Ian Mat Posted June 8, 2015 Share Posted June 8, 2015 I have a Wot 4 which I have built and covered myself using Hobbyking film. This is the first model I have ever attempted to cover and I think I did a reasonable job, however now, after a few dozen flights, the covering is starting to come loose everwhere and the model really needs recovering. My question is... should I recover using the cheap hobbyking film or is there a better covering to use? Also should I be sealing the edges in some way to stop this happening again? Thanks Edited By Ian Mathews on 08/06/2015 22:14:01 Quote Link to comment Share on other sites More sharing options...
leccyflyer Posted June 8, 2015 Share Posted June 8, 2015 Profilm. Quote Link to comment Share on other sites More sharing options...
cymaz Posted June 8, 2015 Share Posted June 8, 2015 PVA or Balsaloc. Some people say they are one and the same....I have no proof of this. See how you get on. Quote Link to comment Share on other sites More sharing options...
Paul Jefferies Posted June 8, 2015 Share Posted June 8, 2015 "PVA or Balsaloc. Some people say they are one and the same.".......... I wondered about this so I did a test using "Litespan" on balsa. On one piece of balsa I used PVA and Balsaloc on the other. It was definitely harder to pull the litespan off the piece that used Balsaloc, ie., Balsaloc gave better adhesion. The test was prior to my first go at covering a model with Litespan and suffice it to say that I wouldn't use it again. As a finish I guess it depends on what you are trying to achieve but I was hoping it would look more like tissue and it looked nothing like I wanted. However my main gripe with it is that it has no adhesive properties of it's own and you have to paint the edges with balsaloc before overlapping with the next piece and inevitably some of the balsaloc shows. Also, heat shrinkage is pretty limited........ Paul Quote Link to comment Share on other sites More sharing options...
Steve Balaam Posted June 8, 2015 Share Posted June 8, 2015 Profilm every time, I use cover grip to seal edges as well Quote Link to comment Share on other sites More sharing options...
fly boy3 Posted June 8, 2015 Share Posted June 8, 2015 Profilm, but hobby king,s covering is just as good, and you get 5 meters for same price as 2 meters of Profilm. Cheers Quote Link to comment Share on other sites More sharing options...
WolstonFlyer Posted June 8, 2015 Share Posted June 8, 2015 Did you get all of the dust off the wood before covering the model, if not that can cause the covering adhesive to fail, and did you get the iron hot enough? I have had no problems with the hobbyking covering so far. Quote Link to comment Share on other sites More sharing options...
Dave Hopkin Posted June 8, 2015 Share Posted June 8, 2015 On the grounds the only stupid question is the one you don't ask and at the risk of insulting the OP - which is NOT intended...... You did peel off the backing film didn't you? Because if you don't the film will stick down a bit but its not secure Apologies if I am teaching granny to suck eggs............. Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted June 8, 2015 Share Posted June 8, 2015 I agree with WF - this may be down to application rather than the film. HK film generally has quite a good reputation. Covering isn't difficult - but it is definitely a "knack" that improves with practise. Do you have any of the old film left? If so why not grab yourself some balsa and experiment a bit? You have to have the wood clean and absolutely dust free. And you need to able to set the iron to two distinct temperatures. The first (slightly lower) temp should activate the adhesive - stick it down well to the structure with that. The second temp (slight higher) should shrink the film without overheating it. With practice you get to recognise these two temperatures and know when the iron is "just right" for sticking or shrinking. But practice is the key word there! BEB Quote Link to comment Share on other sites More sharing options...
ASH. Posted June 8, 2015 Share Posted June 8, 2015 Ian, I would seal the seams/edges throughout the model with Solartrim Clearcoat after covering. It stops it from lifting and oil/fuel getting in underneath. Quote Link to comment Share on other sites More sharing options...
Ernie Posted June 9, 2015 Share Posted June 9, 2015 Hi Ian, Profilm every time, but have you considered very light glass cloth, fixed in place with a water based resin. Won't ever come off, and is highly ding proof. More work, but well worth the effort ernie Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted June 9, 2015 Share Posted June 9, 2015 Posted by Paul Jefferies on 08/06/2015 22:49:53: "PVA or Balsaloc. Some people say they are one and the same.".......... I wondered about this so I did a test using "Litespan" on balsa. On one piece of balsa I used PVA and Balsaloc on the other. It was definitely harder to pull the litespan off the piece that used Balsaloc, ie., Balsaloc gave better adhesion. The test was prior to my first go at covering a model with Litespan and suffice it to say that I wouldn't use it again. As a finish I guess it depends on what you are trying to achieve but I was hoping it would look more like tissue and it looked nothing like I wanted. However my main gripe with it is that it has no adhesive properties of it's own and you have to paint the edges with balsaloc before overlapping with the next piece and inevitably some of the balsaloc shows. Also, heat shrinkage is pretty limited........ Paul Hi I use light span on all my smaller or diesel powered models . I would not use balsaloc though as it just doesn't do the job very well. I use Solarlac Clear coat as an adhesive. It really holds the covering down well even on overlaps .It also enables you to get the lightspan tight without wrinkles before shrinking and gives a brilliant tissue effect if put on with the matt side facing out. It also takes on compound curves well if stretched using a hot air gun (modeling type) . It even fooled our clubs tissue officionardos on more than one occasion. Give it a try . Yes you do have to apply it to the frame but it does help keep the weight down. What problems did you have that caused it not to look like tissue ? If your interested pm me and I will Gladys go over my method of applying it . E.D. Edited By Engine Doctor on 09/06/2015 09:48:33 Quote Link to comment Share on other sites More sharing options...
Ian Mat Posted June 9, 2015 Author Share Posted June 9, 2015 Thanks for all the replies. I was initially happy with the job I did with the cheap hobbyking film and yes I did prepare the balsa before hand and painted it all with watered down PVA. I had no trouble with the film sticking (once I worked out that you had to remove the backing!!!). I think the problem has been the oil residue from the exhaust getting into the seams of the film and once a slight edge is exposed, the film quickly comes off. I don't have any local model shops, so items like balsaloc would have to be mail ordered, I do however have a large tin of polyurethane clear varnish, which I'm fairly sure is glo fuel proof. I will try that on the seams to see if that makes a difference. Quote Link to comment Share on other sites More sharing options...
kc Posted June 9, 2015 Share Posted June 9, 2015 Not mentioned so far is that after ironing down you need to press the film down with a cloth until the adhesive sets - about 20 to 30 seconds with a cold clloth. The process for film is cover the very edges of ailerons etc with Clearcoat. Leave to dry. Iron on the film in sections as BEB said. (also see the Solarfilm instructions on the wrapper or their website. HobbyKing stuff is similar so use Solarfilm instructions. ) increase iron temperature a little then press down in sections and cool with a cloth, move to adjacent section and so on. For any overlaps that wont stay down use Prymol etch primer. ( Solarfilm product ) Paint a little Prymol on the film to be overlaped and leave to dry. Just paint onto the glossy surface. Wait 5 or 10 minutes and iron the overlap down. To repair a used glow model remove all oil residue with meths first, then use Prymol on the overlap area. Apply Clearcoat over any overlap edges and leave to dry. Use a tiny paintbrush and clean Clearcoat ( dont contaminate the main tin with balsa dust from the first application on bare balsa! ) Hoobyking film is at least as good as Solarfilm. Solartex ( Solartex, not Solarfilm ) is easier to use and overlaps are much less likely to lift. More expensive but lasts longer on glow models. Easier to apply around curves. Edited By kc on 09/06/2015 11:00:58 Quote Link to comment Share on other sites More sharing options...
kc Posted June 9, 2015 Share Posted June 9, 2015 Polyurethane paint probably wont stick well to bare film. Clearcoat will. To get any paint to stick to film use Prymol etch primer first. Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted June 9, 2015 Share Posted June 9, 2015 Hello Ian . The varnish you mention will not adhere to the covering so will not help the seal. Order some Clearcoat as this works with the coverings adhesive and effectively stops any fuel that get under the edge from soaking into the balsa especially around the firewall or wing seats . It also really holds down the edges so that film lifting in the first place is very unlikely . With overlaps , give them a wipe over with thinners or something to remove any grease before applying the next sheet. Even finger print/grease can effect the adhesion of the overlap. . Just keep it clean and use plenty of heat on the overlapped section. Good luck and hope you get it sorted. Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted June 9, 2015 Share Posted June 9, 2015 One point I've not seen mentioned is to try to arrange overlaps so that the airstream isn't trying to lift them - eg overlap the top covering slightly onto the underside, maybe 5-10mm. Just enough so that airflow is pushing it down not lifting it. Similarly I cover fuselages applying overlapping panels rear to front, bottom to top. Quote Link to comment Share on other sites More sharing options...
Cuban8 Posted June 9, 2015 Share Posted June 9, 2015 A club mate covered a 3M glider (fully sheeted) with white Hobby King film and the finish remains superb. I honestly thought it was glass and paint until I looked closely. I asked about his technique and he'd doped and sanded the fuz/wings to get a good surface finish, then applied a couple of thin coats of balsa lock and then the film. The price of Profilm is ridiculous at seventeen quid for two metres of solid colour. Quote Link to comment Share on other sites More sharing options...
Steve Houghton Posted June 9, 2015 Share Posted June 9, 2015 Posted by Ian Mathews on 09/06/2015 10:44:15: .... I do however have a large tin of polyurethane clear varnish, which I'm fairly sure is glo fuel proof. I will try that on the seams to see if that makes a difference. Ian, I used to use polyurethane varnish over all the Solarfilm seams on my power models, when you could still buy it (mine was 'Winfield' brand from Woollies!) . It adhered very well, and I never had a lifted seam. The downside is that it yellows with age, and can go a little tacky - whether that matters depends on whether your models last more than 10 years! I recently started to restore an old 1980's model, and had a huge job trying to scrape off the yellowed varnish - it had stuck like glue! I haven't tried the latest water based varnishes. I used Clearcoat on a recent model, both under and over the seams, but some of them are already lifting around the engine bay. I also used some genuine Solarlac paint over parts of the Solarfilm, but that rubs off very easily. Everyone has their own views on the best method - just try one and see what works for you. Quote Link to comment Share on other sites More sharing options...
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