Polyumac foam???

[BriggsMonteith]

Has anyone here ever used Polyumac foam? I had never heard of it before today. I was told that it was a viable alternative to PVC/klegecell foam that the densities/stiffness/longevity were the same. The only practical difference mentioned was that it was not able to be baked in an autoclave...they also said it had better primary bonding with polyester resin. I want the low down from someone who is not a distributor. any thoughts would be appreciated.

-Briggs

[Fanie]

Hi Briggs,

I don't know Polyumac foam at all and haven't googled for it. I use a closed cell Polyethylene foam for various reasons. Not sure what your intent with the foam is.

Whichever foam you decide to use, do not use it for it's structural strength. Sorry if you know that.

[BriggsMonteith]

Thanks Fanie,
I know that the foam isn't used for any tensile strength, but rather shear strength. I actually talked to a tech guy at Polyumac and he said that he knew nothing about sailboats much less about catamarans, but he did say that Sea-Ray power boats were using 8# density in the hulls and 5# In the decks. He gave me a bunch of other technical data that was too technical for me to understand. So I'm pretty much as clueless as when I started.
-Briggs

[Fanie]

Hi Brigs,

The sheer strength comes only from large surfaces ! Any structure you plan to make, keep the strength of the foam out of it as if there is no foam.

There are a number of things foam is used for -

Flotation - must be a closed cell foam, must not absorb water over the long term. The idea is to make the boat and parts unsinkable, there is no such thing as too much flotation, however one should keep in mind that huge pieces of foam also has weight and takes up space.

Stiffen the hull - if glass on the outside and the inside (and the outside has to be full strength). Obviously a good bond between the inside and outside is a must.

Heat insulation - foam has to be temperature neutral and not conduct heat/cold.

Noise insulation - you sleep better if the fish isn't biting

Other properties you should look for -

Must not be flamable, preferably self extingishing

If burnt must not release poisenous gasses

Water condensation must not take place and drip on you

Algea must not grow on it

The foam must be able to flex and stretch without cracking or disintegrating

and more

If no inside glassing (I plan to use mine as the inside finish) colouring,

Pleasant to walk on

Durable to walk on

Easy to replace / maintain damaged areas

Easy to clean

Soft if you fall or bump ie in rough water

UV resistant

Chemicals / acid / fuel resistant

The PE foam I mentioned is expensive, but it complies to most of the above. I have tested a bunch of foams and the PE comes out tops. Weight I use is 33kg/cu m. It works easy, you can cut it, mill it, saw it, lathe it, and it glues stunningly well to resins as well as the silicon type glues like Dow Corning of which there is a gazillion types. Don't use silicon though.

I'm sure someone can come up with more...

What is it you want to do ?

[BriggsMonteith]

I want coring material like klegecell, which is probably what I'll use it's worked really well for me in the past. I just wanted to have a look at what there competitors are offering. Richard Woods Flica is the boat that i want to use it on and he has told me that 5lb per Cubic foot PVC foam is acceptable for all of the applications on this boat. Polyumacs product meets that description but I just want to feel confident in the product.

[Ike]

Polyumac is a brand name, A glance at their website http://www.polyumac.com/ reveals it is polyester foam. They also refer to it as a polyimide foam (http://en.wikipedia.org/wiki/Polyimide_foam) which was a brand name but is now pretty generic. It was developed for NASA as a structural foam. I don't know why it couldn't be used but I would imagine it is expensive compared to PVC foams.

[BriggsMonteith]

Ike,

Actually fiberglass coatings in St Petersburg is selling it for about 2/3 the cost of Klegecell for the same density and it is supposedly an aromatic Polyester foam, this is what Polyumac claims anyway, I don't know what they mean by "aromatic" though. as I re-read the page is claims to be an alternative to PVC though.... but is it as adequate as Klegecelll?

http://www.polyumac.com/standard.htm

-Briggs

[Ilan Voyager]

Unhappily I have not first hand infos on this product.

I would ask technical infos (ciphers...) to Polyumac about the foam and compare them to a reference like Airex. Polyester foams (aromatic is the chemical group of this polyester; stable and solvent resistant.) are good, nothing to compare with the polyurethane foams that are not suitable for boatbuilding.

PVC foams are a rather poor adhesion with polyester (the main problem of Airex and consorts, no problem with epoxy), and polyethilene foams? never saw this stuff, I know only polyethilene honeycomb. Polyethilene is totally unbondable with polyester (and other glues), it has to be hot welded to a polyester cloth screen for composite applications. Polyester foams glues very well.

The list of distributors of Polyumac makes appear serious people, providers of products for structural composites. I would make a trial.

Planning power boats work harder than sail boats even cats, and visibly Polyumac is targeting the market of power boats. So it's seems that this foam can be used on your application.

[Fanie]

The first problem with PVC is it releases chlorine gass when burn which is deadly and can be fatal.

Ilan, the PE foam I use bonds 100% to polyester and epoxy and most glues. It is an absolute marvelous foam. It is not like the PE sheets you buy, which I agree, cannot be glued to anything.

[BriggsMonteith]

Here are te tech sheets for klegecell and polyumac. Polyumac claims to be flame retardent. and since it is not PVC releases no chloride.

http://www.polyumac.com/Aircellproperties.pdf
http://www.diabgroup.com/europe/lite.../R_Grade_E.pdf

The Polyumac T50 And the klegecell R80 are both 5Lb density which is what is called for. I guess a couple of samples is what is needed.

[laurencet]

Did anyone ever get a price for Polyumac
The only other Polyimide foam manufacturer i've come accross is Rohancell but this has always been expensive..
http://www.rohacell.com/product/roha...s/default.aspx

[Fanie]

I made a post this morning and it disappeared

Best is to get samples and play with it.

The Aircell Polyester foam does not indicate it is a closed cell foam. If it was a closed cell foam they would have said so as a primary feature. The water absorbtion specified will be that of the material itself, better make sure.

Same thing with the Klegecell. The 48kg/m^3 is also on the heavy side.

[BriggsMonteith]

Fanie,
this is some of what they write on there website:

AirCell is a closed cell rigid cross linked Aromatic polyester foam core, exclusively design and formulated by Polyumac, Inc., using state of the art polymer technology. This new technology allows Polyumac Inc. to manufacture a new generation structural foam core with outstanding properties of strength, resilience and cost effectiveness as compared to available PVC foam cores.

And here is there web site: http://www.polyumac.com/standard.htm

Laurence, I got a price from Fiberglass Coatings and it was 1500.00 dollars for 750sqft, 5lb 12mm.

Peace,
Briggs

[Fanie]

Ah ok, I had a look and the AirCell looks good. I would still suggest you do a few layups and have a good play with it. It's properties is a lot similar to the foam I use. Would still want to see what it looks like and the price...

[david@boatsmith]

I have just had my supplier reccomend the Aircell foam as well. Did you use it? How did it work? Anybody else with any feed back? BriggsMonteith are you building the Eclipse? I have an order for 1 boat now and one more fella is negotiating with me for another. David 561-632-2628 david@boatsmithfl.com