# Stress Cracking of Aluminium Panels



## peedee (May 10, 2005)

Has anyone experienced cracking of the outer skin aluminium panels, if so how has it been repaired please.

peedee


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## 88905 (May 10, 2005)

Aluminium can be repaired but on a M/H I would say only with difficulty due to what may be behind it.
Usual method would be by rivetting a butt strap across the crack to spread the strains but that requires access from the rear. Welding by mig/tig arc could be used but that would mean removing any flammable matearials behind the job and any it would be more visible than a rivet.
The best way may be to stop the crack by drilling a 1/16 hole at the end of it and putting up with it providing it is not unsightly.
If you are really worried you should try a local engineering firm with experience in Alli as I would doubt if the average body repair shop would have the experience to solve the problem successfully.
One last alternative might be to try stop drilling and aralditing a butt strap across the crack, filling in the crack with araldite also.

This problem is bane of life of "riggers" in the aircraft industry as I doubt there is an aeroplane flying that does not have a multitude of cracks somewhere in ut's structure.

Good Luck

Nobby


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## Anonymous (Nov 10, 2000)

Gosh Nobby, I have not heard the word Rigger (for Airframe fitter) since 1974. Takes me back. I agree that the crack will need stop drilling to prevent it spreading but not sure about the best repair method. Be interesting to hear the views of others.


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## 89057 (May 12, 2005)

Arn't airframes superglued these days?

You could drill either end of crack & superglue a plate over affected area. unless you are planning on going supersonic peedee, then you'll need to hinge the nose too.

Mark


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## 91698 (May 1, 2005)

Without causing panic among the jet-set out there,Nobby is probably right but to an extent.
Many Aircraft are indeed flying with hairline cracks on certain panels,they are of course caused by stress etc.
The procedure for repairing them is simple,a check hole is bored at each end of the crack,this prevents any creep caused by further stress,if the crack is long,a centre groove is cut out so a backing plate can be installed and alloy-welded into place.if the split is small the crack is simply-welded.
A simple touch up with solderlene can cosmetically cover it up.

brez


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## 88966 (May 11, 2005)

Hi,
I owned a Hymer B644 for 3 years before I noticed that it had been 'mended' on one side!
Hymers have horizontal coloured strips on the sides and on one side it had one more than on the other.
I subsequently found out that it had been gouged along the side and repaired by putting this 'patch' over it. It was so big it was not obvious!
I would think that a 'patch' big enough to be a feature stuck on with Sikaflex would be a possibility.
After all who compares one side with the other?
BillD


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## spykal (May 9, 2005)

Hi

Stop the crack with small drill hole at the ends of the crack then cover with a, shaped to suit, aluminium cover plate, glued with araldite, held in place with pop rivets. Depending on where it is situated the shape can be made to look as though it was always meant to be there!

Mike


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## 88726 (May 9, 2005)

hi guys
im with mike on this one cut a strip or ally , cover the back with quality sealant and rivet into place , you can get some decent looking rivets !
then depending on size maybe cover with an air vent grille and nobody will know it aint a vent then investigate the cause unless you already know, you may get some sheet ally from motorhome builders if its a ripple finnish .
hope it helps
cheers
kenny+stella


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## gaspode (May 9, 2005)

Hi

I've had similar problems on an aluminium bodied vintage car and found that the only way was to drill the ends, get at the rear of the panel, rough the surface up and then make up a patch comprising several layers of fibreglass matting which are plastered on using resin. The problem with this of course is that on aluminium as thin as that used for m'home bodies you will create a more rigid area and transfer the stresses elsewhere!

Gaspode


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## 88905 (May 10, 2005)

Only one comment about airframes being a mess of cracks. I am surprised!!!!
BUT I did not mean to cause alarm anyway...just made a point to say that cracks "aint all they are cracked up to be".

nobby
(RAF 57-85)


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## peedee (May 10, 2005)

Thanks for all the suggestions. Seems as though it is not a problem encountered too often on a motorhome from the responses so far. Mind you I judge that on average only about 10 percent of members bother to read posts, probably even less respond but early days on this one yet. 

I have been given the phone number of a fixer so will contact him and see what he says. 

Thanks 
peedee


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## 92622 (May 1, 2005)

nobby said:


> Only one comment about airframes being a mess of cracks. I am surprised!!!!
> BUT I did not mean to cause alarm anyway...just made a point to say that cracks "aint all they are cracked up to be".
> 
> nobby
> (RAF 57-85)


I understand our 24 sqd V.I.P. Yorks based at Topcliffe, failed their civil aviaton certificates after Laker bought them. many of the rivet heads had been polished off !!!...... and plenty of drilled cracks on the wafer thin alli

Won't mention the state of our Yorks after the Berlin airlift.

Geoff_2
( RAF Eng Mech )


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## 88905 (May 10, 2005)

Ah Yes!!!...Memories.

Put the birds to bed then wash and WadPol them till they shined.
Someone got the message eventually though and painted with drab paint so no need to polish after that.

Remember, at Leconfield, One year that Stan Stennet (comedian) was appearing at Bridlington so he flew in every Monday And Out on Sunday to go home for the day. Anyway I and A N Other used to get the job of polishing his Beech Bonanza during the week for which we gor a fiver each (not bad for early 60's I suppose!!!.)

Nobby


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## 91929 (May 1, 2005)

No nobby NOT airframes aluminium panels
If the airframe was to show cracks the kite would be grounded

Thats why the vintage aircraft are stripped down every year and thouroughly tested

The Vulcan had some problem like that.
Our son goes across country for an annual MOT with his at very large cost


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## peedee (May 10, 2005)

PamNPete said:


> The Vulcan had some problem like that.
> Our son goes across country for an annual MOT with his at very large cost


Cor.... I would think it is very expensive running a Vulcan, what's it do to the gallon?

If it cracking happens on aircraft aluminium panels why is it not happening to more motorhomes?

peedee


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## spykal (May 9, 2005)

peedee said:


> PamNPete said:
> 
> 
> > Snipped:
> ...


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## peedee (May 10, 2005)

> Could be because motorhomes don't have too many hard landings and the wings don't flex during flight


Oh I don't know Mike, if our roads get much worse there are going to be far more opportunities for short take offs and landings.

peedee


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## 92622 (May 1, 2005)

nobby said:


> Ah Yes!!!...Memories.
> 
> Put the birds to bed then wash and WadPol them till they shined.
> Someone got the message eventually though and painted with drab paint so no need to polish after that.
> ...


Hey Ho !!......................

' Nostalgia ain't wot it used to be '.........

geoff_2


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