Dessicant powder, CDC flies and floatants.

[Kelvin]

Mike, that's fantastic. I appreciate all the work you put into that. You have answered all my questions and more. Its also a great reference for the future. Thanks again for everyone, its great to hear all the different views. i must admit I like CDC flies and will continue to use them with the knowledge I have gained from this thread.
Cheers
Mark

[bibio1]

I don't use anything. Just rub the CDC on a dry fleece when ur wearing it. Works perfectly, is less problematic and it's quick. CDC never lasts long and I use a lot of it on the Clyde.

[bibio1]

Silica absorbs water but it needs to be dried off. It's awful stuff. Most of the CDC flies I use are emergers so the silica is completely useless. For me fleece wins hands down.

Cheers

Paul

[Traditionalist]

If you get a build up that is because you have not dried the flies sufficiently before using the dessicant. The Dessicant only removes residue, it will not dry completely soaked flies, you need to use Amadou or "wonder-cloth" first.

After use for a while, the Silica gel needs to be dried out. This is done by placing it in an oven. How much use depends on the amount in your container and how often you use it. I usually tip the stuff ( half a plastic 35mm Film can), into a stainless pot after a days fishing, and when I have an amount in there I put it in the oven. This restores the powder completely;

- It will adsorb up to one third of its own weight in water vapour. This adsorption efficiency is approximately  35% greater that typical desiccant clays, making silica gel the preferred choice where weight or efficiency are important factors.
- It has an almost indefinite shelf life if stored in airtight conditions.
- It can be regenerated and reused if required. Gently heating silica gel
will drive off the adsorbed moisture and leave it ready for reuse. ( Twenty minutes at 100°C in an oven).
- It is a very inert material, it will not normally attack or corrode other materials and with the exception of strong alkalis and hydrofluoric acid is itself resistant to attack.
- It is non-toxic and non-flammable.
- It is most frequently and conveniently used packed in a breathable sachet or bag. These are available in a wide range of sizes suitable for use with a wide range of applications.

It ONLY dries flies. If you want dry AND waterproof then you need hydrophobic fumed silica as indicated in the post I linked to.

Putting completely soaked flies into the various dry shake powders, ( including ground silica gel and hydrophobic fumed silica), will only cause the stuff to clump up, and it wont work.  It is essential to remove all excess moisture or slime, blood etc,  before using any of the dessicant/floatant powders or they simply wont work. Slime is one of the best "sinkants" extant! Even relatively dry slime will sink a fly very quickly, and of course it clogs fibres.

Using an oven only applies to silica gel. How other "dry shake" powders may react I do not know.

Of all those I have tried the hydrophobic fumed silica works best, in this the "floatant" component is silicone. This has also been confirmed by many other people.

I don't know all the ingredients of all the powders so if you experiment with them be careful.

[Wildfisher]

If you get a build up that is because you have not dried the flies sufficiently before using the dessicant. The Dessicant only removes residue, it will not dry completely soaked flies, you need to use Amadou or "wonder-cloth" first.

Yes, that's absolutely right. If you dip a soaked fly into dry shake or similar  you will pull out and waste 1/2 the tin. The fly has to be dried as you say, the desiccant does the final grooming very efficiently and really rejuvenates  CDC very well indeed. 

As far as CDC oil goes, never used it, I imagine it would clog up and destroy the feather structure.

[Traditionalist]

Yes, that's absolutely right. If you dip a soaked fly into dry shake or similar  you will pull out and waste 1/2 the tin. The fly has to be dried as you say, the desiccant does the final grooming very efficiently and really rejuvenates  CDC very well indeed. 

As far as CDC oil goes, never used it, I imagine it would clog up and destroy the feather structure.

None of the oil or paste type floatants like GINK etc  will work on CDC. They ALL clog the radial barbules, thus reducing the surface area and the fy will sink more quickly.

"Watershed" does work if the flies are soaked in it, allowed to dry and then fluffed up, but it does not make enough difference to be worthwhile and it wont work "on stream" anyway. It has to dry completely before it works at all. Great on conventional hackled flies though.

Permaflote does not work very well on CDC either, the wax also clogs the radial barbules.

The hydrophobic fumed silica will work on any dry fly and is convenient to use but the flies MUST be pre-dried with Amadou, "wonder cloth" or similar beforehand.

The silicone in the Hydrophobic Fumed Silica works because it is in a semi solid form and heterogeneously but still very thoroughly mixed with the silica, so it does not clog the fibres.

The usual silicone used is polydimethylsiloxane ;

http://en.wikipedia.org/wiki/Silicone_grease

there is no point at all applying ANY  floatant to a completely soaked fly, all that does is seal the moisture in.  the fly must be dry before floatant is applied. Some floatants ( permaflote, Hydrophobic fumed silica) both dry AND treat the fly.  Others are merely floatants.

[Traditionalist]

There is no such thing as "natural" CDC preen oil in bottles.  There are two ways of extracting this, one involves boiling feathers and skimming the oil residue which comes to the top, this is then mixed with solvent and is sold as "preen oil" which it no longer is. Even natural preen oil only resists water for a while and has to be constantly renewed by the bird, using its preen gland and its beak to collect and distribute the oil.  It is a very complex substance and boiling feathers does not extract it properly anyway. The second way is to extract it from preen glands. This would make it one of the most expensive substances in the world, and it is not viable for this reason.

The other stuff commonly sold as "preen gland oil" or similar is purely synthetic and does not work on CDC anyway as it also clogs the barbules.

[keithfish]

on the river i find a good rinse after each fish and a pocket full of kitchen roll will keep your cdc floating most nights.

[Traditionalist]

If you want a very cheap method of drying flies use cat litter, this is invariably a dessicant clay.  Just mash it up a bit in a cloth bag or similar with a hammer.  It is quite efficient but not as good as silca gel.  It also does not waterproof anything only dries it.

This is often just fuller's earth, ( which also makes a first class degreaser, deglinter, for nylon when a little washing up liquid and a few drops of glycerine are added), but there are other types as well, The "crystal" litters are silica gel.
Zeolite, diatomite and sepiolite are all good non-clumping dessicants.

For more info; http://en.wikipedia.org/wiki/Cat_litter

[Traditionalist]

on the river i find a good rinse after each fish and a pocket full of kitchen roll will keep your cdc floating most nights.

Indeed, that works quite well, as will anything that pulls most of the moisture out of the flies. The "wonder cloths" are very good indeed, and work well even without using any floatant, but using hydrophobic fumed silica as well makes them float very well indeed for a long time, and also returns them to pristine condition more or less immediately after catching a fish.