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Lockdown out of the box thinking.


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Hi Folks,

during this damned lockdown I have been doing many and varied jobs on the TR4A.

At the mo' I am doing repairs to the back and front of the offside sill.

It is the areas under the wings that are an issue.

At the back, the bottom of the 'B' post and and the inner sill floor flange were pretty well corroded. These have been cut out and replaced with 1.2mm Zintec. ( I had some, I used it)

I didn;t bend a flange on the floor repair section - this is butt welded to the bottom of the front of the wheel arch. The flange that is spot/plug welded tends to be a magnet for corrosion.

The back of the outer sill was rusty as was the bottom of the closing plate.

Easy enough to cut out the rotten metal and easy enough to butt weld where needed.

However the closing plate and the bottom edge of the sill is  a structure of two pieces help by either spot or plug welds.

The present rusty structure has lasted 20+years so there is no panic about the new metal disappearing in front of my eyes.

I was reading a post the other day talking about adhesive bonding the metal together.

The idea of 'No Nails' holding the sill together does have a certain appeal but maybe for another time.

Being a retired aerospace engineer I have come across many fancy fasteners and I, by chance, have a stash of some exotic one.  I haven;t a part number at the mo'.

The back end of the sill is a very dirty environment and so protection needs to be top notch.

So I am considering to use these fasteners and some Monel pop rivets. They will be hidden from view.

My concern is that when you weld (even spot weld) the protect surface is broken down and can't be re-protected because it is all welded up.

Perhaps I'm going stir crazy and finding problems that are not there. :o

Roger

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I use Bondarust for the main inside body of any repairs (wont be affected by the heat just turns brown) and then weldtru primer on the edges where its going to be spot welded or even Mig welded. Seam sealed over the edge and waxoyled inside, that will outlast all of us. Pop rivets in that location would actually be an MOT fail as its too close to body mount and seat belt mounting.

Stuart.

 

Marks TR5 260.jpg

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Hi Roger,

you have been in aerospace business very long, it opens new possibilities/ options:)
 I would weld it, that’s what I did. A combination of some plug welds and some butt welding. And filled the gaps with wax-oil.

Cheers,

Waldi

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There's me being bl**dy clever and there's you all being very sensible.   How can I not follow your examples.

Ok, I'll weld the sill bottom flange and end plate curved flange.

 

I'm sure somebody came on here two or three years ago and their recently bought TR had Hi-Lok aircraft fasteners holding everything together.

It looked like a hedgehog with Alopecia but as strong as a brick built loo.

 

I wonder where I can use my new tube of 'No Nails'

 

Roger

 

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10 minutes ago, RogerH said:

There's me being bl**dy clever and there's you all being very sensible.   How can I not follow your examples.

Ok, I'll weld the sill bottom flange and end plate curved flange.

 

I'm sure somebody came on here two or three years ago and their recently bought TR had Hi-Lok aircraft fasteners holding everything together.

It looked like a hedgehog with Alopecia but as strong as a brick built loo.

 

I wonder where I can use my new tube of 'No Nails'

 

Roger

 

That was Tony Millwards TR6 The whole shell was bolted together.

Stuart.

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13 minutes ago, stuart said:

That was Tony Millwards TR6 The whole shell was bolted together.

Stuart.

and as I recall we never got to the bottom of how that shell came into existence.

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Hi Roger,

Wish I had your aviation repair knowledge, but I’m not that clever, so stick to welding:)
No, not stick-welding.

Cheers,
Waldi

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1 minute ago, Waldi said:

Hi Roger,

Wish I had your aviation repair knowledge, but I’m not that clever, so stick to welding:)
No, not stick-welding.

Cheers,
Waldi

My work friend Sid used to do jobs for one and all. On one he was asked to weld the front forks back onto a motor bike.

This was done and the chap came along to pick them up. Before he got to the door on the way out the front forks dropped onto the floor.

Sid had created Teflon welding - or non-stick to his friends.

 

Roger

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507630183_AlloyTr4.thumb.jpg.82dcd1521f5aa8bc101667b06903910f.jpgBack in the mid 80s Pete Cox had a full race Alloy TR4 which was pop riveted together...totally. Bulkheads, floors, inner wings, outer wings,  Alloy bonnet, doors and boot lid had been lovingly crafted and then riveted together at 1" intervals and then the outside polished, looked lovely and was extremely fast !. He never had the misfortune to put the shells strength to the ultimate test, but my guess was it would have been good.

Mick Richards

Edited by Motorsport Mickey
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Having started this flight of fancy I must add that there are some excellent fasteners out there.

Ignoring simple nuts and bolts there are pop rivets. But not all pop rivets are equal.  There are two basic types - 'break head' and 'break stem'

The break head type leave the pop rivet hollow. The break stem leaves part of the mandrel inside the rivet and gives it a little more support.

There are then rivets (a bit like pop rivets) that have beautiful mandrels that when pulled through the rivet it forms a virtually solid rivet. These are of a structural quality.

Then there are things that are a cross between rivets and bolts that squeeze a collar onto the fastener and these seriously clamp the structure together - the ones on Tony Millwards TR6 were of this nature.  There are dozens of permutations of single side and double sided fasteners ( blind holes and accessible holes)

Wouldn't it be fun to glue one together - no holes, no fasteners, no drills. So easy.

 

Roger

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50 minutes ago, Motorsport Mickey said:

507630183_AlloyTr4.thumb.jpg.82dcd1521f5aa8bc101667b06903910f.jpgBack in the mid 80s Pete Cox had a full race Alloy TR4 which was pop riveted together...totally. Bulkheads, floors, inner wings, outer wings,  Alloy bonnet, doors and boot lid had been lovingly crafted and then riveted together at 1" intervals and then the outside polished, looked lovely and was extremely fast !. He never had the misfortune to put the shells strength to the ultimate test, but my guess was it would have been good.

Mick Richards

That quick motor was in his workshop, tucked away in the corner last time I was there, 4-5 years ago.

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Hi Folks,

I finished the repair to the rear of the offside sill and the associated floor/wheel arch section.

I needed to tidy up the rear wing where it attached to the sill as that was a little bit rusty. As I worked on it it became obvious that it was more than a little bit rusty; but not terminal.

So I made a new section to replace the bottom forward corner (where it attaches to the sill). This fitted quite well. However on the trial fit I my attention was brought to the rather interesting door gap. 11mm at the top and 3mm at the bottom. If you see these dimensions on a steel ruler they do not look too different, but when you put it on a white car -wow.

The top could not go forward any more than it was and the only way I could see to move the bottom rearwards was to cut :o:o into the wing.

After a bit of head scratching this was the only option I could think of. So a delicate incision was made with the angle grinder - it went at 45 degrees from the wheel arch up to the 10mm below and rearwards of the swage line. This allowed the bottom of the wing to pull back and sit in the newly formed sill step.

This now gave me a cheese wedge of 11mm top and 7mm bottom.  Today I shall do something:blink: to move the top forward and align with the bottom.

My first thoughts are to remove the skin flange at the front where it folds back onto the 'B' post frame, tack weld the skin in place then attach a new flange with a lip that can be filled.

My lead loading is not good so I will stay with my strengths and use a decent filler.

I think I may have to re=spray the wing after all this.

I wonder what will happen.

Roger

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On 4/30/2020 at 7:30 PM, RogerH said:

Wouldn't it be fun to glue one together - no holes, no fasteners, no drills. So easy.

Fokker aircraft used a lot of aluminium to aluminium bonding in their aircraft structures. They perfected the technique to produce very light weight and strong structures with no holes or fasteners thereby increasing fatigue life, reducing cost and weight. They developed very large autoclaves to make the bond.

Mick

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Posted (edited)
10 hours ago, Mick Forey said:

Fokker aircraft used a lot of aluminium to aluminium bonding in their aircraft structures. They perfected the technique to produce very light weight and strong structures with no holes or fasteners thereby increasing fatigue life, reducing cost and weight. They developed very large autoclaves to make the bond.

Mick

Quite so.  It took a few years for the others to catch up but they have, in leaps and bounds.

At the end of the 50's start of the 60 DeHaviland,, Hawkers and all the other wonderful British aircraft manufacturers were into new aircraft design so very good stuff was happening.

The DH121 TRident had its wing stringers and frames adhesively bonded to the skins. With all that flexing etc you would have expected something to give in its thirty year life, but no; they stayed put.  Things happened around the stringers but they stayed stuck. 

Now, however, there is no real need to glue metal together as Carbon Fibre has shown the way ahead.

 

Roger

Edited by RogerH
typo
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Had a job once building harmonic exhaust mounts. All components were electro plated individually. against corrosion then assembled.  The  two brackets were attached to each other with non corroding solid Monel rivets.

I needed a 4x air hammer to get the rivets to close, I guess the original makers had an hydraulic squeezer.

Brackets might rust in service but the rivets did not.

Peter W

image.jpeg

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On 5/3/2020 at 9:50 AM, RogerH said:

Hi Folks,

I finished the repair to the rear of the offside sill and the associated floor/wheel arch section.

I needed to tidy up the rear wing where it attached to the sill as that was a little bit rusty. As I worked on it it became obvious that it was more than a little bit rusty; but not terminal.

So I made a new section to replace the bottom forward corner (where it attaches to the sill). This fitted quite well. However on the trial fit I my attention was brought to the rather interesting door gap. 11mm at the top and 3mm at the bottom. If you see these dimensions on a steel ruler they do not look too different, but when you put it on a white car -wow.

The top could not go forward any more than it was and the only way I could see to move the bottom rearwards was to cut :o:o into the wing.

After a bit of head scratching this was the only option I could think of. So a delicate incision was made with the angle grinder - it went at 45 degrees from the wheel arch up to the 10mm below and rearwards of the swage line. This allowed the bottom of the wing to pull back and sit in the newly formed sill step.

This now gave me a cheese wedge of 11mm top and 7mm bottom.  Today I shall do something:blink: to move the top forward and align with the bottom.

My first thoughts are to remove the skin flange at the front where it folds back onto the 'B' post frame, tack weld the skin in place then attach a new flange with a lip that can be filled.

My lead loading is not good so I will stay with my strengths and use a decent filler.

I think I may have to re=spray the wing after all this.

I wonder what will happen.

Roger

Sorry Roger but thats a lash-up you could have leaded the forward edge of the wing to quite easily equal up the door gap without any of that faffing about. Never ever fill the edge of the panel as it wont last five minutes.If your that desperate you could have just boxed it up and sent it down here and I would have leaded it and you could have then filed it to suit.

Stuart.

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Hi Stuart,

many thanks for the offer but I'm in full flight now  :wacko:  I did consider lead loading but then had a vision of the mess created.

Seriously. I have made an 'L' shaped  length  (15mm x 2mm x 500mm) that runs down the length of the door with the small leg sticking out.

This will be welded to the existing door stiffener and should give a good support for the small amount of filler required.  :mellow:

 

Roger

 

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On 5/3/2020 at 9:50 AM, RogerH said:

Hi Folks,

I finished the repair to the rear of the offside sill and the associated floor/wheel arch section.

I needed to tidy up the rear wing where it attached to the sill as that was a little bit rusty. As I worked on it it became obvious that it was more than a little bit rusty; but not terminal.

So I made a new section to replace the bottom forward corner (where it attaches to the sill). This fitted quite well. However on the trial fit I my attention was brought to the rather interesting door gap. 11mm at the top and 3mm at the bottom. If you see these dimensions on a steel ruler they do not look too different, but when you put it on a white car -wow.

The top could not go forward any more than it was and the only way I could see to move the bottom rearwards was to cut :o:o into the wing.

After a bit of head scratching this was the only option I could think of. So a delicate incision was made with the angle grinder - it went at 45 degrees from the wheel arch up to the 10mm below and rearwards of the swage line. This allowed the bottom of the wing to pull back and sit in the newly formed sill step.

This now gave me a cheese wedge of 11mm top and 7mm bottom.  Today I shall do something:blink: to move the top forward and align with the bottom.

My first thoughts are to remove the skin flange at the front where it folds back onto the 'B' post frame, tack weld the skin in place then attach a new flange with a lip that can be filled.

My lead loading is not good so I will stay with my strengths and use a decent filler.

I think I may have to re=spray the wing after all this.

I wonder what will happen.

Roger

Roger 

The gap is not good I would look elsewhere to find the cause sorry 

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Just watched How to Build British: Aston Martin. Most of the DBS is glued together. Probably not your ordinary Bostick though.

Alan.

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On 5/1/2020 at 3:28 AM, RogerH said:

My work friend Sid used to do jobs for one and all. On one he was asked to weld the front forks back onto a motor bike.

This was done and the chap came along to pick them up. Before he got to the door on the way out the front forks dropped onto the floor.

Sid had created Teflon welding - or non-stick to his friends.

 

Roger

One of our local comedians claims to have invented non-stick velcro.

His other invention was the full scale road map. He said it was a delight to use, but a b***er to fold.

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Just now, Rob Salisbury said:

I can't seem to find my tin of universal solvent anywhere!!

:D:D:lol::lol:

 

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2 hours ago, Rob Salisbury said:

I can't seem to find my tin of universal solvent anywhere!!

 

probably in the pocket of my camouflage trousers

 

Roger

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