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Aerokote Fuel Proofer problem

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Djay07/03/2012 07:59:35
515 forum posts
383 photos

I have just finished my TN Typhoon build and as fuel proof paints are not available here in Dubai sprayed the model with aerosol tin paints.

I then brushed on a layer of Aerokote Matt fuel proofer .

The Aerokote was mixed exactly as per the instructions but after a week it still remains sticky.

if I pick up the fuse it stays stuck to my hand.

I painted a second coat on, ensuring the bottle was well mixed and the correct amaount of activator was added, and this made no difference.

Any idea how I can activate the Aerokote to make it go off fully? Or how I can remove it without to much damage to the paintwork. Failing that what can I spray or paint over the top of it that will go hard.

Also it is suppossed to be matt, but has left a gloss finish.

The Aerokote was brought in December from Slough RC so is not old.

I did test fly the model before fuel proofing it, and it flew superbly powered by an RCV 90.


Olly P07/03/2012 08:09:29
3188 forum posts
181 photos

Darryl, I wonder if it is temperature related?

Drop Aerokote an email and see what they advise.


Djay07/03/2012 08:12:24
515 forum posts
383 photos

Hi Olly.

It would not be related to cold temperature out here, It is the middle of winter and freezing cold for us, but it is around 22 - 25c.

Funnily enough I was just about to drop aerokote a line, and tonite I was going to put a heat gun over it gently to see if it would go off.

The problem is out here the air is full of dust ansd sand so if I fly the plane it will end up like a piece of sandpaper.


Olly P07/03/2012 08:25:40
3188 forum posts
181 photos

I was thinking if it was exo thermic drying then it might be too warm for it to shed the heat?

Djay07/03/2012 08:38:52
515 forum posts
383 photos

It is activated by catalytic action, but the pot it is mixed in does not give out any heat or warmth, unlike glass fibre resin.

Actually that gives me a thought, perhaps I can coat it with glass fibre resin if all else fails, or at least glass covering epoxy, of which I have some spare.


andy watson07/03/2012 08:51:25
1942 forum posts
20 photos

No help for you now, but Phil at fighter aces sells fuel proof paint for scale models, and I am sure he would send them to Dubai.

Djay07/03/2012 08:57:45
515 forum posts
383 photos

Hi Andy.

the problem is shipping.

Even water based paints are not accepted by some delivery companies, in particular the one I use which is a personalised courier company similar to fed ex, and deliver door to door at a fraction of the cost. They charge by actual weight, not volumetric weight.

The paints are normally sent by ship so take an eternity to reach here.

I tend to pick up paints when I am in the UK and put them in my case, well wrapped, but then i have the problem of no spray equipment here, and I do not want to carry aerosols in my case.


GrahamC07/03/2012 09:28:09
1212 forum posts
196 photos

I've used Poly-C sprayed for my build - but the vendors reckon you can get a good finish by painting it. Its water based, and they claim that it is fuel proof enough even for engine bays. (I used Clearcoat on my fire wall.) I see you don't have spraying kit - I would say that it sprays well, but make sure you have a proper ventilator mask if you are going to spray it!

Djay07/03/2012 09:36:35
515 forum posts
383 photos

Hello Graham.

I still have one container of Poly C left in my stock of bits, I will try painting over some hidden areas of sticky bits to see if it dries ok.

Do I need to thin it with water or apply it straight?


sticky fingers07/03/2012 10:03:36
103 forum posts
14 photos

Hello Djay, It sounds, like you have a bad batch of paint there, personally, I woudnt go down the poy C route as you have two entirely different products, one air cures and the other cures by chemical action. Try not to go down the route of messing about and ruin all your hard work, when an email to the Aerokote manufacturers could quickly come up with an acceptable solution. I might add that in a lot of instances ,two part products can have a definitive shelf life, and what you describe seems to be classic signs e.g stickiness and not curing

Regards Dave

Edited By sticky fingers on 07/03/2012 10:04:18

GrahamC07/03/2012 10:18:55
1212 forum posts
196 photos

Yes - I would check with Aerocoat first as suggested. There may be a way of applying catalyst directly to the sticky mess to sort out your immediate problem.

If you do end up having to remove it with thinners etc and then go down the Poly-C route - don't thin it. I rank up and asked about this and they told me not to becasue it affects the chemical composition. Mine is only slightly thicker than milk anyway and went through both a touch up gun and an airbrush fine. I found I had to wipe the nozzle on the touch up gun occasionlly as it was thickening a little around the nozzle and clogging the gun - but that was on the outside of the nozzle.

If you are careful to avoid runs then I find this kind of product applies very evenly with a brush.

GrahamC07/03/2012 10:24:35
1212 forum posts
196 photos

Some people suggest a heat gun as a way of encouraging epoxy that has stayed tacky. Worth a try?

Djay07/03/2012 10:35:50
515 forum posts
383 photos

Thanks for the replies.

John at Deluxe materials has given me some instructions to apply a concentrated mix to the existing sticky coat to see if I can restart the curing process.

i wiil try this tonight, along with gentle heat from a heat gun.


CARPERFECT07/03/2012 11:41:53
243 forum posts
3 photos

AS i worked in a carbody shop for 9 years where we used two part paint, the paint is activated by chemical reaction and heat. As the temp is 20/25 out there this sounds like the activator is the problem or the quantitatives are wrong. and may never go hard. If you could find a car body repairers and ask them if they could place your plane in the paint oven when they are drying the paint on a car this might do it. If it does not all the paint will have to be removed

Essef08/03/2012 19:02:39
47 forum posts

To Djay

You have,nt stated what base the aerosols were you used ie acylic/enamel/cellulose etc etc ,if your still tacky after this period then i'd say the sub coating as reacted with the top coat (state its solvent content) and is'nt allowing the solvents to penetrate outside the fuel proofer and evapoarate hence remaining tacky.

Unfortunately a strip and re-paint will be your only solution in a worse case senario.


Djay09/03/2012 12:43:26
515 forum posts
383 photos

Hello Stephen.

I think it is enamel, it does not say on the can, made by Krylon.

I do not think this is the problem as the mix in the pot did not harden either, despite various mix ratios tried as recommended by deluxe materials.

I managed to remove the sticky layers from the fuse by wiping with isoproply alcohol, but this was boring keeping wiping, so happened to be cleaning an engine so sprayed the wing with fairy power spray and this removed the sticky layer easily. No damage to the paintwork at all.

one final clean and I will paint it with poly c and hope for the best.

problem is I brought 4 bottles of Aerokote, will the other 3 be the same?


Essef09/03/2012 21:17:53
47 forum posts
Posted by Djay on 09/03/2012 12:43:26:

I do not think this is the problem as the mix in the pot did not harden either, despite various mix ratios tried as recommended by deluxe materials.

This does now sound like faulty material, check useby dates and also batch numbers

if you have a different batch number then do a test run with that one and if it cures as it should then apply it to your model.

Should this prove successful then i'd inform the mfg of your problem, hopefully saving someone else from the same fate.


richard cohen09/03/2012 22:01:33
284 forum posts
40 photos


i had exactly the same problem as you are experiencing. Matt aerokote, staying sticky after application . I tried everything...mix was perfect, applied in a warm workshop, and still tacky after 48 hrs. I tried heat and extra concentrated reapplication but to no avail. The chap at Deluxe said he had heard of this before on occasions but couldnt offer a solution. I cleaned it all off with a quick wipe of thinners and used Flair aerosol fuel proofer. Sprayed beautifully out of the can(lovely fine mist) and was touch dry within the hour. Maybe aerkote sets better when sprayed but i wasnt going to risk ruining the airframe so i'll stick with Flair.


Essef10/03/2012 08:34:58
47 forum posts

Atomisation does aid molelcular destruction and so vastly improves the distribution and mixing of two part materials.

Wow hows that for a mouthful of big words on a saturday morning ?

and thats before ive had my weetabix !!!


Del Wheatley10/03/2012 23:32:13
167 forum posts
23 photos

I've just had a similar problem with aerokote,i fuel proofed the engine bay etc on my sky 40 and a week later it's still slightly tacky to the touch.It took about 5 days to dry down o this level and seems to have stopped getting any dryer now.

It was mixed exactly as per the instructions and was bought at a similar time to the op's bottle but from a different store.

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