Screen Printing

How to print caps Part 2

Printing CapsCaps are one of the most popular printed apparel items purchased by consumers. People wear caps day and night, outdoors and inside, and regardless of weather. Yet, most screenprinters would rather not print a cap!

Caps are actually easier to print than shirts. The screens are smaller so less effort is required to prepare and print with cap screens. Why, then, would screenprinters rather not print a cap?

There are simple differences between printing shirts and caps that many screenprinters do not understand. Once a commitment is made to adjust to the differences between printing shirts and caps, a screenprinter will not hesitate to realise the profit potential of caps.

The differences between printing shirts and caps

1. Thin bar

2. Capillary film

3. Cap construction

4. Platen/cap match in size

5. Squeegee

6. Registration guide

In this second part of the article we will focus on cap construction, platen/cap match in size, squeegee and registration guide.

Cap construction

Some caps are easier to print than others. Caps are made for embroidery, transfers and screenprinting. Some caps are good for more than one decorating method. The best caps for screenprinting have flexible front panels whereas embroidery works better with stiff front panels. When purchasing caps for screenprinting, ‘fused buckram’ and most ‘constructed’ caps should be avoided. Those are embroidery caps for most shops. There is a new design available to screenprint fused buckram caps.

‘Unconstructed’ caps, caps with a half moon stay that can be folded out from behind the front panel, and foam-front caps are better to print. Unconstructed caps do not have a lining behind the front panel of the cap. There are some caps described as constructed that will conform to the platen without the new patented design that are excellent for printing.

Most people who today avoid cap printing at some time in the past purchased a fused buckram or other undesirable cap for screenprinting, and then tried to screenprint the cap. They produced poor print quality, got frustrated and quit printing caps. So the cap-printing field is not competitive like shirts – just because most screenprinters did not know caps are made for different decorating methods.

Caps are also sold in different sizes. The smaller caps are the more fashionable and typically are sold to younger consumers. Frequently these are six-panel caps, that is, caps with a seam in the middle of the image area. These caps also command the highest selling prices.

Seams are actually simple to print. Some seams are smooth – as though they have been ironed – whereas others have an irregular surface. The smooth seams are better. To print, place a pad on the platen on either side of the seam. The pad should be the thickness of the seam. If the seam is thinner than the pads, the slot between the two pads and under the seam can be built up with masking tape. Then the print surface will be smooth for printing rather than presenting a ‘speed bump’ or ‘pot hole’ in the road to printing.

The new high-density inks are a wonderful way to compensate for irregular surfaces such as seams and corduroy. They should be used with capillary film and then can be used to print highly opaque images as well as a wide variety of new graphics, including lenticular, 3-D kinetic colour, imitation leather patches and faux embroidery. These inks are a great technological advancement for the screenprinting industry, and yet they print just like standard plastisol inks.

The combination of a high-tension screen, capillary film and high-density ink compensates for the broad range of fabrics used to make caps. Caps can be smooth-foam fronts, twills, brushed cotton, denim or made from a variety of other materials. With 350 suppliers in the USA alone, there are a lot of choices.

Once a screenprinter finds a good cap for printing, the best advice is to stay loyal to that supplier. Don’t change suppliers to save $0.10 [€0.08] per cap. The best way to find the most desirable caps to print is to get a catalogue from the supplier, and examine the photo and description carefully. The caps with flexible front panels, smooth seams for printing, brushed cotton material and a construction that allows the cap to lay down smoothly on the platen being used should be marked in the supplier’s catalogue for future reference.

Several suppliers may be necessary to provide a selection of colours and styles. There are three basic styles. The low-profile, six-panel caps can command the highest profit margins. Golf-style caps should either have a flexible front or half-moon stay behind the front panel. The foam-fronts are the most consistent construction when comparing suppliers.

Platen/cap match in size

The platen size and front-panel size of the cap must match. The front panels of caps have become smaller over the years as fashions have changed. Many screenprinters have been discouraged from printing caps, because the top centre of the image area will not lay down on the platen. The cause is the platen is too large for the front panel of the caps. These screenprinters are using outdated equipment that should be returned to the manufacturer for updating. The new patented design addresses this issue.

Any stretching of the front panel or bending of the peak will create a distorted image. If a shirt is stretched out of shape before printing, the printed image will be distorted. The same occurs with caps. Stretching occurs when the cap is pulled down with so much force that the peak is moved. If the peak is bent down to lay a shirt frame on the cap, the bottom of the image area is stretched to produce a distorted image.


Cap squeegees perform better when the blade has a hard centre, and the blade is either glued in the handle or clamped. Aluminium handles that clamp on the blade work well. Bolts through the handle and blade create distortion in the blade as the squeegee ages, and then shear uneven amounts of ink. The best squeegees are 4–5″ [102–127 mm] long and have a durometer, or hardness, of 70-90-70, or numbers that are close.

Shirt squeegees often are two inches longer than the image is wide. The corners of shirt squeegees flex more than the rest of the blade. The flex produces lower squeegee pressure at the corners, but this is beyond the image area on a shirt screen. With caps, images as close as 1/16″ [1.6 mm] or even 1/2″ [12.7 mm] to the inside of the thin bar of the frame need the same squeegee pressure as the rest of the image. The corner of the squeegee blade must not flex. The 90 durometer centre is hard and will not flex.

Registration guide

Shirt screens typically have images exposed in the centre of the screen, but cap screens are exposed with images close to the thin bar. The cap platens are small compared to shirts so that images must be located accurately before exposure so the image will not print off the top of the cap, be crooked, or be off-centre on the front of the cap. This becomes a greater issue when the total dimension of a multi-colour print has to be exposed.

There is a very simple solution. Trace a cap frame over graph paper and draw a line outside the screen 3/16″ [4.8 mm] from the thin bar. The 3/16″ [4.8 mm] represents the thickest cap peak that will be encountered. Then lay the graph drawing over the platen and trace the platen on the graph paper. Centre lines can be added to the platen drawing for centring images.

Once a plastic sheet is laid over the drawing, each image (or positive) can be located accurately on this representation of the platen and affixed with one piece of cellophane tape. After the several images of a multi-colour job are positioned in registration, two or more pieces of double stick tape should be placed on the top image.

Then lay the coated screen over the drawing of the screen, rub on the double stick tape, and pick the screen up with the image exactly in the right location to be exposed. If wooden blocks are placed on two sides of the drawing along the outside edges of the frame, the wood will locate the screen exactly over the drawing rather than relying on a person to be accurate.

A piece of graph paper, plastic sheet that is usually discarded from capillary film and a few minutes of your time will save countless hours re-making screens.

Printing caps is like printing shirts, except that adjustments have to be made for the screen and cap. For this small commitment a screenprinter can add a very profitable, non-seasonal and non-competitive product to the business. Everyone loves a cap, and caps are fun and easy to print.

About the author:

Named by Impressions Magazine as one of the top innovators of the last 25 years, Roger Jennings holds numerous patents, including all patents for cap printing. He writes for all the trade magazines on technical and business subjects. Roger is President of R Jennings Mfg. Co., which manufactures screenprinting equipment, prints, and provides printing supplies. Some additional articles can be found on  For help with your screenprinting problems, give him a call or e-mail him at