I am working with CNC routers and a lot of MDF, which is great UNLESS you need to paint the edges which are furry in some spots and all open and porus everywhere else.
I build plinths that need to be enamel smooth and show no seams or texture changes.
I have tried so far
Watered PVA (does not capture the hairs, cannot be sanded back as it
does not penetrate very far)Builders bog/Bondo (to sticky to apply easily, high build means
sanding it back tends to eat away at the corners)Automotive Primer-Filler spray, a perfect finish…. in only 18 coats.
Fine spackle filler (terrible texture)
Does anyone out there have the magic bullet?
I'm wondering of a lighter sealant or resin would wick into the wood deeper?
Run a torch over the hairy bits?
Best Answer
You could try brushing the edges with glue. I use Weldbond glue for similar purposes. You can dilute it, maybe a thin coat first to penetrate and seal, followed by a thicker coat to finish it. It's available in large sizes if you'll use a lot. Worst case it's a good glue so even if it doesn't work for your application, it will still be good to have around.
There is a craft product made for decoupage called Modpodge that might work too. They have different formulations, one might work for you.
Wood turners use cyanoacrylate (like SuperGlue) to harden and strengthen wood, usually a thin one that wicks well. It imaging it may be expensive to use, though, I could see MDF soaking up a lot of it. E-ZBond makes it in larger sizes that may be more practical.