Originally Posted by DanTwoLakes
The reason for not steaming leather is that you can damage it. Water and leather do not mix. No leather supplier in the world recommends heating or wetting leather, and steaming does both. The reason for not steaming vinyl is that all you will do is get it wet. If the seat covers are made correctly, they will fit. If they are slightly off then adding some padding will correct them. If they are too small, nothing in the world will make them bigger.
You have to stop thinking of upholstery work as precision work, it's not. You can't adjust upholstery work by millimeters or thousandths of an inch like metal or wood. The original seat covers you copy aren't perfect, far from it. Unless they come from the rolls Royce factory, they are made in a factory on piece work, by someone who could care less about quality. The only thing they are worried about is making the most money they can. There are lots of flaws that the average person doesn't see, even in seats that look like they're perfect.
Doing my seats I definatley figured out what you mean by "precision work". Ive seen how much you can adjust something thats off a little or even a lot and make it look really nice. I wasnt using the steam to install the covers, just for removing any wrinkles once they were completely installed. I saw a video on youtube a while back of ish steaming some leather seats to remove wrinkles, thats why I used it. Worked great, but I dont want to do it if it damages leather. Thanks for all the info Dan its helping me out a lot.