Make the Lid (haga La Tapa)


Introduction: Make the Lid (haga La Tapa)

About: I am leaving Instructables, soon. I am very upset with the turnaround that has the page to post the manufacture of a dildo. Me llamo Osvaldo Julio Schiavoni I speak Spanish, not English. I use automatic tr...

Me inspiré en este instructable.

En casa solemos hacer escabeche de berenjenas o de morrones, y lo almacenamos en frascos de vidrio. Pero al ir a envasar, me ha ocurrido que está el frasco pero no la tapa, cosa que me molesta sobremanera. ¿Alguien tiene una explicación? ¿Cómo puede un ser humano tirar a la basura una tapa de frasco, salvo que esté inutilizable?

Bueno, el caso es que ayer hice una olla llena de escabeche, y cuando fui a guardarlo me encontré con un frasco chico y uno grande a los cuales les faltaba la tapa. Luego de rezongar un poco entre dientes (no sea cosa que me escuche mi mujer), me dije: "más vale prender una vela que maldecir a la compañia eléctrica". Así que les hice la tapita hermética a ambos.

I was inspired by this instructable.

At home we usually make pickled eggplant or peppers, and stored them in glass jars. But going to be packed, I thought that there is the bottle but not the cover, something that bothers me greatly. Does anyone have an explanation? How can a human being throw away a jar lid, unless it is unusable?

Well, the fact is that yesterday I made a pot full of pickled, and when I went to save it I found a small bottle and a large another which lacked the lid. After grumbling a bit between teeth (lest my wife hear), I said: "Better to light a candle than curse the power company." So I did both the tight cap.

Step 1: Elementos (elements)

Un frasco de vidrio sin tapa.
Una botella de PET.
Si es posible, cilíndrica, es decir con paredes lo más lisas posible.
Una tijera.
Una pistola de aire caliente.
Una madera o un trozo de MDF (Medium Density Fibreboard) o similar para proteger la mesa del aire caliente.
Eventualmente, un cúter.
Eventualmente, un alicate.
Ganas de experimentar.


A glass jar without lid.
A PET bottle. If possible, cylindrical, ie with walls as smooth as possible.
A hot air gun.
A piece of wood or MDF (Medium Density Fibreboard) or similar to protect the table from hot air.
Eventually, a cutter.
Eventually, cutting pliers.
Keen to experiment.

Step 2: Cortando (cutting)

Destripar la botella tratando de obtener una lámina plana de PET, dentro de las posibilidades que ofrezca la forma de la botella.

Cortar un círculo de PET de diámetro un poco más grande que la boca del frasco. Más o menos 2 cm más grande. Si la boca del frasco es muy grande, hacer el círculo 3 cm más grande.


Gut the bottle attempting to obtain a flat sheet of PET, within the possibilities offered by the shape of the bottle.

Cut a circle of PET of slightly larger diameter than the mouth of the bottle. About 2 cm larger. If the mouth of the bottle is too big, making the circle 3 cm larger.

Step 3: Aplicando Calor (applying Heat)

Poner el círculo de PET sobre la madera o MDF que protege la mesa.

Luego poner sobre el mismo el frasco de vidrio, boca abajo, tratando de centrar la boca dentro del círculo de PET.

Luego encender la pistola de calor. La mía tiene dos posiciones, usé la más baja. Supongo que con la más alta se corre el riesgo de quemar el PET o romper el frasco.

Mientras se aplica el calor, el PET empezará a doblarse hacia arriba y contraerse alrededor de la boca del frasco. Ir girando con cuidado, para no descentrar el frasco respecto al PET.

Importante 1: Mantener el frasco y el PET bien presionados en contacto con la superficie de abajo, para evitar que el aire caliente pase por debajo y afecte el centro del PET.


Put PET circle on the wood or MDF which protects the table.

Then put over it the glass jar, upside down, trying to center his mouth within the circle of PET.

Then turn the heat gun. Mine has two positions, used the lowest. I guess the higher has the risk of burning PET or breaking bottle.

As heat is applied, the PET begins to bend upward and contract around the mouth of the bottle. Go gently turning, caring not decenter the bottle in PET.

Important 1: Keep the PET and bottle firmly pressed into contact with the bottom surface, to prevent hot air pass beneath and affect the center of the PET.

Step 4: Importante 2 (important 2)

NO ENFRIAR CON AGUA. Esperar unos minutos hasta que el PET se enfríe. Se puede soplar suavemente para acelerar el enfriamiento, pero no mojarlo, porque el vidrio no resistirá el choque térmico y se fracturará.


DO NOT COOL WITH WATER. Wait a few minutes until PET cools. It can be blown gently to accelerate cooling, but don't wet it, because the glass does not withstand the thermal shock and fracture.

Step 5: Verificar (verifying)

Asegurarse de que el PET se haya amoldado aunque sea parcialmente a la rosca del frasco. Si así no fuera, repetir el paso 3.


Ensure that PET is at least partially molded into the thread of the bottle. If it does not, repeat step 3.

Step 6: Tensar La Tapa (tighten the Lid)

Poniendo el frasco boca arriba con su tapa colocada, aplicar UN TOQUE de calor con la pistola en el centro de la nueva tapa, con lo cual esta se contraerá ligeramente. NO PASARSE, porque si se contrae demasiado habrá que descartar la tapa y empezar de nuevo.


Putting the bottle upright with the cap in place, apply A TOUCH of heat gun in the center of the new cap, which this will shrink slightly. Not passed, because if contracted too much, you will have to discard the cover and start over.

Step 7: Sacar La Tapa (removing the Cover)

Si la tapa no sale desenroscándola, es probable que al contraerse haya aprisionado el borde de vidrio que está debajo de la rosca. En ese caso, habrá que cortar con cuidado el PET por encima de ese borde, con un cúter.

Al sacarla, la tapa se arquea ligeramente, pero eso es normal y no la afecta en nada. Solo habrá que poner un poco más de atención al volverla a enroscar.


If the cap does not unscrew and out, is likely to shrink has trapped the glass edge there is below the thread. In this case, you must cut with care the PET over that edge, with a cutter.

Upon removal, the lid is arched slightly, but that is normal and does not affect anything. You just have to put a little more attention to re-tighten.

Step 8: Emprolijar -opcional- (tidying Up -optional-)

Si la estética cuenta, emprolijar el borde de la tapa con la tijera o con el cúter. Tener en cuenta que al contraerse el PET también se engrosa, con lo cual se hace un poco más difícil de cortar. Es probable que haya que usar un alicate para cortarla. Luego se puede alisar el borde con lija mediana.


If aesthetics matter, tidying up the edge of the lid with scissors or cutter. Note that when the PET contracts, it also thickens, which is a bit more difficult to cut. You probably have to use cutting pliers. Then you can smooth the edge with medium sandpaper.



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    Very very clever! Now I am wondering in what other ways it is possible to exploit this tendency of PET to shrink when heated?

    1 reply

    Yes, throbscottle. PET is a very interesting material. You can use it in example to tie pieces using PET strips and then shrink them with a lighter to fasten the pack. Recently I did a garage rack, and I tied the shelves instead of using screws. Success. Another use is to fix a plastic break, making holes in the sides, "sewing" the break and shrinking the strips.

    Osvaldo, Buen trabajo reciclar un material que se suelen desechar.

    Nice work recycling a material that is usually thrown away.

    1 reply

    Thanks, Bill.

    I am improving my English! All Saturdays I am taking English classes from mormon missionaries, and I note a real improve. Maybe in one or two year I dare to do a trip through USA.


    Gracias, Bill.

    Estoy mejorando mi Inglés! Todos los sábados estoy tomando clases de inglés de los misioneros mormones, y noto una mejora real. Tal vez en uno o dos años me atreveré a hacer un viaje por USA.

    This is such a great idea for storing leftover latex paint. Using metal lids results in rusted metal lids, so this is perfect. Thank you for sharing!

    1 reply

    Glad you found it useful, Nina.

    I have not started up my wood lathe again, but I have not forgotten that I promised to send you a bowl. I spend more than a month trying to convert my generator to natural gas, without success. I canceled the project last week.

    Thanks for commenting!

    Interesting idea. How long did this jar seal keep?
    I've had great success with prolonging shelf-life of some foods by removing excess air (by vacuum from mouth or machine) and tight elastic, but I've never thought to use your method.

    For longer periods of storage, maybe add a gasket between the PET and glass?
    I also like the phrase about the power company in your intro.

    1 reply

    Mike, we never allow the canned food be too much time, specially pickles. Then, I don't know how many time it could last. Maybe two or three months, but I'm not sure.

    Surely you can add an EVA (Ethyl Vinyl Acetate) foam gasket. Or styrofoam.

    When I drink yoghurt in sachet/pouch, I take off the remaining air into the pouch before put it into the fridge. That manner it lasts a little more.

    The phrase you like is not mine, I also like it.

    Thanks for commenting!

    Thanks, rlarios! Glad you like it.

    Osvaldo, nice instructible! Several years ago I made some knife sheaths from a thermoplastic called Kydex. Like you I molded it with a heat gun and quickly discovered the value os a cheap pair of cotton gloves! Hope all is going well with you.

    1 reply

    Thanks, knife141. Yes, this time I did the work without hurt my hand!