Formula 27PC Transom Work

[alldodge]

There should be enough room to put the tank in with the engine bulkhead in place. My plan is to grind all the stuff out which is not needed. Still need to remove the last small piece of engine bulkhead on the starboard side up to the outside of the engine stringer. Pick up some 3/4 plywood and start fabing some pieces to replace what was pulled out. Need to have all the structure done before the tank goes in

As before you mentioned I need 60 degrees to do VE resin work so I need some heat or wait for nature to provide. Was just on the US Composites site and reading through their material. Maybe they can fill in some questions I'm starting to ask.

 

[kcassells]

dalete

 

[alldodge]

kcassells That is one long post, even copied the other posters. I read it some time back when I was looking into tank replacement. Might have been a bit easier and less wordy if you just supplied the link.

 

[kcassells]

dalete

 

[alldodge]

Cleaned everything out off the hull and been looking for replacement stuff. One of the things I removed was the 1/4 thick by 1 1 /4 neoprene strips which were on each of the ribs. The tank sits on them prior to pouring in the foam. Figured this cannot be that expensive I'll just replace them. Went looking on line and I might have to go digging in the trash. Solid neoprene appears to be a bit pricey

 

[Scott Danforth]

I myself would look at reinforced urethane strips (conveyor belting) vs neoprene. http://www.mcmaster.com/#flat-drive-belts/=v1x4fb it is what is sandwiched between most 1947-1955 truck frames and the cabs as isolation. if it lasts 60 years old trucks, it will last that long in your boat.

my guess is the original foam was medium density EPDM http://www.mcmaster.com/#epdm-foam-sheets/=v1x5p5

 

[alldodge]

Thanks Scott but the Tank manufacture states this shall be used or no warranty. It is firm but slightly soft, not very much just some. I see it as being a cushion for the tank against the glass ribs. Found one place which wants 2,60 a foot and here on Amazon is out of stock but only has differing sizes

http://www.amazon.com/Neoprene-Durometer-Smooth-Adhesive-Backing/dp/B00CCGWK4O

 

[kcassells]

The point of the Neoprene/warranty is in regards to the reaction other rubbers/plastics have with aluminum, finished or unfinished. So thats exactly what you need to get.
Hop in the trash can and dig em out.

 

[alldodge]

The point of the Neoprene/warranty is in regards to the reaction other rubbers/plastics have with aluminum, finished or unfinished. So thats exactly what you need to get.
Hop in the trash can and dig em out.

We can agree to disagree on this one. The tank like everything else on the boat, you don't want a hard spot. Wood is positioned above the hull so no hard spots happen which can cause cracking. The tanks was and will be again painted, the tank needs something to cushion it self from the hard edge of the glass hull.

 

[kcassells]

What are you talking about in regards to a hard spot? That precedes the Neoprene that you put down on the framed out deck/walls/fiberglassed that were already hopefully installed with out hardspots. ? The neoprene is for a "cushion" minimal to say the least, especially if your foaming. The neoprene is to prevent metalic reaction. Use another material and the aluminum will corrode.

Get it?

 

[tpenfield]

I had to get my neoprene through Amazon, as Mcmaster was too pricey for me as well. I see the neoprene as serving the purpose of keeping the tank up off of the ribs in the hull and in order to do that it has to be of a material that can remain in contact with the tank and not cause any problems - neoprene. Most of the weight of the tank (esp. when full) will be born by the foam.

I do not recall from the pictures, were there metal straps holding the tank down?

 

[alldodge]

I had to get my neoprene through Amazon, as Mcmaster was too pricey for me as well. I see the neoprene as serving the purpose of keeping the tank up off of the ribs in the hull and in order to do that it has to be of a material that can remain in contact with the tank and not cause any problems - neoprene. Most of the weight of the tank (esp. when full) will be born by the foam.

I do not recall from the pictures, were there metal straps holding the tank down?

Agree with you, and no there were no metal straps

 

[Tail_Gunner]

I am going to go thru this myself so may i ask where is the problem with foam supporting the tank, 4lb foam poured into tank cavity would be leaps and bounds ahead of anything else would it not. No hard spots no flex it would seal that tank in place from all directions with equal force..read in movable as you already know.

http://www.uscgboating.org/regulatio...rds_partj.aspx
Each fuel tank intended to be permanently installed, must be made as a separate component and then installed in the boat. Portions of a boat’s structure, i.e. hull surfaces, bulkheads, stringers, floors, decks, frames, etc., may not form part of a fuel tank.
Fuel tanks glued, bonded or foamed-in-place are not considered integral and are therefore acceptable. However, that installation must comply with the applicable portions of this regulation.
Fuel tanks may not be mounted on an engine, except if the engine is part of a portable piece of equipment that is not permanently installed in the boat. If a fuel tank is removed from an engine to be installed in the boat, the installation must comply with the requirements of this standard. Particular attention is directed to the fuel tank vent requirements and the requirements for all openings to be in or at the topmost surface. Many tanks installed on engines have a bottom fuel supply; this fuel tank is not acceptable for installation in a boat.

Opps didnt read it right your just setting it up for a pour my bad.

 

[tpenfield]

Agree with you, and no there were no metal straps

OK, this will be interesting as to how you foam the tank back in. If you merely pour foam in along the sides so that it will flow underneath the tank before expanding ( about 45 seconds ), then the foam will lift the tank right up. I am wondering if Formula encased the tank with the rear berth framing first . . . applied the top foam in a few spots and then filled the underneath & side portions afterwards.

Did you notice the few pieces of garden hose in the foam underneath the tank? That is what they use to 'pump' the liquid foam in to the underside of the tank so it will expand and come up the sides.

 

[kcassells]

Good Admirals advice. lol. So why neoprene AllDodge? Can you let the forum know why you HAVE to use neoprene?
Just wondering cause I'm a neub.

 

[alldodge]

OK, this will be interesting as to how you foam the tank back in. If you merely pour foam in along the sides so that it will flow underneath the tank before expanding ( about 45 seconds ), then the foam will lift the tank right up. I am wondering if Formula encased the tank with the rear berth framing first . . . applied the top foam in a few spots and then filled the underneath & side portions afterwards.

Did you notice the few pieces of garden hose in the foam underneath the tank? That is what they use to 'pump' the liquid foam in to the underside of the tank so it will expand and come up the sides.

According to US Composites the foam will not lift the tank or anything else unless it is in a confined space. I did notice and removed all the hoses. Looks to be Formula used the hoses to pump the foam under the tank and let it flow around. The hoses were between the ribs and there was foam on top of all of them. The neoprene had in most spots very little foam on top of it and none under it. Looks to be the neoprene had adhesive on the bottom which was used to secure it to the bottom and sides, no nails or staples used. The noses were nailed in place.

As with the water tank the gas tank sits on the bottom and foam is pumped in, in my case will be poured in. think just in case I'll measure the height of the tank sitting on the bottom and make sure the top will be at the appropriate level at the engine bay prior to pouring foam. If all is good and to make sure nothing moves I'll secure the top and pour just enough to do the bottom and part of sides. Then install plywood top and pour remaining foam

 

[tpenfield]

According to US Composites the foam will not lift the tank or anything else unless it is in a confined space. . . .
. . . As with the water tank the gas tank sits on the bottom and foam is pumped in, in my case will be poured in. think just in case I'll measure the height of the tank sitting on the bottom and make sure the top will be at the appropriate level at the engine bay prior to pouring foam. If all is good and to make sure nothing moves I'll secure the top and pour just enough to do the bottom and part of sides. Then install plywood top and pour remaining foam

OK, I just want to put it out there, based on my experience with the foam . . .

During the initial stages of the pour and the initial expansion the foam/liquid will be fairly 'free-flowing' and will not have any considerable power versus the weight of the tank. It is in the later stages of the foam expansion when it begins to solidify yet some areas are still expanding that it will do the lifting sort of thing. So, those would be during the 4th and 5th minutes of the 5 minute expansion/curing process.

I know that on my tank installation, the foam put so much upward pressure on the tank and the aluminum straps that held the tank down, that it actually pulled out a couple of the 8 (eight) 3" screws that were holding the straps down. Probably pulled the screws about 1/8" or so, not much, but it would be hard to say how much the foam would have lifted the tank if the straps were not there at all and the tank was 'free-floating'.

My only concern is that if in the later stages of the foam expansion, it lifts your tank up and inch or so and solidifies, you could have a mess on your hands for reassembling the aft berth.

 

[Woodonglass]

Uhmmm, I'd STRONGLY recommend you listen to the voice of experience and NOT USC!!! When the foam starts to "KICK" and expand it WILL lift your tank, and anything else that's not properly tied down to resist the pressure it exerts. Anyone who's worked with it "KNOWS" what that stuff is capable of doing when it comes to pressure build up!!!

 

[tpenfield]

I read somewhere that the foam can/does exert about 5 psi as it expands. Based on the approximate size of the tank, there is the potential for 9,000 lbs of lifting force. Since much of that force will go towards expanding the foam up along the sides of the tank, very little of the force will go towards lifting the tank . . . so let's say only10-20% of the total potential will lift the tank . . . still leaves 900-1,800 lbs. that can lift the tank.

 

[Tail_Gunner]

What eveyone is saying is quite true, as to why US would say it wont lift the tank or the circumstance's that could happen under is baffling. I actually stood on my deck so the foam would compact and let it lift me almost a 1". I can tell you foam need's to be at 80 degrees for maxium expansion...so maybe 50 degrees would tame it down abit

Below is a pic of how i foamed the deck, the guide rail's or stops actually caught the deck on the rise i stood in the middle and watched raise like a loaf of bread...rather rapidly however. Notice the far right corner that's how low the deck started it rose over a inch in all.

Actually worked quite well i used 9lb foam....Its my ss icebreaker...:lol: