 20 Aug 2007 19:43:45 -0000, wrote:
What are the relative merits of polyester resin vs epoxy resin? I think epoxy is somewhat stronger, and kayaks are famous for hitting rocks. For a dingy that may not matter as much. I heard epoxy costs more, but if you end up with a lot of work in it, why end up with something second rate. Casady |
Polyester vs Epoxy resin for dinghy/kayak construction?
On Mon, 20 Aug 2007 17:18:24 -0700, "Lew Hodgett"
wrote: wrote: Did you know that you seem to have posted three copies of the same message? I don't really mind all that much, but I thought you might like to know. Casady |
Polyester vs Epoxy resin for dinghy/kayak construction?
"Richard Casady" writes: Did you know that you seem to have posted three copies of the same message? After the fact, yes. It was my problem. Lew |
Polyester vs Epoxy resin for dinghy/kayak construction?
"Lew Polyester/roving produces a rather brittle, heavy laminate. Epoxy/knitted glass produces a more ductile, lighter weight laminate. Pound for pound, polyester and woven roving cost less per pound, but you use more pounds, so the cost differences tend to disappear. Epoxy, knitted glass and a 1/2" Airex foam core would produce a very light weight, bullet proof, dinghy or kayak. Just remember three things. 1)You will buy a commercial dinghy for less money than you will spend to build one. 2)You build one because you want to do it. 3)Once you use epoxy and knitted glass, you will never consider polyester again. Lew is right on every particular. |
Polyester vs Epoxy resin for dinghy/kayak construction?
Lew is right on every particular.
Yes... but. Lew's Knitted glass - when bought in 'roll' quantites is about a dollar-a-pound more expensive than woven roving. Traditional thinking is that woven fabric is used primarily with fiberglass 'mat' in a polyester layup, one between the other. The basic reason for this is that the woven, i.e. "over, under, repeat" nature of the w.r. causes "hollows" where the 'high' strands cross-over the 'low' strands of glass. The mat (in addition to providing significant bulk, and sucking up a lot of resin) is thought to "tie" the woven layers together, by bridging these 'hollows.' Now, in a large epoxy resin layup one can significantly reduce the cost, while maintaining adequate strength by continuing to use woven- roving. The mat is forsaken in favor of a slurry of milled fibers and a little cab-o-sil mixed to a 'light cream' consistency. That is, layer of w.r. wet out with straight epoxy. Squeege. Trowel in a slurry of epoxy / milled fibers / cab-o-sil, then next layer of w.r. Finish wet-out with straight epoxy. Squeege. Repeat. The milled fiber + cab-o-sil slurry is filling the hollows and providing a tie for the next layer of woven fabric. A 10 lb bag of cab-o-sil is like way cheap, and will last the entire project. A 50 lb bag of milled fibers is similarly inexpensive. And, becuase we've eliminated the mat, resin-to-glass ratio's of 50 / 50 are easily achived. So, in a large project where cost is a concern my belief is that one ought not write-off woven roving as being a suitable material. MW |
Polyester vs Epoxy resin for dinghy/kayak construction?
wrote: Lew is right on every particular. Yes... but. Lew's Knitted glass - when bought in 'roll' quantites is about a dollar-a-pound more expensive than woven roving. Traditional thinking is that woven fabric is used primarily with fiberglass 'mat' in a polyester layup, one between the other. The basic reason for this is that the woven, i.e. "over, under, repeat" nature of the w.r. causes "hollows" where the 'high' strands cross-over the 'low' strands of glass. The mat (in addition to providing significant bulk, and sucking up a lot of resin) is thought to "tie" the woven layers together, by bridging these 'hollows.' Now, in a large epoxy resin layup one can significantly reduce the cost, while maintaining adequate strength by continuing to use woven- roving. The mat is forsaken in favor of a slurry of milled fibers and a little cab-o-sil mixed to a 'light cream' consistency. That is, layer of w.r. wet out with straight epoxy. Squeege. Trowel in a slurry of epoxy / milled fibers / cab-o-sil, then next layer of w.r. Finish wet-out with straight epoxy. Squeege. Repeat. The milled fiber + cab-o-sil slurry is filling the hollows and providing a tie for the next layer of woven fabric. A 10 lb bag of cab-o-sil is like way cheap, and will last the entire project. A 50 lb bag of milled fibers is similarly inexpensive. And, becuase we've eliminated the mat, resin-to-glass ratio's of 50 / 50 are easily achived. So, in a large project where cost is a concern my belief is that one ought not write-off woven roving as being a suitable material. About the only thing missing from the above is a little spit and some baling wire. Lew |
Polyester vs Epoxy resin for dinghy/kayak construction?
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Polyester vs Epoxy resin for dinghy/kayak construction?
On Tue, 21 Aug 2007 11:58:39 -0700, "Lew Hodgett"
wrote stuff and I replied: "Richard Casady" writes: Did you know that you seem to have posted three copies of the same message? After the fact, yes. It was my problem. Lew Hey! If you mean what you say, get out there and _say_ it, man! G Human bevaviour: Bestiality with a brain |
Polyester vs Epoxy resin for dinghy/kayak construction?
"Lew Hodgett" wrote in message ... wrote: What are the relative merits of polyester resin vs epoxy resin? Trying to compare polyester and woven roving to epoxy and knitted glass is like trying to compare oranges and apples. Both are "fiberglass" laminates, but the similarity ends there. About the best you get is 35%glass/65%resin using woven roving, mat, and polyester. OTOH, it is quite common to get a 50%glass/50%resin using knitted glass and epoxy. This laminate does not require any mat. Bottom line.................... Polyester/roving produces a rather brittle, heavy laminate. Epoxy/knitted glass produces a more ductile, lighter weight laminate. Pound for pound, polyester and woven roving cost less per pound, but you use more pounds, so the cost differences tend to disappear. Epoxy, knitted glass and a 1/2" Airex foam core would produce a very light weight, bullet proof, dinghy or kayak. Just remember three things. 1)You will buy a commercial dinghy for less money than you will spend to build one. 2)You build one because you want to do it. 3)Once you use epoxy and knitted glass, you will never consider polyester again. I have never actually built anything with fg, but have done numerous repairs. I have always used woven cloth with epoxy, and haven't heard the term "knitted" before. A google search showed it was the same as unidirection fabric. Is that correct, or is knitted something else? |
Polyester vs Epoxy resin for dinghy/kayak construction?
"Toller" wrote: I have never actually built anything with fg, but have done numerous repairs. I have always used woven cloth with epoxy, and haven't heard the term "knitted" before. A google search showed it was the same as unidirection fabric. Is that correct, or is knitted something else? Woven fabric looks like a burlap bag, a very coarse weave. Knitted fabric looks like suit fabric, very fine, tightly knitted fabric. Do a Google for Knytex, then DB170. That will get you to a double bias (+/-45), 17 oz/sq yard material. It is about all I use these days. There are also what are known as "Uni" fabrics which have the fiber oriented either 0 or 90 degrees to the run of the roll. Lew |
Polyester vs Epoxy resin for dinghy/kayak construction?
Knitted glass consists of two or more layers of unidirectional glass which
are knitted together. It's available with the glass at 0 and 90 degrees and with the glass at +-45 degrees. It is less expensive per pound than glasss fabric. Because the fibers are not crimped by weaving, it's stronger and, for a given glass content, thinner and therefore it needs less epoxy to fill. So, for structural purposes, it's superior to mat & roving and to cloth. It often does not finish as smooth as cloth, so a top laminate of cloth is a good way to finish . "Toller" wrote in message ... "Lew Hodgett" wrote in message ... wrote: What are the relative merits of polyester resin vs epoxy resin? Trying to compare polyester and woven roving to epoxy and knitted glass is like trying to compare oranges and apples. Both are "fiberglass" laminates, but the similarity ends there. About the best you get is 35%glass/65%resin using woven roving, mat, and polyester. OTOH, it is quite common to get a 50%glass/50%resin using knitted glass and epoxy. This laminate does not require any mat. Bottom line.................... Polyester/roving produces a rather brittle, heavy laminate. Epoxy/knitted glass produces a more ductile, lighter weight laminate. Pound for pound, polyester and woven roving cost less per pound, but you use more pounds, so the cost differences tend to disappear. Epoxy, knitted glass and a 1/2" Airex foam core would produce a very light weight, bullet proof, dinghy or kayak. Just remember three things. 1)You will buy a commercial dinghy for less money than you will spend to build one. 2)You build one because you want to do it. 3)Once you use epoxy and knitted glass, you will never consider polyester again. I have never actually built anything with fg, but have done numerous repairs. I have always used woven cloth with epoxy, and haven't heard the term "knitted" before. A google search showed it was the same as unidirection fabric. Is that correct, or is knitted something else? |
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