Hobbyking Covering Film

[Gary Manuel]

I built a WOT4 Classic earlier this year and covered it exclusively with Hobbyking Covering Film.

It went on really well and I was truly impressed by the ease of application and finished result. That was three months ago.

Doing a bit of maintenance today and discovered this along the underside of the fuselage, which picks up the exhaust and crank-case breather waste.

Fuel appears to be eating into any area where it comes into contact with a cut edge of covering film.

This area was made worse as I tried to iron out a ripple, which turned out to be a bubble of fuel under the outer layer. It's completely melted the adhesive / dye.

It's a matter of time before I will need to strip the model and recover it with something else.

I have another model which is also about 3 months but with a DLE55RA engine. The film does not appear to be affected by the petrol / oil mix from this (yet), but I'll keep my eye on it.

The film is still excellent for electric powered models so don't let me put anyone off - it's just no good with glow fuel. Needless to say, I won't be using it again for this

[kevin b]

See what you mean. It's not the film that is porous, but the adhesive/paint that reacts. Probably with the methanol in unburnt fuel. I must admit on my trainer I have fuel proofed all the edges of the Solarfilm that are likely to get guey, just in case. I think actually Solarfilm recomend that you do that anyway.

Kevinb.

[Martin Harris - Moderator]

Was it using high nitro content fuel?

[Gary Manuel]

I should have said what fuel I have used.

Started on Model Technics Bekra 10%, then switched to Model Technics ProPower 10% due to supply difficulties.

I have subsequently gone round all the edges with nail varnish - probably too late. Even so, it shouldn't have reacted as bad as this. One thing I did notice when putting the film on is that the adhesive layer is quite a bit thicker than solarfilm etc, and tends to ooze out a little when heat sealing. Maybe the thicker layer is more prone to soaking up the fuel and allowing it to ingress under the plastic layer?

[GrahamWh]

Thanks Gary - worth knowing. Have you put feedback on the HK site?

[Gary Manuel]

Posted by GrahamWh on 27/07/2014 22:50:12:

Thanks Gary - worth knowing. Have you put feedback on the HK site?

No but I will.

[Martin Harris - Moderator]

Sounds like clearcoating the seams would be a good idea...but before first use,

Edited By Martin Harris on 27/07/2014 23:53:14

[Gary Manuel]

Clearcoating the seams is absolutely essential I would say.

I'm pretty sure that the only effect that glow fuel has on Solarfilm is to cause it to peel at the edges, not to soak up the fuel like this stuff does. It might be OK if a perfect seal around the edge can be achieved and maintained. Time will tell I guess.

[Bob Cotsford]

I've not noticed this effect on the HK films I've used which include white, black/white check, blue/white check and orange, and I've not seen any comments about this on the various RCG HK covering threads. If it was only one colour you might put it down to a quality control blip but it looks to have affected both yellow and orange on you Wot.

I've only seen that effect when using diesels in Solarfilm film covered models. What do you use to clean the models after flying?

[Masher]

I've used a lot of HK covering on IC models and had no problems. My Acrowot look alike has been flown many many times over the last 18 months and film is still fine - red and white used mainly

[Gary Manuel]

Thanks for the feedback Bob - I've never seen any feedback confirming that anyone has successfully used HK covering with Glow fuel. Most have used it on electric powered models.

I use a mix of water, meths and washing up liquid for cleaning. Not sure I'd have got right into the cracks of the undercarriage when cleaning or with clear varnish to seal the edges though.

I'm wondering whether it could be anything to do with the the SICAL additive in the ProPower fuel I switched to, although I haven't noticed any adverse effects on the Oracover on an ARTF using the same fuel supply, but I haven't flown this as much as the WOT4.

I'm no chemist but the description of SICAL suggests that it has lots of "ACTIVE" ingredients and chemical reactions going on!

**LINK**

Also uses EDL2 synthetic oil rather than Caster oil - here's the ingredients - note the bit at the bottom about SICAL:

**LINK**

If this turns out to be the culprit, maybe I'm being unfair pointing the finger at Hobbyking covering film - hope so because I like it apart from this effect.

[Gary Manuel]

Thanks for the feedback Masher.

Your post must have come in while I was writing my last one.

Sorry for double post - couldn't edit it to thank Masher

[Anthony Scott 2]

I have been using HK red film & noticed that the adhesive bleeds out along a joint leaving a very small white line.

Tony

[Jon H]

I have 5 colours of hobbyking film on 3 different models and have had no issues at all. I have found it to be excellent and am very surprised to see this.

I have had the issue with a white line of escaped adhesive but that was fixed in seconds with a wipe of a rag soaked in meths

My fuel is 5% nitro, 15% ML70 and however much SICAL they put in the Laser 5 fuel

Edited By Jon Harper on 28/07/2014 13:08:01

[Gary Manuel]

The white line cleans off using meths

Not sure whether that's a good thing or not as it suggests that the adhesive isn't fully inert.

[john stones 1 - Moderator]

Whatever the cause Gary, something is attacking it, its not just the one colour either ? which maybe rules out a bad batch. Also sounds like it's just you that has the issue ? If it's your cleaning fluid it would show on all your models electric as well. I would pour a bit of propower on a test piece myself ?

John

[Bob Cotsford]

Gary, all brands of film adhesives wipe off with meths, it's what I use to clean my iron! As it also cleans the white adhesive line left where the film shrinks back along the edges I wonder if it's your cleaning concoction that's doing the damage?  Presumably you don't wash your electric models off with a degreasing mix?

Edited By Bob Cotsford on 28/07/2014 14:03:08

[john stones 1 - Moderator]

He might Bob, but I should have said petrol, because he said Dusty is covered in H.K film

John

[Gary Manuel]

Back in from a pleasant evenings flying

I tend to use petrol for cleaning petrol fueled models, and just a damp cloth when needed for cleaning mud splashes off electrics.

I'm going to try adding a few drops of fuel and cleaning mix onto a few samples of covering film (HK and Solarfilm), marking them up to show what they are and leaving them for a while to see what happens. I'll publish my lab report here.

I've been using my water / meths / fairy liquid for a while a while and the WOT4 is the only one with a problem. I'm not ruling anything out though. My spray bottle is half full so I've got plenty of the suspect mix to go at.

[Gary Manuel]

The results are in and they are surprising (to me anyway).

Also turned out to be a bit more difficult than I expected.

I laid out four samples of Hobbyking red film, which was one of the affected colours alongside four samples of Profilm. The Hobbyking film appears white as it is a 3 layer system with white adhesive. The Profilm appears dark blue.

I then applied 10 drops of fluid onto each of the 8 samples.

The fluids I used were:

1. Cleaning mix I use, made up of Water, approx 10% meths and a few drops of washing up liquid.
2. Model Technics Propower 10 (with SICAL and 18% EDL2).
3. Neat methelated spirits
4. 50% Propower 10 and Methelated spirits mix.

I found that the Methelated spirits and Cleaning mix evaporated (or soaked in?) quite quickly so I added another 10 drops to each sample. I also added a further 8 samples as above into liquid samples in plastic tubs and kept them submerged by adding a modellers pin to each one.

The samples were then left overnight................

These are the results:

As I suspected, the samples left in the plastic tubs showed the greatest effects- due to greater exposure, so I shall only post pictures of these.

1. Cleaner Mix

Profilm soaked in Cleaner mix. No obvious effect. Eventually dried out and looks re-useable.

Hobbyking film soaked in Cleaner mix. No obvious effect. Eventually dried out and looks re-useable.

2. Propower fuel.

Profilm soaked in Propower fuel. Same effect as observed on my WOT4. Complete breakdown of adhesive and separation from backing.

Hobbyking film soaked in Propower fuel. Similar effect as observed on my WOT4. Partial breakdown of adhesive and separation from backing. Can be mechanically separated very easily.

3. Neat Meths.

Profilm soaked in Neat Meths. Slight wrinkling around the edges. Eventually dried out and looks re-useable.

Hobbyking film soaked in Neat Meths. Slight wrinkling around the edges. Eventually dried out and looks re-useable.

3. Propower and Meths mix.

Profilm soaked in Propower / Meths mix. Similar effect as observed on my WOT4. Partial breakdown of adhesive and separation from backing.

Hobbyking film soaked in Propower / Meths mix. Marginal breakdown of adhesive and separation from backing.

Conclusion

From these tests, it would appear that Profilm and Hobbyking film are both affected by exposure to Model Technics Propower 10, with Profilm reacting to a greater degree. Note however, that once affected, the Hobbyking colour / adhesive layers separate from the plastic layer much easier than the Profilm. Both films also react with neat Meths but the effects are temporary.

I believe that Meths is safe to be used neat, for cleaning edges of film / tools and as an additive to cleaning fluids. The fluid causing the effects I have reported on both films appears to be ProPower 10 fuel.

I would like to see similar tests undertaken with other types of fuel to determine whether the additives in Propower are causing the problem, or whether all glow fuels would give the same results. Unfortunately I do not have any other fuel available to test.

I will certainly be sealing all my glow model seams from now on. I will also be switching back to Bekra 10 fuel (if I can get it) and running a similar test.

Not sure why I am seeing the effects on Hobbyking film and not on others. I suspect it may be to do with the thickness of the colour / adhesive layers, allowing seepage into the seams.

I hope these tests have been of interest.

[kevin b]

I think you will get similar results from most fuels. I'm sure I read it that covering films are mostly fuel proof, but to seal joints, particularly where fuel or its residue are likely to splash. This also applies to the "Tex" type materials. Any glue will break down under the right circumstances. Either by solvent, heat, light, or just age.

kevinb.

[Gary Manuel]

KB - I think you are right.

Main point of the tests was to eliminate the possibility that I've been scoring home goals with my cleaning fluid.

[Codename-John]

Interesting results, ive not long bought some of their Red, yellow and red + yellow checked covering from a reseller at Cosford and got a little worried, You may need to ask a mod to change the Title and subtitle of your thread then

Warning - Nitromethane is bad for film adhesives ? lol

[Cuban8]

I've been using 'Elbow Grease' cleaning spray available from Poundland and Asda for cleaning all of my models for several years now. For general cleaning down at the field, a 50:50 mix with water is fine and gets off fuel residue with no affect on any covering surface (including decals and paint). Goes a long way as well. Being water based it doesn't affect my hands which are a bit sensitive to harsh chemicals and detergents after 40 years of working in industry..

Well worth a try next time you spot it on the shelves.

Edited By Cuban8 on 30/07/2014 07:41:53

[Gary Manuel]

Moderator

What do you think? Title a little misleading / unfair on Hobbyking? Fact remains I'm still having problems with HK film in practice and not other stuff, but I appear to be the only one.

Thanks Cuban8.

I've seen some of our members using Elbow Grease and it looks really good. Certainly better than my mixture which I mainly use because I have everything available. I'll keep my eye out for some.