Lamination Film

[Basil]

Yes as you say the prep' is essential, it makes or breaks the finish , I spent a period a week , for a  whole year at day release college doing prep and there application methods. There was only a Ltd number of paint systems available then. Cellulose was almost the only thing to use, for automotive. My fellow students where part of the team to introduce 'Colouriser' emulsions. I could go on!!!.

I am still trying to decide which paint to use !!!!. I want water based brushed , prefer semi gloss/matt  to high gloss. Like the solvent based chroma products , but a limited colour pallette, and possible recoat/ masking tape problems. Looked at the 'Graphite' Paints  (Ron), there are so many on the site I dont know where to begin. How far does a spray can cover?. 

Ron, what would you suggest I look at. I have no objection to using cans or solvent based cans.But there are so many on the site, its frightening!!!!

Regards from a very puzzled BAS

Edited March 23, 2023 by Basil

[Ron Gray]

Bas, have a look at these, a splendid colour range. Regarding coverage, all I can say is that I gave the LA-7 undersides 2 coats of blue and there was plenty left in the can! I would also suggest buying some spare nozzles as it saves having to clean them if they get blocked!
 

Colours

Edited March 23, 2023 by Ron Gray

[Edgeflyer]

On 18/03/2023 at 09:51, Engine Doctor said:

 Hi Basil TBH I have only tried brushing the Guild Chroma gloss at present on models due to not wanting overspray on everything in the workshop. That's the problem with enamel paints , the overspray is usually still wet enough to stick when it lands and is sometime a so an so to get off . 

The test pieces have in the past  been both  sprayed and brushed but mostly brushed. I used artist acrylic, humbrol matt and gloss, solarlac and some two pack. All resist a tough fingernail and masking tape test very well. The test piece that's been in the greenhouse for a couple of years is still tight and shows no sign of uv damage . The paint on one corner ( sprayed red solarlac) however is showing signs of uv degrading an is flaking slightly. But what model would be subjected to that sort of abuse ?

 

A word of  caution re the matt finish on the lamination film. On my Elf Bipe I accidentally smudged some epoxy on the covering and never noticed it until it was days old and properly cured. I tried various solvents to remove it inc cellulose thinner, white spirit and some cyano remover liquid. Nothing touched the epoxy but after a lot of rubbing the matt finish started to dissappear.  A small spot of clear still with a tiny dob of epoxy now stands out where the epoxy was hardly noticeable!  Now hidden with a painted trim stripe.

For masking the lam film I use fine line tape. It sticks very well and leaves a crisp line when removed . For best results remove masking while paint is still wet or before it's cured.

Did you try heating the epoxy with a heat gun? I usually find it peels off when softened with heat.

 

[Basil]

22 hours ago, Ron Gray said:

Bas, have a look at these, a splendid colour range. Regarding coverage, all I can say is that I gave the LA-7 undersides 2 coats of blue and there was plenty left in the can! I would also suggest buying some spare nozzles as it saves having to clean them if they get blocked!
 

Colours

I assume that you can't /should not, be applying without a primer ?. Assume that primer should be abraded . What grit would you suggest. I ask as I am wary due to working on areas of unsupported film. I have applied chroma colours direct without primer on the laminate almost a year ago, looks OK today

Thanks Ron in advance.

Bas

[Ron Gray]

TBH I haven't tried it without primer but graffiti paint's adhesion properties are pretty good, after all it's designed for spraying on external walls etc! Regarding rubbing down, I use the finest grit paper I have, usually some bits that have worn out and which normally would be consigned to the bin! Laminating film is very strong so I wouldn't worry too much about breaking it when sanding, even if you did another great advantage of lam film is that when stuck on as a repair you can hardly see the patch.

 

There is another technique when applying paint to lam film and that is to apply it to the film before applying the film. You spray the underside (adhesive side) first then apply as normal! Never tried it but I'm told that it works a treat!

[Basil]

Wow, that  sounds a bit fiddly, dont fancy working with the adhesive side open to gathering all the dust/dirt etc then painting, storing whist waiting for the paint to dry.

The unprimed paint surface that I painted was finely abraded before application of the paint, by the way, it still looks OK.

Thanks again Ron.Just that I find the whole thing a bit daunting . I have also made an attempt to make a repair, as you say, not difficult, good result.

Bas

[Basil]

I would ask this question; Can you use sanding sealer on the airframe before applying laminate or film in order to improve the surface?. Rosin, a major component of sanding sealer has a melting point of 100-120 deg 'C' . Or, what's the best way of improving the surface under normal circumstances?

Bas

[Ron Gray]

Why would you want to improve the surface? You certainly don't need to if you're apply lam film and if you do seal the surface it could well cause the lam film to stick too easily (and not come off!). I brushed in a diluted coat of epoxy on the TE of my LA-7 as it is very thin (foam core with the veneer sheets coming together to form the edge) and I wanted it to have some extra strength. When I came to apply the lam film I just touched the iron (tack temp circa 100º) on it and that was it, I couldn't lift it off!

[Basil]

Ron, to make sure that the film has a smooth surface by smoothing the substrate by using sanding sealer. Obviously not required.  Just 240 then!!!

Bas

[Ron Gray]

1 hour ago, Basil said:

Just 240 then!!!

Yup and dusting down of course!

Edited March 27, 2023 by Ron Gray

[Basil]

Thanks Ron, Bas

[Engine Doctor]

On 26/03/2023 at 16:20, Basil said:

I would ask this question; Can you use sanding sealer on the airframe before applying laminate or film in order to improve the surface?. Rosin, a major component of sanding sealer has a melting point of 100-120 deg 'C' . Or, what's the best way of improving the surface under normal circumstances?

Bas

Sanding sealer will actually worsen adhesion as its composed mainly of  rosin or talc suspended in the dope. This breaks away easily . If you want to improve adhesion just coat with diluted dope which will also raise the grain, allow to dry then sand lightly and dust off before ironing on the covering if better grip is needed say on an under-cambered wing then apply a thin  coat of Deluxe  Cover Grip or similar 

Edited March 28, 2023 by Engine Doctor

[Erfolg]

I am very close to finishing my latest model. This is what I think I have found.

 

• The film seems to adhere well to plain balsa.
• Does adhere to PLA although the poor surface finish from my 3d printer is not perfect, just adequate.
• I found that doped tissue seems to adhere well.
• Tissue sprayed seems to provide a really satisfactory finish.
• I purchased gloss film, No Prep, sprayed with Paint Pot emulsion, adherence not good.

The only issue is how to paint gloss film as a system.

 

 

[Ron Gray]

Key the gloss lam film with very fine sandpaper or Scotch pad. You are aiming to get rid of the gloss but remember to thoroughly clean off the dust and anything else (I use isopropyl).

[Engine Doctor]

19 hours ago, Ron Gray said:

Key the gloss lam film with very fine sandpaper or Scotch pad. You are aiming to get rid of the gloss but remember to thoroughly clean off the dust and anything else (I use isopropyl).

As Ron says abrade to get a matt finish . You can buy Scotch type pads that are impregnated with a fine abrasive . They are used to flat car paint for repair . The grey are equivalent to 600 grit . They are also far mor flexible and suitable for flatting covering material and don't have sharp corners to puncture it Any car paint factors stock them or find them on ebay . The red and green are coarser grit 

Edited April 6, 2023 by Engine Doctor

[Wilco Wingco]

After reading all this information I want to cover my Majestic Major, I think in mat, so it will keep the vintage look and feel. Is there any information about the thickness of Lam to use that is best suited to the size and weight of the finished model?. It will be powered by a 61FS engine. 

[Ron Gray]

I use 38 micron on all of my models covered with lam film, I know others have used heavier grades but I haven’t found the need to change!

[David Hazell 1]

I covered my A10 in supermatt 42 micron (I asked for 38, but ended up with 42, ho hum). I _expected_ the paint to adhere really well, but it really doesn't, it's flaking off all over the place. I use a cloth dampened with isopropyl alcohol to rub over the whole model to ensure dust free, but it wasn't enough. Expect to have to properly key any lam film no matter what the finish if you don't want paint flaking off. I will make sure I go the extra step next time!

[Engine Doctor]

Just my opinion but a model like the Majestic Major would be beter off with the 75 micron covering and an airframe that big will take the few extra geams easily. It will add far more rigidity to the wings and frame. The 38 micron i have is a lot more stretchy than than the 75 micron. It mat be just that particular brand ? The 75 used on my Elf Bipe earlier in this thread is tight as a drum and gives extra support to the stick structures once shrunk and ironed onto the ribs etc after shrinking.

[Mike Chantler]

After seeing some of these posts, I used 75 micron film directly onto of EPS on a 60" slope model. When it's really windy it gets lots of ballast and bad landings on the hill(!) Despite this it's surviving very well.

 

 

I accidently started covering it with 150 micron film 🤔, and couldn't understand why it wouldn't go round the sub-trailing edge! Then I read the description on the packet!

Model has 3mm cedar LE, 5mm square balsa sub-TE, carbon end caps and two 6mm carbon rod full length spars, the film gets lightly stretched across that frame work. (In a previous version I didn't have end caps or balsa TE - and not surprisingly the eps got a bit crushed after a while and the film looked awful)

 

Thanks for all the info everyone 🙂

 

[Wilco Wingco]

Thanks chaps for all the replies and opinions. Sounds like you pays your money and rakes your choice. As regards "painting". I was wondering if I could cover the whole airframe in lam and then "trim" it in solarfilm, thus avoiding the paint flaking issue?. 

 

[Outrunner]

15 minutes ago, Wilco Wingco said:

Thanks chaps for all the replies and opinions. Sounds like you pays your money and rakes your choice. As regards "painting". I was wondering if I could cover the whole airframe in lam and then "trim" it in solarfilm, thus avoiding the paint flaking issue?. 

 

Wilco, I recovered my old Junior 60 in laminating film and then covered with tissue using cheap B&Q water based varnish, looks like old fashioned tissue covering but tough as old boots.

 

 

[Erfolg]

My experience is very much the same as "Outrunner".

 

As time past, I became less of a fan of Solafilm. The films from the Far East, have become much better than SF and cheaper. Also still available. 

 

The lamination type film and tissue is not new, apparently used by the free flighters for years. I guess there will be links as to the techniques, eliminating any need to experiment. The approach is certainly a low cost and effective method.

[Mike Chantler]

From Silent Flight December/January 1997: 

 

 

he had a really series of articles in electric and silent flight mags  🙂

 

and see and see https://www.freeflightsupplies.co.uk/index.php/products/lightweight-covering-materials

[PDB]

I’ve used laminating film on a DLG wing:

 

 

I’m building a Hobbycraft foamboard model and putting a glow engine in it. Anyone see an issue with spraying colour onto the foam board first then covering in laminating film to fuel proof it? Tried some small test pieces and it came out ok, anyone else tried it?