Going foamless

[Woodonglass]

Re: Going foamless

Hope the job comes through the way you want. Hmmm, I don't see any glassed bulkheads??? Maybe I need to get my eyes checked. Guess I'll call the optometrist and get an appointment. OH WAIT, maybe, just maybe, it's because you didn't post any pics!!!! We LOVE pics!!!!

 

[westexasrepublic]

Re: Going foamless

I used heavy duty plastic from wal mart, with a layer of WD-40 to prevent sticking to the deck...

this method ensured 2 things, Full expansion of foam to the bottom of deck with no air pockets AND most important I didnt have to cut holes in my pretty, solid one piece, brand new deck to pour the foam.

NO SANDING just a little trimming from overflow, I dont know why more people dont do it?

 

[Yacht Dr.]

Re: Going foamless

I used heavy duty plastic from wal mart, with a layer of WD-40 to prevent sticking to the deck...

this method ensured 2 things, Full expansion of foam to the bottom of deck with no air pockets AND most important I didnt have to cut holes in my pretty, solid one piece, brand new deck to pour the foam.

How does this method ensure that there are no air pockets? Do you just raise and lower the waxed deck until you have no pockets ?

Why is it a bad Idea to cut holes in a secured deck when applying 2 part foam ? The deck is more structural this way ?

NO SANDING just a little trimming from overflow, I dont know why more people dont do it?

I personally like the underside stuck to the the 2 part foam ..

Im not trying to discount your idea ( good idea for a few applications ) but I personally dont think it would be a good idea for a full foam filled underdeck application.

Just me though..

YD.

 

[fishbone77]

Re: Going foamless

Hey Logan,

I'm actually at a similar point in my own project - from what I've been reading (and the PROs can confirm or correct me if I'm wrong), there is also some structural value in having the foam actually bind to the bottom of the deck - kind of helps tie the deck and the hull together into one unit. "Oops" and WOG have both had great things to say about foam application in other threads.

 

[Woodonglass]

Re: Going foamless

Yeah, I have to say, I'm not a Pro but everything I've read and learned have led me to believe that when foaming a hull it's best to allow the foam to adhere to the structure. I do know that others here on the forum have done what you have done. If your hull design does not require the foam as structural support then basically this is just for flotation. Having air pockets etc. will not really matter. Some people don't even attach the deck to the stringers. Leave it free floating. Important to tab it to the sides of the hull. I agree with YD in that Personally I would recommend attaching the deck to the stringers, hull and I would allow the foam to stick to everything. But like YD, that's IS just my personal preference. It's your boat and you can do as you see fit. I have no rock solid data or experience to support it one way or the other.

 

[jones01m]

Re: Going foamless

Logan, I don't think there is anything partucularly wrong with westexasrepulic's approach, but personally I came to the conclusion that the deck-then-pour method was the best way to go. I started the below thread on the topic and received good input. I also ran an experiement to determine the void filling capability of the "pour after" method - this result speaks for itself.

http://forums.iboats.com/showthread.php?t=535442

If you use epoxy PB to hold down your deck the foam expansion will not create enough force (I used 4lb foam by the way) to pull it away from the stringer - at least it will not fail in the bond.

I couldn't be more pleased with the results of my pour. It is unbelievably solid.

 

[fishbone77]

Re: Going foamless

Good call Jones, I knew I had seen a thread on this somewhere...subscribed to it now so I don't lose it!

 

[BillP]

Re: Going foamless

The problem I had with pouring into holes (once) is the foam started expanding and prevented the rest of the pour from flowing out evenly. It was out of sight and about 24" away on a straight run next to a main fore/aft stringer. The domino effect was too much foam in a concentrated area. It bowed 1/2" marine ply deck with 3 of us standing (learned quickly this doesn't work) on it...total deflection was about 4" in that section. It broke the floor loose from the stringers and was a major redo. Lesson learned for pouring in holes was make lots of pour holes, be very careful with measuring, pour as fast as possible and don't rely on weights to hold back much. Like already posted by YD, pour out a complete bucket and the film left in the bucket will expand over the top and make a giant muffin. I hope nobody has this happen to them but be aware it can happen and adding weight may or may not stop the expansion or destruction. This happened to me exactly 46 yrs ago and still ranks high on my inexperienced and stupid list for boatwork.

As the saying goes...Wisdom is learning from other's mistakes...experience is learning from your own mistakes.

bp

 

[Yacht Dr.]

Re: Going foamless

I hope nobody has this happen to them but be aware it can happen and adding weight may or may not stop the expansion or destruction. This happened to me exactly 46 yrs ago and still ranks high on my inexperienced and stupid list for boatwork.

Yea..the last time this happened was when I was applying some graphics to a SR laguna while the 'new' guy ( that apparently had loads of experience with floors ) was foaming a deck.

POWWWW !!!!!! I mean Loud !!! almost gave me a heart attack LOL .

The pressures involved when that stuff has no were to go is Enormous ! Weight does not do crapola LOL.

Know what your doing when foaming the deck..or hope you did a crappy job tabbing/sealing in the deck .. or you might not get a ' POP ' .. but an unforgettable experience ..

YD.

 

[logan944t]

Re: Going foamless

OH WAIT, maybe, just maybe, it's because you didn't post any pics!!!! We LOVE pics!!!!

Yep-- pics later today. Ive been orienting at a new job and had forgotten how physically demanding it was so I havent gotten to work on the boat at all.


Im gonna use the deck then pour method. Partially because I think its the method that has fewer things to go wrong and largely because I want the foam to stick.

Im still glassing the outer strings ( taking my time to make sure there are no voids) and have made them a bit higher than the middle stringer so the deck will have a lower area running down the middle to channel water into the aft bilge/drain area.

Im pretty sure Im gonna be using epoxy PB to stick the deck down--adding weights--and a few stainless fasteners --then tabbing--then pouring. I originally ordered the epoxy for something else and havent even tried it out yet.

Considering the original setup from the factory --2 layers of roving for the hull ( Altho in some places I have my doubts about that) --1 layer of csm as the stringer around wood ( middle stringer is 1 layer of roving) Im pretty confident that it will be much stronger after Im done. Im adding csm to the stringer to bulk them up then a layer of 1708. In between the stringers-- on the hull--its getting a layer of 1708 tied into the stringers and hull sides. Then 2 lb foam.


Im getting anxious to get back out on the water. Still have to take care of the engines issues and then all the registry mess-----this job cuts into boat building time.

 

[logan944t]

Re: Going foamless

Looks like working on the boat today is out -- its raining--so here are some pics:





Stringer and bulkhead-- bulkhead ( on right) has one layer of csm on it. Stringer is still open on top. Foam was smoothed and filleted but still had areas where it was difficult to get the csm flat on the foam. I found that by cutting strategically I could get it to lay flat and neat.





Port side middle stringer with one layer of csm. I have to recut the drain hole in the center. The bulkheads area bout double the thickness the factory put in.




Emmons bayou this morning. About 1/4 mile of bayou then emmons bay opens-- and thru the narrow cut is St andrews bay where I fish. The bayou can be very shallow ( 2 " or so) during the winter months at low tide--to above the dock ( on the bottom left + 4') at high tide in the summer. Catfish, reds, shark, rays, remoras are abundant.

 

[fishbone77]

Re: Going foamless

Congrats on the job Logan! Stringers are looking great! Eager to hear about how your deck install and foam pour go!

 

[logan944t]

Re: Going foamless

I was able to work for about 6 hours today. I was able to put down a layer of 1708 on the hull and up the sides of the stringers on 2/3's of the boat. I have the bow section and the transom area left for 1708. I was also able to glass some strips of 1708 on top of the stringers --just for thickness to have screws have something to bite if I use them. I still need to put "caps" of csm on the stringers over these strips.

I used 5 x 32 oz of resin and 5' of the 1708.

I have some areas of the 1708 that look like they werent wetted out properly. I have no idea what caused this -- there was plenty of resin applied first--then the 1708 --then more resin. Its not air bubbles either. Im not concerned-- Ill either grind them out or leave them since they are in non critical areas where foam will be.

Some things I learned.

1) Fillets are good. Big fillets are better. Huge fillets are best. Much easier to lay the glass evenly and it adheres --no air bubbles.

2) Always have extra glass ready to lay in case you mixed too much resin. I hate watching 20 oz of resin kick in the container because I mixed too much.

 

[logan944t]

Re: Going foamless

Tried to work on the boat yesterday --got rained out. So when it started training today I was determined to push forward anyway. IM glad I did I had a kickass day.






This is simply the best layup Ive ever done. A piece of 1708, wetted perfectly and no air bubbles. I found out that if I pull the 1708 slightly it will absord resin much faster and leave no unwetted parts.




The entire hull now has a single layer of 1708 that runs up the sides of the stringers as well as the bulkheads. The tops of the stringers are capped with 2 layers of csm.


I still have sustantial work left on the transom area.

I wanted to address something I read in another thread. When I sanded the tops of the stringers to get the foam to the right hieght I sanded into all the little air bubbles in the foam. In order to fix this problem I brushed 2 layers of just resin on the tops --waited till it kicked then laid a layer of 1708 along the top. Then a layer of csm.


Tommorrow I will install pvc drains thru the bulkheads and fabricate the transom stringer connections.

Im real close to putting the deck on....finally......

 

[fishbone77]

Re: Going foamless

Looks awesome Logan! Glad to hear that you're homing in on the deck!

 

[logan944t]

Re: Going foamless

Ive seen the spec stats on 2 lb foam on US Composites website. But no where did it relate adhesive strength. So I set out to find out how sticky 2 lb foam is.




The setup:


2lb foam from US Composites


Pieces of 3/4" marine ply.



I made 4 molds from the ply on wax paper and poured the foam in. I let it harden then removed the vertical sides--which left me with a top and bottom of ply with foam in the middle. I drilled holes on the outer wings of the ply-- not touching the foam centers. All foam/ply pieces were 2" wide by 7" long giving about 14 square inchs.



The process:

I started out with some rope passed thru the top holes of each foam/ply pices. I then attached a rope to the bottom foam/ply piece and hung barbell wieghts and then winched it off the floor. If the bond between the foam and ply didnt fail--or the foam come apart--then I added weight until failure.



The question:

I wanted to know if the coating on the bottom of the deck would make a difference if I wasnt using csm or 1708--but just a plain coating.



These pieces were coated with a latex paint I had laying around. There were also pieces coated with poly, epoxy and just the raw wood.

 

[logan944t]

Re: Going foamless

The results:




Failure was achieved on every piece between 95-105 lbs.



The poly failed the earliest-- showing a clear debonding between the wood and the foam altho a piece of foam was still attached.








Raw wood showed some debonding.




Epoxy has the least debonding.





Conclusion:



For all the difference ( about 10 lbs) it doesnt matter. The failures were all partially a bonding failure as well as the foam failing.

I think it is interesting to note that the 14 square inchs held 100 lbs from just the foam alone. However, add in sheering forces from laterel movement of the hull sides and that number could be reduced significantly--but I have no way to test something like that. A deck will need some sort or dedicated adhesive of mechanucal fasteners and the foam just adds to the mix.

 

[fishbone77]

Re: Going foamless

Interesting results Logan! As far as the sheering forces are concerned, it seems to me that with the deck tabbed to the hull and fastened to the stringers, there would not be much flex in that area for sheering forces to be generated anyway. Provided, of course, that the volume being filled with the foam was not overly large, and that foam filled the void well. But that's just me thinking...and as people have said before...that can be dangerous

 

[logan944t]

Re: Going foamless

Interesting results Logan! As far as the sheering forces are concerned, it seems to me that with the deck tabbed to the hull and fastened to the stringers, there would not be much flex in that area for sheering forces to be generated anyway. Provided, of course, that the volume being filled with the foam was not overly large, and that foam filled the void well. But that's just me thinking...and as people have said before...that can be dangerous

Yea-- I forgot about the deck being secured to the stringers. That would change things for the better. Dangerous doesnt happen until a cutting torch is involved.


I have 3 of 4 pieces of the deck secured to the stringers. I went with pl premium and screws. Most of the screws stayed tight --a few just spun. I also used 8 batteries and numerous paving stones until the PL was cured( 24 hours).

Unfortunately I ran out of foam and still have 2 spaces to fill--so work is at a standstill until I can order more.


The difference in the boat is night and day. The hull used to creak and groan when I was walking inside-- now the boat transfers the load and the trailer makes noise. The boat feels like it is all one piece.

 

[fishbone77]

Re: Going foamless

Glad to hear you're making progress - can't wait to see pics! I'm also in the "waiting for supplies" mode - I've ordered more epoxy, but will need some warmer temperatures before I can use it anyway.

Just curious - did you use 3/4" plywood for the deck? I seem to remember that you were trying to flex it slightly with the idea of helping water drain off it - how did it go?