Hi David
That's how we cure our 1A33 (20 hours at 90C).  It is supposed to be
fully cured at this point.  It is resistant to IPA when cured this way.

If James' application does use air ambient cure < 30 days, then that
likely is why he's having problems - a full cure should help
considerably.

regards,

Graham Collins
Process Engineer,
Northrop Grumman Canada Corporation
Halifax
(902) 873-2000 ext 6215

>>> [log in to unmask] 10/26/04 08:33PM >>>
Chris,

Have you tried this?

The only way I could determine if the cure was complete as to try to
remove it with IPA. It simply became impossible to remove after 3 or 4
weeks.

It would probably save time and money for James to get a copy of
IPC-HDBK-830 the Conformal Coating Handbook.

Chris Almeras wrote:

>If I'm not mistaken, you can heat cure 1A33 for 20 hours @ 90C, or 30
hours @ 75C, but I would try a 2 part urethane.
>
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]]On Behalf Of David Douthit
>Sent: Tuesday, October 26, 2004 6:02 PM
>To: [log in to unmask]
>Subject: Re: [TN] conformal coating
>
>
>James,
>
>If I'm not mistaken 1A33 is a 1 part urethane coating that requires
>extended curing times (>500 hrs) at room temperature. This coating is
a
>two stage "cure". The stage is the evaporation of the solvents which
>leaves a "touchable surface that feels dry. The second stage is the
>"cross-linkage" that takes place when oxygen molecules permeate the
>coating. Any attempts to "clean" surfaces coated with 1A33 before
>this "cross-link" curing is complete will result in damage. The major
>selling point for 1A33 is that it is easily removed and replaced for
>repair work for two or three weeks after it is applied.
>
>Because the "cross-link" portion of the cure requires oxygen, heat
does
>not accelerate the curing process.
>
>Just have them wait 30 days befor cleaning or use a 2 part urethane.
>
>David A. Douthit
>Manager
>LoCan LLC
>
>James TerVeen wrote:
>
>
>
>>I am looking for a conformal coating that can withstand the use of a
>>cleaner (Lixton TS-974)
>>We have a customer who uses our parts that are coated with Humiseal
1A33
>>and is cleaning them in an ultrasonic cleaner that has Lixton TS-974
in it.
>>They are complaining that the coating is coming off.  With the
ingredients
>>I see below there is no wonder.   So my first question was, is there
a
>>conformal coating that will withstand this material or if not is
there a
>>better cleaner I could recommend that will not remove the humiseal.
>>Remember it has to go into an ultrasonic cleaner.
>>
>>Thank in advance.
>>
>>
>>The ingredients are in this material are:
>>LIXTON
>>
>>50 - 10%    4-Hydroxy-4-methyl-pentan-2-0n
>>2.5 - 10%   N-methyl-2-pyrrolidome
>>2.5%           Alkylaminethoxylat
>>2.5%           modifiziertes Fettalkoholetethoxylat
>>
>>
>>

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