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Can fiberglass grow back?

V

Vlad

Well Known Member
I have to confess - I measured the part three times and still cut short on one side. Guys secure your fiberglass parts good. Tape them good, do keeper clecos whatever it takes to prevent this. Somehow the Holy Cowl misaligned and I ended with this. Can I grow it back? If yes, any tips? Bob already suggested to buy new cowling :) and Tom recommended to start new thread because of common mistake. I saw somewhere a builder added safely about 1/8 but I have almost 3/16th gap. It is not all over the cowl, just about 11 inches long then it gradually decreases to zero.


fiberglass.jpg
 
Yes, it can grow back!

I did a similar thing, do to some stupidity with a spacer between the spinner and cowl at a crucial fitting. I basically built the trailing edge back up using a form on the outside of the cowl made from duct tape and vinyl tape (for it's non-stick properties), then laid up what I needed inside that, Used some glass tape and resin, flox and such to finish, and no one can see what happened - still invisible 3 years and 850 hours later....

Paul
 
Short answer is yes

The long answer is it's gonna take a lot of sanding. We trained on this kind of thing back in aviation structures school. Essentially what you want to do is bevel the edge over a 2 inch distance so that at the edge, the fiberglass is paper thin and gradually tapers up to the full thickness about 2 inches from the edge. Then do multiple lay-ups to rebuild the thickness and extend the edge as you need it. After that a bunch more sanding will be necessary to smooth it all out.

Sorry to hear about your problem, but it is fixable with some time and effort.
 
Paul, Mike, much appreciated. I feel better now.

Anyone has a technique illustrated?
 
It's not difficult at all. Lay some duct tape in the area to fix and all areas that you don't want to stick. Put the finished side of the tape facing any areas where the epoxy will go. Place some light weight cloth...2 to 3 oz onto the duct taped repair. Mix up a batch of epoxy with about a 50 50 mix of milled fiber and flox until it's creamy and buttery, not too thick, just enough not to run. Mix a smell amount of epoxy to wet the cloth laying on the tape. Spread the flox/fiber mix onto the cloth and lay another light weight piece of glass cloth on top. Make sure the cloth is fully wetted a then place a piece of peel ply on top of the cloth, forming it to the shape ot the outside of the cowl. Clean all excess up with acetone and let it cure. Peel off the peel ply then pop off the cowl. Trim as needed. Sounds simple and it really is. I did a fix on my cowl at the front edge near the inlet nad it came out really good. It is a strong as the cowl edges as far as I can tell.

назовите меня, если я могу помочь. Много раз я сделал эту задачу.
 
Спасибо большое Рик за подробную инструкцию. Маленький вопрос - уточни пожалуйста спецификацию lightweight cloth. А терпения у меня хватит.

Кстати, а ты поздравил нашего нового Русскоговорящего члена VAF из Украины? Он вчера зарегистрировался и зовут его Юрий. Он строит РВ7.

Еще раз благодарю за разъяснения по стеклопластику.
С уважением
 
Vladyspassky said:
Спасибо большое Рик за подробную инструкцию. Маленький вопрос - уточни пожалуйста спецификацию lightweight cloth. А терпения у меня хватит.

Кстати, а ты поздравил нашего нового Русскоговорящего члена VAF из Украины? Он вчера зарегистрировался и зовут его Юрий. Он строит РВ7.

Еще раз благодарю за разъяснения по стеклопластику.
С уважением
Click to expand...


Took the words right out of my mouth. :p
 
Sorry Vlad...Glass cloth is rated by weight per square yard, to do this repair use light cloth to hold all the resins together. If the cloth is too thick your repair will be too thick and hard to blend into the existing material. Take a look at a local hobby shop, they may have small amounts of 3 oz cloth or similar weights. It's not too critical, just beware of anything lighter like 3/4 or 1 oz ...it's too light to do you any good. I was in your neck of the woods last Wednesday night visiting family in New York City, shoulda looked you up!!! Last time I was in Bayonne was to drop off a car going to Germany.

Here is a link to Aircraft Spruce for light cloth... 3 oz should od fine but I'm sure others will have different methods as well.

http://www.aircraftspruce.com/catalog/cmpages/120.php
 
Here we go. Is it really no big deal Jamie? No man I need something complicated I have time:D it's cold anyway. Not for Russian, for airplane and fiberglass:D
 
Rick S. said:
Halogen heat lamps work wonders!!! It will make your epoxy think it's summer time!!
Click to expand...

No super heat in the shop at this time - Landlady watching the meter:D Следующий раз когда будешь в Нью Йорке дай знать Заезжай на чашечку чая



Ron: Rick is fluent in Russian and he needs some practice. He wasn't communicating since Cold War!You never know when he will need it again:)
 
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Hi Vlad,
I work in Jersey City and I'd love to get a look at your project. I'm getting ready to retrofit a Holy Cowl on my -4, except I have that freezing cold hanger problem, as well.
Give us a ring.
Bill Prouty
RV-4 Flying
(908) 310-6859
 
Excellent!

whiskeypapa said:
Hi Vlad,
I work in Jersey City and I'd love to get a look at your project. I'm getting ready to retrofit a Holy Cowl on my -4, except I have that freezing cold hanger problem, as well.
Give us a ring.
Bill Prouty
RV-4 Flying
(908) 310-6859
Click to expand...

Bill it will be my pleasure if you stop by I need extra hand to hold a wrench on under side of the fuselage. There are not many of us RV builders in NYC burbs. Only one visited my shop during 2006-2009 build period. Thank you RobinH for motivation!

Check your PM,
 
Man, I did something similiar with fitting my own cowl this weekend. I had the top aligned perfectly but when fitting the bottom, thought I had messed up, so I re-trimmed to cowl (removing 1/8" on one side tapering to 0 on the other), THEN realized I made a mistake and did indeed have it right the first time, so I had to trim off another 1/8", losing nearly another 1/4" overall in the process. There went my clearance between the prop spinner and front of the cowl.

However, I was thinking of just building up the front of the cowl. The area just behind the spinner is skewed anyway. That is, on the right side, the cowl is pretty much parallel to the spinner plate, but on the left, it is skewed towards the aft by a good quarter inch. (In other words, if straigt up is 0 degrees of angle and the left is -90 degrees and the right is +90 degrees, the gap at 0 and 90 is (or rather was) about 1/8", but at -90 degrees is 1/2 inch.) It seems easier to build up the front ring of the cowling than to rebuild the aft part, or am I missing something?
 
Jeff,

Build up the back first. People gave me good directions how to and it seems doable. Then correct behind the spinner. Check Bob Barrows method.

Mike,

Get rid of stereotypes ( Russians = vodka ), we already discovered Jamaican and Trinidadian rum which is double proof. Heats shop faster and stays warm longer:D
 
No glass here.

-28F yesterday. No glass work here for awhile but I did powerwash a crankcase outside. I could barely walk back with the frozen jeans.
Vlad, what is wrong with your printer? Your font is all whacky.
 
aerhed said:
-28F yesterday. No glass work here .......
Vlad, what is wrong with your printer? Your font is all whacky.
Click to expand...

:D Nothing wrong. Just after certain (body )temperature English alphabet turns into Cyrillic. Ask RickS he knows.
 
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