tpenfield

I have been reading up a little bit about the 2-part urethane foam that I will be using to secure the tank into the fuel bay ( 4 lb/cu ft density foam). Looks like I will need/want to raise the temperature of the foam liquid parts and the fuel tank bay in order to get decent expansion of the foam and an adequate fill.

I have a 20 cubic foot 'kit' - basically (2) 5 gallon containers of parts A and B . . . The 20 cubic feet is based on an 80 degree F working temperature. I'll be working in about 60-65 degrees. According to the supplier, the expansion rate of the foam is about half of the spec when used at 50 degrees F. I think that if I pre-heat the liquid and the fuel tank bay . . . Maybe get it more into the 70-75 degree range and the liquid in the 80-85 degree range . . I should be OK.

Anyone have experience or advice for using the 2-part foam in colder temps?

tpenfield

I got the fuel tank foamed in today, so that is a good milestone. The temperatures were decent and I pre-heated the foam liquid parts, so the foaming action was OK. I don't think I got the full 20 cubic feet . . . more like 16 cubic feet, but it was enough.

Here is a video of the day foaming the storage compartment floor and the fuel tank. It is speeded up by 3X so as not to take as long.

http://www.youtube.com/watch?v=0rbvNS7f_Xk Tomorrow, I'll trim the foam and glass over the storage compartment floor.

tpenfield

Another update . . .

I got the foam trimmed today and things prepped for the final bit of fiberglassing.

Storage compartment floor


Fuel Tank Bay


I did the fiberglassing late in the day, but there is still a bit more to go.

masi242

Nice job I watched the vid great job your tank is not going anywhere

tpenfield

Yea, I hope it all stays put. Adhesion is the number 1 thing with foamed in tanks. Of course there is no way to tell, except time will tell.

An unusual thing that I noticed is that there were some expansion/contraction noises coming from the tank the day after I foamed it in. Only noticed it once or twice. Maybe just due to temperature changes, etc.

The tank did get fairly warm when I was foaming it, I'd say 90 degrees F range.

Pilotpete

I watched the videos, and I can't believe how fast he stirs!

;-)

HT32BSX115

That was outstanding!

tpenfield

Another quick update . . .

I coated the trimmed foam with polyurethane as a means of preventing water from condensation from working its way into the foam.



I also have coated the bulkhead with polyurethane . . . I find it a bit easier to use for engine room coating rather than gelcoat.



Today, I hope to get the waste tank installed and the deck hatch laid back down. Things are starting to go together !!!

tpenfield

It's a boat again !!!

Pretty good weekend on the final stages of the bulkhead replacement project . . .

I glassed the mid-cabin storage compartment floor (deck) . . .


Then it was a matter of installing the waste tank and connecting the hoses and electrical. . .

Here is the waste tank carrier installed.


Here is all the 'stuff' hooked up . . .


The deck hatch was laid back down and the helm seat assembly put into place.


The helm seat is still loose, but time was running out in the day. So, that will be done next time. I have a few days off this coming week, so I should be able to finish it up and move onto the regular pre-season prep work.

tpenfield

Well, I am getting near the end of this project and thought to take some time to reflect . . .

1) It all started out with a higher than normal moisture level reading in the main bulkhead, which separates the fuel bay and the engine room. This bulkhead is also a major junction point for the major stringers in the boat.

2) That lead to some diagnostic and remediation efforts to understand the propagation of moisture to joining areas.

3) There was some moisture found in the lower portions of the foam in the fuel bay by drilling some test holes and core samples.

4) Based on the diagnostics done, a decision was made (by me) to remove & replace the center section of the main bulkhead.

5) Upon removal of the bulkhead, an additional issue was noticed, in that the fuel tank was no longer adhering to the foam. This was the most probable cause for the collection of moisture in the fuel bay and the bulkhead.

(I believe it was Audiofn who mentioned that the problems usually go further than you think . . . )

6) Upon removal of the fuel tank and related foam, moisture was also noted in the forward bulkhead. It was not too bad, but it warranted looking further forward into the mid cabin storage area.

7) The storage area floor was in a progressed stage of moisture and partial rotting, so that extended the scope of the repairs to the mid-section of the boat.

8) Along the way, I looked at the structure of the boat in terms of stiffening the structure. Bonding the cockpit sole to the stringer grid would be a way of adding some rigidity to the boat. I contacted Formula Tech Support about this idea. They indicated that although it would add some strength it was not really necessary and may result in some crazing of the gelcoat in some areas of the cockpit sole. I decided to go ahead and bond the cockpit sole to the stringer grid, figuring that this would be my only chance.

9) Additionally, I had asked Formula about the built-in flotation that is used in the structure. I was interested to know if the boat had enough flotation to remain afloat in an 'unplanned event'. I also did my own estimations and calculations to determine if the boat could stay afloat. It turned out that I should probably add some flotation to insure that the boat would remain on the surface, if it ever became flooded/mostly submerged. So, I added approximately 24 cubic feet of flotation to the boat.

10) Then it was a matter of putting it all back together . . .

So, what started out as a wet bulkhead, expanded in scope based on both what I found as the underlying cause of the moisture as well as some improvements made along the way.

Total time for the work was about 6 months from the first cut into the bulkhead . . . my hopes are that this boat will be good for a very long time, probably the rest of its useful life.