Jump to content

Recommended Posts

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

Share this post


Link to post
Share on other sites

Do a search for Divinyl Cell.

Share this post


Link to post
Share on other sites

Ive mailed John to ask if anything has changed, but when I wrote my review the floats were made of closed cell polyethylene foam. Im not quite sure if there are different densities with different flotation properties.

Share this post


Link to post
Share on other sites

I believe is a type of closed cell polyethylene foam which is available in various densities, weights and therefore, buoyancy.

 

Divinlycell appears to be the trademark of a Scandinavian polyethylene foam manufacturer. A quick 'google' didn't reveal a UK supplier.

 

Thanks, Tim

Share this post


Link to post
Share on other sites

Tim, Alex - the material you are looking for is called Divinycell

 

A few of us here in california have special ordered it and used it.

 

Scott

Share this post


Link to post
Share on other sites
So which one would you order for the US dealer. 1 1/4 inch?

Not sure they will cut larger sizes to order. Worth a call to them. I ordered the 1/2 inch -- I am going to put some in the Ikelite tray and then rig additional as needed, below the tray.

Share this post


Link to post
Share on other sites

I plan to call the fiberglasssupply folks, probably to order this:

 

L18-1094 Quarter Sheet 1/2” H-80 Divinycell Plain, 42.8” x 24”

 

but also to ask if the 1" and 1.5" can be ordered in quarter sheets. If not, then it would be good to know if some adhesive can be used to build up thickness. Despite the waste of material, it wouldn't cost a whole lot to build up blocks large enough to "clamshell" strobes. Does anyone happen to know of a marine-durable adhesive for this stuff?

 

Seems very sensible to go DIY on this, not only because of the cost, but because of the trial-and-error nature of balancing a rig.

 

It just occurred to me that with an arm-diameter half-round router bit (and a router table), it would probably be very easy to produce sheet-length pieces ready to cut to arm-lengths, then clamshell the two halves.

Edited by tubino

Share this post


Link to post
Share on other sites

This topic pops up here every couple years since 2002 so a search might offer more answers. The quick answer is any material suitable for use as a boat hull coring material (which Divinycell is) and any adhesive similarly suitable. Epoxy and fiberglass resin work.

 

I could see making my own float if it were something Stix didn't offer. In what way will DIY foam arm floats be better than Stix ones? Inon is now offering some monster float arms as well.

Share this post


Link to post
Share on other sites
I could see making my own float if it were something Stix didn't offer. In what way will DIY foam arm floats be better than Stix ones? Inon is now offering some monster float arms as well.

 

Why make floats? In my case:

 

1) being cheap is a point of pride

 

2) I want the flexibility to make ones that are optimal for my setup(s), determined by trial and error, with options to put on arms, strobes, housing, tray, mask... okay, just kidding on that last one.

 

3) genetic predisposition to make stuff, esp. to make stuff the way I want it. I'm building speakers now with Altec 15" drivers, backloaded horn cab (30 cu ft volume) and round wood 500hz. tractrix horns with compression drivers and my own crossover. It's just BETTER than anything I can buy. My wife asks what's wrong with the Tannoy DMT 15 studio monitors we already have -- but I want something better. My wife asks why build a single-ended directly-heated triode amp using 845's and a power supply the size of a wheelbarrow when this other expensive tube amp we have sounds so good. Answer: I want something better, and I can build it myself.

 

I think I'll be happier in the long run if I can make a bunch and stick them where they work, and not worry about making a bunch I don't use.

Share this post


Link to post
Share on other sites

. Does anyone happen to know of a marine-durable adhesive for this stuff?

 

I've used industrial poly urathane construction glue in a tube $US 4.00

Been in use 3 years and still intact.

After constructing my arm floats, I coated them with 2 part fiber glass gel to make a hard outer coating to protect the edges from chipping away.

Share this post


Link to post
Share on other sites

I think any theoretical benefit to build flotation optimal for your rig will be negated when you reconfigure your lenses and ports. You can "split the difference" with existing products. If you simply enjoy the DIY aspect then I understand but I don't think you'll outperform off-the-shelf solutions. If you do, I'd like to see the results.

 

When I made mine, it was a port collar and there were no foam arm floats on the market. I also helped a friend build their arms floats. Now there are not only several options but configurable port collars as well. Considering how much I paid for a sheet of divinylcell at the time, a Stix collar at $40 is a bargain.

Share this post


Link to post
Share on other sites

Craig, can you recall which density of Divinycell you used? Looking at their datasheet ( http://www.diabgroup.com/americas/u_litera...df/HCP_DS_U.pdf ) it would seem as though the least dense HCP 30 has sufficient compressive strength ( 5% reduction in volume at 30-39 bar ).

Share this post


Link to post
Share on other sites

It was a long time ago so I am not sure. I called Amphibico and they told me the product and the weight they used. I believe it was 70. I agree that the lighter ones should be suitable but I was worried about impact damage. I subsequently glassed mine so that turned out to be moot.

Share this post


Link to post
Share on other sites

Tim

 

Did you find a UK supplier for this? I have had a look and come up with nothing.

 

Daniel

Share this post


Link to post
Share on other sites
Tim

 

Did you find a UK supplier for this? I have had a look and come up with nothing.

 

Daniel

 

Hi Daniel

 

Click here ( http://www.diabgroup.com/europe/purchase/e_purc_1.html# ) and follow the link. Divinycell HCP30 is the more expensive varient of H200 ( http://www.diabgroup.com/europe/literature...pdf/H_DS_EU.pdf ). Essentially, HCP grade have full QA certification. The H grades do not. However, even H200 is £230.00 plus VAT for a 620 x 800 x 50 mm sheet...

 

Hope this helps, Tim

Share this post


Link to post
Share on other sites

I just ordered several square feet of 1/2" H-80 from fiberglasssupply to play with. I'm planning on expirimenting with heat-forming it to collar strobes, and also possibly some other scoring techniques to get the shapes I desire. I'll let you know how it goes and post pics if I get satisfactory results.

Share this post


Link to post
Share on other sites

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:

http://www.moldingsbest.com/Polyethylene.html

http://www.vulcorp.com/webstuff/pefoam.htm

 

Thanks!

Chris

Edited by in_minsk_we_trust

Share this post


Link to post
Share on other sites
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:

http://www.moldingsbest.com/Polyethylene.html

http://www.vulcorp.com/webstuff/pefoam.htm

 

Thanks!

Chris

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

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites

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!

Share this post


Link to post
Share on other sites
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!

Edited by Timmoranuk

Share this post


Link to post
Share on other sites

Sponsors

Advertisements



×
×
  • Create New...