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PWC Workshop: Cast Iron Welding
Part of our beloved hobby is the restoration/maintanance of the aged & tired vehicle. Just recently we have started a series of repair samples under the name "PreWarCar Workshop". In this week's Workshop
we like to show you the problem with cracks in cast iron.
Say, you've got a special car. Only a few still exist. And then you find out there are cracks in your cylinderhead. That can be quite a problem if the material is cast iron. Welding the 'normal' way is difficult and sometimes nearly impossible. And to have a new one cast is very expensive. One of the options is to braze it with bronze. A decent procedure for certain parts. You first drill a small hole at the begin and end of the crack, make a V-shape in the crack, clean it, heat the material until it is red hot and then let the bronze flow in the crack.
This is good for some cracks but not strong enough for all repairs. I had this problem with one of my cars and found a company called Cast Iron Welding Services ltd. close to Leicester, UK. The name says it all. The only thing they do all day is repairing cast iron. The way they weld is different from most other welding methods and it looked very simple (but isn't that always the case that things look easy when a craftman is doing his thing...!).
They start with cutting all the bad areas from the cast iron. The missing bits being replaced with inlays of newly cast iron. After cleaning, a furnace is created around the part with bricks and a big heater.
The furnace will burn for a day and night, so the complete part is the good temperature for the next step. The welding itself is comparable with the bronze blazing . A torch to heat even more and let a cast iron rod flow in the cracks. The material becomes one and is as strong as the original cast material.
After machining it is nearly impossible to see where repair and original meet. But more important, the cylinder is usable again (they even offer a 12 months warrenty) .
If you have any experience with repairing cast iron, or you have another interesting subject for the Pre-War Workshop-section, please let us know!
(photos courtesy Cast Iron Welding)
Gepubliceerd:
dinsdag mei 3rd, 2016
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Reacties
Onbekend
06 Mei 2016, 07:37
Onbekend
05 Mei 2016, 05:22
Used the same method of welding cast iron. The real secret was in ensuring the cooling process was even and gradual. Used to pack the repaired paret in lime and leave it for a few days. Worked every time.
Lees verder
Onbekend
05 Mei 2016, 04:50
Are there any new age solutions? I’m very much in favour of processes that apply minimum stress to original components.
A number of years ago I knew a fellow who had a Lancia Kappa of about 1919 vintage. It had a porous block and the ultimate new age solution was deemed to be
to have it industrially cleaned of all residues and the for it then to be impregnated with a new liquid epoxy of some sort in a vacuums chamber to remedy the porosity.
No longer in touch with the owner but i understand this process is now commercially available through Loctite and perhaps others.
Lees verder
A number of years ago I knew a fellow who had a Lancia Kappa of about 1919 vintage. It had a porous block and the ultimate new age solution was deemed to be
to have it industrially cleaned of all residues and the for it then to be impregnated with a new liquid epoxy of some sort in a vacuums chamber to remedy the porosity.
No longer in touch with the owner but i understand this process is now commercially available through Loctite and perhaps others.
Onbekend
04 Mei 2016, 16:25
Had a GREAT(and old) welding/iron shop in my CITY, I only accumulated equipment(and classes).
Brazing is a poor sub, way different coefficient of expansion.
REMEMBER, it took mucho miles before the crack, so no matter what the repair procedure, it might seem EXQUISITE, if you take it easy on the ROADS AND MILEAGE, which are 95% of the crowd.
My old shop welded a couple of "stove legs", carried hot weight, simply stick welded the cast iron, but I was not there.
Lees verder
Brazing is a poor sub, way different coefficient of expansion.
REMEMBER, it took mucho miles before the crack, so no matter what the repair procedure, it might seem EXQUISITE, if you take it easy on the ROADS AND MILEAGE, which are 95% of the crowd.
My old shop welded a couple of "stove legs", carried hot weight, simply stick welded the cast iron, but I was not there.
Onbekend
04 Mei 2016, 14:49
I had the blocks of my 1910 Mitchell repaired in this manner. Metal stitching won't always work — in my case, three of the four ears were broken off the flanges that support the exhaust manifold. There is no undue stress... in fact, the process done correctly will relieve stress in the metal. What isn't mentioned is that after the weld is done, the part is buried in sand allowing it to cool as slowly as it was originally heated.
Lees verder
Onbekend
04 Mei 2016, 10:36
I have had many metal stitching repairs carried out on Riley blocks and cylinder heads. The procedure has always been completely successful. I was warned to be careful of cast iron welding, particularly for cylinder blocks, as the process often causes slight distortions and the crankshaft bearing housings have to been re-machined. This does not always happen, but depends on the metallurgy of the original material.
Lees verder
Onbekend
04 Mei 2016, 10:30
Intresting procedure - but probably bringing a lot of temperature stresss into the workpiece . What about laser welding as an alternative - they are advertising it here in germany more often. Are there any big disadvantages?
Lees verder
Onbekend
04 Mei 2016, 07:44
Cracks in cylinder blocks and heads are a problem with Singer engines of the thirties. New heads are available for the 4 cylinder 9's but the 6 cylinder blocks are a different matter. I had my 1933 2 litre one cold stitched on both sides and the top face and the problem we'd had for over 40 years disappeared as if by magic!
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Onbekend
04 Mei 2016, 06:58
When we did up my Silver Ghost the blocks were very furred inside and there were two old stitched repairs in the cast water jacket. Rather than use (inferior we must presume) new blocks, the old repairs were dug out, moulds of the defects were made and they were cast in iron and then stitched into place. Then reboring and liners etc were done. Worked a treat. Car goes like the clappers.
Lees verder
Onbekend
04 Mei 2016, 06:53
I used the same company in Hinckley last year to replace a broken corner on my LaFrance block and valve
access cover, fantastic job
Jim
Lees verder
access cover, fantastic job
Jim
Onbekend
04 Mei 2016, 05:52
I had a cracked 6 cylinder engine block, a 1934 Humber where the crack was between the middle 2 cylinders. Since this welding can be tricky business and the part is lost if not done properly, we did metal stitching which worked very well.
Lees verder
Onbekend
04 Mei 2016, 05:43
Very interesting. This kind of work requires a certain skill. Once messed up, the part will then be lost forever. I had a cracked block in my 1934 Humber where the crack was seen between the middle 2 cylinders. We had to remove the head as a plug had broken and then discovered this. We did not weld, we did metal stitching and it worked very well. The engine is now running very well.
Lees verder
For 12 months it worked fine but then the canal broke next to the weld and I decided to close that way of delivery by a metal plug. Instead I made of thin copper pipe a new way of delivering the oil to the head and that turned out the best solution. The same happened with a Singer Le Mans 9hp cylinderhead that I repaired a couple of times just to keep the car running but in the end I replaced the head with a new cast that cost me a arm and leg...!