Pourable foam

I have an application in a boat for 8lb pourable closed cell foam. It will be fibregalss encased but underwater. I am trying to understand what would happen if their was puncturing of the fibreglass encasement.

I have not been able to get any data on the potential water absorbtion. One source suggested essentially nil another 100%. Does anyone have accurate data. Are there success stories of using pourable foam in this way, are their horror stories? Are there ways to reduce the water absorption?

Thanks
Brian Rodwell

 

Porable foam

The first question is: what type of foam are you using (polyurethane, polyiso, syntactic, etc.)? Also, is this intended to be a structural foam, or just for bouyancy? It's been my experience that most pourable foams are open cell, while the sheet stock PVC's/SAN's and near 100% closed cell.

 

Urethane foam

He is a reference to one of the suppliers:

http://www.uscomposites.com/foam.html

They use the words 'resists the aborption of water'.

The area of application has only low compressive loads.

 

Brian,
I'm in the process of testing this foam as I post. I've had several questions on the foam after deciding to use as a filler in my dual rudder set-up on my 40' cat. Seems many out there don't understand the definition of closed cell so I'll post the IRC (Institute for Reasearch and construction) Post in the Canadian digest.
http://irc.nrc-cnrc.gc.ca/cbd/cbd166e.html
I mixed a small amount today. 6oz of pourable foam and a equal part 6 oz of activator and let it cure. Photo below. This amount produced a little more than a 1/2 gallon container. I plan to let it cure for 24 hrs and weigh the piece on a digital scale. I then plan to sebmerse just below a mooring ball in a salt water situation. Only water that doesn't freeze up here. I hope to leave it under for 2 months retreiving once a week for a weight measurment.. I can keep you postd if you like
Regards
Bob C.

 

ClarkT

Looks like the A/B foam I've been using. It develops a film on the surface exposed to air so you might shave off that film before dunking the foam.

Please post the results when you know about the foam, I'd be very intrested to know the facts behind the marketing.

 

Does some one use sprayed urethane foam used in home insulation?
I look for pourable foam and I find one at $7.50/cubic feet and I have to mix and pour all the foam. My local insulator contractor propose to me to spray Urethane foam for $10.00/cubic feet and I dont have anything to do myself. I need 80 cubic feet of foam.

 

From what I understand from our vendor, the typical home insulation foam and the pourable A/B foam are the same thing. The insulation contractors run it through a heater and mixer so it kicks in seconds instead of the typical 1.5 minutes. We have had some luck ordering a 'special' foam that has a lower exotherm and takes an extra long time to kick (3 minutes). This allows us time to mix and then pour the foam which then rises from the puddle poured to the bottom of the mold. We are shooting for a void free foam pour and have had luck with this special grade of foam. The other stuff kicks too quick and voids are left all over the place.

 

I received data sheet for insulation urethane foam.

http://www.basf.com/basf-canada/productsheets/walltite/walltite-E.pdf

http://www.basf.com/basf-canada/productsheets/walltite/CCMC12840-E.pdf

I ask the compagnie BASF about what they think for marine application of this product and I wait their answer.

 

The walltight product is a comercial house building insulation. I don't think its intension was intended to be used in a marine situation. I also didn't like seeing the words (OPEN CELL CONTENT) listed in the discription but please let us know what their reply is. I have cut the surface of the test piece of foam as Clark T. suggested and submersed in a pail of water. This foam is a closed cell foam intended for marine application and was purchased from Fiberglass Coatings Inc. in Tampa Fla. www.fgci.com
I first weighed the dry foam and it came in at 7.5 oz. I then dipped the foam piece to allow the pourosity and surface area to absorb some of its weight and it then weighed 7.8 oz. I will now weigh once a week and record the differences. I also saved the bucket that was used for the form and this will give a base for testing expansion or swelling. Does anyone else have sugestions for testing?

 

About WALLTITE and open cell, the word is listed but they write less then 1% so I think that is a good caracteristic. Does some body can fin caracteristic of buoyancy pourable foam to compare. US Composite and other sell foam but as is without official technical data.

NASSAW: About you test, I think that you are in the good way but I find that 0.3 oz or 8.4 ml of water trapped in foam in big (4% of total weight). Do you try to shake the foam and air jet clean exterior foam after the first immersion but before weigh. The same operation will be do at each weigh.

 

For example, I look the water absorbtion of WALLTITE insulation foam and it is 2.5 %. At a difference of weight about 4% for the first check, a 2.5% difference will be non-significatif

 

The 1st dip was to check the difference in weight with the surface area covered in water. I didn't mean to use the word absorb. The foam was only in the water for a few seconds and I'm sure there was no water actually absorbed into the foam. I did this for my own reference and will blow dry the surface before the 1st of a several week test. Hope your not in a hurry

 

Don't forget that water pressure increases VERY rapidly for just 10' down. It is not like air.

 

pourable foam test

Gentlemen
Seven days into my simple test I pulled the piece from the water. Blew it of with air as someone sugested and put it back on the scale. The scale fluxuated betwen 7.5 and 7.6 settling at 7.6. I wish I had a more accurate scale but will have to settle on this digital with a tenth of an ounce incriments.
Visiualy the surface of the foam looks unchanged. placed the piece back in the bucket i used to cast and could see no change it the size. Its only been 7 days so I took a picture and placed it back in the water and will recheck in another week. I'll post the photo below.
Cyclops, Thanks for the input but depth doesn't have much to do with my application. We're building a 40' cat and used the foam in the rudders and if the rudders see more than 4' of depth. There will be alot worse things to worry about than the foam
Regards
Bob C.

 

7 more days have past, 14 days total and the weight came in again at 7.6. The test piece has gained 1 3/4 to 2% of its total weight. Visualy the piece has not changed and is still very hard to the touch. About the same as when I first made it. I'll wait 14 more days before the next weigh in.
Regards
Bob C