El decapante en gel permite decapar el barniz.

Yes. Decapante is treated as a masculine noun here, so it takes el: el decapante.

In this sentence, decapante means a stripping product or paint/varnish remover. Even though many nouns ending in -e can be either masculine or feminine, you simply have to learn the gender with the word. Here, it is masculine.

Here, decapante is a noun, not just an adjective. It refers to a chemical product used to remove paint, varnish, or similar coatings.

So el decapante en gel means something like the gel stripper or the gel stripping product.

You may also see related forms:

• decapar = to strip/remove a coating
• decapante = stripping product / stripper

It may sound repetitive to an English speaker, but it is completely natural in Spanish.

• decapante = the product
• decapar = the action

So the structure is basically:

• The stripping product allows stripping the varnish

Spanish often repeats related words like this when one is a noun and the other is a verb. It sounds technical and normal, especially in instructions or product descriptions.

En gel means in gel form or as a gel.

The preposition en is commonly used in Spanish to describe the form, material, or presentation of a product:

• champú en seco = dry shampoo
• detergente en polvo = powder detergent
• pintura en spray = spray paint
• decapante en gel = gel stripper

So en gel describes the type or consistency of the product.

Because permitir can be followed directly by an infinitive.

Pattern:

• permitir + infinitive

Examples:

• permite limpiar = it allows cleaning / it allows you to clean
• permite abrir = it allows opening / it lets you open
• permite decapar = it allows stripping

You do not add a before the infinitive here.

If a person is mentioned, Spanish often uses:

• permitir a alguien + infinitive

For example:

• El producto permite al usuario decapar el barniz. = The product allows the user to strip the varnish.

Permite is the 3rd person singular present tense of permitir.

Its subject is el decapante en gel, which is singular, so the verb is singular too:

• El decapante en gel permite...

It means:

• allows
• makes possible
• sometimes lets

So grammatically, it is:

• subject: El decapante en gel
• verb: permite
• infinitive phrase: decapar el barniz

Spanish often uses the definite article more than English does.

Here, el barniz refers to the varnish being removed, and that sounds natural in Spanish. In technical or instructional language, Spanish commonly includes the article with materials or substances:

• limpiar la superficie
• retirar la pintura
• quitar el barniz

In some contexts, article omission is possible, but decapar el barniz is the most natural version here.

Barniz means varnish. It is the protective or decorative coating applied to wood and other surfaces.

It is a masculine noun:

• el barniz

Be careful not to confuse it with:

• pintura = paint
• esmalte = enamel / nail polish / glaze, depending on context
• laca = lacquer

It is natural, but it sounds technical and informational, like something you might read:

• on a product label
• in DIY instructions
• in a hardware or renovation context

It is not the kind of sentence used in everyday casual conversation unless you are specifically talking about restoration, furniture, or paint removal.

In standard Peninsular Spanish, it would be approximately:

el de-ka-PAN-te en JEL per-MI-te de-ka-PAR el bar-NIZ

A few useful pronunciation points:

• c before a in decapante / decapar sounds like a normal k
• g in gel sounds like a strong throaty Spanish j
• z in barniz in most of Spain sounds like th in think

So in much of Spain, barniz sounds roughly like bar-NEETH.

Yes, but only depending on style.

Possible English equivalents are:

• allows
• lets
• makes it possible to

In a technical sentence like this, allows is usually the best match. Lets is more conversational and less typical for product descriptions.

So permite decapar el barniz is most naturally understood as allows you to strip the varnish or allows the varnish to be stripped, depending on the context.