I've got a quick question about thinning polyurethane. I use a two-component polyurethane that consists of a base and a hardener. The can states that I should dilute it by 10-30%. Does this 30% refer to just the base or the total of both base and hardener? I've also been experimenting with the dilution because my initial attempts at wiping it on resulted in streaks and it got sticky really quickly. Since then, I've thinned it out more than recommended, and while the application improved, I'm worried about any negative effects this might have aside from the obvious reduction in strength.
3 Answers
Keep an eye on sheen; thinning too much can affect how it dries and gives a smooth finish. It might even impact how well the layers bond together, which is important for durability.
Thinning a two-part system like yours can be risky. Definitely check in with the manufacturer before going crazy with dilution!
Thinning can actually work to your advantage! Just keep in mind that you'll need to apply more coats to get the same durability. I’ve heard of some folks using a mix where they do 1/3 polyurethane, 1/3 mineral spirits, and 1/3 boiled linseed oil for a nice finish. Wipe it on for best results!
That blend sounds nice! I usually go with a 3-2-1 method—1 part oil, 2 parts poly, and about 3 parts mineral spirits. Adjust for wiping versus vertical surfaces, of course.
I’ve also used a similar mix, adding beeswax, so my poly is diluted a lot, but it yields an amazing finish!