Bullseye, I have used UltraCote on several builds and it is far easier to get a good job with Ultracote than with Mono...... I use a covering iron. I think you will have better results with the iron than with the gun. Your temp control is much more consistent. Make sure you calibrate your iron. I take a kitchen digital thermometer and find the dial location that corresponds to about 230 and 330 degrees. Apply the covering at the lower setting as you mentioned. Go back over the complete structure at the low setting. Then tighten to remove wrinkles at the higher setting. And as mentioned above, you must relieve gas build up in hollow structures. Also, if I have gas bubbles form at the higher temp setting when tightening the Ultracote over a solid surface area, I use a very small pin and poke several holes in the area that forms the bubbles. After the job is completed you will not see these tiny pin holes.