Tissue covering balsa model - fifth ring of hell?

[sabu]

Hey all, I'm hoping to get some advice. I'm having a hell of a time covering a balsa model with tissue (Guillow's Spirit of St. Louis). Is doing this without wrinkles and otherwise getting a smooth, professional finish some kind of black art? Is it something that really takes a lot of time and practice to get right or am I just a total moron (I certainly wouldn't rule out the latter!). My model is for display purposes, not flight, so weight is not a concern - it can be as heavy as it wants to as far as I'm concerned. What I do want is as smooth and good looking a finish as I can possibly get.

I'm using a product called Aero Gloss Dope from Midwest Products. The bottle says it is Gloss Clear. I'm using it without thinner as recommended by the hobby shop I purchased it from. The tissue I'm using is that which came with the kit. I usually wet the frame with dope, let it get a bit sticky, put the tissue on and then brush on additional dope directly on the tissue, and then I pull the tissue as tight as I can without breaking the tissue or the wood I'm pulling against (which really isn't a lot of force mind you - I'm not reefing or it with all my might or anything)

It's my understanding that the dope should pull the tissue tight, but my experience is more that that the dope just hardens the tissue...if it's even just a little loose when first put on the frame, it will generally remain loose once it dries.

Maybe my framing is as good as it needs to be to do this properly? Maybe I'm using tissue pieces that are too large? My method could be completely wrong? I've kind of settled on the idea that this is my first model and it's just not going to be as nice as I wanted it to be, but I wanted to post this message to see if I'm maybe just doing something very wrong.

I am aware of and I have read some of the other posts on this and will continue to locate and read the others. So far however they're not really helping too much....any help, thoughts or just general comments on the above would be appreciated.

[WIDDOG]

I read a post from a super skilled modeler. In the post he talked about the "Grain" direction of the tissue. He recommended the this booklet page 12. I understand it's kind of a fundamental point

[Bill Gaylord]

Scigs30 has numerous threads with tissue covering info. All coverings are somewhat of a black art, where the little tricks and tips make all the difference.

[Blucenturion]

Do know that an imperfectly stretched section, or for that matter, a puncture, can be fixed, and it's a bit of fun to do so. Fun, because you make a careful measurement of the section, spread the adhesive, and slide your replacement on. If you miss, try again. You will improve with practice, and you will have cheated Murphy's Law, which is most satisfying. So while this may not seem to answer your question, it kinda does, because until you reach that skill level you're desirous of, this can make an acceptable outcome. I do miss the old time dope, though. That used to make for real tight skins.

[gmwahl]

When using full strength dope in the past to stick the tissue to the frame, I have always applied it to the frame full strength (after applying the seal coat of dope to the frame and then sanding smooth), let this adhesive coat dry, and then use dope thinner to apply over the top of the tissue to reactivate the underlying dope and cause it to grab the tissue. It sounds like the way that you are doing it with applying dope over the tissue will cause problems with the consistency with which it shrinks.

If you insist on using dope to attach the tissue, then try doing it with the thinner to activate the dope to adhere the tissue to the parts of the frame that you want it to stick to. I usually only stick the tissue to the perimeter of the area that I am covering and don't bother with the structure within that perimeter. Then, LIGHTLY mist the tissue with water and let it dry to get the tissue to shrink nice and evenly. after the tissue has dried, you can then use 50/50 dope/thinner to put a few coats on the model and it should re-shrink and stay tight. It will also cause it to stick to the framing members within the original perimeter of the area that you covered.

These days I just use a permanent glue stick to attach the tissue (wet or dry) and after it has dried and been water shrunk, I seal it with dope mixed 50/50 with thinner for a couple coats and then finish with whatever finish suites my fancy.

Mike

[scigs30]

I have done numerous posts about covering and I hope its helps. Dumas puts out a great video on applying tissue and worth getting.

[Coloradoken]

IMG_0786 rev6.jpg

I have always had trouble doing a good job of putting on tissue so my Spirit of St Louis doesn't have any!

[zoltron55]

its not hard, preparation is key. sand the frame with a fine sandpaper(300-400 grit). I have used wood glue thinned 50 per cent with water to glue the tissue on the frame. then let glue dry, use a spray bottle with water to wet the tissue (some guys use windex) let dry it will shrink. free flight a light coat of spray clear. glow fuel proof dope electric what ever your heart desires static display as many coats as you want remember light coats many times looks better than a few heavy coats. it is the same as learning music practice makes perfect

[Bill Gaylord]

Here's how I'd finsh the Ryan NYP, although not using tissue. Actually been thinking of building one lately.
Just finished a model using Coverite Microlite iron-on white film. Rustolem American Accents metallic aluminum covers well, adding little weight. The 26" span rc jet with battery weighs 8.3oz, which is why I use this covering. Not much heavier than painted tissue.

[sabu]

Thanks to everyone for all your replies. Covering was finally completed a couple days ago. It got better as I went along. The tail surfaces were first - those are positively awful. I did the fuselage next, and finally the wing. The entire process got better as I went along. I wanted the main wing to be done the best so I saved it for last and that did seem to help. For me, I took away 2 main lessons for next time (which I hope will help other newbies):

1) completely disregard the instructions in terms of how many individual pieces of tissue should be used to cover each part. The instructions describe using very large pieces for each part but that makes eliminating wrinkles exceedingly difficult and is a very frustrating process. Using more pieces of tissue makes this tremendously easier. Remember, my model is for static display only so the extra weight incurred where the tissue overlaps is not a concern for me, but this may make a difference if you're building for flight.

2) imperfections in fit are a result of imperfections in your framing job. I thought I had done a pretty good job on the frame of each piece but what I learned was that even the most minor imperfection in terms of the frame (like a very small difference in the height of one former vs the one beside it) can result in wrinkles in the tissue that are very hard to eliminate

Thanks again for all the replies. I did read the other posts that were recommended to me and they were also helpful.

[DenisCullinan]

"zoltran55" is right on the beam when he says to wet the attached tissue with water. You'll get a tight shrinking result.

[GGB14]

If I'm applying tissue to small sections for the silage at at time (as the directions suggest) How do I avoid a patchwork of seams on the finish model?