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Speaking of the difference, I've often wondered if they use different
resins in vacuum molds. In the roller method, the epoxies are fairly stiff (usually due to the "induction" time in which the catalyst acts on the resin), but it would seem to me to achieve proper penetration of the glass in a vacuum system, the liquids would be fairly light. Yes/No? *************** I was invited to the 25th Anniversary celebration of a local manufacturer, Nordic Tug. They had a few hundred people in attendance, from all across the country, and almost all were Nordic Tug owners. Impressive turnout during one of our rare snowy days and in the middle of January, but it was like the gathering of an enthusiastic clan. I digress.... Nordic had a number of vessels on display in all stages of build and fitout. Nordic had set up a demonstration of vacuum bag, or infusion molding, in the laminate shop. We observed the molding of a cabin top. The gelcoated mold gets one layer of vinylester resin prior to the layup. This is to prevent "shrinkage" which could spoil the exterior appearance of the finished component. The glass mat and coring materials are then laid in place. For the cabintop, Nordic uses three different weights of mat in the layup and I would need to dig out my notes to be specific as to how many ounces each fabric is rated. Many of the superstructural components in a Nordic are cored, and a combination of serrated balsa as well as synthetic coring materials are used in the buildup. All coring material is designed to allow resin to flow throughout the layer, vastly reducing any liklihood of a future separation between the FRP and the core. There is a difference in the layup process when preparing for infusion molding. There are certain materials included that promote the flow of resin throughout the layup and the entire process is conducted with an emphasis upon assuring a maximum, thorough wet out. It isn't just the same layup one would use with roller laminating and then vaccum infused. Once the layup is completed, a plastic sheet (vacuum bag) is placed over the mold and some plastic tubed "plumbing" installed to remove the air from the bag and create a vacuum. When the vaccum has been estabished, the technician uses an electronic sensing device to check the perimeter and the central vacuum connections for any leaks. After the integrity of the vaccum is assured, the infusion begins. Nordic uses vinylester resin. The technician explained to us that a number of factors are considered when adding the catalyst to the resin, including ambient temperature, of course. The resin itself was heated to a controlled temperature, (about 70-degrees), and then the catalyst was added. It would be hard for me to compare the density of the infusion method resin with what the density might have been in a roller lamination- but I have no doubt that the mixture was calculated to be optimal for infusion molding. A valve was opened to allow the mixture to flow into the mold, and during the minutes required for the dark colored resin to spread throughout the mold the technician was constantly monitoring the flow and spread of the liquid. The greater atmospheric pressure outside the bag helped press and squeeze the resin into the mat. Nordic has been infusion molding cabin parts for some time now, and has become so confident in the process that beginning in March or April they will begin vacuum bagging their hulls as well. When you put a ten year hull warranty on a million dollar boat (some of the larger models are now well over the 7-figure mark), you want to be sure the technology is first rate. There are some potential advantages, in my opinion. For instance, the assurance of a "wet" layup. I suspect that in many of the traditional "hand laminate" processes there are gaps at lunch times, shift changes, etc where an underlying layer of glass is allowed to cure just a bit more than desirable before the next layer is applied....possible source for future delam. There is less opportunity for dirt, dust, etc to find its way into the laminate and that can additionally help reduce the liklihood of eventual blistering. The use of chopped strand to build up thickness is inconsistent with vacuum bag molding. Opinons from OZ not withstanding, there is no reason to assume that infusion molding will always be done poorly and traditional roller laminating always done well. I'd be happy with a well built boat constructed through either process. |
#2
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#3
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#4
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Our Ms. Smith wrote:
All syn coring materials are closed cell, the resin is NOT intended to "saturate" the core other than the outer surfaces where hopefully the glass skins will be properly bonded. ************ That is correct. The coring materials do have grooves, depressions, kerfs, etc to increase the amount of the surface area exposed to resin. If you take a hole saw to a cored layup and examine the plug, you will see resin within the core layer (in the channels and passages where it is supposed to be). Resin can flow laterally across the core. Next, speaking about the various layers of mat used in infusion molding compared to roller lamination, Ms. Smith observed: It can't be the "same" because normal cloth & mat won't flow the resins freely enough, the problem which you unwittingly admit is that uniform wetout is an issue & excess resin in glass is almost as damaging the finished laminate as not enough resin ******************** So then it is your opinion that vacuum bag molding can *never* be done correctly because it has to be differently from other methods? If everybody thought that way, we wouldn't even have fiberglass boats- let alone be arguing about laminate methods. * None of her points beyond here were expressed without personal insult, so I'll not dignify any of them with a reply. |
#5
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wrote in message oups.com... Our Ms. Smith wrote: All syn coring materials are closed cell, the resin is NOT intended to "saturate" the core other than the outer surfaces where hopefully the glass skins will be properly bonded. ************ That is correct. The coring materials do have grooves, depressions, kerfs, etc to increase the amount of the surface area exposed to resin. If you take a hole saw to a cored layup and examine the plug, you will see resin within the core layer (in the channels and passages where it is supposed to be). Resin can flow laterally across the core. Next, speaking about the various layers of mat used in infusion molding compared to roller lamination, Ms. Smith observed: It can't be the "same" because normal cloth & mat won't flow the resins freely enough, the problem which you unwittingly admit is that uniform wetout is an issue & excess resin in glass is almost as damaging the finished laminate as not enough resin ******************** So then it is your opinion that vacuum bag molding can *never* be done correctly because it has to be differently from other methods? If everybody thought that way, we wouldn't even have fiberglass boats- let alone be arguing about laminate methods. * None of her points beyond here were expressed without personal insult, so I'll not dignify any of them with a reply. Postings with personal insults? Something you are getting quite good at lately Chuck, sometimes reaching as low as one would expect from a 2nd grader, certainly not from an adult as you say you are. |
#6
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Hurtwit the hypocrite remarked:
Postings with personal insults? Something you are getting quite good at lately Chuck, sometimes reaching as low as one would expect from a 2nd grader, certainly not from an adult as you say you are. *********** I've been taking lessons from an asshole in Ohio. The half-witted SOB never posts a line without attacking somebody, and then runs crying about his hurt feelings whenever anybody says "boo" back at him. My little sister used to act the same way, before she grew out of it. Come to think of it, Jim, you live in Ohio too! On the off chance that you run into the asshole I'm referring to, give him my regards, OK? I've got to go clear the hundred dollar bills from the front porch, they're beginning to blow around the neighborhood and folks will certainly complain. |
#7
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wrote in message ups.com... Hurtwit the hypocrite remarked: Postings with personal insults? Something you are getting quite good at lately Chuck, sometimes reaching as low as one would expect from a 2nd grader, certainly not from an adult as you say you are. *********** I've been taking lessons from an asshole in Ohio. The half-witted SOB never posts a line without attacking somebody, and then runs crying about his hurt feelings whenever anybody says "boo" back at him. My little sister used to act the same way, before she grew out of it. Come to think of it, Jim, you live in Ohio too! On the off chance that you run into the asshole I'm referring to, give him my regards, OK? I've got to go clear the hundred dollar bills from the front porch, they're beginning to blow around the neighborhood and folks will certainly complain. Grow up Chucky. And give it up already because you are looking quite the fool and whiner. |
#8
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#9
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#10
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Smith wrote:
So again Chuckles you try to cover your BS?? The core is not intended to be saturated with resin?? If it is knifed or shaped that is usually so it can more easily take on the required compound shapes required & has naught to do with trying to get resin "inside" the core itself. Honestly Chuckles you were clearly more at home selling used cars than coming here with this marketing BS, it won't fly:-) ********** Once again, according to the laminate shop foreman for a major manufacturer, you're wrong. Any flexible material could be used for coring without having to cut grooves, depessions, etc through or into the body of the material. Tell me, do they need to cut grooves or "egg craters" in to glass mat down in OZ? Maybe you'd like to explain how half inch blasa coring with a saw kerf every inch is going to conform to much of a curve? How do they manage to keep the resin out of these indents, cuts, and depresssions in the southern hemisphere, and why would that be a good thing? The irregular surfaces certainly assist in binding the core to the laminate. What a burden it must be for you to have to go through life knowing every thing about every subject, considering your own opinion to unassailable fact, and unable to discuss anything without a personal attack for emphasis. If you were half the pro you pretend to be, you would discuss technical issues in a professional manner. If you were even half the half pro you pretend to be, you could manage to make a post without spending 10-15 minutes typing out a long attack on another poster (usually not even involved in the discussion) at the bottom of every message. |
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