Taping 101

THE TAPE


3M manufactures a product called VHB tape (Very High Bond).  The tape is called an adhesive transfer system.  It is a strip of paper with a bead of adhesive on one side.  In use, you lay a strip of the tape on one surface, adhesive side down, and rub the paper hard so that the adhesive sticks to the surface.  Then you peel away the paper.  That leaves a strip of pure adhesive on the surface.  Now you can put another object on that strip and rub or melt it into the adhesive.  The bond can be extremely strong.


Tape 1_s


One limit to working with this tape is that the paper backing will not curve to the side.  All the operations and shapes using this tape must be based on straight line designs.  For me this hasn't been much of a limitation since I have a long list of geometric designs using straight lines.  Maybe someday I'll look at curves.


EQUIPMENT


3M VHB 9460 tape

Scissors

Something to rub hard; thumb nail, Popsicle stick, dress makers creaser, pot scraper.

Optional  (but highly recommended)  hobby iron.

Straight edges.  I like aluminum yardsticks.

Weights, lots of weights.  Bean bags, plastic peanut butter jars filled with stones or old tire weights, old hammer heads...




APPLYING TAPE


Cut your cloth with a straight edge.  The paper backing on the tape keeps it from following curves and corners.  I hot cut, but I don’t think it matters if you use a rotary cutter or a blade.  Since the edge will have adhesive near it, any raveling will quickly run into glue and be stopped.  Lay a straight edge so it doesn’t move easily.


Tape 2_s


Measure out a piece of tape roughly two inches longer than your cloth.


Tape 3_s



To cut the tape I just drop the roll on the edge of the table and cut the overhang.


Tape 4_s


In placing the tape, I work left to right.  Without letting the tape touch the surface, I set my left hand down near where I want the tape to be.  I then look at the right end and set down that hand.  Notice in the picture you can see a narrow strip of cloth showing below the tape.  You want to set the tape 1 or 2 mm., 1/16 inch, from the edge. (Digression: one of the complaints of building with tape is that any exposed glue collects sand and dirt.  Solution: don’t expose any glue.  Leave that little bit of cloth beyond the tape.)  


Tape 5_s


I set down the tape in my left hand, pressing it onto the table and the first little bit of the cloth.  Using small motions of my right hand to keep the tape in the right place, I slowly slide my left fingers across the tape.


Tape 6_s


Notice the cloth exposed to the right of the tape.


Tape 7_s


Now rub the paper to apply pressure which will (hopefully) press the adhesive onto the cloth.  Also rub the excess tape on the table so you can strip off the paper and leave the glue on the table.  Three tools which work are thumb nails, popsicle sticks, and dress maker creasers.  I use the creaser, with its gentle curves it is less likely to catch an edge and lift the tape.  Thumb nails work well, but get sore with a long session.  Sticks are ok, but tend to catch edges.


Tape 8_s


Ideally, when you rub you will press every bit of tape into the cloth.  You could accomplish this if you had enough time to hit every spot (Maybe you’re obsessive and will do that.)  My pattern is to rub diagonal lines across the tape.  However between the pressed lines there my be diagonal unpressed gaps.  So then I rub the length of the tape, trying to press both edges and the middle on various sweeps.  This should chop up any diagonal gaps into little unpressed gaps.  If your surface is really flat, you may be able to just use the straight edge of the creaser with a lot of force.  As you work you’ll get a feel for how much rubbing you have to do.  The colder your work space, the more rubbing needed.  Under about 60 degrees, the tape will not transfer well to the cloth.


Tape 9_s


After you’re satisfied with the rubbing, go to one end and lift the paper without lifting the glue off the table.  


Tape10_s


Then slowly pull the paper off the glue.  In most cases the adhesive on the table will provide sufficient resistance to pull the paper off. Otherwise put your finger near the end of the cloth.


Tape11_s


If the glue wants to lift off the cloth, a low angle of pulling may help.


Tape12_s


When you have the paper off, scrape the excess glue off the table.  Always account for your excess glue.  If you leave any on your table, later in the project it is sure to grab a piece of cloth  just as you put it into position and screw up that next step.  (Voice of experience.)  Have a waste basket handy and drop all your little rolls of excess glue into it.  Any that land on the floor and get stepped on are a pain to clean up.


Tape13_s


Successful application is a smooth layer of glue on the cloth.


Tape14_s


As you’re pulling watch where the paper is separating from the glue.  If the glue starts lifting from the cloth, stop.


Tape15_s


Lower the paper and re-rub to get the glue to stick to the cloth, then carefuuly resume pulling.


Tape16_s


Gaps in the glue reduce the adhered surface area and, therefore, reduce the strength of the bond.  If the gap is on the edge of the glue line, it allows sand and dirt to get into the joint and weaken it, and is also unsightly.



MORE ABOUT THE TAPE

The tape I use is 3M VHB (very high bond) adhesive transfer tape.  It can be ordered in various widths and with different thicknesses of adhesive.  #9460PC has 2 mil of adhesive, #9469PC has 5 mil, and #9473 has 10 mil.  

For most of my projects, I use 1/4 inch 3M VHB 9460 tape.  When hemming edges that I want a little stiffer or stronger, I use 3/8 or 1/2 inch VHB 9460 or 9469.  On bigger kites I use 9469, 3/8 or 1/2 inch..  I have found no other tape that can stand up to the rigors of a kite flapping in the wind; no double sided tape, no dress maker’s tape.


SOURCES

Construction Products Corp.  They say any size, any amount.

http://www.cpcdoesadhesivesandtapes.com/


R. S. Hughes

1/2 inch 3M VHB 9460 tape and larger, high shipping costs

http://www.rshughes.com/



IRONING


After you join the cloths in a hem or seams, you have to get the glue to adhere to both surfaces.  There are two general ways, rubbing and ironing.  Rubbing hard on the joint forces the glue against both surfaces.  This works, as I have some kites several years old that have flown a lot and show no signs of separation.  The initial bond is weaker than ironing, but seems to get stronger as it ages (diffusion into the cloth, maybe).  


Ironing melts the glue into both cloths immediately.  This is especially significant if you a trimming cloth from the back side of an appliqué.  With ironing I will trim immediately with good results; with rubbing I always had trouble with the seams separating.


You can iron large sections of a project with a regular iron set fairly low (experiment).  However, excess glue will melt onto the iron and spread across the cloth (sticky and unsightly).  Try putting a piece of plain brown paper over the project to protect the iron.  If your iron is gunked up with adhesive, try running it over an anti-static dryer sheet, like Bounce.


I prefer to use a hobby iron and I iron each seam and hem as soon as I make it.  Hobby irons are usually sold with a spade shaped foot.  I substitute a straight narrow foot.  Experiment with settings.   You want to melt the glue but not melt or pucker the cloth.  The setting I use on the model seen here Is about the 9 o'clock position.  


TapeIron_s


TENSION vs PEELING


Join two pieces of cloth well with tape and try to pull them apart.  Very difficult.  Pry apart the ends of the seam apart and pull on them. They will peel apart like a well oiled zipper.  Hems never seem to peel.  When making seams, try to hide the ends so they can’t separate.  For instance, if you’re joining two cloths and hemming, make the seam first so the the hem folds over the end of the seam and it can’t separate.


Things you add on can be a problem, like the fin on a delta.  If you just make a simple seam, it will pull off the kite easily.  However if you fold down the fin and add a second cloth on the back of the seam, it will hold well.  


This section is just a quick warning.  I’ll say more whenever I get to writing a section on design, but I wanted to orient your thoughts in case you get to work before then.  Read Dick Curran's article in Kitelines Winter/Spring 1995 for more design advice.