hey everyone! long time user of instructables, but this is the first time ive gotten around to posting something.
so basically my car unfortunately didnt come with cupholders, so when i was driving my drink (coke or water, never alcohol, kids dont drink and drive) was always between my legs. that made driving quite difficult. so i set out to put some in. please bear with me through this ible as im an aussie and therefore use the metric system

Step 1: What Youll Need

hardware:
two 80mm pvc sockets which are actually about 76mm at the narrow end if you can fit the next size up i would reccomend it.
an 80mm gutter plug which is the black foam in the picture.
some silcone, a bit of superglue and some vehicle body filler (bondo or the like) although almost any gap filler will work

tools:
a drill with appropriate size hole saw bit
sandpaper
a dremel or rotary tool (optional)
something to cut the gutterplug in half, i used a hack saw, a hot wire cutter would be best.

Step 2: Mark and Drill!

first thing you need to do is use the hole saw to cut a template, mark some templates where you want to mount the cupholders and drill, or you could try your luck and go for it. but if youre using the same sockets i am, youll need about 12mm inbetween the two.

Step 3: Test Fitting.

next test fit, sand, grind, cut more if you need too. otherwise test both from the bottom. if they fit, great next step, if not sand your hole out a bit more until they do.

Step 4: Adding a Base

so here i have cut my gutter plug in half, run some superglue around the top and bottom edge ( a mm or 2 from the top/bottom) and pushed the pvc over the top while sitting it on a flat surface to ensure it was flush, let it dry for a minute. then you can move on.

Step 5: Silicone Them In!

youre almost there! slot your cupholders in and silicone them in place and preferably leave them overnight to make sure they cure properly, depending on your application you may need to make a suppor for your cupholders but mine are hitting the floor of my car so they should be fine.

Step 6: Bog It Up!

mix up your body filler and fill in your gaps, i did two applications but one is enough, as long as youre happy with it. i just wanted the gaps to be flush

Step 7: Thats It, Youre Done!

give it a clean, scraping off extra filler and silicone and stick em in your car or boat or even your couch! thanks for reading i hop i helped!

future edits will be to cut them down a bit, and give it a paint job. but theyre functional.