Why gas lenses work...

[chevy2]

Found these pics while brousing on the Weldcraft site and thought worth sharing of coloured gas flowing through a regular collet and then through a gas lens which shows a more dense and directed flow to the weldpool area,

regular collet and ceramic...

and with a gas lens...

 

[justmental]

i use them all the time now.
and use a lot less gas

 

[Autofabrica]

I used a gas lens today 2.4mm kit with No7 gas cup welding 2mm 1050 aluminium sheets and I had great results.

I want to know as well is there difference between let say eBay gas lens kit and CK gas lens kit, in terms of performance?

 

[chevy2]

I used a gas lens today 2.4mm kit with No7 gas cup welding 2mm 1050 aluminium sheets and I had great results.

I want to know as well is there difference between let say eBay gas lens kit and CK gas lens kit, in terms of performance?

I havn't noticed any difference in the gas lenses from my local welding supplies and the chinese ones i got from shopriver on ebay?

for those that dont use them you'll find your argon goes further and they soon pay for themselves as i rarely use more than 5LPM.

 

[chunkolini]

Why does anybody use anything else?

 

[wheresmejumper]

access?

 

[chevy2]

Why does anybody use anything else?

Quite simple really,
the welding machines come with the cheapest torch parts, ie regular collets.

so unless you use forums like this or work as a welder or with other welders you probably would never know the gas lenses were an option,

infact i only found out about them a few years back even though i've tig welded around 20 years, had seen them but never knew their use?

 

[chevy2]

access?

they often can be as versatile due to being able to let the tungsten out further.

 

[hotrodder]

Deja Vu

Gas lens demo photos from the Miller site (they were photobucket so i've saved 'em and uploaded here in case they disappear)...

Gas lenses let you extend the tungsten further for those hard to reach spots and (in the case of the smaller ceramics, say #5 or #7) you can get away with slightly lower flow rates- pics should make it obvious why

As Runnach said, you'll need gas lens collet bodies as well as the ceramics and IIRC for your torches you may need a different/additional insulator. These are for a wp-20 but the white disc is an additional insulator to adapt the larger gas lens to the torch

 

[PhillipM]

Soooo, why don't we have them for MIG's yet?

Okay, the wire and the harsher arc would reduce the effect, but it should still be better, no?

 

[chevy2]

Soooo, why don't we have them for MIG's yet?

Okay, the wire and the harsher arc would reduce the effect, but it should still be better, no?

the spatter would probably block the wire gauze?

 

[PhillipM]

Hmm, maybe, I don't often end up with spatter that far up the nozzle but I suppose on upside down/high power jobs it could be an issue.

 

[Piero]

I hate to be the spanner in the works but I wouldn't be to sold on a gas lanze.

Shock horror! !!!!

Fearing not being popular. As most don't actually like different opinions but I have been involved in flowing of cylinder heads and the like for many years.
Its not my day job but neither the les I do understand the moment of gas

Normal ceramics collets etc
I personally get a very small needle file and file the exit holes in the collets so as to create a swerling affect. Much like a vortex.
The ceramics need to be bulb like at the top end were they meet the torch.

The gas is exiting sideways and hits the ceramic face on creating a confusion and a possible bottle neck near the exit portion of the ceramic.

So In practical turms the gas lenze could be seen as better.
The gas is exiting stright down the ceramic.
The gauze is restriting the flow and as such they have widend the serfice earea to alow for no losses.
But in doing so. They have slowed down the flow rate.
In the fat part of the ceramic of a gas lenze. It holding twice as much gas.
They will be a pressure drop
Not a good thing.

Theres a lot more to it then that but I have not given it to much thought
Have a look at what fronius use as a ceramic etc

 

[FranV8]

Piero, you're not making a lot of sense. Pressure drop does indeed involve restricting flow, which you don't want in a cylinder head, but if you can get good gas coverage and lower gas flow when tig welding you are winning on both fronts. Why would you want to use more gas?

In fact, with a conventional shroud, you can see from these photos why they say not to use excessive gas flows, the vortexes where the gas meets the air will cause contamination by pulling air in and mixing with the shielding zone at higher flows.

Think I may be off to order some gas lenses for my WP17...

 

[Piero]

I am sorry to say frank but yr making no sence.

Restected flow will infact increase pressure.

What I am saying is that a gas lenze trys to address one problem but crates an other.

Unless you understand flowing you wont follow what I am saying.

Simply take the cross section of the largest part of the ceramic of a gas lenze.
If it was x say.
Now cover it with mesh as in a gas lenze. The cross section is reduced.
Hence why they use a larger ceramic.
This larger ceramic causses a loss in pressure and slows down the flow rate.

 

[justmental]

they all have there uses and i use mine all the time.
I have a few different size's and find using the smaller ones are better when working round tube work.
pics of the ones i have.

and its bigger brother

and the standard gas lense

 

[wheresmejumper]

the pyrex cup i use doesnt increase at start or reduce diameter at the exit

well,until it broke
rapid welding want 40 quid delivered for a replacement

 

[Piero]

I did start my post by saying people dont like different opinions.

I am only trying to open yr eyes guys.

How many people have seen tried them silly water savers for a house hold tap.

The gas lenze works on the same principles
Now how many water savers have ended up in the bin.

 

[justmental]

the pyrex cup i use doesnt increase at start or reduce diameter at the exit

well,until it broke
rapid welding want 40 quid delivered for a replacement

is most of that postage wheresmejumper

 

[PhillipM]

They will be a pressure drop
Not a good thing.

I've got 200 bar to play with on the pressure side, I don't think it's an issue, I'm not trying to force as much gas through the lense as possible, because it's a none issue, all you want is a nice, evenly distributed laminar flow.....basically, comparing it to a cylinder head flow makes no sense whatsoever.
Neither does comparing it to a water saver.