TR4/4A Early TR4 seat pans

[RJCOX]

I'm most likely going to rebuild a rusty seat pan. My thoughts are towards fabricating a repair panel and welding it in.

Any thoughts on what gauge of metal and how to form the center recess?

 

[DavidApp]

I bought my TR3 seat pans from a company in Australia. They do a really good job. Looks like they do not have the TR4 seats but they may not be listed yet.

David

http://www.kas-kilmartin.com.au

 

[RJCOX]

Thought about some TR3 pans, but the differences in structure made me pause.

Did you use the TR4 rails or TR3 rails?

 

[TomMull]

You can hammer form it over a wooden buck. It's a bit drastic and brutal but it works. I use an air hammer with both hard and soft anvils but a decent bunch of hammers will do also. You'll need to be a bit of a wood worker to make the buck (wooden form). There are lots of videos on hammer forming. It will probably be easier to make the recess separately and weld it onto the pan but you can do it in one piece. It's just harder to get it all flat.
I think the original was 18 ga and anything thicker will be extremely difficult to work.
If you're interested I'm quite sure I have a good TR4 pan. PM if so.
Tom

 

[2long]

I am pretty sure the early TR4s used seats like the late TR3.

Dan

 

[Frank Canale]

Like Tom said 18 gauge is about as heavy as you want to try and hammer form. I am almost done with the boot floor out of 18 gauge. Lots of hammering over wooden bucks along with shrinking and stretching to keep the stress out of the panel. Frank

 

[RJCOX]

@2long
Pans are a bit different with a large square depression in the center almost an inch deep. Unknown what that accomplishes, but they're different enough to make me want to try and fix it.
@Frank
Should I warm the metal some (propane) before the hammering the deep part?

 

[TomMull]

Heating it will add another stretching and shrinking variable that you don't want and will harden the metal which you also don't want. Tom

 

[Madflyer]

If it is a small repair ribs my not be needed. finding a old one cut and fill as need easier or a flat 18 with cross support added on under side. Is it front or back of pan?? TIG or Stick weld. Sheet metal shops may have stamps to match your cut out say 12 x 12 done deal. Or new panel bigger job. Madflyer

 

[RJCOX]

Swiss cheese on the bottom of the depression, rips and mangled on two mounts. You can't even tell where the mount ribbing was. I thought I might pattern the remaining side since it's symmetrical.

The metal had thinned out so much that some weight bent the metal. Besides effort, the cost of fabbing a repair panel is nada, so no great loss if I fail.

Granted, finding an awesome set for free would make my decade, but I am realistic, so until then...

 

[Frank Canale]

This is a brief description on how I form my panels. I use 1/4" MDF to make the forms (bucks). I use double stick to hold the form in place. Then I flip the panel over.
I use the same !/4" MDF doubled up to clamp on the top side so the metal is sandwiched between the wood. I use spacers to hold the chasing tool away from the buck so that the forming matches the original.
This shows the metal needing to be shrunk on the ends. Once you start forming down the ends the stretched metal has no where to go and so needs to be shrunk. Basic just hammer it down flat. To hammer form 18 gauge I use a blunted chisel with a 3 LB hammer. It takes a lot of force to form 18 Gauge.
This shows the panel flat on the table. The forming takes little time but getting the panel flat without any stress in it takes a lot of time. I am certainly not a professional panel beater, I am still a little heavy with my hammer blows. It takes me a little while to planish out the hammer marks. Some come out and some are too deep to get out so the primer will fix most of that. Frank

 

[RJCOX]

So, MDF is hard enough? Great, plenty of that around. Got blunt chisels and the various hammers.

I actually made a rear closing panel with an anvil, 18g, and an 11oz hammer. Came out ok, but didn't use a buck. I've got access to band saws and the like so forming bucks should be cake.

I actually considered making bucks of negative and positive and the use a vice to press it in but the size and location in the panel might preclude that.

 

[Frank Canale]

MDF works fine. Easy to cut and shape. Do test forming on small piece to get the thickness you need to match what you are reproducing. Your buck will need to be a little thicker than what the original part. The boot floor ribs are 3/16” tall. I used 1/4” MDF and worked great. Ended up right at 3/16” tall. It is not as easy as it looks on the videos. My first boot floor got scrapped, but I learned how to do it so not all is lost. Frank

 

[Frank Canale]

I left out the part where I lay out where I am hammer forming on both sides of the panel so I know where to stick the buck and when you flip it over you know where to clamp the hold down piece.

 

[RJCOX]

Just got an original seat pan for the folding seat from Tom. It's in great shape (for being almost 60 years old) and quite useable. I definitely can get a good pattern off of it to make a repair panel for the non-folding seat. Now I just need to find the time.

Ron

 

[DavidApp]

Just for fun I did a quick and dirty test piece following your plans. Using 1/4" Masonite as a buck. Need to refine my punch.

David

 

[RJCOX]

That's really pretty good.
I've got a cold chisel with a blunter edge, but I'd take that result in a heartbeat.

 

[Frank Canale]

Great job, David. A little planishing and that will be a great panel. When I started out my boot floor the first one looked a lot like that but mine is all curled up and warped. The magic is controlling the panel so it stays flat. I think it is great for others to give it a try. Sheetmetal is pretty inexpensive and sometimes you luck out and a sheetmetal company will give you a small drop so there is not much to loose but a little time. Frank

 

[RJCOX]

My closest Sheetmetal Depot is an hour away, but worth the drive. Their cutting charge is outrageous so I try to get their smaller leftovers, but I haven't needed anything bigger than 24x24 yet.

 

[TomMull]

My closest Sheetmetal Depot is an hour away, but worth the drive. Their cutting charge is outrageous so I try to get their smaller leftovers, but I haven't needed anything bigger than 24x24 yet.

Ron, When you start making panels, you'll use up a lot of steel. I buy full sheets. Last I knew they were about $45 for 18 ga. I think they are about twice that since COVID. I then cut them into 4x4, 2x4 and 2x2 pieces for easy storage and access. I use an electric hand shear, which I find indispensable. 4 x 8 will just fit in my van but I find it easier to manage them in my trailer.
Tom