I have a small quantity of old brass carburettors’ that i cannot buy floats for any longer.
What filament would anyone recommend that will withstand floating in unleaded fuel.
I am sort of leaning towards PETG basic, but being new to 3D printing I’m not sure.
Any help greatly appreciated.
I am using a PS1
from w11 copilot…
When it comes to plastic carburetor float bowls, the specific type of plastic can vary. However, one common material used for plastic float bowls is nylon. Nylon is chosen for its durability, resistance to fuel and chemicals, and overall suitability for this application. It’s lightweight, transparent (allowing you to see the fuel level), and can withstand the conditions inside a carburetor.
Remember that the exact type of plastic may vary depending on the manufacturer and the specific carburetor model. If you’re dealing with a particular carburetor, it’s best to refer to the manufacturer’s documentation or specifications for precise details. 
PETG is fuel resistant but I don’t think I’d trust it to be immersed constantly, or to not leak through the layers. You could however coat the printed part in fuel tank repair epoxy, or print the float to use as a mould to make one out of brass, like most floats are made of.
I’ve used PETG to make carb parts and airboxes for production runs before, it’s even resistant to nitromethane, it’s one of the best plastics we can print easily for chemical resistance.
Many thanks everyone
I will try PETG first with 2 proto types , one using just PETG and another coated in a protective layer
Many thanks
Is that something you can paint onto it, or it more like a putty that you would have to smear on? This might relate to that other thread, where the guy wants to waterproof (100% guaranteed) his 3D printed enclosure…
I don’t know whether 2K spray epoxy (such as that made by spraymax) would work for such things, but it’s certainly easy to apply.and so far hasn’t let me down.
Yes, it’s an epoxy paint which is fuel proof. It’s usually used to repair motorcycle fuel tanks that have rusted inside.
1 Like
Petg is unsuitable for long term immersion in petrol. Do they make the plastic petrol ‘cans’ friom petg?. When it disolves, it will most likely clog up fuel lines, carb jets etc.
I found this wrt nylon, which you can print on a ps1. Nylon Chemical Compatibility Chart (calpaclab.com)
1 Like
They’re usually HDPE, but that is so they have great impact resistance against accidents and cracking. PETG is fine for petrol, and a lot of small fuel bottles are PET. The surface can degrade with extended (multiple years) of exposure but that’s about all that happens.
The biggest issue with PET-G is if you use any solvent based fuel cleaners through your carbs, acetone and similar varnish removers, which are common in cleaners, will degrade it.
edit: If you want the best option, print it in PP, but PP is a pita to print with.
There may (?) be a potential gotcha lurking in the background, though, and that is that maybe none of the printer filaments is a pure PETG, or a pure PP, or a pure anything. From what I’ve been reading elsewhere, they very likely may have other additives mixed in with them to give them better characteristics.
The big question then: what if the fuel is a solvent for any or possibly all of the additives? What effect might that have on whether or not the float still floats?
AFAIK, those additives aren’t generally disclosed. If they were, then I suppose you could go down the list and find out the chemical compatability of each one of them.
Am I wrong? If not, then the possible solution offered above of applying a tank repair epoxy might be worth exploring right from the get-go.