Polishing Perspex Oxy Acetylene – help needed, please?

[David Rogers]

Oxy-Acetylene runs incredibly hot. I certainly wouldn’t recommend it for flame polishing. It’s one of the hottest gas/oxy combinations around with a good mix – and one of the dirtiest / most sooty if your oxy is too low to try & get a cool flame.

Not saying you CAN’T use it – but what little experience I have of gas welding / cutting v flame polishing make me think it’s not a good idea.

Whatever flame you use has to be quite cool & soft or you risk setting it on fire…you know the deal. Working your way along and you hear this little crackle as you spent too long getting started at the corner…look and it fizzing away ruining the job.

I’d go for a bigger / wider flame, possibly a small butane gas torch with some of the air inlet restricted to lower the temperature whilst still maintaining a good flame shape. (What I’ve used for years).

edited to add.

I’ve used an MEK booster previously in a polisher – temp around 1750 C. Oxy Acet can get up to 3000 / 3500C

Dave

[Unknown Member]

Thanks for the detailed reply buddy!

Was talking to my neighbour a few moments ago over a coffee and he suggested using a small handle held Mapp Gas bottle.

Seems to be a lot cleaner and we can keep a few bottle on the shelf.

The flame polishers are good but just don’t hold the flame long enough – Will report back after using the Mapp Gas! 🙄

Many Thanks

James

[Ian Johnston]

We Use Oxy Acetylene for 10mm – 25mm clear items that need polished as the larger flame gets a more even result,
But TBH it’s only because we already have it here,and therefore don’t have any extra rental costs on gas Bottles.
If i didn’t have it already i’d do what a Local Plastics company here does and use Pure Hydrogen.
It doesn’t smoke the edge of the Acrylic and gives exceptional results, Use a fine Brazing torch end for the flame

Ian

[Unknown Member]

Ian….Thanks buddy!

I will give that a go as well.

Amazed at the replies on this thread so quickly!

As you can see from the image below we do a lot of these for trade and its just becoming a little bit of a headache with the polishers just need something quicker.

When you have 200 letters to do it can become an issue and bottleneck production some what – Extra tea being drunk and a lot of sitting around too! Of course whilst working

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[Steve Morgan]

I think you should look into the costs an Oxy/Acetylene setup, it might turn out to be rather expensive.

First off you’ll need at a minimum; Gauges, hoses anti flash back arresters torch and nozzles, depending on you building situation and insurance arrangements you may have to store the oxygen outside in a proper secure steel cage. Additionally depending on your location will depend on whether you collect or have the gas delivered, around £55 a delivery currently from BOC, then there is the rental and individual refill cost dependant on bottle size and of course training someone to use and look after the equipment.

I have what is called a PortaPak which uses very small bottles with an annual rent of around £150 and a pair of bottles about £60 (I collect mine) but I only use it for welding. Dave is correct – you can achieve a very hot flame about 3000°C, don’t forget it needs to melt steel, and it can also produce more sooty smuts to drop out of the air than burning and old tyre in the workshop.

A small handheld Mapp gas torch seems to be a lot less involved.

Steve

[Unknown Member]

Steve…

Thanks for this

Mapp gas it is me thinks

[Vince Francis]

Get them laser cut, comes polished and saves you the problem 😉

[George Elsmore]

laser all the way

[Unknown Member]

Some on my biggest clients have rejected laser due to the line effect you get on the edge…

[Kevin Flowers]

James
check the link out, i have seen stuff leave a cnc with a finish better that flame polishing

http://toolingblog.com/2015/01/05/cutti … polishing/

Kev

[Vince Francis]

James, to be fair I use this all the time & never noticed a line. Maybe its how the set up is on the laser

[Unknown Member]

I will try to find some images and upload them….