Finally Got Started
Finally Got Started (21/11/2006)
First order of business for the Avon (according to all the build diaries) is to do the majority of the panelling, starting with the bottom floor pan panels. These are the largest panels on the car, and require the car to rotated on its tressel, most tend to lay it flat, but I have found it easier to work on the car whilst it is sitting on its side.
The panels supplied by Tiger are as promised (by them) very generous. They have been professionally cut however with acres of material to spare. I have never done any serious metal work before, so I decided to trim the panels in the old fashioned way, with aircraft shears. I bought a set of three, left hand cut, right hand cut and straight cut shears.
My test cuts on some spare material, were encouraging, I found I could be quite accurate with them, but also trim closer and closer to my mark without any wild jagged edges.
The basic plan calls for attaching the panel to the chassis by means of clamps to line it up. I recommend using quick release clamps or sprung loaded clamps. G clamps are ok, but a pain when you are winding them in and out whilst trying to balance a panel, they are ok once the panel is actually in place.
Once the panel is in place, I simply drew around it with a felt marker, took the panel off, clamped it to a work bench and started to cut with the shears. I initially cut quite wide of the line, bit as confidence grew got closer to the line. O always left an extra millimeter or so to allow for filing and tidying of the edge.
Rippling
I soon found the problem with using aircraft shears is the slight rippling effect that shows on the metal each time the blades close. The shears also left a slight serated mark in the metal. I also found it difficult over long panels to get a truly straight finish.
Doing a bit of research I found 4 other ways of cutting aluminium.
From what i've read you need to have an many teeth (teeth per inch or TPI) to cut metal as possible. 22 TPI minimum. However others have had experience of overheating of the blade and the metal with too many teeth. So I settled for a blade with 25 TPI. It not an exact science this, as nowhere on the packet does it say how many TPI. So I had to divide the length of the blade by the width of the teeth.
Disaster
I did not get on well at all with the jigsaw. I found that whilst it gave a neat unrippled cut the tendency was for the teeth to snag and lift the aluminium causing very undesirable bending. Fortunately I was able to bash these back into shape with a hammer without leaving any lasting mark. I decided to switch back to the aircraft shears. I found a better technique was to go as close to the line as I dare in one cut, rather than doing what I had done before, snipping bits off here and there. I left a little extra room again so that any rippling could be filed out with a large metal file. I also found it important to keep oiling the blades with WD40 to ensure a smooth cut and an easy blade action.
Filing
I managed to clean up the first panel with a coarse file. I used a technique of clamping the panel to the car, releasing the area I wanted to file, then covering the chassis with masking tape to prevent damage, filing the panel and then constantly checking against the chassis rail.
One the panel was finished I used a small fine craft file to carefully tidy up the edges.
De-Burring
I found a great tool on ScrewFix, for removing the sharp edges from the panels. The deburring tool, looks like a pen, it has a curved blade, the idea is you run the blade along the sharp edge and it trims away the metal and leaves a curved surface. It works quite well and quite quickly.
Drilling the Panels
With my completed panel clamped to the chassis, I used a steel rule to mark out the rivet spaces. Tiger recommends spacing the rivets approximately 75mm or 3 inches apart. However one thing it does not tell you, is how close to the edge of the to drill the hole for the rivet. Eventually after doing some estimation based on other build diaries I decided on 10mm from the edge of the panel. I felt this was far enough out to prevent the panel slipping out from under the rivet, but close enough to the edge to prevent the panel from lifting from the chassis.
I was advised to use 3.5mm metal drill bits for the rivets. This indeed made life much easier as it gave me a little leeway with the position of the panels and reduced the chances of getting a hole that did not fit.
The Avon floor pans require drilling all the way around the outside of the panel. Across the middle former, down the two longitudinal formers and although not required I also rivetting across the foot well strip at the front. Please note due to the thickness of teh steel on the other side 8mm rivets were required here.
With all the hole drilled, I removed the panel and cleaned the chassis surface and the panel surfaces with a deagreasant (I used brake cleaner).
Sealing the Panels
The sealant I used was black automotive silicon. This has a polyurethane base and is mildly adhesive. It comes in white, black or clear. I picked black as my chassis is powder coated in black, so any overrun would not be noticeable.
All the books or instructions I have read comment on using a 'thin' bead of sealant applied to to chassis rail. No-one could exactly quantify how much that meant. I cut the nozzle of the sealant gun to give an approximate 3mm wide bead of sealant. On a 25mm wide chassis rail I thought this was ample. If you are getting lots of sealant squeezing out of the panels then you are using too much.
Sealing the panels before rivetting helps in three ways.
Rivetting
Its estimated that over 1000 rivets are required to correctly panel a Tiger Avon. There was no way I was using a hand rivetter to do this, so I purchased an air rivetter to take the pain out of rivetting the panels.
My basic method consisted of putting most of the rivets into position before rivetting them. This would help me ensure the panel did not shift, and all rivets correctly filled their holes.
I then rivetting each of the 4 corners to lock the panel in place, before rivetting the rest.
(26/11/2006)
I have completed the floor pans and the driver footwell plate so far.
First order of business for the Avon (according to all the build diaries) is to do the majority of the panelling, starting with the bottom floor pan panels. These are the largest panels on the car, and require the car to rotated on its tressel, most tend to lay it flat, but I have found it easier to work on the car whilst it is sitting on its side.
The panels supplied by Tiger are as promised (by them) very generous. They have been professionally cut however with acres of material to spare. I have never done any serious metal work before, so I decided to trim the panels in the old fashioned way, with aircraft shears. I bought a set of three, left hand cut, right hand cut and straight cut shears.
My test cuts on some spare material, were encouraging, I found I could be quite accurate with them, but also trim closer and closer to my mark without any wild jagged edges.
The basic plan calls for attaching the panel to the chassis by means of clamps to line it up. I recommend using quick release clamps or sprung loaded clamps. G clamps are ok, but a pain when you are winding them in and out whilst trying to balance a panel, they are ok once the panel is actually in place.
Once the panel is in place, I simply drew around it with a felt marker, took the panel off, clamped it to a work bench and started to cut with the shears. I initially cut quite wide of the line, bit as confidence grew got closer to the line. O always left an extra millimeter or so to allow for filing and tidying of the edge.
Rippling
I soon found the problem with using aircraft shears is the slight rippling effect that shows on the metal each time the blades close. The shears also left a slight serated mark in the metal. I also found it difficult over long panels to get a truly straight finish.
Doing a bit of research I found 4 other ways of cutting aluminium.
- Jigsaw with fine metal blades
- Band or scroll saw with fine blade
- Nibbler or Air shears
- Scoring and breaking the metal
From what i've read you need to have an many teeth (teeth per inch or TPI) to cut metal as possible. 22 TPI minimum. However others have had experience of overheating of the blade and the metal with too many teeth. So I settled for a blade with 25 TPI. It not an exact science this, as nowhere on the packet does it say how many TPI. So I had to divide the length of the blade by the width of the teeth.
Disaster
I did not get on well at all with the jigsaw. I found that whilst it gave a neat unrippled cut the tendency was for the teeth to snag and lift the aluminium causing very undesirable bending. Fortunately I was able to bash these back into shape with a hammer without leaving any lasting mark. I decided to switch back to the aircraft shears. I found a better technique was to go as close to the line as I dare in one cut, rather than doing what I had done before, snipping bits off here and there. I left a little extra room again so that any rippling could be filed out with a large metal file. I also found it important to keep oiling the blades with WD40 to ensure a smooth cut and an easy blade action.
Filing
I managed to clean up the first panel with a coarse file. I used a technique of clamping the panel to the car, releasing the area I wanted to file, then covering the chassis with masking tape to prevent damage, filing the panel and then constantly checking against the chassis rail.
One the panel was finished I used a small fine craft file to carefully tidy up the edges.
De-Burring
I found a great tool on ScrewFix, for removing the sharp edges from the panels. The deburring tool, looks like a pen, it has a curved blade, the idea is you run the blade along the sharp edge and it trims away the metal and leaves a curved surface. It works quite well and quite quickly.
Drilling the Panels
With my completed panel clamped to the chassis, I used a steel rule to mark out the rivet spaces. Tiger recommends spacing the rivets approximately 75mm or 3 inches apart. However one thing it does not tell you, is how close to the edge of the to drill the hole for the rivet. Eventually after doing some estimation based on other build diaries I decided on 10mm from the edge of the panel. I felt this was far enough out to prevent the panel slipping out from under the rivet, but close enough to the edge to prevent the panel from lifting from the chassis.
I was advised to use 3.5mm metal drill bits for the rivets. This indeed made life much easier as it gave me a little leeway with the position of the panels and reduced the chances of getting a hole that did not fit.
The Avon floor pans require drilling all the way around the outside of the panel. Across the middle former, down the two longitudinal formers and although not required I also rivetting across the foot well strip at the front. Please note due to the thickness of teh steel on the other side 8mm rivets were required here.
With all the hole drilled, I removed the panel and cleaned the chassis surface and the panel surfaces with a deagreasant (I used brake cleaner).
Sealing the Panels
The sealant I used was black automotive silicon. This has a polyurethane base and is mildly adhesive. It comes in white, black or clear. I picked black as my chassis is powder coated in black, so any overrun would not be noticeable.
All the books or instructions I have read comment on using a 'thin' bead of sealant applied to to chassis rail. No-one could exactly quantify how much that meant. I cut the nozzle of the sealant gun to give an approximate 3mm wide bead of sealant. On a 25mm wide chassis rail I thought this was ample. If you are getting lots of sealant squeezing out of the panels then you are using too much.
Sealing the panels before rivetting helps in three ways.
- Sticks the panel to the chassis
- Acts as a shock absorber so the panel doesn't rattle when the car is in motion
- Helps to seal the aluminium panel from the steel helping prevent corrosion. Aluminium has quite a high corrision factor.
Rivetting
Its estimated that over 1000 rivets are required to correctly panel a Tiger Avon. There was no way I was using a hand rivetter to do this, so I purchased an air rivetter to take the pain out of rivetting the panels.
My basic method consisted of putting most of the rivets into position before rivetting them. This would help me ensure the panel did not shift, and all rivets correctly filled their holes.
I then rivetting each of the 4 corners to lock the panel in place, before rivetting the rest.
(26/11/2006)
I have completed the floor pans and the driver footwell plate so far.
First panel held in place ready for rivetting
Panel 1 completed
Hole cut for the steering colum shaft to go through
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