Toner transfer method for making PC boards is very practical and economical. The use of heat for the transferring is not. Large boards expand with heat (more than the laser print) and heat is applied to the paper side (with iron) and not to the bottom (toner) contacting the copper layer. Too much heat melts and deforms the toner, too little heat and it won't adhere uniformly. This technique involves the use of 2 very common chemicals: ACETONE and ETHYL ALCOHOL. Acetone can be replaced by Toluene, Xylene and many other solvents. Proportions will vary for each. I have been using this method for over 16 years with success. It is very important to find the right paper & toner. In general, the ones used for the normal iron/laminator method will work. With some toners, you might have to alter the suggested proportions.