talk me out of it: using pipe in a convertible top

The real Type 12 datsun phaeton had a convertible top: 

https://www.deviantart.com/rlkitterman/art/1933-Datsun-Type-12-493077745

My look-alike car does not have a top.  I'd like to fix that.

I want to build the frame for a convertible top on a 1930's style car.  I've been messing around with conduit, but I'm now assessing alternatives, even pipe, which I believe . not good at taking repeated structural abuse without failure.  Why would I even consider pipe? ( it is probably cheaper, and it is MUCH easier to find)   Why should I probably not? strength/durability - I know that it fails easier than tube, and has a reputation for being brittle and killing folks who try to use it for cages and roll bars....but this is not a roll bar situation . 

convince me that it would be a bad idea to try using pipe for part of the frame that I will stretch fabric over.  Do you think the pressure of air pushing on fabric during driving would be enough to make the pipe crack and or bend?

The pipe is a little thinner than the tubing, but they are pretty close. I think I can make the weld joining them strong by putting a piece of metal round rod in the middle that they are both welded to instead of just making a simple butt weld

... And two pieces of pipe would give me all the length I would need to make much taller top bows than the commercial frame I've been messing with

Schedule 30 pipe is steel and will bend with a hand conduit bender. The drawbacks would be the rough surface and the fact that pipe is measured by inside diameter and will have a non standard outside diameter.  I see no reason not to use it.

I don't see cracking as an issue with steel pipe.

That being said a steel yard would have C.R.E.W. steel tubing that would have a nice smooth surface and be available in almost any O D. and wall thickness you would want for likely less money than pipe at a big box store.

Samurais have an ordinary aluminum tube holding up the rear soft top. Looks similar to what you might see in one of those lawn chairs with elastic webbing.

This on the other hand was PVC pipe in the middle and aluminum channel on the ends IIRC? Very entertaining but not exactly practical Might've been more practical but less entertaining with stronger attachments...

I built a support for a Land Rover bikini top  out of conduit years ago. For holding up a top, it did just fine. 

In reply to GameboyRMH :

Okay, I say that's definitely a vote against the PVC pieces for a top frame  

The samurai using aluminum is surprising

Trent said:

Schedule 30 pipe is steel and will bend with a hand conduit bender. The drawbacks would be the rough surface and the fact that pipe is measured by inside diameter and will have a non standard outside diameter.  I see no reason not to use it.

 

 I had not even considered bending it before.  The fact that it is possible is great news

Trent said:

The drawbacks would be the rough surface and the fact that pipe is measured by inside diameter and will have a non standard outside diameter.  I see no reason not to use it.

I don't see cracking as an issue with steel pipe.

 

Again, this is very encouraging.  

Trent said:

That being said a steel yard would have C.R.E.W. steel tubing that would have a nice smooth surface and be available in almost any O D. and wall thickness you would want for likely less money than pipe at a big box store.

I think you may have a better steel yard than us.  Our local one is Mine & Mill.  I was recently grousing in my build thread about them going months without 3/16 flat rod - in ANY width - for several months.  Their situation for round tubing is just as dire

Keith Tanner said:

I built a support for a Land Rover bikini top  out of conduit years ago. For holding up a top, it did just fine. 

this is makes me a happy camper.  I was starting to loose faith in my conduit plans.  Consider the faith restored.  

What diameter conduit did you use.

In reply to JoeyM :

It was in 2001 or 2002, so I don't remember all the specs :) I suspect it was 1", the OD was determined by an existing hole in the body that I used to mount it.

I've still got the top and frame, I'll see if I can find it and measure. 

I would probably buy and modify one of these..  it includes too bows that I'm sure can be modified with some bending, sleeving, or welding.  

$120 Bimini Top

The tubing for that Bimini top is available from upholstery wholesalers I know because I've delivered it. There are upholsters all over the place and some may well get supplies for you.

Edit: I see you're a biology teacher could a Home Ec or Art teacher help out in acquiring material?

In reply to JoeyM :

According to Google you have several options including at least one Metal Supermarket chain store less than 9 miles from Mine and Mill in Lakeland

nocones said:

I would probably buy and modify one of these..  it includes too bows that I'm sure can be modified with some bending, sleeving, or welding.  

$120 Bimini Top

 

Hmmm....This is a really good idea, and cheaper than the roadster top I boght to modify.  I am wishing I had asked this question earlier

Trent said:

In reply to JoeyM :

According to Google you have several options including at least one Metal Supermarket chain store less than 9 miles from Mine and Mill in Lakeland

!!!Thank you!!!  I literally thought M&M was the only place to go in polk county.  I will be calling Metal Supermarkets tomorrow to see what they have in stock.  This could be really important, even more so for flat rod than tubing

Rons said:

The tubing for that Bimini top is available from upholstery wholesalers I know because I've delivered it. There are upholsters all over the place and some may well get supplies for you.

Edit: I see you're a biology teacher could a Home Ec or Art teacher help out in acquiring material?

I don't have any contacts with them, but I will try reaching out.  That could be really useful, especially if they can also get sunbrella fabric

In reply to JoeyM :

Be aware that a Bimini top on a boat is only rated for about 40 mph. Not a problem on my boat which only goes 38.