Hello expertens,

Yesterday I decieded to recover the GP Spad because it has so many wrinkles that make even the show wining Sharpei cringes. Anyway I used UltraCote as the material and everytime I used the HG, the edges pulls back and you guess it, it wrinkles even more. So I did it again and tucked the edges in more with more overlap. Still the heat from the HG still peels the edges away and but luckily, not to the point I have to recover. I think the best way now is NOT using the HG but use the iron instead because the latter allows you to apply heat where needed rather than blasting with heat that eventually will unseat the seems. A search on RCU indicates some felt HG should not be even used when covering. I think the HG makes things more complicated than needs be but can you get the same results WITHOUT the use of the HG? I would love to shrink with the HG but with weak adhesive layer of UC, HG just does not seem to work well in this case. Comments appreciated. DP

I just ran into this issue myself.

A HG is neat for shrinking large areas. Areas that are well away from seams. In smaller areas, especially close to seams, the airpressure of the HG pulls the seams apart.

I chose to purchase a second iron. My first iron, I keep at "adhering" temp. The new on at shrinking temp. On my latest project, what I fought (and lost) for over an hour with a HG. I got shrunk up better with the secon iron in less than 5 minutes.

Just my $0.02.

I use a HG all the time for big and small areas. Ultracote is a low temp film and requires careful use of the HG. Hit the area with heat and pull the HG away; the Uc will continue to shrink. If you keep the HG on until the wrinkle is gone you will overshrink it. Also UC (and MC) need to be burnished on solid surfaces. I have successfully ironed sections of UC together with a 1/4" overlap to create a sheet of covering with a pattern and then tightened it with the HG with no problem. It DOES take practice and patience.

I still have to use an iron to draw out those little corner wrinkles.
Walt

To Stop this from happening use some balsa-rite on the wood edges before covering. The balsa-rite works awesome and goes a long way. You will never have another pulled edge. Also another thing that helps is to cover both sides of your piece and then shrink. I use a small drill to poke a hole in one end or the other to let the air escape so you don't get any "poofing"

Agreeing with what was said above, UltraCoat does not shrink like Monocoat.
Seal all edges with an iron - only the iron.
Avoid using the HG on solid surfaces and seams.
Wrinkles on solid surfaces can be removed by hovering the iron on and around the wrinkle. Often, a HG will just make nice bubbles on solid surfaces.
When using a HG, try a little heat and remove. Let cool and repeat as necessary.

I have de-warped wings with a HG and I don't know how I would get along without one!

Good luck.

Using a heat gun is fine. The edges pulling are a characteristic of Ultracote. It has a lower temp adhesive than Monokote, it stays gooey longer while cooling and the adhesive doesn't seem to be quite as strong in my opinion. This means that the edges can pull if you aren't careful. Make sure you have a 3/8" or so overlap minimum. Be sure not to heat the seam when shrinking whether it is with a heat gun or an iron. Sometimes I will put a couple layers of masking tape over the seam to help protect them from heat or even some wet strips of paper towel or something. It is also good to hold the heat gun back a little further and take your time; don't try to make it instantly shrink or you could over heat it.

Ultracote is a great covering as is Monokote but they have different characteristics that cause peculiarities in both. The heat gun is a great tool but you have to kind of adapt how you use it depending on the covering and what you are doing. It just takes practice. You might make a mistake or two along the way, we all do.