Hello John
I may oneday even get to the point of beginning a kit with proper accelerated
tailplanes.
All my accelerated tailplanes are blushed (Stickey). I think thet they were in
too high humidity when curing. How can flight crafters do this? I talked to Bob
about it, and will be honest with you, i wonder if he has ever talked with
aeropoxy???
Aeropoxy loves heat.
Once you reach a certain temperature, the TGA will be that temperature. Now if
you post Cure at a lesser temperature for many hours, it will elevate TGA to
~194 degrees F..
First off, I would support structures on anything over a hundred degrees. I will
just use plywood and set furring strip spacers here and there.
I don't think many post cures will hurt anything. The problem is the time spent
doing it. No matter what, a post cure is probably a great idea prior to fill,
and a great idea after fill and prior to paint.
I will need to do another one now because you do not want to work on stickey
surfaces, and thus far i like Nevilles procedure the best at dealing with,
although the most work.
The manual talkes bout post cures, and think the manual number is under 120F.
Neville talks below no more than 150F. I talked to a guy in Europa Florida. i
forget his name, but the hands on guy @ Europa USA. I do not think i will take
his advise. He said put it in the hot sun for an hour or so then flip. Don't
worry bout UV. You need to be able to keep your finger on it for 2 or 3 seconds,
or it is too hot. he thought 160F minimum and 180F Max. Could also put in the
back of a SUV in the hot sun.
I am gonna get hold of some blue foam and see what temp it distorts.
My gut is 140 to 150 for 10 hours at this point, then for the blush, will scrub
real hard with brissle brush and detergent then sand a bit. if no come all the
way off, may try a bit of denatured alcohol, and a bit more sanding, and a wash.
then will heat for a few hours to get moisture out.
Later
Ron Parigoris
"This is not a reply to the original question, but a question
> along the same lines.
> I take it from the replies so far that there is no danger of
> softening and warping the tailplane, rudder, flaps and ailerons
> at a temperature of 55C. Therefore no special support is needed.
> Is that correct?
> Also, I believe I was told to not cure the parts until just before filling
> and sanding"
Here is a reply I got:
Ron,
I have the same situation going on. The stickiness comes and goes with humidity
it seems. Neville tells me the pre-skinned surfaces have to be post cured, then
given a good scrubbing with a
brush and strong detergent. They shouldn't be handled with bare hands after post
curing and cleaning until after they are filled, primed and painted.
Here's the text of what Neville sent me regarding this issue:
Hi John,
The ''tacky'' surface you have on you pre-skinned parts is not unusual, but is
no cause for concern, this will be ''burnt off'' when you post cure them later.
The way I do that now is to make up a ''oven'' from packing box cardboard,
effectively a tunnel over the parts, with an electric fan heater blowing thru',
monitor the temps with a digital
thermometer (Radio Shack) to not more than 60 degrees C for 10 hours. Throttle
the airflow thru' the tunnel with a simple sluice gate door at each end, slowing
the throughflow increases the
temp.
This will set the ''memory'' of the resin so it has to be subjected to a higher
temp before it will ''move'' again, this is why white is the recomended colour
(note the correct spelling !)
After the post cure process, I then scrub vigorously the surface with a strong
detergent solution and a stiff brush (nail brush?) Wash off all the detergent
with fresh water, and put back into the
''oven'' for a couple of hours to dry them completely, do not touch them with
bare hands from this time!
The surface will then need to be scuff sanded for filling, vacuum all the dust
before applying the filler, use the supplied Expancell/resin mix for filling, do
not be tempted to purchase a filler
material from another source, i will mention no names, but it is twice as heavy
as the Expancell, and MUCH harder to sand, if you mix the Expancell dry enough.
I have seen so much BS on the forum about filling, I often wonder what colour
the sun is on these people's planet !
Get back to me if you need further advice,
Cheers,
Nev.
Regards,
John Lawton
Dunlap, TN
A-245 - Up on it's feet by middle of next week!
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