So after some research on the web I've found several closed cell polyethylene foams that I believe are the same thing as Divinycell but have one further question to pose..
I've found foam in densities from 1.7lb to 12lb/cu.ft.. Divinycell, as you may know, comes in 5lb or 6lb varieties. How would the buoyancy characteristics of the 12lb polyethylene differ from the 6lb Divinycell? Would it offer increased or decreased bouyancy? Would the increased density offer less compression at depth? Would the 1.7lb be brittle and more likely to degrade over time?
Sorry if this is a dumb question but I have no experience handling this stuff..
Here are two of the suppliers I've been looking at for your reference:
So after some research on the web I've found several closed cell polyethylene foams that I believe are the same thing as Divinycell but have one further question to pose..
I've found foam in densities from 1.7lb to 12lb/cu.ft.. Divinycell, as you may know, comes in 5lb or 6lb varieties. How would the buoyancy characteristics of the 12lb polyethylene differ from the 6lb Divinycell? Would it offer increased or decreased bouyancy? Would the increased density offer less compression at depth? Would the 1.7lb be brittle and more likely to degrade over time?
Sorry if this is a dumb question but I have no experience handling this stuff..
Here are two of the suppliers I've been looking at for your reference:
I think that the density tells you the flotation. A cubic foot of divinycell that weighs 5 lbs and one that weighs 10 pounds both displace a cubic foot (7.5 gallons of water). Lighter foam with the same displacement means it can hold up more mass therefore more bouyant. NO?
Bill
I think that the density tells you the flotation. A cubic foot of divinycell that weighs 5 lbs and one that weighs 10 pounds both displace a cubic foot (7.5 gallons of water). Lighter foam with the same displacement means it can hold up more mass therefore more bouyant. NO?
Bill
The density, usually expressed as kg /M3, is an indication of buoyancy but also resistance to compression. Whilst a low density foam will have greater buoyancy on the surface than a high density foam, the situation will change with increasing depth / pressure. As a starting point, I'd recommend looking at a density of around 80 kg / M3. The Divinycell www site has some interesting data sheets to look at which quantify the degree of compression when related to density and pressure.
Hey Tim
Just to let you know those foam tubes you gave me are still working a treat. I've done about 40 dives now at KBR with them. they do compress but re-form without a problem. Still would welcome a bit more lift on my gear - but these help.
Thanks again mate!
Hey Tim
Just to let you know those foam tubes you gave me are still working a treat. I've done about 40 dives now at KBR with them. they do compress but re-form without a problem. Still would welcome a bit more lift on my gear - but these help.
Thanks again mate!
I'm glad they work for you Tim. Since we met, I've given them a good try myself and shy of 25 metres they do provide an advantage. Their density is about 45 kg per M3 so in an ideal world, something about 80 kg per M3 probably have the required resistance to compression at recreational depths (< 40 metres) and therefore maintain adequate buoyancy. Unfortunately, the maximum density polyethylene foam can be extruded into tube is 45 kg per M3. To obtain greater density material is possible but it will incur significant manufacturing costs in CNC or water jet cutting. Hope the new job is going well. Take care and shoot straight!
I made my floats from Dyvinal (?).
To strengthen the edges from chipping, I painted the floats with 2 coats of 2 part fiber glass gel. I put in some black dye and the results look good. And after 2 years there are no chips or major dents.
I made my floats from Dyvinal (?).
To strengthen the edges from chipping, I painted the floats with 2 coats of 2 part fiber glass gel. I put in some black dye and the results look good. And after 2 years there are no chips or major dents.
The ideal solution is indeed Divynicell though the manufacturing costs and minimum volume of cnc or water jet cutting 30mm ID / 70mm OD tubes (to slip over ULCS buoyancy arms) are alarming.
The ideal solution is indeed Divynicell though the manufacturing costs and minimum volume of cnc or water jet cutting 30mm ID / 70mm OD tubes (to slip over ULCS buoyancy arms) are alarming.
We have looked at both Divinycell and Corecell but neither are as tough as the Stix foam. I have the impression that the Stix stuff is a closed cell polyolefin that has some plasticizer in the pellets before molding, but am too lazy to look since the Stix stuff is cheap enough.
Bill
I'm looking for a durable, non-compressable, closed cell foam like the foam on the Stix arms and floatation belts. Does anyone know what this foam is called? Thanks in advance, Tim
It is not cheap prices vari from $2-10 per board foot. When ordered in industrial quantities.
This foam comes in large blocks and we saw it up and laminate skins onto it to make panels at www.cattcousa.com
So after some research on the web I've found several closed cell polyethylene foams that I believe are the same thing as Divinycell but have one further question to pose..
I've found foam in densities from 1.7lb to 12lb/cu.ft.. Divinycell, as you may know, comes in 5lb or 6lb varieties. How would the buoyancy characteristics of the 12lb polyethylene differ from the 6lb Divinycell? Would it offer increased or decreased bouyancy? Would the increased density offer less compression at depth? Would the 1.7lb be brittle and more likely to degrade over time?
Sorry if this is a dumb question but I have no experience handling this stuff..
Here are two of the suppliers I've been looking at for your reference:
