under deck foam

wallbanger2

Petty Officer 3rd Class
Joined
Jul 12, 2003
Messages
80
Re: under deck foam

Here's a little "fact" that you may want to take into account in your debate. This comes from the Great Stuff website:<br /><br />6. Can I insulate my walls with GREAT STUFF? <br />GREAT STUFF sealant is designed to fill cracks and gaps. It does not cure properly if it is used to fill large voids unless it is put down in layers and allowed to cure before the next layer is applied. Do not use GREAT STUFF to fill enclosed voids such as behind or under tub surrounds. <br /><br />This sounds to me like they wouldn't recomend using it to do the entire boat. But then again thats just my opinion.
 

JasonJ

Rear Admiral
Joined
Aug 20, 2001
Messages
4,163
Re: under deck foam

RTW2112, are you smoking crack? Do you take a long, slow drag and fill your lungs, causing brain damage?<br /><br />Lets see....Don't tell Boston Whaler that foam can't be used for structure, or their through...Don't tell pretty much every bass boat builder either, considering they force foam in under pressure in all voids to-you guessed it-ADD STRUCTURE! <br /><br />If you are so horny for Great Stuff, good for you, but it is not intended for the application you are so obsessed with pushing. Can it be used? You bet it can, and he will probably be alright with it, but it is not advised. <br /><br />As far as density, the more dense the foam, the more weight and pressure it can withstand. Great Stuff looks liked light and fluffy whipped cream compared to a good 2 part foam. Laying it down in the void? Yeah, you can do that, but is it the calculated amount to displace enough volume to keep the boat at the surface when swamped? That is how you do it, and if that means you have to fill the entire void to get the displacement volume you need, then that is what you do. No ifs and or buts. If you are not going to put in enough, don't put in any.<br /><br />As far as what I used for my boat, it was all purchased from a place that, say it with me people, REBUILDS AND REPAIRS BOATS! As far as wood goes, marine grade doesn't prevent rot, you just get no voids and get to spend more money. Now PRESSURE TREATED PLY is a better bet, if you can get the good dry stuff or let the regular pressure treated stuff dry.<br /><br />In conclusion, don't be spoutin' off, you are ill informed and in fact are defending YOUR opinion. I could give a rats arse what people use on their boats, but I will always recommend they check all options, and hopefully won't kill themselves with a poorly rebuilt boat. Wanna go some more? I can do this all day.........
 

JasonJ

Rear Admiral
Joined
Aug 20, 2001
Messages
4,163
Re: under deck foam

Normally, my education level doesn't allow for the interaction with idiocy that I am seeing here, but sometimes I just have to dive on in. If I took my boat to an actual professional place of business and discovered that an inferior product was used, I would take them to court. It is one thing for a backyard boat builder to use something like Great Stuff, its his boat, its his business. To actually have the nerve to come on to an internet message forum and attack someone, and then laughably tell everyone here that a place of business is using a home product for a marine application is just insane. <br /><br />Once again, I'll spell this out for you, since your lack of maturity is taking over, that I never said the Great Stuff wouldn't work. It will work. It just will be more difficult to deal with, and after an extended period of time, it is more likely to absorb water than 2 part. 30 days underwater without saturation, while fairly impressive, means little. Try a year, two years, ten years, and see if it has absorbed water. Yes, even 2 part can saturate, but it takes a very long time of continued exposure, far longer than a home product.<br /><br />I guess you have difficulty grasping the concept of bouyancy. If a 19 foot boat weighs 2000 pounds fully rigged, how much water must be displaced to keep it afloat? 30 cubic feet. How many boats have 30 cubic feet of volume under their floors? not many. So what is an optimal way to do this? fill as much of the void as possible. Boat builders also sprayed foam up under the sides, splashwell, all sorts of places to try to help.<br /><br />Again, don't sleep through this, take a boat like Boaston Whaler, who uses foam for its structure. The smaller boats consist almost entirely of foam, and they have been doing this since the 50s. Take all those "composite" premanufactured stringer systems that are foam sandwiched between layers of fiberglass. Foam has good structural uses, it can't be discounted. As for keeping the boat you talked about from sinking, that is great. I cannot swim, so the thought of getting holed and sinking makes me want to vomit, so that is why I went with foam, to prevent exactly what happened with the boat you talk about.<br /><br />As for the "mopes" who bag on Bayliner, they bag for a reason. there was a period of time where Bayliner was not using enough layers in the hull layup, to save costs, and also they have always been known for marginal fit and finish. You combine the slack manufacturing techniques with the fact that a lot of people don't care for their boats very well, and combine all that with the fact that Bayliner cranked a lot of boats out means you end up with a lot of boats in bad condition. I personally like they way some of the Bayliners look, and have considered find a dogged out one, stripping it, and laying up the extra layers needed. Yeah, it would not be wise as an investement, but I would end up with a boat that looks good and won't crack if you fart too hard.<br /><br />In conclusion, how alienating do you think it is to come onto a message forum and start calling people morons, especially since you have only posted 32 times? We all come to this place to get different ideas, different opinions on how to do something. Some ideas are crazy, some are grounded in fact, but they all gives people different options to explore. Some of us have little money, some are loaded. All of us just want the best boat we can build or repair. You are in no position to come on and so rudely insult others who do not share your opinion. I normally do no participate in such behavior, it is immature, but I am taking exception in this case and will continue until a moderator steps in. The saddest thing of all is any new person who comes on is going to see this little exchange and may be turned off, figured this is another one of those message forums chok full of E-rage, people who are gutless in the real world but are balls up on the internet. I just hope the original poster had learned enough to decide what route to take, and not be discouraged by your poor attitude, and my need to defend myself against your lack of civility.<br /><br />Great Stuff. Stays crunchy, even in milk... :D
 

CTD

Petty Officer 1st Class
Joined
Nov 13, 2002
Messages
234
Re: under deck foam

A surf board is a good example of foam for structural use.
 

Spidybot

Lieutenant Commander
Joined
Apr 4, 2002
Messages
1,734
Re: under deck foam

Jason and RTW,<br /><br />This whole conversation emphasizes the importance of preparing any project and doing ones homework as good as possible. Also that you have to do this for yourself as many will offer advice based on their beliefs rather than on scientific knowledge.<br /><br />Normally a job can be done in one of more ways, several kinds of material can be used for an application. Manufacturers recommends the use for each and it is up to you if do, or do not, follow this. <br /><br />I can follow the arguments from both but won't add fuel to fire by adding my personal opinion.<br /><br />'Crack' & 'moron' were unfair attacks, did not do anything to help this topic and was a waste of good time.<br /><br />RWT: You state some qualities of the stuff you like. Among these are that it kept it's shape after staying under water, kept a hull OK even after damage and more. This is proof of the foam's structural properties. And a surfboard has as much to do in this thread as to tell that.<br /><br />It is not important to me if you believe it but the highest capacities in this industry all agree on: <br /><br />
Structural foams are defined by their density. Polyurethane foams range in density from as little as 2 pounds per cubic foot to as much as 55 pounds per cubic foot. Foams with a density of 15 pounds per cubic foot and greater are commonly called structural polyurethane foams.<br /><br />What about strength? The flexural modulus of structural polyurethane foams increases as the density increases. An unreinforced structural polyurethane foam with a density of 15 pounds per cubic foot has a flexural modulus of approximately 30,000 psi. A foam with a density of 40 pounds per cubic foot has a flexural modulus of about 170,000 psi. The highest modulus for an unreinforced structural polyurethane foam is approximately 250,000 psi.<br /><br />To the surprise of traditional composite fabricators, well-designed parts made with structural foam polyurethane RIM systems often require no glass fiber or other reinforcement to achieve the strength and rigidity required for the application. For example, roofs and side panels for agricultural tractors and combines are molded with an unreinforced grade of Bayer's Baydur® structural foam polyurethane RIM system.<br />
The mentioned example of agricultural tractors is part of the quote and does not in any way refer to a boat make or model. Members who like to dig further into this can do a Google search for polyurethane foam structural properties and browse the 6.510 hits.
 

JasonJ

Rear Admiral
Joined
Aug 20, 2001
Messages
4,163
Re: under deck foam

I am not going to stand for being villified for defending myself. RTW2112 expressed his success with a product, and when it was pointed out that it may have not been the best way to go, he reacted poorly. While I agree that the "crack" comment wasn't necessary, and I'll apologize for that individual comment, his overall reaction towards what I have had to say is so poor that it is almost incomprehensible.<br /><br />I remember when the internet first came out. Real spiffy, we get to share ideas and converse with people all over the world. Without this, we all would build our little projects, and have no one but our friends to show it to, and have a heck of a time finding information when we need it. Now we can push a few buttons and get all the information we want, and share our projects with a vast array of people with the same interest. The downside is we also have to deal with people who lack basic respect. <br /><br />While I am sure RTW2112 has a lot of good information to share and can be helpful, he did not need to attack me or my way of doing things. No, there is no one right way of doing things, but there are different, and I hate to say it, more recommended ways of doing things. I feel I was singled out and attacked for no reason, and I reacted accordingly. Again, I appologize for the "crack" comment, but I do not appologize for defending myself from a person who has contributed very little but has felt that attacking someone who does not share his belief is the right way to go. If this is how it works here, I will have no choice but to stop using this forum. I have so much better things to do with my life than waste it on immature people who have no social respect.<br /><br />Once again, I just hope new people havn't read this and been turned off. This entire thing has been an embarrasment, but I will never regret defending myself. The end.
 

dakotashooter2

Petty Officer 2nd Class
Joined
Jun 10, 2003
Messages
125
Re: under deck foam

I would like to ad a comment about the UL listing of Great Stuff. Such listings are only valid if the product is used for its "intended" purpose. testing for such products is done under very specific perameters and use of the product outside those perameters renders the listing useless. In the construction business a listed product must be installed in the exactly manner the manufacturer had it tested or it may fail. While Great Stuff is fire retardant (not the same as fireproof or non-flamable)I doubt it is tested under conditions where its application involves large volume (such as would be used in a boat) or where there is a chance of fuel contamination (not unheard of in boats). In addition it is designed as a sealant/insulator and not for its boyancy properties which are basically a byproduct. Will it work? Sure, at least for a while. Will it work as good as a product specifically designed for boats? No. I'll admit to using Great Stuff in a boat but not as my primary floatation. I use it as a filler and adhesive to supplement closed cell foam (block). I think it has some valid uses in a boat but NOT as primary floatation. I've also heard some comment to using empty bottles under the deck and it probably will work OK MOST of the time but what happens if yousplit a hull or punch a large hole and the bottles (your floatation) spill out<br />or you fish in the temperature extremes common in my area 30-100 degrees. Those empty bottles can expand and contract enough to drastically effect their boyancy. Just food for thought.
 
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