# What is the sweet smell from a rich oxyacetylene flame?

**URL:** <https://boards.straightdope.com/t/what-is-the-sweet-smell-from-a-rich-oxyacetylene-flame/777423>\
**Category:** Factual Questions\
**Created:** [January 17, 2017, 10:14pm UTC](https://boards.straightdope.com/t/what-is-the-sweet-smell-from-a-rich-oxyacetylene-flame/777423 "2017-01-17T22:14:42Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\
**Post date:** [January 17, 2017, 10:14pm UTC](https://boards.straightdope.com/t/what-is-the-sweet-smell-from-a-rich-oxyacetylene-flame/777423/1 "2017-01-17T22:14:42Z")

</div>

Subject line says it. It’s been a while since I worked with an oxyacetylene torch, but ISTR a sweet smell when the flame burns rich. Is there a specific combustion product that’s creating that smell?

---

<div class="post-metadata">

**Author:** ![anomalous1](https://avatars.discourse-cdn.com/v4/letter/a/e56c9b/32.png) [@anomalous1](https://boards.straightdope.com/u/anomalous1)\
**Post date:** [January 17, 2017, 10:24pm UTC](https://boards.straightdope.com/t/what-is-the-sweet-smell-from-a-rich-oxyacetylene-flame/777423/2 "2017-01-17T22:24:45Z")

</div>

Impurities in the mixture can create this smell. The gas is usually odorless otherwise.  
Not sure what impurities though.

---

<div class="post-metadata">

**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\
**Post date:** [January 17, 2017, 10:56pm UTC](https://boards.straightdope.com/t/what-is-the-sweet-smell-from-a-rich-oxyacetylene-flame/777423/3 "2017-01-17T22:56:37Z")

</div>

impurities … toxic impurities such as traces of phosphine and arsine, which give it a distinct garlic-like smell

other stuff in tank on purpose… acetone or dimethylformamide

---

<div class="post-metadata">

**Author:** ![Amateur\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)\
**Post date:** [January 17, 2017, 11:36pm UTC](https://boards.straightdope.com/t/what-is-the-sweet-smell-from-a-rich-oxyacetylene-flame/777423/4 "2017-01-17T23:36:00Z")

</div>

Eyebrows.

---

<div class="post-metadata">

**Author:** ![GaryM](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garym/32/241_2.png) [@GaryM](https://boards.straightdope.com/u/GaryM)\
**Post date:** [January 18, 2017, 1:37am UTC](https://boards.straightdope.com/t/what-is-the-sweet-smell-from-a-rich-oxyacetylene-flame/777423/5 "2017-01-18T01:37:13Z")

</div>

Acetylene is desolved in acetone in the tank. Acetylene compressed to much over 20 in so psi can detonate. At least that’s what I learned in A&P Mechanics school 50 years ago.

Sent from my LG-V495 using Tapatalk

---

<div class="post-metadata">

**Author:** ![mixdenny](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mixdenny/32/2962_2.png) [@mixdenny](https://boards.straightdope.com/u/mixdenny)\
**Post date:** [January 18, 2017, 2:11am UTC](https://boards.straightdope.com/t/what-is-the-sweet-smell-from-a-rich-oxyacetylene-flame/777423/6 "2017-01-18T02:11:50Z")

</div>

Hmm, I was just using my torch a few days ago and don’t remember any smell, just soot from soft starts.

Dennis