LAME question: Window seals on unpressurised singles
Guest
Posts: n/a
LAME question: Window seals on unpressurised singles
Here's a quick one for the LAME's and DIY pilots out there:
The window seals on my late 70's Archer are a bit grotty, which in drier parts of the country where the machine used to live didn't really matter, but with the recent heavy rains in Queensland, I've had to shovel out a few inches of water from behind the front seats, and of course this isn't really great for the interior or anything else in the machine for that matter.
Question here is can I just take some run of the mill silicone sealant and replace the old gunk, or is there some sort of rule that would prevent me from doing so? Am I running the risk of making things worse by taking this into my own hands, are there any alternatives (other than getting the custom cover which is on the to do also)?!
Cheers!
The window seals on my late 70's Archer are a bit grotty, which in drier parts of the country where the machine used to live didn't really matter, but with the recent heavy rains in Queensland, I've had to shovel out a few inches of water from behind the front seats, and of course this isn't really great for the interior or anything else in the machine for that matter.
Question here is can I just take some run of the mill silicone sealant and replace the old gunk, or is there some sort of rule that would prevent me from doing so? Am I running the risk of making things worse by taking this into my own hands, are there any alternatives (other than getting the custom cover which is on the to do also)?!
Cheers!
Join Date: May 2008
Location: Somewhere
Posts: 283
Likes: 0
Received 0 Likes
on
0 Posts
Sched 8 maintenance in the CAR's of what a Pilot is allowed to conduct includes removal and resealing of side windows in an unpressurised aircraft.
May as well take the time to take yours out, clean them up properly and re-seal. Day job, two days if you REALLY want to clean everything up (that is, getting a steel brush to the frame then spraying some primer to protect them).
Done it on a PA28 body before whilst learning a thing or two, wasn't too hard. Funny thing was, the pilot's windshield - which a LAMEy fitted - leaked and mine didn't!
Use Sikaflex.
May as well take the time to take yours out, clean them up properly and re-seal. Day job, two days if you REALLY want to clean everything up (that is, getting a steel brush to the frame then spraying some primer to protect them).
Done it on a PA28 body before whilst learning a thing or two, wasn't too hard. Funny thing was, the pilot's windshield - which a LAMEy fitted - leaked and mine didn't!
Use Sikaflex.
Moderator
"...take some run of the mill silicone sealant..."
Grandpa Aerotart
DONT EVER use a steel/wire brush on your aluminium airframe...unless you want to ruin it. Microscopic bits of steel will break off and be left behind in the aluminium...very, VERY bad news.
Use scotchbright.
Don't just use any old sikaflex type material...one type is compatible with aluminium and the other will literally eat the metal away completely. Look at the leading edge rib in my vertical stab for where some moron got lazy and instead of using the rubber grommet that is just inches away put silastic there instead...it has dissolved the first couple of inches of rib.
By all means do it yourself if you want to but get professional advice first.
Use scotchbright.
Don't just use any old sikaflex type material...one type is compatible with aluminium and the other will literally eat the metal away completely. Look at the leading edge rib in my vertical stab for where some moron got lazy and instead of using the rubber grommet that is just inches away put silastic there instead...it has dissolved the first couple of inches of rib.
By all means do it yourself if you want to but get professional advice first.
Last edited by Chimbu chuckles; 14th Apr 2009 at 08:31.
Join Date: Jun 2004
Location: Australia
Posts: 63
Likes: 0
Received 0 Likes
on
0 Posts
would you really risk it?
Please don't use standard silicone or sikaflex. If you feel the need to do it your self order some pr1422 or ps 870 (which has chromate in it to prevent corrosion).
I know it is expensive but maybe there is a maint facility close by that has some expired P.R. which would be fine and a lot better than using sikaflex or any other sellys product.
PS870 is about $75 a tube which when put down right will prevent corrosion around he window and also prevent water getting in and corroding the floor.
It will be money well spent in the long run and since it will be right there in the eyes of casa if they ramp you it will save you a lot of embarrassment.
I know it is expensive but maybe there is a maint facility close by that has some expired P.R. which would be fine and a lot better than using sikaflex or any other sellys product.
PS870 is about $75 a tube which when put down right will prevent corrosion around he window and also prevent water getting in and corroding the floor.
It will be money well spent in the long run and since it will be right there in the eyes of casa if they ramp you it will save you a lot of embarrassment.
Join Date: Aug 2007
Location: Sydney
Age: 54
Posts: 192
Likes: 0
Received 0 Likes
on
0 Posts
your window may of sealed and the lame fitted one leaked,but at least the ali frame that is holding it in position (lame window)will still be there in a few years as for your repair it will become very costly.....Pay cheap ,pay twice
Join Date: Apr 2002
Location: Alice Springs
Posts: 1,744
Likes: 0
Received 0 Likes
on
0 Posts
Leaky Pipers
I found that Pipers still leaked and accumulated water on the floor even when they had a canvas cover covering ALL the windows and windscreen.
They often sit nose up a bit, and I think the water came in through the air vents from the leading edge of the wing to the floor level air outlets.
They often sit nose up a bit, and I think the water came in through the air vents from the leading edge of the wing to the floor level air outlets.
Join Date: Jan 2008
Location: turn L @ Taupo, just past the Niagra Falls...
Posts: 596
Received 0 Likes
on
0 Posts
Damn fine thread
Perhaps someone (with a valuable tip like this threads) should start a pilot maintenance thread, highlighting the pitfalls and lessons learned!!! We could all benefit from that!
Perhaps someone (with a valuable tip like this threads) should start a pilot maintenance thread, highlighting the pitfalls and lessons learned!!! We could all benefit from that!
Silicon can also be detrimental to the perspex. Silicon is not silicon and there are different cure types. You can see fine cracks around the eddge of some aeroplane windows. In many cases this is caused by the use of silicon. Lp Aero are recommending the use of Bostik 1100FS Fast Set Polyurethane Sealant.
Most silicones use an acetic acid cure mechanism (you can smell it) that eats aluminium. It's not suitable ever, get some PR1422, its messy to use and although once your stuff is stuck in you will never get it out in one piece, but that shouldn't matter.
Join Date: Sep 2007
Location: Up left - Down right
Posts: 946
Likes: 0
Received 0 Likes
on
0 Posts
I can just see the log book now.
Report
"Cockpit windshield seals in poor condition"
Action
"Windshields resealed IAW pprune.org/d-g-general-aviation-questions/369888-lame-question-
Report
"Cockpit windshield seals in poor condition"
Action
"Windshields resealed IAW pprune.org/d-g-general-aviation-questions/369888-lame-question-
Last edited by Short_Circuit; 15th Apr 2009 at 05:26. Reason: Just for comic relief.
Plank Bender, I'm a LAME, and I would be using PR1428 if you can get your hands on it? Tho it dries a deep purple colour, it is highly flexible and UV resistant, specifically made for windshields, especially floating ones like Cessna's, or Piper windows attached by screwed on tabs.
The PR1422 is brown in colour when dried, but was made for fuel tanks and degreasing resistant, tho not very UV or flexible when aged cured. It would do for several years, but PR1428 would be better. Then you could also apply 2-pack touch-up paint via a touch-up brush over sealant. Job would be very presentable & professional
The Bostik stuff that others are talking about, should be of Neutral Cure only, and would be found in a Paint Trade Centre outlet of some sort. Neutral Cure marine sikaflex would also be allowed, and it maybe a pre-mixed colour the same as your pre-coloured to your aircraft paint work.
Personally I'm fussy in those situations of windows, and would only use a plastic or phenolic or nylon scraper to remove old sealant. Just remove the remaining sealant with Isopropanyl, Toulene, or a goo remover. Don't be scratching it like others recommend!!!! Why scratch a good fine surface unless there is corrosion there??!! Scratching an alodined coating off alloy would be like scratching your skin with a knife blade to make sure old skin cells were removed, tho no cancer there
... Unless corrosion, just clean surface, and re-apply. Perfection is for visible areas, and without a trained person or eye on job, all your doing is prompting future problems.
NEVER USE A WIRE BRUSH!!!! ... maybe if you PM me, we can talk on phone, but you should be alright with the above directions.
PS - use a good quality masking tape, and not too large a filler bead of sealant, just enough to do the job of keeping the water out, and not enough for the sun to harden, and your washing methods to risk catching the bead of sealant off.
The PR1422 is brown in colour when dried, but was made for fuel tanks and degreasing resistant, tho not very UV or flexible when aged cured. It would do for several years, but PR1428 would be better. Then you could also apply 2-pack touch-up paint via a touch-up brush over sealant. Job would be very presentable & professional
The Bostik stuff that others are talking about, should be of Neutral Cure only, and would be found in a Paint Trade Centre outlet of some sort. Neutral Cure marine sikaflex would also be allowed, and it maybe a pre-mixed colour the same as your pre-coloured to your aircraft paint work.
Personally I'm fussy in those situations of windows, and would only use a plastic or phenolic or nylon scraper to remove old sealant. Just remove the remaining sealant with Isopropanyl, Toulene, or a goo remover. Don't be scratching it like others recommend!!!! Why scratch a good fine surface unless there is corrosion there??!! Scratching an alodined coating off alloy would be like scratching your skin with a knife blade to make sure old skin cells were removed, tho no cancer there
... Unless corrosion, just clean surface, and re-apply. Perfection is for visible areas, and without a trained person or eye on job, all your doing is prompting future problems.NEVER USE A WIRE BRUSH!!!!
... maybe if you PM me, we can talk on phone, but you should be alright with the above directions.PS - use a good quality masking tape, and not too large a filler bead of sealant, just enough to do the job of keeping the water out, and not enough for the sun to harden, and your washing methods to risk catching the bead of sealant off.
Moderator
Now discovered why not to use Silicone sealant around aluminum - it has a ph of 8.85, thus is very alkaline and would corrode most metals.
Join Date: Jul 2007
Location: in the classroom of life
Age: 55
Posts: 6,864
Likes: 0
Received 1 Like
on
1 Post
Yep
A Neutral cure and SIKA make the good stuff is the way to go for most jobs.
This is the stuff I think the LAME's want you to use. Bunnings do not stock it!
http://buyat.ppg.com/REP_aerospace_f...ts/pr1428a.pdf
A Neutral cure and SIKA make the good stuff is the way to go for most jobs.
This is the stuff I think the LAME's want you to use. Bunnings do not stock it!
http://buyat.ppg.com/REP_aerospace_f...ts/pr1428a.pdf
and FFS be carefull when rescrewing any bolts or screws..........
Those connection points probably haven't moved in 10 or more years and are now just a congealed amalgam of metallic salts...... meaning that it is extremely easy to strip what still remains of any thread.
Those connection points probably haven't moved in 10 or more years and are now just a congealed amalgam of metallic salts...... meaning that it is extremely easy to strip what still remains of any thread.
Join Date: Aug 2008
Location: Perth
Age: 50
Posts: 50
Likes: 0
Received 0 Likes
on
0 Posts
lmao
love this ****, keeps me employed,
your Archer wasn't built by Massey-Ferguson
use whatever you want from where ever you want at the cheapest possible price you can get it
the PROPER stuff is more than likely a a PRC product, they are expensive relatively speaking, , but if used properly do NOT cause the damage mentioned in previous posts,
1422 works well for everything (ask bombardier, embraer and boeing) but sticks like **** to a blanket, makes window removal a pain in the arse, put a piece of string in it so the next guy can pull the string out and thereby cut the sealant
or 1428 the cool purple stuff that is 'low adhesion' makes the window come out easier, i have also used it to seal floor boards
if you are dead set on being a tightass buy some rtv 1345 at least, it comes in 3 colors
and please use the steel wire brush to clean up the frames, better yet get an angle grinder the hole for the window will be enlarged making it better, however a plastic or phenolic scraper sharpened on belt sander will do the perfect job
if the screws are rusty and siezed, drill em out and replace em, screws are pennies each, so are the nuts
another option is simply put a bead around the edge of the window and frame, without removing the window, this has the benefit of doing the required sealing, and not making a mess out of the window when you try to remove it, and frankly would be my first go , however i would use the proper sealant and masking tape, and in this case any masking tape will do
this is why engineers are engineers
hell
love this ****, keeps me employed,
your Archer wasn't built by Massey-Ferguson
use whatever you want from where ever you want at the cheapest possible price you can get it
the PROPER stuff is more than likely a a PRC product, they are expensive relatively speaking, , but if used properly do NOT cause the damage mentioned in previous posts,
1422 works well for everything (ask bombardier, embraer and boeing) but sticks like **** to a blanket, makes window removal a pain in the arse, put a piece of string in it so the next guy can pull the string out and thereby cut the sealant
or 1428 the cool purple stuff that is 'low adhesion' makes the window come out easier, i have also used it to seal floor boards
if you are dead set on being a tightass buy some rtv 1345 at least, it comes in 3 colors
and please use the steel wire brush to clean up the frames, better yet get an angle grinder the hole for the window will be enlarged making it better, however a plastic or phenolic scraper sharpened on belt sander will do the perfect job
if the screws are rusty and siezed, drill em out and replace em, screws are pennies each, so are the nuts
another option is simply put a bead around the edge of the window and frame, without removing the window, this has the benefit of doing the required sealing, and not making a mess out of the window when you try to remove it, and frankly would be my first go , however i would use the proper sealant and masking tape, and in this case any masking tape will do
this is why engineers are engineers
hell