Listed below are some tips and techniques for optimizing glue spreader usage in the woodshop.
1 End seal leakage: Leakage sometimes results from over tightening, which can deform the backing plate. Check to see that the roll ends clean and flush and the sealing surface is flat.
2 Determining the glue spread rate: To determine the spread rate, cut a sample of stock exactly 1 square foot, then weigh it on a gram scale. Next, pass it through the machine and weigh again. Subtract the first weight from the second. If the stock is coated on both sides, multiply the differ-ence in weight by 1.1 for spread in pounds per thousand square feet. If only one side of the sample is coated, multiply by 2.2.
3 Changing the coating thickness: Increase the “doctor roll to coating roll” pressure for a thinner coating and decrease for a thicker coating. Also, roll groove patterns are designed to apply coats within certain thickness ranges.
4 Uneven coating: The rolls may not be parallel, or the sub-strate could be uneven. Prolonged running of smaller pieces also can cause uneven roll wear. If the glue is pushed off the tail end of the board, there may be too much coating on the rollers, or the feed gap is too tight. Try raising the upper roll slightly (0.005).