GB2234525A - Dried electrolytic pad for electroplating - Google Patents

Abstract

A pad is manufactured from absorbent material, to the shape and dimensions required for it to act as a portable carrier of an electrolyte, between a metallic anode and cathode in an electroplating process, the pad is then soaked in an appropriate electrolyte, either during or after manufacture, then dried, so as to produce a dried electrolytic pad. The pad is free from the hazards associated with handling, storing and transporting liquid electrolytes, and is ready to be reactivated by the addition of water.

Description

DRIED ELECTROLYTIC PAD This invention relates to a pad, soaked in a solution of an electrolyte; the pad has been dried for ease of packing, storing and transportation, and to facilitate application by any unskilled user.

The process of in situ electroplating of metallic articles, using a variety of anode materials connected to a metallic cathode via an electrolyte absorbed in a portable pad, gel or membrane, has been previously documented. In such a process, the packing of the electrolyte in liquid form, and its subsequent transportation and loading on to the porous pad, presents the manufacturer and user with some difficulties. Difficulties are also experienced by the user with the application of an electrolyte in the form of a paste or gel.

According to the present invention there is provided a pad of cotton wool or similar absorbent material, which has been soaked in the electrolytic solution, and then dried, so that the cations and anions of the electrolyte are deposited homogeneously throughout the pad. The pad can now be packed, stored, transported and loaded into the electroplating tool, without any. danger of spillage of the electrolyte. The hazards inherent in the use of concentrated and potentially corrosive solutions are thus avoided, so far as all those involved in the aforementioned processes are concerned; in particular, the user, who may be unskilled, is not exposed to such hazards.

After loading tnto the electroplating tool, the conductance of the electrolyte is regenerated by adding a specified amount of water, so as to restore the electrolyte to its original solution form, wherein the anions and cations are free to move under the influence of a direct current electrical supply.

A specific embodiment of the invention will now be described by way of example, with reference to the accompanying drawings in which Figure 1 shows the pad soaked in electrolyte being pre-formed in a hollow tube.

Figure 2 illustrates the pad being pushed from its forming tube into a drying trough, prior to the said trough being placed in an oven.

Figure 3 shows the dried cylindrical pad being sliced into cylinders of the length required for insertion into the tool.

Figure 4 shows the dried pad being loaded into the electroplating tool.

Figure 5 indicates how the requisite amount of water could be added to the pad to regenerate its conducting power.

Figure 6(a) shows another type of tool, with the pad, soaked in electrolyte, surrounding the anode, prior to drying.

Figure 6(b) illustrates how such a pad, dried "in situ", has its conducting ability regenerated by being lowered into a container holding the requisite amount of water.

Referring to the drawings, the pad 11 comprises a piece of cotton wool wadding which in Fig. 1 has been soaked in the desired electrolyte (say zinc sulphate solution for the purpose of galvanising) and forced into the glass tube 12, in order to pre-form it into the desired cylindrical shape.

In Fig. 2(a) the soaked cotton wool cylinder 11 is shown being pushed from its glass forming cylinder by means of a piston 13 into an open semi-cylindrical trough 14. This trough serves to avoid deformation of the pad during the drying process. A section through the trough and pad is shown in Fig 2(b).

The hard dried cylindrical pad is shown in Fig. 3 being chopped by the blade 15 into shorter cylinders, of length suitable for insertion into the electroplating (eg. galvanising) tool. This step may be omitted if a cylinder of the requisite length is pre-formed and dried as in Figs. 1 and 2.

The section of the pad 16 is shown in Fig. 4 being pushed into the tool, in this instance a galvanising tool, wherein the anode 17 is manufactured from zinc foil.

Fig. 5(a) shows the section of pad 16 pushed down to the anode in the end 19 of the tool, with a measured amount of water 20 being added so as to re-activate the conducting ability of the pad, and in Fig.

5(b) the distance 19 has been shortened by pushing down the piston 18 (see Fig. 4), so as to make electrical contact, via the conducting pad, between the anode within the tool and the cathode 25 which is the metallic article being plated.

In Fig. 6 a simpler version of a plating tool is illustrated. The electrode 21 (say zinc, if galvanising is required), is already surrounded by the pad 22, which is soaked in the electrolyte (say zinc sulphate solution). The pad is held in position by the folds in the zinc, and the width of the pad is greater than the width of the zinc so that contact between the zinc electrode and the metallic article being plated is not possible except via the pad. The whole tool can thus be dried "in situ" by placing it in an oven. Fig. 6(b) shows how such a dried pad can be re-activated by placing it in a measured volume of water 23 retained in a suitable container 24. The tool is then ready for use, as shown in Fig. 5(b) if the electrode 21 is made the anode of a direct current supply (say the positive pole of a car battery or battery charger) and the tool is applied to a metallic cathode (say a negatively earthed car body, or a metallic article connected to the negative pole of the battery charger), contact again being made via the electrolyte which is retained in the pad.

It should be noted that although the embodiment of the invention specified herein refers to the galvanising of metallic articles, so that the electrolyte referred to is zinc sulphate solution, the invention can equally well be applied to any electroplating solution, and will be especially appropriate if the electroplating process involves electrolytes which, in solution form, are particularly hazardous from the point of view of packaging, storage, transportation and use.

Claims (4)

CLAIMS '

1. A dried electrolytic pad comprising a wad of absorbent material, pre-soaked in a solution of an electrolyte, and subsequently dried, ready to be reactivated by the addition of water.

2. A pad as described in Claim 1, pre-formed to fit into an open tube fitted with a piston, as a means of causing electrical contact, after wetting, between the piston, connected to one pole, and a metallic article located at the open end of the tube and connected to the opposite pole, of an electrolytic circuit.

3. A pad as described in Claim 1, pre-formed around a metallic electrode of any desired shape, so that electrical contact between this metallic electrode and the opposite pole proceeds via the electrolyte within the pad, after wetting.

4. A dried electrolytic pad substantially as described here in, with reference to figures 1 - 6 of the drawings in the Patent Application.