I have been working with dying my own cork. I have found that rite dye for clothes (liquid form) will color the cork. The only problem I am having is getting good penetration. I only leave it in the dye for 2 hours. This has caused the dye to get a small way into the cork. This would work for surface coverage, but did not meet my need for through coloring so I can shape it afterwords. i will let you know if I come up with anything else.
John

Rodbuilding, cheaper than therapy.

Did you try using vacuum pressure? You should find the results to be significantly different.

You might consider turning the cork first, then applying the dye.

One other test you need to make, is to see if the end product will be colorfast. Sometimes it takes hot water or a touch of vinegar to "set" the dye into the item being dyed. You'll want to test this, otherwise the dye may leave you the first few times the grip gets wet.

..............

I did not use the vacuum for this first test. I did rinse it in hot water. I then wet it again and there was no color on my hands from handling. I am going to keep playing with it.

Rodbuilding, cheaper than therapy.

Cork is a closed cell material and does not absorb moisture very deeply.

Otherwise it would never have been used for fishing net floats for centuries.

I would think to fully saturate with dye, you must have the ability to use a fair amount of pressure (vaccuum).

Yes cork is closed cell, but that is at atmopheric pressure. Is it the same say 60ft below the surface (in essence, a small vacuum), or will water eventually penetrate that far down? The problem then becomes how much pressure will it take to penetrate the cork fully? Now if that amount of pressure is greater than the cork can withstand, it simply cannot happen.

A perfect vacuum can only develop 14.6 psi (one atmosphere) of pressure. If you can place the cork and dye in a pressurized container, the pressure that can be obtained is only limited by the strength of the container and the energy available.

I'm guessing that a carrier like chloroform will penetrate further than water due to its lower surface tension and viscosity. Chloroform has about half of the viscosity and surface tension of water. Most petroleum products would be better than water for the same reason, but obviously have their health and safety drawbacks.

John,
A couple of questions.
1. Are you using water that is near the boiling point during your dying process. The hotter the water, the better the dye penetration.
2. Have you tried a batch, where you have left the cork in for 24 hours?

3. If you want to use vacuum, it is not that difficult to make a vacuum system. A relatively inexpensive vacuum pump and sealing system can do a good job of providing vacuum to get better dye absorbtion into the cork.

4. Many years ago, I build a vacuum system when I was doing fiberglass assembly. I sumply used thick plastic film to enclosed the objects and then pulled a good vacuum on the work under assembly and held the vacuum for 24 hours until the glue was well set.
Essentially, the same thing that boat manufacturers do during the assembly of fiberglass boats.

++++++++++++++++
I did a bit of searching and here is a very good article on a very simple and inexpensive vacuum chamber made from PVC pipes which can be used to vacuum dye cork:

[www.joewoodworker.com]

The only thing that you need to add is a vacuum pump.
You can easily obtain relatively vacuum pumps from various surplus stores. It is much easier to get a good vacuum with an inexpensive pump than it takes to get a bunch of pressure from an air compressor.
The only thing you need to get is to about 20 inches of vacuum for a very good job.

[www.joewoodworker.com]

There are a couple of things you really should add to the apparatus as listed above if you want to do a good job with this vacuum system.

1. You want to add a vacuum check valve in the vacuum line as it comes from the pump to the pvc vessle. The reason for this is that you would like the vacuum to be able to pull a vacuum and then have the check valve hold the vacuum with no further pumping action required.
2. It would also be a good idea to add a T in the line with a bleed valve in the T branch. i.e. keep the bleed valve closed, when doing the dying process, but then after turning off the vacuum pump, you can gradually open the bleed valve to bleed off the vacuum, wihtout having the solution boil up too quickly and blow out the vacuum line.
3. It is also a good idea to add a vacuum gauge on the vessle side of the check valve to know the actual state of the vacuum in the vessle as well as to insure that there is vacuum present to do its job.

Good luck
Roger




Take care
Roger

John,

I experimented with rite dye about three ago and had no luck. I did what Tom said, turn the grip then install the dye and tried different way to set the dye on the grip. I even used a seal-a-meal, using a 6" grip with dye on the grip and in the bag then vacuum & seal it for 24 hours. After fishing with this grip for a few hours the dye came off in my hands. I found another dye call Dye-na-Flow that has more of a even color but still had the same problem of the dye rubbing off. Like Phil said cork is a closed cell material and won't adsorb moisture. One way to keep the dye on is to epoxy the grip after you install the dye.

John if you have any question let me know, and can tell you everything I tried experimenting with dyes.



Lynn Williams

John, as this seems to be sort of an R&D project at the moment, if you should decide to use vacuum and not want to invest as much as Roger's system, there is a less expensive way.

A length of PVC and two end caps, with a fitting (even a plastic one could be epoxied in place) would suffice as the work chamber.

Harbor Freight sells a hand operated vacuum pump with gauge and release valve and an assortment of hose and fittings for about fifteen bucks that would do fine for this.

How many inches of vacuum from a shop vac?? If you are going to have hot to boiling water I would suspect you could use a home canning jar and lids to make a reasonable vacuum and just store it until ready. I would guess that the better the cork grade the harder it would be to dye. You probably want to dye thinner rings as well.

I would dump the dye and cork into a simple weed sprayer and start pumping. A good sprayer should give you about 30 psi or about twice the pressure that you will get out of the best vacuum pump that money can buy.

With a garden sprayer, you will be pressurizing it, not drawing a vacuum. Vacuum is a negative pressure.

You may want to remember that as you lower the pressure, the boiling temp. lowers. For instance, at a vacuum reading of 29.02 inches of mercury (approaching almost zero pressure) water will boil at 76 degrees F.

Reference to first sentence----Before this turns into an engineering thread, vacuum is a negative gauge pressure, but a positive absolute pressure.



Edited 1 time(s). Last edit at 04/07/2009 02:19PM by C. Royce Harrelson.

Treated lumber is placed in a vacuum chamber for a period of time to draw a vacuum in the pores of the wood. Then the treating fluid is introduced into the chamber while still under vacuum. the fluid will then be sucked into the pores of the wood. It may work with the cork, maybe not. However, treated wood is substantially heavier than un treated wood.
banjo

They don't call it "pressure treated lumber" for nothing. A vacuum is used to remove air from around the cell to make room for the preservative, but pressure is added to drive in the preservative.

[www.woodtreaters.com]

There is a big difference between wood and cork, even though cork is a bark from trees. Wood does have pores, cork does not. Wwoods cellulose fibers are also bound by lignin which dissolves with heat and water, even better under pressure.

As cork is quite elastic, pressure will cause the cells to compress, but it will take great pressure to collapse the cells enough to open them to fluids, if successful you then lose the elastic softness which many appreciate about cork.

Attempts to dye cork have been tried many times over the years.................unsuccessfully!

Today to get colored cork it is done by combining ground cork with a substance that will accept a color medium.