Tip for Smoothing Silicone Caulk

100% silicone caulk has great adhesion and flexibility, making it the best choice for caulking around a bathtub, but it’s so sticky it can be hard to spread out evenly.

To make it easier to spread silicone caulking:

  • Put denatured alcohol in a plant mister type spray bottle.
  • Use a caulking gun to apply a bead of 100% silicone caulk to the joint.
  • Apply a fine mist of denatured alcohol to the caulking bead using the spray bottle.
  • Use your finger to smooth the bead of caulking with your finger before the alcohol evaporates.

Watch this video to find out more.

Further Information

Joe Truini: I’m caulking this tub with 100% silicone caulk. And I like using 100% silicone for two reasons. One, it’s got great adhesion—it sticks to almost anything. And it’s really flexible, so over time it won’t break free.

Now, the downside of 100% silicone is it is not water soluble, so you’ll have to clean up with a solvent. And also, it’s so sticky that when you try to smooth it out with your finger, sometimes you can either pull it out of the joint or leave a really rough surface.

So, here is the trick, and this works great. I learned this trick from a reader, Herman. And what he suggested is using denatured alcohol. You put it in a little pump sprayer like this, a little plant mister, and just very lightly mist the surface.

That’s all you need, just a little light coating. And that allows your finger to just glide right along. Look at that. How perfect is that? What you end up with is a perfectly smooth bead, each and every time.


  1. This was one of best how-to tips I’ve come across. I wish I had known about this when I recaulked some seams on my RV; what a mess that was (and still is). My shower stall came out perfect thanks to your tip. I found out that starting with a uniform bead is important for a good result.

    Thanks for the great tip!


  2. Hi Wally, I’m so glad that our silicone-smoothing tip worked for you. It’s often the little tricks that really make the difference. Thanks again and good luck!–Joe. T.

  3. Hi ,

    I was wondering if isopropyl alcohol will work just as well as denatured alcohol to smooth out 100% silicone caulking around your tub? And if not why?

    Thank you,


  4. Learn from my very recent mistake: This does NOT work with isopropyl alcohol, which prevents the silicone from curing. 5 days later and all the silicone caulking I put around the tub is still soft and sticky like plasticine so I’ll have to do it all over again.

  5. Can denatured ETHANOL be used to smooth silicone caulk? I found an old bottle of it in my garage but it probably lost it’s “punch”

  6. I live in a third world country where most items are as rare as hen’s teeth. I read somewhere that flute, clarinets and saxophone pads coated with silicone sealant make them perfectly leakproof. I have been in the instrument refurbishing business for more than fifty years and obtaining new pads and other parts was no problem but due to the economic situation, import of luxury items is no longer permitted. Instrument pads are available cheaply from
    amazon, India but are are of very poor quality made in
    china. I tried coating pads with silicone sealant and the layer could not be made smooth as it kept sticking to finger, spatulas, or sticks. Denatured alcohol is unheard of over here but alcoholic drinks are available though extremely costly. Can i use vodka or pure ethanol to prevent sticking of the finger to the silicone layer as it is smoothed.
    Thank you sincerely for any help.

    • Vivian, pure ethanol will work fine, but it should be full strength! Not “watered down” vodka, more moonshine or fuel type. Must evaporate fast. One trick with this is you do have to “sweep quickly” with your finger, smooth consistent speed, don’t slow down too much. Distilled ethanol is easier to get than isopropyl alcohol in many places anyway.

      • Thanks for sharing your thoughts with the Today’s Homeowner community, Greg!
        TH community members helping other TH community members — we love it. 🙂

  7. This tip for smoothing silicone caulk is fantastic, and I am thankful that you shared this tip here. I will use this tip in one of my caulking projects, and it will be valuable for me.


Please enter your comment!
Please enter your name here