Expanded Polystyrene Foam

[eyes]

Hi!
I've been trying to learn more about flotation foams because i saw here in the Dominican Republic people using Expanded Polystyrene Foam Blocks to fill under boat floors for flotation (Flat floor Pangas). They told me you can get little water abosortion using it but my concern is in the structural matter.
Has anyone use this foam for that purpose? Does it have any advantage, besides water abosortion?
You can find this stuff in 4' X 8' ply or bigger, and you can tell the height you need for your work (1", 12", 24"...). Maybe it can be shapped cut to fit the desire space.

[jimslade]

Sorry that material is for insulation only and will melt if gasoline or oil touches it. Use the proper stuff please.

[Specmar.Aus]

Hello Jim
As a Senior Member perhaps you can direct us to a approved Flotation Foam web site.
Where can we access the ABYC and US Coast-Guard approvals for this material.


We here in Aus have only last year come on line re Flotation Foam and Buoyancy materials and methods for power vessels under 20 feet.

Any info would be great,

Cheers Specmar.Aus

[eyes]

Hi Jimslade
I didn't say i was going to use it but the thing is that i saw people here repairing boat floors using that kind of foam.
I've also found this site doing a little research about it:
http://www.koolfoam.com.au/boat.htm

[Rusty Bucket]

Hey eyes, I'm building an aluminum "panga" and I use polystyrene foam in the floors of my boat. If you buy foam that's certified for use in a habitable structure then you will see that it has to meet a minium standard for fire retardance. I also coat the surfaces that are exposed with exterior latex paint. If you are going to operate a uscg inspected vessel in U.S. waters and carry passengers you might want to clear it with them first. If you intend to have gasoline in your bilges then I suggest that you might have problems that transcend the question of what kind of foam you use for floatation. I'm not trying to convince you to do it one way or another just letting you know how I do it. I believe the recreational boatbuilding world might learn something from the Dominicans, your heretical friend rusty.

[jimslade]

If there are any boat builders in your area they may sell to you.
It comes in two parts. Mixed 1 to 1 and will expand to thirty times its size. You have to be careful using it. Unless there are relief holes I've seen it split a fiberglass joint. Usually referred to foam flotation not expanded styrene.

[eyes]

Yes Jim, i know wich is the right one.
One of my childhood friend here in DR is the owner of a Fiberglass supply co. so ihave no problem with that.
I was refering to the other foam because it was strange to see people using it for boat flotation purpose, even if it melts with gas,acetone...
I was wondering if someone have done the same thing in a boat.
If i use a product it has to be approved by the USCG, then i will know it's safe.
I've also found another site for foams:
http://www.marinefoam.com/flotation-foam.html

[Lancerbye]

The only reason people are using expanded polystirene foam is that it is cheap in comparison to 2 part urathane pour in foam. I have seen it used for dock floatation where it is encapsulated in concrete. This stuff breaks up real easily and a lot of it is found on the surfline. Its true that it doesn't absorb water but it will melt when exposed to a variety of paints and poly based chemicals. Its insulation properties are, I believe half that of Styrofoam and about a 6th that of closed cell urathane foam. (the stuff most commonly used.)

[Rusty Bucket]

Hey Lancerbye, Thanks for the response. It's true that polystyrene foam is cheap compared to expanded eurathane but it also has other properties that are superior. Polystyrene is truly closed cell, eurathane on the other hand is "closed" cell relative to it's density, the denser the higher it's resistance to absorbsion. Polystyrene does melt when exposed to gasoline and other petrochemicals and shouldn't be used where it will come in contact with those chemicals, but if utilized properly polystyrenes can make excellent flotation materials. I suggest that anyone who has an interest in using polystyrene as floatation material check out the U.S. Coastgard web site @ uscgboating.org/ and look at the "Boat Builders Handbook", and ASTMD-2842.
I know that there is conventional wisdom that condems the use of certain materials in boatbuilding but I believe they are the result of jumping to conclusions and myths. Like most things, sometimes it's just not so simple. Regards, rusty

[Lancerbye]

Thanks for the link. (I am a Canadian)
By my interpretation of the floatation material test, poly styrene foam wouldn't pass. Now I could be wrong.

FEDERAL LAW

183.114 Test of flotation materials.

(a) Vapor test. The flotation material must not reduce in buoyant force more than 5 percent after being immersed in a fully saturated gasoline vapor atmosphere for 30 days at a minimum temperature of 38 deg. C.

(b) 24-hour gasoline test. The flotation material must not reduce in buoyant force more than 5 percent after being immersed for 24 hours at 23 plus or minus 2 deg.C in reference fuel B, of ASTM D 471 (incorporated by reference, see Sec. 183.5).

(c) 30-day gasoline test. The flotation material must not reduce in buoyant force more than 5 percent after being immersed for 30 days at 23 plus or minus 2 deg.C in reference fuel B, of ASTM D 471 (incorporated by reference, see Sec. 183.5).

(d) 24-hour oil test. The flotation material must not reduce in buoyant force more than 5 percent after being immersed for 24 hours at 23 plus or minus 2 deg.C in reference oil No. 2, of ASTM D 471 (incorporated by reference, see Sec. 183.5).

(e) 30-day oil test. The flotation material must not reduce in buoyant force more than 5 percent after being immersed for 30 days at 23 plus or minus 2 deg.C in reference oil No. 2, of ASTM D 471 (incorporated by reference, see Sec. 183.5).

(f) 24-hour bilge cleaner test. The flotation material must not reduce in buoyant force more than 5 percent after being immersed for 24 hours at 23 plus or minus 2 deg.C in a 5-percent solution of trisodium phosphate in water.

(g) 30-day bilge cleaner test. The flotation material must not reduce in buoyant force more than 5 percent after being immersed for 30 days at 23 plus or minus 2 deg.C in a 5-percent solution of trisodium phosphate in water.

(h) The buoyant force reduction in paragraphs (a) through (g) of this section is measured in accordance with ASTM D 2842 (incorporated by reference, see Sec. 183.5).


Table 183.114 - Flotation Performance Tests

NOTES:

The change in volume and buoyancy is measured in accordance with ASTM D-2842. The maxi mum size of a test sample shall be 6” x 6” x 3” and cut by the same method used to shape it for use in the boat.
Flotation material does not have to be gasoline, oil, gasoline vapor or trisodium solution-resistant if:
a. Used in manually propelled boats;

b. Installed outside the engine compartment more than 4 inches above the lowest point where liquid can collect when the boat is in its static floating position; or

c. Enclosed or encased in an enclosure that permits no more than one-quarter ounce of fresh water per hour to enter when the enclosure is submerged to a depth of 12 inches.

Cellular plastic used to encase fuel tanks is allowed to count as a flotation material, but it must conform to the following applicable conditions (33 CFR 183.516 of the USCG Fuels Systems regulations):
For the purposes of these tests, ASTM oils and ASTM fuels, and a trisodium phosphate solution have been selected which approximate typical marine products with which flotation material may come in contact in actual service.
ASTM reference fuel B provides typical swelling effects produced by commercial gasolines, and ASTM No. 2 reference oil has been chosen since it characterizes the nearest aniline point of a petroleum- based oil used in marine service. The aniline point of petroleum oil determines the swelling action of the oil. Reference fuel B consists of 70% Isooctane and 30% Toluene, in volume (Isooctane conforming to Section Annex A2.8, Motor Fuels Section of 1973-74 ASTM Manual for Rating Motor, Diesel and Aviation Fuels; Toluene conforming to ASTM D-362 for Industrial Grade Toluene).
For a full explanation of the test fuels, refer to ASTM D-471.

[Rusty Bucket]

Hey, Thanks for the reply. I don't consider myself an expert on the subject and I have no doubt that I could be wrong about this.....but, did you check out the notes following the test requirments, ie; outside the engine compartment, 4" above the lowest point of bilge water collection at static waterline or totally enclosed in water proof container is exempt from test. What kind of foam do you find in those two metal enclosures found at the front and rear of a aluminum jon boat? I enjoy these conversations becouse I like to challenge my own assumptions and beliefs, thus my remark about things not being so simple all the time, at least not till the meds kick in! regards, rusty.....ps, how do you attach links?, thanks

[eyes]

Guys, thanks for the info.
Rusty. just write the link and it will appear as one.

[Carib_Builder]

eyes I am interested in Boat Building in the DR could you contact me?

[Lancerbye]

Hey Rusty Bucket

I guess that when there are to many obsticles in the way I tend to sail around them. My experience with foam come mainly from my rebuilding of a 34' double ended commercial fishing boat. I had to put in insulated fish holds . Being of the frugal nature and liking a challenge I opted for the pour in type of foam ($100 gets you 13 cu.ft of foam ) it can go into all the corners, sticks to everything and is closed cell and waterproof. I also used the polystyrene expanded bead foam in sheets for insulation in the cabin walls and ceiling. All products have preferred usages, but there is not usually a strictly defined demarcation for these uses. Imagination and inventiveness (frugality) are the signs of a liberated builder. LOL

[eyes]

Carib_Builder
I have 4 year degree in Marketing-Advertising and Graphic Design but I currently own a small furniture manufacturing company here at DR. I'm not a boatbuilder. I just love fishing and boating and i'm on my way to repair a center console boat. I also used to make and repair surfboards as a hobby. If there is anything i can help you with here just let me know.
A friend of mine is the owner of a fiberglass related company and he supplies all the manufacturers here. Most people know each other here also, 48,000 KM2 island.