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wcfvw69 
Samba Purist
Joined: June 10, 2004
Posts: 13389
Location: Arizona
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 Posted: Wed Nov 14, 2018 8:06 pm Post subject: Re: Fixing the heating: removing/repairing heat exchangers |
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| Globespotter wrote: |
| BusDaddy - you never cease to amaze me with your ability to come up with stuff like this! |
No shit! He must spend hours everyday reading/studying VW manuals! 
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Decades of VW and VW parts restoration experience.
The Samba member since 2004.
**Now rebuilding throttle bodies for VW's and Porsche's**
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 50332
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| Posted: Wed Nov 14, 2018 11:27 pm Post subject: Re: Fixing the heating: removing/repairing heat exchangers |
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| ivwshane wrote: |
However I didn't use high temp powder because I figured that they wouldn't be getting hotter than 300°.
Excuse the dust.
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The two risers that connect the heat exchangers to the flapper valves may well see temperatures higher than 300°F, but likely not has hot as 300°C. |
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ivwshane
Samba Member
Joined: May 19, 2011
Posts: 1920
Location: Sacramento ca
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| Posted: Thu Nov 15, 2018 1:51 am Post subject: Re: Fixing the heating: removing/repairing heat exchangers |
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| Wildthings wrote: |
| ivwshane wrote: |
However I didn't use high temp powder because I figured that they wouldn't be getting hotter than 300°.
Excuse the dust.
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The two risers that connect the heat exchangers to the flapper valves may well see temperatures higher than 300°F, but likely not has hot as 300°C. |
Yeah, I was going by this:
Normal powder coat will do about 350°f and the high temp powder I got has a temp range of 600-1200°f.
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77 westy 2.0 FI
69 ghia coup 1600dp
70 single cab |
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ivwshane
Samba Member
Joined: May 19, 2011
Posts: 1920
Location: Sacramento ca
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| Posted: Mon Jan 21, 2019 10:26 pm Post subject: Re: Fixing the heating: removing/repairing heat exchangers |
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So I started the refurbishing process today. So far I've done the "easy" stuff. I'll be doing one at a time just in case I mess up I'll only need to replace one 
Here they are separated so I can see what I have to work with.
After initial cleaning
After and blasting.
Picture of the sand blasted and partially powder coated internal pipe.
The normal areas will need to be fixed, hopefully this will be a task I can complete, otherwise more money:(
I haven't seen an answer to this question yet but many have asked it. VW tact welded the skins on but I see a lot of people completely sealing them, why?
I'll be using everyone's advice and experience in order to fix these (including things from other threads), so if anyone has any other advice to give, I'm all ears!
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77 westy 2.0 FI
69 ghia coup 1600dp
70 single cab
Last edited by ivwshane on Tue Jan 22, 2019 12:19 am; edited 1 time in total |
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SGKent
Samba Member
Joined: October 30, 2007
Posts: 41031
Location: Citrus Heights CA (Near Sacramento)
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| Posted: Mon Jan 21, 2019 11:45 pm Post subject: Re: Fixing the heating: removing/repairing heat exchangers |
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be careful of the asbestos
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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69BahamaYellow
Samba Member
Joined: April 22, 2011
Posts: 536
Location: Talbott, TN
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| Posted: Tue Jan 22, 2019 6:42 am Post subject: Re: Fixing the heating: removing/repairing heat exchangers |
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| ivwshane wrote: |
| VW tact welded the skins on but I see a lot of people completely sealing them, why? |
If you've gone to the trouble of taking these things apart, then git rid of that asbestos insulation (carefully) and replace it with new fiberglass, so your heat will no longer have that oily VW stinky smell. This is also why you seal them up completely when you put them back together (I used high temp ultra copper RTV sealer on mine), that way, if you have a valve cover leak, you don't get oil weeping back into your heat exchangers. |
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ivwshane
Samba Member
Joined: May 19, 2011
Posts: 1920
Location: Sacramento ca
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| Posted: Tue Jan 22, 2019 7:36 am Post subject: Re: Fixing the heating: removing/repairing heat exchangers |
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| 69BahamaYellow wrote: |
| ivwshane wrote: |
| VW tact welded the skins on but I see a lot of people completely sealing them, why? |
If you've gone to the trouble of taking these things apart, then git rid of that asbestos insulation (carefully) and replace it with new fiberglass, so your heat will no longer have that oily VW stinky smell. This is also why you seal them up completely when you put them back together (I used high temp ultra copper RTV sealer on mine), that way, if you have a valve cover leak, you don't get oil weeping back into your heat exchangers. |
I'll be replacing the asbestos with this foil backed heatshield.
https://www.amazon.com/gp/aw/d/B0051UPAK4?psc=1&ref=ppx_pop_mob_b_asin_image
I'll also be wrapping the two pipes with it as well (since the metal heatshields were not salvageable). I contemplated on using header wrap but I think this stuff performs better and is easier to replace if need be.
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77 westy 2.0 FI
69 ghia coup 1600dp
70 single cab |
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ivwshane
Samba Member
Joined: May 19, 2011
Posts: 1920
Location: Sacramento ca
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| Posted: Wed Apr 17, 2019 8:55 am Post subject: Re: Fixing the heating: removing/repairing heat exchangers |
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Is there a hand tool available that crimps the seams? I'm looking to get a tighter, more uniform fit. I've tried pliers but they don't offer enough force.
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77 westy 2.0 FI
69 ghia coup 1600dp
70 single cab |
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ivwshane
Samba Member
Joined: May 19, 2011
Posts: 1920
Location: Sacramento ca
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| Posted: Wed Apr 17, 2019 9:04 am Post subject: Re: Fixing the heating: removing/repairing heat exchangers |
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My welding of the sheet metal did not go as expected as my skill and I'm guessing my welder are sub par:(
As a last resort, has anyone ever taken apart the newer aftermarket heat exchangers and replaced the heat pipe with an OEM one? I know the newer boxes are spot welded so I would hope the welds could be drilled out to separate the two halves and then put in an OE pipe and some heat shield. And yes I know it would a crap ton of money to do this.
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77 westy 2.0 FI
69 ghia coup 1600dp
70 single cab |
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69BahamaYellow
Samba Member
Joined: April 22, 2011
Posts: 536
Location: Talbott, TN
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| Posted: Wed Apr 17, 2019 1:06 pm Post subject: Re: Fixing the heating: removing/repairing heat exchangers |
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| ivwshane wrote: |
| My welding of the sheet metal did not go as expected as my skill and I'm guessing my welder are sub par:( |
What kind of welder are you using? My heat exchanger tins were in worse shape than yours and my Lincoln Handy MIG was perfect for the job. Just use the lowest heat setting and medium wire speed. You also need Argon / CO2 blended gas with plain wire and NOT the flux core wire with no gas.
You can also use a piece of copper clamped behind the weld zone as a heat sink/form to weld up larger holes without a filler piece. The copper acts as a guide for the molten metal and it won't stick. I just used a couple pieces of soft copper plumbing pipe, when I did mine. You can pound that into any shape you want, and just clamp that behind the hole you want to fill.
When you're done, just grind it smooth with a Dremel tool for a nearlyinvisible repair.
Here's what mine looked like after repairs
And here's what I started with
Regarding the fit, I used the leather pliers pictured to take things apart and the hand seamer to close them back up. The hammer and dolly were used to really seal them up tight and makes them look as if they had never been apart. The pic below shows the finished product. Yes, I know I should have replaced the krusty exhaust flanges too, but I'll deal with that, if they ever start leaking...
Last edited by 69BahamaYellow on Wed Apr 17, 2019 1:35 pm; edited 1 time in total |
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 50332
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| Posted: Wed Apr 17, 2019 1:28 pm Post subject: Re: Fixing the heating: removing/repairing heat exchangers |
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| Visegrips or 420/430 Channelocks will crimp the seams. |
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ivwshane
Samba Member
Joined: May 19, 2011
Posts: 1920
Location: Sacramento ca
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69BahamaYellow
Samba Member
Joined: April 22, 2011
Posts: 536
Location: Talbott, TN
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| Posted: Thu Apr 18, 2019 12:14 pm Post subject: Re: Fixing the heating: removing/repairing heat exchangers |
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That Harbor Freight Welder should work fine. It probably came with a gas regulator, so just go by your local industrial gas supplier and pick up a cylinder of 75% Argon / 25% CO2. They will charge you about $100 for the cylinder and first fill up and about $25 for just a fill up. Seems like I can go through 3 full spools of wire per fillup of gas, so it will last you a really long time. Just make sure to close the bottle valve between uses. Those cylinders are charged to nearly 2000 PSI, so it's a guarantee you'll loose gas through that cheap regulator they give you if you don't turn it off between uses, and because the cylinder is under so much pressure, be extremely careful not to knock it over and damage the valve!!
Also choose the thinnest gage spool of plain steel wire you can use on your welder (it probably came with different size tips, depending on the gage of wire you're using. You will be absolutely amazed at how good you can weld with gas vs the flux core wire.
Also, the technique is different for gas vs flux. with gas, you should angle the welding tip and "push" the weld bead in the direction you are welding. With flux you angle the tip and "pull" the weld bead so the slag floats to the top. That could have been part of your problem. With gas, you can pull the trigger for just a couple seconds to get a molten puddle going, and then release the trigger. When the puddle just about stops glowing through your welding lens, pull the trigger again to make the next puddle. This "stitching" technique lets you fill holes in really thin metal without burning through.
One final tip, get one of those cheap auto darkening welding helmets from HF. Totally worth it, since it really helps you get started in the right spot for clean welds with minimal grinding |
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