Vintage Garden Syringe Sprayers    

Back Piston assembly

The ‘cotton reel’ piston assembly is usually soldered on, but can be screwed on. The top picture here shows the assembly without any packing. The packing was originally either cotton string, a thick cotton thread or occasionally a strip of material. The packing could be replaced by the gardener using almost any cotton material to hand. The cotton expands when wet and makes a seal within the barrel. Artificial materials would not have the same properties and can’t be used. Repair involves removing the old packing and replacing it. I have found that ordinary cotton string which can be bought in a ball for a few pence works fairly well. Typically a ‘cotton reel’ will need about 6 feet to get three layers. The aim is to get just the right amount so that when compressed it makes an air tight seal within the barrel. The string needs to be applied evenly so that it is just above the level of the sides of the ‘cotton reel’. Too much will make the plunger stiff, too little will not provide the required seal. Medium or thick cotton thread can be used to make a finer adjustment.  Click to link to some thoughts on the best way of replacing the packing.  This type of piston is sometimes said to indicate pre WW II  manufacture, but Mysto and others were selling syringes post war  using both this type and also cup washer types.  It is, however, true that cup washers generally indicate a later date.    

Cotton Reel’ Type

Cotton string. Approx. 1 mm thick

Medium cotton thread.

‘Cup Washer’ Type

The idea of using two back to back cup washers was patented by John William Davenport (GB189909065 2/3/1900). Typically the end of the pump rod is threaded and the components fit onto this. Firstly the back nut which acts as a stop. Followed by a metal washer, then the cup washers, back to back, followed by a second metal washer and then the final locking nut. There are a number of variations on this format. There is sometimes an additional locking nut, and sometimes an additional metal washer between the two cup washers. It is normally possible to salvage the washers and nuts, but if they are not made of brass they can sometimes be corroded and unusable. The nuts and washers will be imperial sizes, but replacements are fairly easy to obtain. It is the external diameter of the washer which is important and metric washers of the right external diameter can be drilled to the correct size.  The rod end may need to be re-threaded. In nearly every case the cup washers will need replacing. Cup washers in some sizes can be bought from Base Camp (see links) or on Ebay, but they are not cheap. They can be made fairly simply.  Click below for further information.


For further information on how cup washers work  

For information on buying and fitting cup washers

For information on making your own

‘Composite’ and Other types

Composite types have a ‘cotton reel’ piston assembly and also a cup washer. The ones I have seen have a single cup washer with the cup facing forward, positioned in front of the ‘cotton reel’. There may be other configurations, but I would expect that the cup washer would face forward, because there is a tendency on the sprayers using the ‘cotton reel’ for liquid to get past the piston and for it to come out of the air vent. A forward facing cup washer would prevent this. There is also Stone’s Adjustable piston, which is an unusual construction.  Also some special designs.


Some sprayers appear to have just one cup washer, but it may be that the other one has ben removed at some time or has perished. There are some syringes which only ever had the one cup washer. Often these appear to be specially designed for the syringe and are exactly the right thickness to work effectively. Cup washers were not always leather and some original washers appear to be made of synthetic material. There appears to be synthetic cup washers which are moulded to include two cups back to back. Some washers appear to have a metal washer actually moulded into them . Normally, no matter what the original configuration, it is probably best to use two back to back cup washers as a replacement .

‘Cotton reel’ type plus a cup washer.

Stones adjustable