Fibreglass odour

Steve

I have used 2 rebreathers that have have glass and I think kevlar fibre scrubbers. They had no odour at all. Every thing else I can think of that is made of fibreglass has a clear and distinct smell. You certainly wouldn't want on in the loop of a rebreather.

I'm considering using a fibreglass (or similar) made scrubber for the home build I'm working on. How do i do it and make it safe and pleasant to have as a part of a rebreather?

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DeepBlueInnovation

You could get one of those purty smelling pine tree air fresheners that bogans hang in their cars

One in the inhale counterlung should do the trick

pirateeye

You could give West System Resin a try odor is nearly eliminated out of the gate, give it a coat of gel coat and odor should not really be an issue. I have never tried it on a breather before but have used it alot on boat projects. I actually plan on building a more robust shell for my Dolphin with west.

Of course this is just my two cents.........

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S. Marc

My recommendation would be to use a good quality 2 part epoxy instead of the fiberglass resin. I believe it is stronger, and the smell once it cures is just not there at all. It also is easier to work with IMHO.

I have used "cold cure" 2 part epoxy on a number of projects, including extending the lids on biopak rebreathers and repairing biopak center sections and scrubbers. It bonds to just about everything and is food grade with zero smell once it cures. It can be used with fibreglass cloth or mesh, or kevlar. It does not seem to be effected by dramatic temperature changes. It also does not have styrene in it which is a nasty substance.

Marc

Sandy

I built a scrubber for my biopak from epoxy resin. (as smarc recomends) It cures quickly and is stable. Its a little more awkward when you do the layup but one of the best products for the job. My scrubber holds a hair under 2kg of absorbent and houses my sensors as well. It seems stable in the presence of absorbent but I did have an issue with paint. I spray painted the scrubber gloss grey with a spray can and let it dry for a couple of months. When I unpacked the scrubber after my first dive the paint had turned to powder on surfaces which were in contact with the absorbent. It brushed off the fiberglass and even washed away with water. I don't believe there was enough air movement to bring the paint particles into the breathing mix (or through the porex membrane) but I was not pleased. The paint all washed off inside and out with acetone and now I'm using it with just the epoxy finish. Don't paint yours is all I can recommend.

Attached Images

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S. Marc

There are dyes that can be used with epoxy resins that are mixed at the time of mixing the epoxy.

Skipbreather

Hi Steve-

“Fiberglass” is a broad and often misused term.

Composites 101: Composite materials are in general made up of two parts: a structural part and the matrix that holds it. In the common FRP (fiberglass reinforced plastic) used in inexpensive boats and other cheap parts, the structural part is glass fibers and the matrix is usually catalyzed polyester resin. Poly has that unmistakable smell you are most likely associating w/ fiberglass- it seems to never finish off gassing. Higher quality boats are made w/ a different chemical system for the matrix, two part epoxys. In between in both quality and cost as far as matrix selections go is vinyl esters.

Fibers are made from all manner of materials. Glass we know. Carbon fiber and Kevlar (arimid fiber) are also well know. There are countless grades and weaves of all types. Even boron fibers have been used in an aluminum matrix for exotic aviation applications. Fibers can be used unwoven- called roving- or woven into cloth.

For homebuilt Rebreather use, I would only use a quality two part room temperature cure epoxy as my matrix. I’ve used the mentioned West system w/ excellent results on a large number of projects. Once cured it has very little off gassing. When it comes to choosing the structural part for your project, fiberglass cloth is inexpensive and can do most jobs well if weave & number of plies are thought out well. For higher performance/ strength/ stiffness @ a correspondingly higher price carbon and Kevlar can be used.

Best,
Ken

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dive2dive2000

Hi Ken,

What does "very little off gassing" mean? If I was to make a bucket or can to hold my scrubber, would using a resin be a problem from an off gassing perspective?

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Safe Diving,
Martin

Skipbreather

Hi Martin-

"A resin". WHICH resin? Epoxy = no. Polyester = yes.

I started to compose a long winded explanation, but then decided the following might be more useful:

A fully cured epoxy system *that was mixed in the manufacturer’s specified ratio* has no real smell at all. Hand sanding will also generally produce no smell. Power sanding that significantly heats up the laminate might produce a minor smell.

Catalyzed polyester resins never really finish curing. You can stick your nose near an older laminate and often detect a smell. Hand sand any and most folks will usually smell it. Power sand it even briefly and anyone will smell it. Power sand it until it gets hot and it will absolutely REEK.

The fibers that the epoxy/ polyester encapsulate have no influence on the smell- but might have a big one on how easy it is to sand once cured. Kevlar in particular is a royal PITA to cleanly sand so folks press harder w/ power sander, things heat up excessively, and a delightful aroma of some sort wafts away from the work piece being abused.

Ken

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dive2dive2000

So basically if it is going to be a part of the loop use epoxy resin. Have you used the WEST system for parts that were in the loop?

BTW thank you for your input

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Safe Diving,
Martin