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Hi! Welcome back to my newsletter :) If you’re new here, I’m Kara! I’m a licensed nail tech and a certified educator and I love gabbing on about nails and nail health. This month I’m focusing on a few educational topics here that I always get asked about. First up, the age old question:

What is the difference between builder gel, hard gel and rubber base?

One thing I want to call out before we even get into the specifics, is that every brand is going to have their own version or title for these types of products. Honestly, it can get really confusing because brands will call their products whatever is trending or make up something new to make it seem like an innovative product, and that makes it really confusing for consumers to know what to use and how to use it. So it’s really important to understand what the product is that you’re using and how it functions, moreso than what a brand labels it as.

What is Builder Gel?

High Level Explanation: A thicker gel that can be used to build an overlay on top of the nail and give it a thicker structure, which adds strength and can be used to help nails grow longer without breaking.

Builder gel is the umbrella term for any gel that’s used as I stated above. What sets it apart are the characteristics of builder gel like the post cured hardness, the viscosity, how you apply it, if you need to file it, if it can be used for extensions, and so on.

You should be able to get all of this information from the brand that you’re using and if you can’t, in my opinion you shouldn’t be using it. Because 1 - how are you supposed to know how to use the gel or what type of nails the gel works for if they don’t tell you, and 2 - I just think it’s SO important to only work with trustworthy gel brands who will directly communicate with customers for safety and best results.

Just so you know, I only work with and recommend professional gel brands that I fully trust. I’ve either met the owners of the brands, or someone from the team, or I’ve met the owners of the nail supply companies and I feel confident in using them and suggesting them to you all too! Ok now let’s break down the

Types Of Builder Gel:

For this purpose, let’s break these gels into two categories: soft and hard builder gel.

Soft Gel:

High Level Explanation: A porous gel that can be soaked off with acetone. Generally has some level of flexibility.

Other Names: Semi-hard gel, structure gel, builder base, builder in a bottle, rubber gel, rubber base, overlay gel… am I forgetting anything else? 😂 Like I mentioned above, the characteristics of the gel will depend on the formula, how it’s applied, and how it wears on the nail.

Rubber Base:

This is truly just a name that a brand came up with somewhere, but at it’s core, it’s usually a softer, more flexible builder gel that can be used as a base coat underneath less flexible products to increase adhesion. AND you can also build small overlays with it.

Who it’s good for: softer, weaker, damaged nails that need really adhesive flexible products for better retention. It can also be applied in a thinner layer as a base coat for less flexible builder gels. This gel will NOT give the nails very much strength, so if it’s worn alone, it’s better for shorter nails. This will also usually not last as long on the nails because of the flexibility. I’d say you can probably get like 10-14 days of wear on average out of this.

If you are trying to grow your nails and they are damaged or weak, this is actually a great product to start with by doing regular overlay manicures and adding protection to the nails so they can start to grow. After they grow and feel a little stronger, you can switch to a less flexible gel like semi-hard gel or hard gel.

How to remove it: Since this is a soft gel, it can be soaked off with acetone after you file off the top layers. If you want to use an e-file to do that, I’d recommend using a sanding band with a lower grit (my favorite ones linked here). I wouldn’t use a carbide bit because this gel is just really soft and you could damage the nails more easily.

My favorites: Kinetics Max Base and Kokoist Mega Stick Base. I typically apply these underneath less flexible builder gels, but you CAN do a small overlay on short nails.

Semi-Hard Builder Gel:

High Level Explanation: A builder gel that has a thicker viscosity and a higher post cured hardness than rubber base, but can still be soaked off with acetone. This is where most builder gels (despite what each brand calls them) will fall.

Who It’s Good For: In my experience, this product works best on nails that fall somewhere between the weaker to strong range, but not for anyone who has really damaged nails or extremely strong nails.

It’s an amazing product for anyone who wants that classic russian manicure look, who wants to add strength to their nails but still have some flexibility, and grow them longer without breakage. It’s also a great option for anyone who wants to be able to more easily fully remove their gel because it can be soaked off with acetone.

Not all semi-hard builders work for everyone, so this is where it’s important to understand the characteristics of each product to choose the best one for your nails.

Why is flexibility important? It seems counterintuitive to put a flexible product on your nails when you actually don’t want them to bend and break, but a flexible product can actually help prevent breakage. Flexible gel is able to move and bend and flex just a little with your natural nail. So instead of snapping or breaking whenever your nail touches a surface (like typing or something a little harder like accidentally hitting your hand on a counter - I do this a lot lol), the gel has the ability to move WITH your nail so that it can actually stay adhered.

If you’ve ever had a nail enhancement that’s TOO hard, like acrylic or dip, you might have experienced how it can literally rip off your nail in one piece because it essentially has zero flexibility and physically can’t stay attached to your nail when there’s some sort of force.

How to remove it: Since this is a soft gel, it can be soaked off with acetone after you file off the top layers. If you want to use an e-file to do that, I recommend using a carbide bit to quickly file down the overlay before soaking. You can also do rebalances with these types of gels. Here’s a video that explains that process!

Here are some of my favorites:

*If you have weaker nails, or if the brand recommends, you can/might want to put a layer of base or rubber base on underneath these gels. I usually do this regardless of the product, because I don’t want my gel to lift.

Kinetics Fiber Base Gel: This is a builder gel that has tiny nylon fibers inside the formula that add extra strength and durability to the nails. It’s made for thin, delicate nails because the fibers in the formula add a really nice layer of protection and they can feel really supported. I also love this gel as someone who has longer, stronger nails personally. The fibers gave my nails a nice amount of strength, and I would say it has a similar flexibility to Nail Thoughts (below).

Other things to note: this product should be worn with a base gel underneath, it should not be used for extensions, and it can be used on weaker to medium strong, short to medium-long nails. If you need something stronger, I would recommend any of the gels below!

Nail Thoughts 3-in-1 Builder Base Gels: These are great for people who have a little bit of strength already, and if your nails are on the weaker side, I’d highly recommend doing a thin layer of Mega Stick Base underneath so this doesn’t lift.

This gel has a little flexibility so it’s great for helping flexible nails get stronger, while also providing support and strength so they can go without breaking. It’s also great for stronger nails because the post-cured hardness is higher and it can adhere well and feels really supportive.

I like this think of Nail Thoughts as a product that can generally work well for most people as long as your nails aren’t extremely damaged or rigid.

Other things to note: it can be used on short to medium-long nails, and you can build short extensions with it.

Kokoist Platinum Filler Base: This is a 2-in-1 base and builder gel, if you need additional adhesion, I’d recommend putting Mega Stick Base on underneath. I would not recommend this gel if you have very weak, bendy, damaged nails.

This builder gel has a higher post cured hardness than Nail Thoughts and I LOVE it for when my nails are longer because it feels so strong and supportive. It still has some flexibility, but it is noticeably more rigid than Nail Thoughts too.

Because of this, I think this specific builder gel is better for people who like to wear their nails medium-long to long, and who just want additional strength and less flexibility.

Other things to note: it can be used on short to long nails, and you can build short extensions with it.

Hard Gel:

High Level Explanation: A non-porous gel that can not be soaked off with acetone. Generally has some level of flexibility still but is more rigid than soft gel.

Hard gel seems to be sweeping the nation right now! I don’t know about you but I’m seeing it all over social media and I’ve heard a bunch of nail techs say they are either jumping on the hard gel train or they’re reaching for it more and more.

I have been using hard gel for a few months personally, and I’m really loving it. It has similarities to soft gel, but also has to be treated differently to be used properly!

I think this deserves it’s own dedicated post, so I will be putting that out next week, with way more information on what it is, how to use it, etc. If you have any specific questions, please leave a comment. And make sure you’re subscribed too so you don’t miss it!

See you next week! 💋