Clearing rust from heater tubes

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BigOldMac
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Clearing rust from heater tubes

Post by BigOldMac » Fri Oct 12, 2018 5:27 pm

If this is covered elsewhere on the forum apologies... but I can't find it. A mate an I have the same problem, if we use the heaters on our '64 and '65 buses we end up choking on rust particles. Any tips on how to 'descale the hear tubes? Thanks
Devaluing my VW's every day
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JonnyCJ
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Re: Clearing rust from heater tubes

Post by JonnyCJ » Fri Oct 12, 2018 6:40 pm

Shot blast and then powder coat ?

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BJ1
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Re: Clearing rust from heater tubes

Post by BJ1 » Sun Oct 14, 2018 9:51 am

JonnyCJ wrote:
Fri Oct 12, 2018 6:40 pm
Shot blast and then powder coat ?
I think he is talking about rust inside the heater tubes so blasting and painting won't do it! The only way to deal with this is to chop th etubes out from under the bus and replace them with some expensive new tubes. Not a difficult job to do in the garage with a hoist but you need to be able to weld. You may be lucky and get away with just replacing the cheap long tube as this is usually the first to rust through.
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Who.Me?
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Re: Clearing rust from heater tubes

Post by Who.Me? » Sun Oct 14, 2018 10:40 am

Pull the engine, get a shop vac with a really long hose and stove it up the tubes until it reaches the cab? Then follow up with a spray of phosphoric acid to kill the rust so it doesn't do it again.

Empty the shop vac first and check it after to find all the goodies the previous owner dropped down the cab vents.

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BJ1
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Re: Clearing rust from heater tubes

Post by BJ1 » Mon Oct 15, 2018 8:14 am

Who.Me? wrote:
Sun Oct 14, 2018 10:40 am
Pull the engine, get a shop vac with a really long hose and stove it up the tubes until it reaches the cab? Then follow up with a spray of phosphoric acid to kill the rust so it doesn't do it again.

Empty the shop vac first and check it after to find all the goodies the previous owner dropped down the cab vents.
Yes - this certainly stops the flakes but by the time rust starts appearing at the vents it's likely that the long tube is almost toast. But nothing beats the smell of hot phosphoric acid in the cab!!!
1966 Westy in Velvet Green - being restored
1967 Devon from Devon still in Devon
1967 Sundial from Idaho
1971 Westfalia from LA
1971 patina Delux from Montana now living in Germany
1972 Devon now owned by No 1 son!

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BigOldMac
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Re: Clearing rust from heater tubes

Post by BigOldMac » Mon Oct 15, 2018 9:05 pm

Cheers for the advice... Its got belly pans and the underside is completely untouched/original, so I don't want to cut it all about to replace the tubes, so hot acid it is
Devaluing my VW's every day
'67 Split
'65 21w Samba
'56 Oval

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Who.Me?
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Re: Clearing rust from heater tubes

Post by Who.Me? » Tue Oct 16, 2018 12:55 pm

BigOldMac wrote:
Mon Oct 15, 2018 9:05 pm
Cheers for the advice... Its got belly pans and the underside is completely untouched/original, so I don't want to cut it all about to replace the tubes, so hot acid it is
For the avoidance of doubt, you don't need to heat the acid.

I buy 85% phosphoric from ebay and make up my own solution. Dilute it well in plenty of water. I dilute the 85% stuff in four times the volume of water (e.g. add 1 litre of 85% phosphoric to 4 litres of water). That'll do a lot of rust.

Caution - !!!Use cold water and ALWAYS add the acid to the water!!! When the acid mixes with water, it will give off some heat

Science bit - If you pour water in to acid, you'll start with a little water in a lot of acid. The heat it gives off can be enough to boil that little bit of water and that can cause it to spit acid in your face/eyes. If you pour the acid in to the water (slowly) you're starting with a small amount of acid in a lot of water. The water will take up the heat and it won't boil. I recommend you wear glasses though.

The acid isn't particularly dangerous if diluted as above, but if you spill it on your clothes, don't leave it, go and change. I got my sleaves wet with the stuff when I did the underside of my truck and ended up with slight acid burns on my arms (sunburn strength). I didn't notice the pain until later.

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Re: Clearing rust from heater tubes

Post by BigOldMac » Tue Oct 16, 2018 1:06 pm

appreciate the advice. Many thanks to you all
Devaluing my VW's every day
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'65 21w Samba
'56 Oval

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vwJim
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Re: Clearing rust from heater tubes

Post by vwJim » Tue Oct 16, 2018 7:36 pm

Great detail.
Supplying quality in house designed items plus parts from SCAT, Kennedy Clutches, CB Performance & FIRETEC. Also fitting service including modifications & mechanical upgrades.

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