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General Forum => General Discussion => Topic started by: whiskers on January 18, 2020, 04:56:16 AM



Title: Diesel fuel proofer
Post by: whiskers on January 18, 2020, 04:56:16 AM
Neither of my local model emporiums have fuel proofer (that tells a story in it's own right!). I was therefore wondering if good old polyurethane varnish (I have tin of Humbrol hanging about somewhere) will do the trick...or anything else?


Title: Re: Diesel fuel proofer
Post by: Big G on January 18, 2020, 05:22:47 AM
Rustin's one-pack varnish is fine for diesel, but you may have to warm it a little to thin it out a bit. Are you applying it over dope or paint? The Humbrol varnish should be OK, too.

G


Title: Re: Diesel fuel proofer
Post by: whiskers on January 18, 2020, 05:48:46 AM
Over dope...


Title: Re: Diesel fuel proofer
Post by: billdennis747 on January 18, 2020, 06:22:30 AM
Agree - any polyurethane one-tin varnish will be fine. I've been using yacht varnish inside engine bays but can't remember why. Diesel shouldn't harm any gloss finish; it just gets sticky if left so it needs cleaning off whatever. I get as much off as I can; Ivan Taylor has a patented mixture of Fairy Liquid and white spirit. Then a wipe with ether.
On scale models I still use aerokote 2 pack, mainly because I've got quite adept at mixing matt and gloss to get what I want.


Title: Re: Diesel fuel proofer
Post by: Big G on January 18, 2020, 07:14:20 AM
The best currently-available proofer for both diesel and glo (up to about 25% nitro) is Rustin's 2-Pack 'Plastic Coating'. This is the same basic formulation as the original Tufkote. Current Tufkote is rubbish - it's way too viscous and I've heard stories that it doesn't bond too well to dope or paint.

One small tip - rattle-can car-paint is proof against diesel (not glo fuel of any description) and doesn't need a further coat of proofer. The stuff I use is called CarPlan - not quite as good IMHO as the old Duplicolor, but good enough.

G


Title: Re: Diesel fuel proofer
Post by: Squirrelnet on January 18, 2020, 10:57:38 AM
I've used polyurethane varnish on models with no problems too

I have say my experience with Halfords rattle can acrylic car paint is that it's not fuelproof, diesel fuel seems to dissolve the paint so cleaning the fuel off results in a coloured rag ! For scale models I now, like Bill, use aerokote in a variety of finishes


Title: Re: Diesel fuel proofer
Post by: whiskers on January 20, 2020, 02:47:48 AM
That's great. Good old poly then. Thanks fellas.


Title: Re: Diesel fuel proofer
Post by: Big G on January 20, 2020, 06:04:39 AM
I should have said in my earlier post that acrylic rattle-can is not fuel-proof. Also, other varnishes and lacquers will not adhere to it. I built a Don Still Stuka Stunt a few years ago (lovely to fly with an LA25) and finished it in black acrylic. I proofed it with a deLuxe products 2-part melamine lacquer (as per Tufkote, Aerokote, etc), but when it was cured the slightest touch of the finish produced star-cracks and flaking. There was no 'key' between the paint and the lacquer. I had to remove the whole lot, down to the dope - which is a task I hope never to do again.

For years I used DupliColor, which was a genuine cellulose-based rattle-can paint. Lovely stuff, but the H&S nannies got hold of it, and changed the formula. It was never as good, and went off the market. I now use CarPlan rattle-can, the label of which carefully avoids the word 'cellulose', because it isn't. However, it's good stuff with good coverage, and is definitely proof to diesel.

I worked for years in the coatings industry, and know only too well how the H&S wallahs can ruin a perfectly good product.

Hope this helps.

G


Title: Re: Diesel fuel proofer
Post by: charlieman on January 20, 2020, 02:16:55 PM
From what I've read, diesel fuel doesn't affect Nitrate dope finishes. Am I misinformed?

Butyrate will stand up against glo fuels but becomes iffy with higher nitro content.


Title: Re: Diesel fuel proofer
Post by: ffkiwi on January 20, 2020, 04:29:28 PM
From what I've read, diesel fuel doesn't affect Nitrate dope finishes. Am I misinformed?

Butyrate will stand up against glo fuels but becomes iffy with higher nitro content.

No you are not-nitrate dope finishes will stand up to diesel.....BUT...of course if you are using castor based fuel  you still get a stick mess that can be hard to clean off.....for FF scale -where sometimes it is not practical to use any kind of fuel proofer because it alters the finish tone, it has been long established practice (especially in the UK) to use mineral oil based diesel fuel....where the exhaust residue wipes off quite easily. Given that such models are usually turning large props at low revs, the use of mineral oil does not seem to come at any disadvantage in performance or engine longevity....and since the fuel element of the fuel is kerosene, there are no miscibility problems.....in fact in the 50s and 60s it was common practice for the bigger names in the modelling business in the UK, such as Mercury Models, ED etc to offer two lines of diesel fuel-one mineral oil based, the other castor based....the castor based one always being the 'premium' grade-and priced accordingly....

I am unsure though, how engines would stand up to prolonged extended running on mineral oil fuels-such as you would encounter in a C/L or R/C situation where they are running for minutes on end, under widely varying loads and throttle settings.

Personally-as regards fuel proofers, I use good old polyurethane varnish for diesel models, and a two part epoxy wood preservative-'Everdure' by International Paints on glow models-this goes on over tissue without any problems, and is compatible with dope-or at least nitrate (which is all I use) dope-so patching and repairs are not a problem.

When it comes to being bullet proof though-in the paint department....nothing seems to beat the two part polyurethanes....marine 'reaction lacquer'....I have power model fuselages done with this 30+ years old (nearer to 40 than 30!) that have never seen less than 30% nitro-still as good as new....but it is hard stuff to get, the colours are fairly limited-and it is nasty stuff to use....as well as being heavy!   The biggest bugbear I have with it these days is the hardener is only available in 4 litre cans for an outrageous price-well over $100......and it goes off rapidly after you first open the can, whereas the paint itself lasts in the can for decades...

 ChrisM
 'ffkiwi'


Title: Re: Diesel fuel proofer
Post by: vintagemike on January 21, 2020, 04:15:15 AM
The two part polyurethane route is one I agree with, I used to have access to a supply used for furniture. I sprayed the fuselage of  a KK Gaucho with it, totally fuelproof, I expect when armegeddon finally visits this planet all there will be left are cockroaches and this model!! One thing with poly, read very carefully the instructions especially the H & S bit, poly is a nasty stuff, lots of evil substances in it (arsenic for one) not for the faint hearted!


Title: Re: Diesel fuel proofer
Post by: Big G on January 21, 2020, 06:12:03 AM
When I was flying TR a good few years ago, I proofed a couple of Rossi Goodyears using International 2-Pack Poly-U lacquer. Totally proof against any fuel we put through those Rossis - but: heavy. Probably doesn't matter too much on a small model, but I wouldn't want to use it on a full-size stunter. Or a FF model.

G


Title: Re: Diesel fuel proofer
Post by: ffkiwi on January 21, 2020, 03:32:50 PM
When I was flying TR a good few years ago, I proofed a couple of Rossi Goodyears using International 2-Pack Poly-U lacquer. Totally proof against any fuel we put through those Rossis - but: heavy. Probably doesn't matter too much on a small model, but I wouldn't want to use it on a full-size stunter. Or a FF model.

G

Big G-the very stuff I used!....though it's had a few changes of labelling over the years.   I only used it on FF power duration fuselages...including my first 'Cuddy' (a design you'll no doubt recall) in about '81 or '82-which I still have-the flying surfaces are rather tatty-but the fuselage is still near pristine! I used skyblue, yellow, white and the maroon over the years-not surprisingly the white turned out to be the heaviest...

ChrisM
'ffkiwi'


Title: Re: Diesel fuel proofer
Post by: Big G on January 21, 2020, 03:47:29 PM
Chris,

'Cuddy' was my first 1/2A model. Designed by Tony Cordes IIRC. Somewhere I still have the plan. It flew well with a bog standard TD.

International paints and lacquers and other of their products are still available from boat chandlers. Not cheap!

G


Title: Re: Diesel fuel proofer
Post by: fred on January 21, 2020, 10:20:31 PM
Epoxy...  Lo viscosity Laminating types work well.


Title: Re: Diesel fuel proofer
Post by: Big G on January 22, 2020, 04:08:38 AM
Epoxy...  Lo viscosity Laminating types work well.

At great expense.....overkill for diesel fuel, which is what the OP was looking at. Also, I'm not sure that thin epoxies will actually take to a paint surface, due to their high surface-tension I believe.

G


Title: Re: Diesel fuel proofer
Post by: ffkiwi on January 22, 2020, 05:48:11 AM
Chris,

'Cuddy' was my first 1/2A model. Designed by Tony Cordes IIRC. Somewhere I still have the plan. It flew well with a bog standard TD.

International paints and lacquers and other of their products are still available from boat chandlers. Not cheap!

G

Mine too-served me well....and though damned heavy (no fault of the designer!) it would always turn in a reliable time...which is more than i can say for some of its successors.....I've just built another one 35+ years on....for our 'kiwi power' event same as your 'brit power' I think-the 1.5 PB diesel class....Cuddy #2 sports a Webra red head beam radial job up front. still to be covered, finished etc....needless to say this one WON'T be getting reaction lacquer....though it will sport one or two refinements in the form of a plug in skid and removeable fin....in the aid of improved transport/packability...

 C


Title: Re: Diesel fuel proofer
Post by: lincoln on January 22, 2020, 07:52:02 AM
Bill:
Fairey liquid? Do you get that by squeezing certain British airplanes? Or do you milk them? I'm surprised you don't take the Bard's advice and use eye of newt.


Title: Re: Diesel fuel proofer
Post by: billdennis747 on January 22, 2020, 09:30:55 AM
Lincoln
I can imagine Fairy (no e) liquid looks very odd to the non-British! It is the most well-known of our dishwashing liquids.
We also have (or maybe no longer) Sqezy. I realised I was a pedant at a very early age when I worried about the missing u. I assume Sqezy originated at a time when things squeezable were a novelty, as opposed to chipping soap off a block with a chisel.


Title: Re: Diesel fuel proofer
Post by: lincoln on January 22, 2020, 02:45:15 PM
I guess I should have used a smiley. Now it's your turn to mis-spell Boeing or something like that.

We have some silly names for soap and detergent over here as well. Sometimes I wash dishes at midnight with Dawn.

We hardly ever see diesel model engines here. However, if someone near Boston needs ether, I have a can or two. The guy who gave them to me is from Europe, of course, but has gone over to gliders. I might save one can for the snowblower, at least until it gets an overdue tune up.