I have filament of type PLA +. This is for a pot outside. Does a sealant help with strength as well as moisture?
It depends on the sealant.
As this is for the outside, a sealant will help to stop moisture getting in, you would require one with UV protection qualities to stop fading as UV will damage the material over time.
There are materials designed specifically for UV issues as well as heat like ASA that might be better suited, but, I have been assured by others that well maintained PLA can live a long and useful live outside for plants and such.
If you were creating a house number or name sign, ASA might be a better fit.
But it doesn’t really add strength?
Thanks.
PLA+ isn’t really that much stronger than PLA, sometimes it isn’t any different and it simply used to market the material.
If you are using it to pot plants, standard PLA will be fine unless you plan to throw the pots around and against walls. Very little strength is required for potted plants. If you are aiming for lots of soil and the biggest pot you can get, increase the wall count and the infill density, plus, use a gyroid infill or something other than grid. That will hold the weight.
If you are really concerned you can add strength by looking to different materials.
Your printer can print ABS which is considered stronger, PETG which is a bit stronger but adds some impact resistance due to the material properties.
If you have the hardened steel nozzle and the hardened gears for the hit end, you could print the materials which include glass or carbon fibre.
An inexpensive PLA CF is available that will be much stronger than type PLA/PLA+.