Doculam painting

[Matt Piatkowski]

Hello,
I have covered partially damaged Pathfinder wing with Doculam and I am pleased with results.
Now, I am looking for some way to paint it - either bottom side with glue before covering or top surface.

Is this possible?

If yes, what kind of paint has to be used?

Thank you.
Matt

[Chancey Chorney]

Possible, by all means. How you ask, well... I have not yet painted mine, but I know what I am going to do. There are 2 options on painting. First is to spray the glue side/underside before installing the covering. I have heard I believe that most use aerosol paints from the craft stores. Myself, I am going method two. Install the covering, scuff it well with a scuff pad, I will be using red/maroon myself, but do feel that the grey would work just as well. then I will clean the surface well then paint it using the appropriate paints, or whatever you want. Just make sure it is fuelproofed at the end of it all.

[Brent Williams]

I have painted both the inside and outside of lamination film.  Yes, I'm a cheapskate....I have 3000ft of 1mil lamination film...and I am expecting delivery of different variety of polyester film to test.

I wanted a transparent look, so I painted the adhesive side with sapphire blue Design Master Tint-It floral dye, and I painted the outside with safety yellow Rustoleum.  Turned out nice.  Unfortunately, I crashed the plane violently and sheared the wings off.  The covering on unsmashed part of the two crashed wing panels is still drum tight a year and half later.  

You can obtain Design Master stuff at most craft stores.  

There are also several threads on painting doculam over at RCGroups.com

[Avaiojet]

Brent,

I think you're on to something. You should do a step by step tinting, covering and painting build.

CB

[Keith Renecle]

Hi Matt,

I sprayed a test wing with auto lacquer and it seems to be holding up well. I rubbed the film with 600 water paper first as Larry Renger suggested with SLC and it takes the paint rather well. I'll report back later to see how it lasts. This film makes for a very rigid wing as well and feels almost like Monocote. I also tried it over medium weight tissue but my personal opinion is that the un-doped tissue underneath just adds weight. Maybe Polyspan fuses more with the film as it gets heated but tissue does not, so don't bother with that idea.

Keith R

[Matt Piatkowski]

Hi Keith and everybody else,
I would like to paint the glue side of Doculam with something opaque and bright, for example:http://dmcolor.com/products/tangerine/, and then cover the wing.
Following Brent experiments, I will test this idea as I still do not know if spraying the Doculam glue with paint degrades it adherence to balsa after heating and to what degree.The appearance issues are not extremely important for me but I would like to have more or less uniform opaque coloring. Again, the test will show.

Yes....Doculam adds a lot of bending and torsional stiffness and is, in my opinion, sufficient for large wings, 60+" span, ~700 in ^2, with open bays or even completely balsa skinned. There is no need for extra polyspan or tissue underneath. The in-plane shear strength of Doculam alone is sufficient and, judging from my old P-finder wing appearance, Doculam stayed drum tight for the last five months.

The balsa to which Doculam will adhere should be, however, sealed with multiple sanded dope coats to reasonably smooth the balsa surface. Nitrate can be used as Doculam is raw fuel proof 100% but edges of it must be sealed with something to protect the glue. Thin CA will do but it is a messy job.

If all this works, I will use this method for four large wings for my future planes. Two of these planes will have ICE (Jett60 with pipe and Ro-Jett76 with header/muffler), one will be electric with Black Tiger 4250 C and the last one will be Wilk PZL P-38, with fully skinned balsa 65" wing and two electric motors.

Regards and Happy Flying,
M



 

[john e. holliday]

You do realize CA is not fuel proof?   Of course if you are flying electric don't let us slimers help you with out wearing clean gloves.

[Matt Piatkowski]

Hi John,
Interesting!
I used CA on structure and edges of covering (mostly Ultracote) around engines and fuel tanks for the last three years and have not seen any signs of fuel caused "CA erosion".

Perhaps if CA is exposed for a long time to the raw fuel with high nitromethane content it will soften or became rubbery?

Could you, please, clarify the details?
Regards,
Matt

[Matt Piatkowski]

Hello,
Thin CA can be used to seal the Doculam edge and protect the Doculam edge.
Please see the attached.
Thank you,
Matt

[Fredvon4]

I guess I must be just different....

I find a lot of just plain old dopes and glues to be rather resilient to Glow fuel EXHAUST..I assume because the exhaust residue is MOSTLY un-burned castor or synth oils

I tend to design my tank placements --and over flows ---to prevent RAW fuel on any part of the airplane

Like many can attest... preventing spent exhaust seeping into and soaking into interior wood structures is hard to do and over time--- wood models gain weight, might degrade glue joints, and many times makes repairs hard to do, due to the oil soaked areas...and K2R is not easy to find

I had one thoroughly oil soaked S-1 ringmaster from my Dad... ...building a new fresh Pat Johnston S-1 kit was faster and lighter than trying to resurrect the OIL soaked* dinosaur...

Jest sayin

*Added in... OIL Soaked from 30 years of use.... but the outside finish (Dope and silk) other than dirty was still good...

I think my dad, back when I was age 4 or 5, taught me to NOT spill caustic chemicals on things....

Bottom line is;

I think a LOT of our typical glues or dopes will seal well against OIL incursion--------and once I seal  with --what ever method
 I would never test with 35%~ 100% Nitro or any other caustic solvent....IMO__the environment to protect against is SPENT GLOW FUEL...by definition Mostly Hot OIL

OK, I admit, a bit grumpy...but I gotta ask... who are all these folks who need a finish impervious to RAW 25%~60% Nitro anyway?

[George]

Hi John,
Interesting!
I used CA on structure and edges of covering (mostly Ultracote) around engines and fuel tanks for the last three years and have not seen any signs of fuel caused "CA erosion".

Perhaps if CA is exposed for a long time to the raw fuel with high nitromethane content it will soften or became rubbery?

Could you, please, clarify the details?
Regards,
Matt

One of the CA removers I have is 100% nitromethane...but you can't argue with success. Just keep it in mind.  

George