Sciencemadness Discussion Board

858D Hot Air Gun

Sulaiman - 23-12-2017 at 02:57

As a general purpose heating tool I am considering buying a Hot Air Rework Gun
the 858D, which seems to be the current Chinese consumer standard offering.
Relatively cheap (GBP22.60), plenty of spares available, 700W (maybe) heating power and gentle breeze..
https://www.ebay.co.uk/itm/936-858D-998D-Digital-SMD-Solderi...

I imagine using it instead of a gas torch or bunsen burner or heating mantle, for generally heating stuff up,
and possibly as the key component of a hot air bath for Hg and H2SO4 distillations.

Any comments please - before I make a mistake ?

On the assumption that I will probably buy one, this thread should migrate to a mini-review

violet sin - 23-12-2017 at 04:18

I have a harbor freight heat gun that was really affordable, ~13 $US if I recall correctly. I have not used it for chemistry, but heating other things yep. good, so far at least. melts roofing tar too.
https://www.harborfreight.com/1500-watt-dual-temperature-hea...
but you can find it on sale for ~9$ some times.

more guess work on the temp out, but I'm pretty sure I saw some PID and electronics projects from you. you could take the time to marry the technologies, or just buy one. but my concern there, after only a brief look that is, would be that the link you provide outputs too little air? it doesn't look robust, enough to boil too much solution. if you work on small scale that could be fine.

well there are my 2 cents worth, from a tired tired guy at 4:17am... ahhh coffee, a love/hate affair for the late night driver. too little you want to nap in the car, too much and welll... here we are.

https://www.youtube.com/watch?v=aGSFZ2eadaA
and then there is LOW tec

[Edited on 23-12-2017 by violet sin]

Dr.Bob - 23-12-2017 at 06:06

I doubt the item shown can provide near as much heat as a torch or mantle can in a useful fashion. We use hot air guns at work that look like hair driers, but put out 1500 watts, and have adjustable outputs, with slow air flows, so the air can get very hot if set high enough. These are great for warming solutions, heating glassware to dry (without flames), and much more. The industrial ones are pricy, but last a long time in a lab, cheaper ones like Horror Fraught Tools are fine for occasional use, but most I have seen have died quickly under real use. You can likely get a cheap hair drier at Walmart and do as well or better.

Magpie - 23-12-2017 at 09:20

I got one of those Chinese hot air guns (2000w, I believe) for a birthday present from my son. It is very handy for unclogging condensers on the fly, etc.

Bert - 23-12-2017 at 11:12

I have been using one of these since 1992, it is unkillable. Old fashioned Milwaukee tools I dustrial model, like the one on left in this picture.

Last summer I got one of the little inline $15.00 (cheap!) units, it died after less than 15 minutes of use. You get what you pay for-

milwaukee-heat-gun+005.jpg - 62kB

aga - 23-12-2017 at 12:13

A big problem with using an air gun in place of a mantle or flame is simply how to spread out the heat.

Once spread out adequately 700 Watts isn't really that much.

SWIM - 23-12-2017 at 19:40

Ever seen those old steam bath heaters they used to have in chem labs?

They come up cheap on Ebay sometimes and one would be easy to convert to a hot air bath.

Just put the nozzle for your air gun in the steam input and insulate the body.

With the different sized rings it could handle many sizes of flasks.

From what I've read of your posts you seem to be a person quite comfortable with electronics. Maybe you should consider buying a regular heat gun with more power and adding a controller for temperature yourself.

You could give it various extra features that would be handy for your application, like the ability for it to monitor flask temperature as an option instead of air output temperature.

SWIM - 25-12-2017 at 16:46

Just noticed the specs on that model say 450C as max temp.

Might have trouble distilling sulfuric acid or mercury with that.

The limiting factor in an air bath is the transfer of the heat to the flask, and I think a 100 to 150 degree difference between boiling point of the solution and the heat gun's max temperature might not be enough to give a good boiling rate.

Some other heat guns have outputs up around 600C, which would leave a good margin for error and inefficiency.

Edit: Just picked up a lot of laboratory steam baths and spare parts at auction. Looking forward to trying one out for hot air when they're delivered. (I've already got a hot air gun for paint stripping)

I'm not incredibly enthusiastic about this idea, but the steamers were too cheap to pass up so as long as I've got some why not give it a shot.

I wonder what temp you need to make benzene from benzoic acid? If an air bath can pull that off, it might give better yields as there's a lot of decomposition when doing that reaction with a flame.



[Edited on 26-12-2017 by SWIM]

NEMO-Chemistry - 26-12-2017 at 02:03

Quote: Originally posted by Sulaiman  
As a general purpose heating tool I am considering buying a Hot Air Rework Gun
the 858D, which seems to be the current Chinese consumer standard offering.
Relatively cheap (GBP22.60), plenty of spares available, 700W (maybe) heating power and gentle breeze..
https://www.ebay.co.uk/itm/936-858D-998D-Digital-SMD-Solderi...

I imagine using it instead of a gas torch or bunsen burner or heating mantle, for generally heating stuff up,
and possibly as the key component of a hot air bath for Hg and H2SO4 distillations.

Any comments please - before I make a mistake ?

On the assumption that I will probably buy one, this thread should migrate to a mini-review

I got one the soldering stations with the same type gune, useful for lower heat stuff for sure. Higher heat and you want a cheap (ish)paint stripper gun, i use a variac with mine except...

The fan also goes slower and if your careful you can burn the element out, spreading temperature seems easy enough with foil in a couple of layers. The dun was useful for keeping a soxhlet warm the other day, but i doubt i would use it for much general use..