Best rails position on frame in a dusty workspace

I would have said stay < 30kg with gantry ends, Z axis and torch, wires etc.
The torch lifter is hard to get under 5kg, the torch is about 1kg so Tommy's target implies use of belts which you may or may not want to use.

Thanks for those details Rod.
What is your opinion about belts?

I have seen that Tommy use it on his tables, but I mainly see rack and pinions on commercial tables, and on DIY ones too.

I used to use belts on mine (HTD5M), I now use rack and pinion MOD1, bought here if you are in europe (as they were very cheap imo)
www.motedis.co.uk/shop/index.php
they ship from germany
they also have a lot of other motedis websites in US, mexico etc etc.
they are not into chit chat, just order and send whatever you order there is no phone support and the email support is "interesting" if they get something wrong (I asked for 8mm pinions and got 1/4" pinions....)
www.motedis.co.uk/shop/DIY.php
but I would buy from them again anytime

I know a guy that uses chain..... yes chain and sprockets and he has made I believe 9 tables and sold a lot of designs for others

When we were looking at commercialising tables, I looked at belts with an Aussie company. They involved the German engineers and the word was not to use them. The Steel used to reinforce belts was not stainless so not rated for any water splash due to rust damaging the belts. I might add we were not looking at dainty belts, more like 20-30mm wide to handle the torque and acceleration we were shooting for.

Use Kevlar reinforced belts instead of steel ones.

Todd wrote:

Use Kevlar reinforced belts instead of steel ones.

Too long ago but I think it might have been steel for the torque required or the supplier did not offer kevlar. Not a lot of choice in the colonies..

Ok, thanks. I have easily founds Kevlar ones in France. So I will go for this solution.

I am thinking since few days about how to protect Y axis rails. I do not want to let rails exposed to dust, so I have found two solutions. The first one is to use "below covers" like this :
 
Those cover would be placed like on this picture :
 

The second one is to use a special Z head design with spacer to be able to put fairings on top of rails. Those fairings would be made of bent aluminum sheet and positioned like the violet lines on this picture :
 
It is cheaper and simpler to install, but I am worried about geometry issues that this solution could cause. The moment created under the rails in particular.
What do you think about these two solutions ?

Currently, the Y rails are the HGR15 ones, the beam is a 80x120 profile like this one :
 

The whole gantry without Y motor and torch is about 25kg. So I am pretty close to the target weight.