bertram31.com

Well, I don't know if anyone of the faithful would think of it as a Christmas Present, but for those of you interested in using expandable urethane foam & not sure of the process, here's a present for you...

Merry Christmas, Happy Hanukkah , & Best Wishes for a Great New Year!

New Addition to the Tips Section:
Working With Two Part Expandable Urethane Foam

Stuff looks great, but does it bond well to cured polyester frp, epoxy?

Thanks Patrick,

Do I assume this is the product you would recommend for replacing the foam beneath the deck of my B-20 Sportsman whenever I get around to the re-build? Merry Christmas to you and yours as well!

Tommy

so, Capt P. does this stuff have any insulating value? Looking ahead, at the tubb express project, and it's intended use(floating condo/drinking platform) . Probably be a winter apt in boston. The one year we left it in it was cold, very cold. And expensive to heat, REAL expensive. While the things gutted, I'd like to get as much insulation on the hull and in the headliner ribs as I can. Would this stuff work ? or is there a better product?

Would that stuff keep the TuBBB floating?

Matt,

Urethane will adhere exceptionally well to any preped surface. Will not stick to things like waxed paper, polyethlene, etc. Gorilla glue is a one part urethane. Low density foams have no strucrural value but higher density foams can be as hard as a rock & very strong.

Tommy,

The density you'd want for the Sportsman would be 4 lb, which has more structural capacity than lower densities while still very good flotation quality.

Timmy,

Insulating a boat is like shoveling sand against the tide... Where most of the thermal transfer takes place is through the wetted surfaces of the hull. But if you were to try to apply foam to vertical and overhead surfaces, you want to spray it on. Like: http://www.foampower.com/ I think that your efforts to do so would less than productive though...

Urethane foam isn't in itself flamable, but within a foam covered area, the foam will act as a reflector to heat and thereby intensify an internal fire very rapidly. Once the urethane does start to char & burn the fumes are exceptionally deadly. Code for foamed walls and ceilings in buildings require a barrier between the interior space & the foam, usually 1/2" sheet rock. The barrier keeps the foam from reflecting heat for a longer time, possibly allowing the fire to be extinguished. Un-shielded, urethane foam can intensify a small fire from 500 degrees to over 5,000 degrees in a matter of seconds. (see: http://www.monolithic.com/foam/fire_hazard/index.html)

Br,

Patrick

Capt. Pat.
Would this be a suitable product for injecting into the void between the house and flybridge. I'd like to remove some of the potential compression where the front legs of the half tower land. Thought that injecting some foam into the area through the windshield bolt acces points might allow that load to be spread out a little more. Haven't had any issues yet but this was the first year of "real" use
What's your thought?

I use it to foam in my center fuel tank on my 31 with the 4lb. But be ready to pour it when you mix the A & B parts together, works great!

DQ

JP,

Don't think the pourable material would work for you at this point, but you might be able to use an injectable foam. Similar to spray, but uses a different mixing nozzel. Only problem is finding it in a 4-6 lb density. 2-3 lb really isn't going to add any strength. You'd also want to use a slow rise foam that's designed to rise and fill at a less aggressive rate.

All of the pour foams are going to require a fairly large hole to pour through. When Da' Judge foamed under his deck he hole sawed to about 1 1/2" or 2" access holes. Maybe he'll catch this thread input on his techniques.

Br,

Patrick

I thought you were building us all models of 31's formed out of expandable foam.

What a jip.

JP- I think we sometimes use an injectable foam at work and often in different densities. Unfortunately everyone is on Vacation until the 2nd of January. When they do get back I will get some sources/info on the injectable variety if they have any. I think there is a supplier in northern Jersey.

Merry Christmas and Happy New Year- Happy belated Hannukah, belated Ramadan, and an early happy Lohri to any Hindu eagle jockies on the site.

Patrick
I will take your post as a Christmas present..........I have done a little fiberglass work over the years but to be perfectly honest I have never had a good working knowledge of the products and proper application.

Although I have always had positive results I have relied on experienced people to tell me what products to use.

The epoxy sold by US Composites is a good bit less expensive than West Systems that I have been purchasing locally. Is the US Composites brand epoxy comparable in quality to the West Systems????? Would you use it for hull repairs and engine room laminating etc??????

Again thanks for the Urethane Foam post as well as all of the other Boat Building Tips that you so generously share with us.

Harry

Harry,

All of my epoxy comes from US Composites. It's every bit as good as West System. The last time I bought any West System has to be around 15 years ago...

There are only about three chemical companies in the United States that manufacture epoxy resins & maybe a dozen that make the hardeners. All suppliers who label their brand product buy their materials from these few manufacturers.

West System Epoxy is the trade name of Gougeon Brothers, Inc., is an excellent product line, & more readily available due to marketing sources like West Marine, Boat Owner's Warehouse, & BoatUS, but it's highly over rated & comes from one of the same sources as any other supplier.

Same thing can be said for Raka, System Three, & other brand names...

Another thing about West System that I don't like is their 10:1 mixing ratios. It's far easier to screw up the ratio and get a bad mix with 10:1 than it is with a 2 or 3:1 ratio. Epoxy systems are ratio specific. Too much or too little hardener & the mix won't work. Not like polyester or vinylester resins & MEKP.

Br,

Patrick