Do inner sill heater tubes survive the Envirostrip process?

[AndrewSlater]

I was hoping to send my car to Envirostrip prior to my bodyshop starting welding repairs and painting.

I was hoping not to disturb my inner ( or outer ) sills before the process so I asked Envirostrip if there process would damage the heater tubes in the sills.
They said "Its best to remove the heater tubes by cutting them out from the inner sill"

Does anyone know if they survive the process or have any experience of this?

I ask as my bodyshop guy felt that my inner sills were fine and I didn't need to disturb them.

I don't really want to go down the Envirostrip route if it is going to add too many extra complications and cost.

Anyone got any thoughts?

Thanks
Andrew

[Nick Moss]

If you are going for the full Envirostrip then the silencer tubes will be toast (literally). Cut the inner inner sill open to remove them

[AndrewSlater]

Thanks for the quick response Nick.

I hadn't considered the easier option of taking them out from that side.

Are the tubes attached to this metal with the straps and if so how easy is it to remove the cut outsif they attached to the tubes?

[Nick Moss]

The clips come out with the panel, it's very easy

[fetuhoe]

If you don't take them out they will turn to ash during the thermal processing and then when the shell is dipped the 'acid' solution will soak into the ash, sit in the bottom of the sill and rot the entire structure quite quickly.

[AndrewSlater]

Thanks for all the help.

To clarify my car is a '74 911 so I expect it has heater tubes of the cardboard variety.

How long does the access panel need to be ( I can't see the other end in Nicks photo )?
Also how are the tubes removed ( do they simply slide along until an end drops off or do they concertina? ) - just trying to visualise how much space in the access panel you need to manoeuvre them out.

Thanks
Andrew

[Nick Moss]

[AndrewSlater]

Thanks Nick - much appreciated.

Andrew

[AndrewSlater]

I have now removed the heater tubes ( see my restoration thread for detail viewtopic.php?f=28&t=51455 )

Are there any precautions to prevent the heater tubes being damaged when welding the panels back in?
I'm concerned that my bottom cut lines are close to the centre of the tubes so the welding joint will be very close to the tube.
Should I be too concerned or will the tubes catch fire or be damaged?

Thanks
Andrew

[AndrewSlater]

I'm now at the stage where my bodyshop are asking if I have any special requirements with regard to paint/protection for the heater tube area before the tubes are refitted and the metal sections welded back in.

The concern is how well any paint will survive the welding process.

Can anyone let me know how they normally treat this area before it goes back together?
As always any advice and wisdom greatly appreciated.
Andrew

[Loz]

Personally, I'd go with a good 2pk epoxy primer in there.

Hth

[AndrewSlater]

Thanks for the suggestion Laurence - I think my guy is worried it won't fully survive the welding process above it - but not sure what others do at this point.
(PS How is the restoration of 'our' car going )
If anyone knows any better tried and tested solution please let me know.

[inaglasshouse]

If anyone knows any better tried and tested solution please let me know.

I asked a man who knows. Barry Carter, specifically.
Here's what he said (I checked first that it was OK to post it here):

As for your query, I do the whole area in a particularly tenacious black etch primer which dries with a satin finish. It hates welding heat though, so it gets zipped back off where the welds will be. These areas get hit with Wurth Zinc Hell (Bright Zinc), a spot-weld friendly, highly conductive and high zinc content, fully weld-able primer. This doesn't create acidic compounds when welded and is very good quality.

I find this combination works well. Beware the temptation to build up lots of layers of paint within cavities. Unless absolutely perfectly keyed, you risk delamination of the coats over time, which means any cavity wax ends up sitting on the top layer of paint, away from the metal. A couple of heavy passes with the black etch is plenty enough. Out of interest, there are a lot of dipped cars out there with absolutely nothing within their cavities or seams. To be fair, even untouched 911's display bare metal in some places when they come apart, which shows even the factory didn't get 100% coverage 100% of the time. What is remarkable is how often this is bright shiny silver coloured steel, 40 years and more since it last saw light.

Hope this helps with the query, and of course it's only what I do, there will be dozens of opinions on this I'm sure.

Hope this helps, cheers, Richard

[Loz]

Thanks for the suggestion Laurence........

(PS How is the restoration of 'our' car going ).......

yes it's going well thanks Andrew, albeit a bit slower than what I'd originally anticipated. No real problems as such, more a case of wanting to do it right first time which for me means check a million times, a heavy dose of procrastination, and eventually take the plunge! Only yesterday, I finally reached a point where I felt happy about tacking in the suspension pan.

Good luck with your restoration.

[AndrewSlater]

Thanks for the response Richard (and Barry ) - much appreciated - sounds a sensible approach.

As for y'our' car Laurence - glad its coming together nicely - try to keep the updates coming.