Re-Painting a fabric aircraft

[trevelyan]

The owner of the D62 Condor im flying wants to change the colour scheme of the aircraft. She currently has the original grey / white scheme from when built back in 1994, and could do with a bit of a facelift. (the aircraft is on a PFA Permit)

He has been told that this can be done with the correct paint, and applied in a dust free environment using a small roller. Has anyone carried out a repaint on a fabric aeroplane using this "technique"?

Im curious as to what the correct paint(s) are, as I guess it will require a degree of elasticity. The wings, tail and elevator are fabric covered, the body and cowlings a mixture of wood and GRP.

Would be gratefull for any advice / contacts, have searched in the usual places but cant find anything about doing a DIY repaint on this type of a/c in any detail. (will also put this on the Rollason site)

Cheers in advance

:ok:

[stiknruda]

Trevelyan,

I have painted 2 fabric aircraft and have repainted numerous other fabric components (I've seen one rudder 3 times!).

My knowledge/experience is limited to 2pack epoxy polyurethanes applied with a spray gun - either hvlp or conventional.

I have heard of a roller being used but have never seen the results. If I can be of help drop me a pm and I'll let you have my phone number.

Stik

[djpil]

A friend owns a Citabria done in 2 pack many years ago. Fabric is in good condition but the paint is peeling off. No way to really fix it without new fabric. A couple of local Decathlons done in 2 pack. Every now and then they spray another coat over the top but can still see the areas that have cracked and peeled.

My mechanic would murder me if I did anything other than classic Randolph dope. (http://www.ceconite.com/) He reckons there should be a law against polyurethane on fabric.

"Correct paint" - depends on what is on the aeroplane now. Essential to find out before doing anything.
http://www.polyfiber.com/techquestions/rejuvenating/index.htm

[Croqueteer]

I've done a test piece using Jawel synthetic at £18 for five ltrs, and it seems to work well, and remains flexible. In the past I have used cellulose with the smallest drop of castor oil, and it still looked good after 10 years.

[DubTrub]

Many aviation paints can be rejuvenated, because they are either vinyl (as in Poly-Tone) or cellulose (as in dope..or even automotive cellulose).

Many commercial two-pack paints (usually VERY glossy) are adapted for aviation use by adding a plasticiser, but because they become inert (hard) after curing, cannot be rejuvenated.

The problem is, all "flexible" paints become inflexible after a while, because of the evaporation of the plasticisers. The rejuvenating process highlighted by djpil re-applies plasticisers, so prolonging the longevity.

Unfortunately, this cannot be done to any two-pack paint.

The answer to ensuring longevity of a paint finish on a fabric aircraft is therefore to use a process that
a) contains plasticisers (or other flex agents) and
b) is single pack and therefore can be rejuvenated.

The disadvantages with this is that
i) generally, the "wet-look" gloss is only available from two-pack aviation paints and
ii) long-life paint finishes last too long, meaning that the structure never gets looked at for decades.
iii) single-part paints tend to be less tolerant of chemical attack (as in avgas, mogas, oils etc, but to be fair they are still fairly tolerant...especially dope.)


trevelyan In my limited experience, the most common causes of cracked/peeling paint is inadequate application of the first sealing coat, and/or using a spray filler to get the "wet-look" gloss.

I do know of roller-applied finishes in the USA that look almost as good as sprayed. The trick is to use a thinned-down wet coat to permit self-levelling before drying (but no vertical surfaces; they will "curtain"); and to use the little foam rollers. The paints I have seen include household vinyl paints (such as Dulux), which are inherently flexible. Personally, I would always spray using approved paints, because the last thing you want to do is to bugger up the whole aircraft for a few hundred quids worth of paint.

djpil is correct in that to determine with what to overcoat, you need to determine the existing paint (try the following on a small area where it won't show):

If cellulose thinners takes it off quickly, it is probably dope. Only ever overcoat with dope, else you will probably set up a reaction which will involve recovering the fabric.
If cellulose thinners doesn't take it off, try some Stits reducer...if this takes it off quickly, it's probably Stits.
If this doesn't takes it off, it's probably a two-pack paint (probably automotive) in which case it will need sanding to provide a key for any subsequent coats.
In all cases, re-painting will add weight, so new W&B required.

I suggest you contact your PFA Inspector for his advice.

DT

[J.A.F.O.]

I've seen an aircraft that was done with the roller technique and it looked better than the badly sprayed one next to it. I'm even thinking of trying it myself this summer.

You're not going to get a beautifully glossy fantastic finish but the aircraft I saw did not deserve its sobriquet of "The Artex Bomber".

[trevelyan]

all, much thanks for the fantastic advice and experience youve offered, im certainly better educated about this than 24hrs ago.

Thanks fo the offer of the call Stik, ill collate all the info and may very well take your offer up!

Cheers again.

:)

[J.A.F.O.]

Is there anyone out there who can give me some advice on using the coloured dopes that you can buy?

[shortstripper]

Hi,

I'm not going to give his number out on a public forum, but look up Rob Millinship through the PFA. He is an invaluable source of information on anything to do with aircraft spraying. I have found him to be extremely approachable and only to willing to talk me through the various processes needed to produce a really nice finish.

SS