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Alloy porosity
I may be about to buy, from a scrapyard, a set of 5 replacement wheels
for the recently purchased car to get a spare wheel, proper sized tyres and wheels that fit the wheel nuts. In the past, I've often been told that the reason for a slow puncture was that the alloy wheels had gone porous. More recently, I've been told that the cylinder head on a certain vehicle had gone porous and that was why it chuffed when cold. I have always wondered whether this is a standard get-rid-of-him phrase taught as part of the Car Mechanics PhD (Hons) course, or whether alloy does actually start to leak. Does anyone know? Is there any sort of standard test, like wheel tapping, that can detect this sort of rot? -- Bill |
Alloy porosity
"Bill" wrote in message ... I may be about to buy, from a scrapyard, a set of 5 replacement wheels for the recently purchased car to get a spare wheel, proper sized tyres and wheels that fit the wheel nuts. In the past, I've often been told that the reason for a slow puncture was that the alloy wheels had gone porous. More recently, I've been told that the cylinder head on a certain vehicle had gone porous and that was why it chuffed when cold. I have always wondered whether this is a standard get-rid-of-him phrase taught as part of the Car Mechanics PhD (Hons) course, or whether alloy does actually start to leak. Does anyone know? Is there any sort of standard test, like wheel tapping, that can detect this sort of rot? I have found them to leak and the seal goes at the rim ...... |
Alloy porosity
On 01/10/2017 19:06, Bill wrote:
I may be about to buy, from a scrapyard, a set of 5 replacement wheels for the recently purchased car to get a spare wheel, proper sized tyres and wheels that fit the wheel nuts. In the past, I've often been told that the reason for a slow puncture was that the alloy wheels had gone porous. More recently, I've been told that the cylinder head on a certain vehicle had gone porous and that was why it chuffed when cold. I have always wondered whether this is a standard get-rid-of-him phrase taught as part of the Car Mechanics PhD (Hons) course, or whether alloy does actually start to leak. Does anyone know? Is there any sort of standard test, like wheel tapping, that can detect this sort of rot? Paint them well before the tyres are fitted, they will probably be fine. Testing would cost more than a new wheel. |
Alloy porosity
On 01/10/2017 19:23, Retro Futurist ... wrote:
"Bill" wrote in message ... I may be about to buy, from a scrapyard, a set of 5 replacement wheels for the recently purchased car to get a spare wheel, proper sized tyres and wheels that fit the wheel nuts. In the past, I've often been told that the reason for a slow puncture was that the alloy wheels had gone porous. More recently, I've been told that the cylinder head on a certain vehicle had gone porous and that was why it chuffed when cold. I have always wondered whether this is a standard get-rid-of-him phrase taught as part of the Car Mechanics PhD (Hons) course, or whether alloy does actually start to leak. Does anyone know? Is there any sort of standard test, like wheel tapping, that can detect this sort of rot? I have found them to leak and the seal goes at the rim ...... That's just happened to me, 57 plate Zafira with 61k miles. NSR very slow leak, taking a couple of weeks to lose more than a few psi. Fixed at the local tyre place by cleaning the rim and applying fresh sealer. Two months ago; so far, so good. -- Peter |
Alloy porosity
In message , MrCheerful
writes On 01/10/2017 19:06, Bill wrote: I may be about to buy, from a scrapyard, a set of 5 replacement wheels for the recently purchased car to get a spare wheel, proper sized tyres and wheels that fit the wheel nuts. In the past, I've often been told that the reason for a slow puncture was that the alloy wheels had gone porous. More recently, I've been told that the cylinder head on a certain vehicle had gone porous and that was why it chuffed when cold. I have always wondered whether this is a standard get-rid-of-him phrase taught as part of the Car Mechanics PhD (Hons) course, or whether alloy does actually start to leak. Does anyone know? Is there any sort of standard test, like wheel tapping, that can detect this sort of rot? Paint them well before the tyres are fitted, they will probably be fine. Testing would cost more than a new wheel. When you say paint, what with and inside or outside the wheel? Or is this referring to painting the edges, or more, with sealant. Sorry if this is a stupid question, but I'm just learning how little I know about wheels and tyres. -- Bill |
Alloy porosity
Bill laid this down on his screen :
When you say paint, what with and inside or outside the wheel? Or is this referring to painting the edges, or more, with sealant. No point to adding it to the outside, it needs to be inside. The problem with alloy rims, is that the salt and water corrodes the alloy, causing a poor seal to develop between tyre and wheel rim. The corrosion needs to be cleaned off down to bare metal, then the bare metal painted to protect it. |
Alloy porosity
On 01/10/2017 19:33, Ramsman wrote:
I have found them to leak and the seal goes at the rim ...... That's just happened to me, 57 plate Zafira with 61k miles. NSR very slow leak, taking a couple of weeks to lose more than a few psi. Fixed at the local tyre place by cleaning the rim and applying fresh sealer. Two months ago; so far, so good. The annoying thing is that you can't fit an inner tube to the things. |
Alloy porosity
On 01/10/2017 20:15, Harry Bloomfield wrote:
Bill laid this down on his screen : When you say paint, what with and inside or outside the wheel? Or is this referring to painting the edges, or more, with sealant. No point to adding it to the outside, it needs to be inside. The problem with alloy rims, is that the salt and water corrodes the alloy, causing a poor seal to develop between tyre and wheel rim. The corrosion needs to be cleaned off down to bare metal, then the bare metal painted to protect it. There are plenty of places that will refurbish wheels to better than new, but it is not cheap and takes a few days or so. One of my customers had his Lexus wheels refurbed because they leaked extensively and they were fine afterwards, iirc it was about 200 for all five. For my wheels I strip the tyre, clean the inner rim up, and use a belt sander on the important seal area around the edge, then spray them with etch primer, then some silver wheel paint, works fine, even if you miss out the etch primer. |
Alloy porosity
On 01/10/2017 20:37, MrCheerful wrote:
There are plenty of places that will refurbish wheels to better than new, but it is not cheap and takes a few days or so.* One of my customers had his Lexus wheels refurbed because they leaked extensively and they were fine afterwards, iirc it was about 200 for all five. Mine were done by Toyota on a recall when the car was a year or so old. They lasted over 10 years, and then started to leak on the rims. I had them redone, and they are bubbling in places only 4 years later. Andy |
Alloy porosity
On 01/10/2017 20:37, MrCheerful wrote:
On 01/10/2017 20:15, Harry Bloomfield wrote: Bill laid this down on his screen : When you say paint, what with and inside or outside the wheel? Or is this referring to painting the edges, or more, with sealant. No point to adding it to the outside, it needs to be inside. The problem with alloy rims, is that the salt and water corrodes the alloy, causing a poor seal to develop between tyre and wheel rim. The corrosion needs to be cleaned off down to bare metal, then the bare metal painted to protect it. There are plenty of places that will refurbish wheels to better than new, but it is not cheap and takes a few days or so.* One of my customers had his Lexus wheels refurbed because they leaked extensively and they were fine afterwards, iirc it was about 200 for all five. For my wheels I strip the tyre, clean the inner rim up, and use a belt sander on the important seal area around the edge, then spray them with etch primer, then some silver wheel paint, works fine, even if you miss out the etch primer. +1 When I was at university, my father used to edit the magazine "Paint Technology". I used to write all my exam revision notes on his galley proofs (fan-fold paper, about 5 inches wide, very convenient for summarising key points). Towards the end of my professional career, I found myself approving contracts placed with the Paint Research Association at Teddington, which had been one of his very regular stamping grounds. |
Alloy porosity
On 01-Oct-17 7:06 PM, Bill wrote:
I may be about to buy, from a scrapyard, a set of 5 replacement wheels for the recently purchased car to get a spare wheel, proper sized tyres and wheels that fit the wheel nuts. In the past, I've often been told that the reason for a slow puncture was that the alloy wheels had gone porous. More recently, I've been told that the cylinder head on a certain vehicle had gone porous and that was why it chuffed when cold. I have always wondered whether this is a standard get-rid-of-him phrase taught as part of the Car Mechanics PhD (Hons) course, or whether alloy does actually start to leak. Does anyone know? Is there any sort of standard test, like wheel tapping, that can detect this sort of rot? Porosity is something that will have been there from manufacture. Over time the pores can open up and then it leaks. Cylinder head would have to be removed and pressure tested. Though just running something like steel seal will cure most pinholes. Wheels you will never find the pore, just paint the inside of the rim. It seems that epoxy is not longer considered to be best but some sort of acrylic. Royal Enfield couldn't cast a non-porous crankcase with integral oil tank for the 250 Crusader to save their lives. They all had yellow paint on the inside to stop the oil leaking out. |
Alloy porosity
On 01/10/2017 19:33, Ramsman wrote:
On 01/10/2017 19:23, Retro Futurist ... wrote: "Bill" wrote in message ... I may be about to buy, from a scrapyard, a set of 5 replacement wheels for the recently purchased car to get a spare wheel, proper sized tyres and wheels that fit the wheel nuts. In the past, I've often been told that the reason for a slow puncture was that the alloy wheels had gone porous. More recently, I've been told that the cylinder head on a certain vehicle had gone porous and that was why it chuffed when cold. I have always wondered whether this is a standard get-rid-of-him phrase taught as part of the Car Mechanics PhD (Hons) course, or whether alloy does actually start to leak. Does anyone know? Is there any sort of standard test, like wheel tapping, that can detect this sort of rot? I have found them to leak and the seal goes at the rim ...... That's just happened to me, 57 plate Zafira with 61k miles. NSR very slow leak, taking a couple of weeks to lose more than a few psi. Fixed at the local tyre place by cleaning the rim and applying fresh sealer. Two months ago; so far, so good. +1. I have a very good local tyre place and he knew by the wheel (2007 Audi) that the inner rim had likely corroded slightly and leaked. Cleaned it 6 months ago and it's needed no air in that time. -- Cheers, Rob |
Alloy porosity
On 01/10/2017 19:06, Bill wrote:
I may be about to buy, from a scrapyard, a set of 5 replacement wheels for the recently purchased car to get a spare wheel, proper sized tyres and wheels that fit the wheel nuts. In the past, I've often been told that the reason for a slow puncture was that the alloy wheels had gone porous. More recently, I've been told that the cylinder head on a certain vehicle had gone porous and that was why it chuffed when cold. I have always wondered whether this is a standard get-rid-of-him phrase taught as part of the Car Mechanics PhD (Hons) course, or whether alloy does actually start to leak. Does anyone know? Is there any sort of standard test, like wheel tapping, that can detect this sort of rot? I think the cylinder problem and the wheel problem are different. Alloy wheels are normally varnished or painted to prevent corrosion. But flexing of the tyre against the seat area can remove the coating. The crevice between the tyre and the rim is then more liable to corrosion from water and, especially, salt during the winter. The alloy becomes pitted, leaving a leak path. The greasy lubricant used when new tyres are fitted can help prevent this, but once you have pits the only real solution is to to remove them by abrasion, and to "paint" the metal surface to prevent further corrosion before the tyre is re-fitted. Decent tyre suppliers should be able to sort this out. |
Alloy porosity
On Sunday, 1 October 2017 19:06:37 UTC+1, Bill wrote:
I may be about to buy, from a scrapyard, a set of 5 replacement wheels for the recently purchased car to get a spare wheel, proper sized tyres and wheels that fit the wheel nuts. In the past, I've often been told that the reason for a slow puncture was that the alloy wheels had gone porous. More recently, I've been told that the cylinder head on a certain vehicle had gone porous and that was why it chuffed when cold. I have always wondered whether this is a standard get-rid-of-him phrase taught as part of the Car Mechanics PhD (Hons) course, or whether alloy does actually start to leak. Does anyone know? Is there any sort of standard test, like wheel tapping, that can detect this sort of rot? -- Bill Alloy wheels are laquered inside to get over this problem. |
Alloy porosity
On Sun, 01 Oct 2017 22:54:06 -0700, harry wrote:
On Sunday, 1 October 2017 19:06:37 UTC+1, Bill wrote: I may be about to buy, from a scrapyard, a set of 5 replacement wheels for the recently purchased car to get a spare wheel, proper sized tyres and wheels that fit the wheel nuts. In the past, I've often been told that the reason for a slow puncture was that the alloy wheels had gone porous. More recently, I've been told that the cylinder head on a certain vehicle had gone porous and that was why it chuffed when cold. I have always wondered whether this is a standard get-rid-of-him phrase taught as part of the Car Mechanics PhD (Hons) course, or whether alloy does actually start to leak. Does anyone know? Is there any sort of standard test, like wheel tapping, that can detect this sort of rot? -- Bill Alloy wheels are laquered inside to get over this problem. Until the lacquer flakes off (as it did on my 5 year old car). I ended up getting all of the wheels skimmed and re-lacquered. -- My posts are my copyright and if @diy_forums or Home Owners' Hub wish to copy them they can pay me £1 a message. Use the BIG mirror service in the UK: http://www.mirrorservice.org *lightning surge protection* - a w_tom conductor |
Alloy porosity
In article ,
Bill wrote: I may be about to buy, from a scrapyard, a set of 5 replacement wheels for the recently purchased car to get a spare wheel, proper sized tyres and wheels that fit the wheel nuts. In the past, I've often been told that the reason for a slow puncture was that the alloy wheels had gone porous. More recently, I've been told that the cylinder head on a certain vehicle had gone porous and that was why it chuffed when cold. I have always wondered whether this is a standard get-rid-of-him phrase taught as part of the Car Mechanics PhD (Hons) course, or whether alloy does actually start to leak. Does anyone know? Is there any sort of standard test, like wheel tapping, that can detect this sort of rot? Alloy wheels are generally painted (or coated with something similar to paint). If the paint is damaged where the tyre meets the rim they are more likely to leak. As they will often corrode where the paint is damaged. -- *When cheese gets its picture taken, what does it say? * Dave Plowman London SW To e-mail, change noise into sound. |
Alloy porosity
On 01/10/2017 20:22, Ade wrote:
On 01/10/2017 19:33, Ramsman wrote: I have found them to leak and the seal goes at the rim ...... That's just happened to me, 57 plate Zafira with 61k miles. NSR very slow leak, taking a couple of weeks to lose more than a few psi. Fixed at the local tyre place by cleaning the rim and applying fresh sealer. Two months ago; so far, so good. The annoying thing is that you can't fit an inner tube to the things. Why not? -- Michael Chare |
Alloy porosity
Dave Plowman (News) wrote:
In article , Bill wrote: I may be about to buy, from a scrapyard, a set of 5 replacement wheels for the recently purchased car to get a spare wheel, proper sized tyres and wheels that fit the wheel nuts. In the past, I've often been told that the reason for a slow puncture was that the alloy wheels had gone porous. More recently, I've been told that the cylinder head on a certain vehicle had gone porous and that was why it chuffed when cold. I have always wondered whether this is a standard get-rid-of-him phrase taught as part of the Car Mechanics PhD (Hons) course, or whether alloy does actually start to leak. Does anyone know? Is there any sort of standard test, like wheel tapping, that can detect this sort of rot? Alloy wheels are generally painted (or coated with something similar to paint). If the paint is damaged where the tyre meets the rim they are more likely to leak. As they will often corrode where the paint is damaged. I have some that got scratched by some weights that were crimped around the rim, instead of glued, like they seem to be now; and this is where they have corroded and now leak slowly. |
Alloy porosity
In article ,
Bill wrote: I have always wondered whether this is a standard get-rid-of-him phrase taught as part of the Car Mechanics PhD (Hons) course, or whether alloy does actually start to leak. Just the usual meja ********. If alloy really did go porous, your engine would soon be scrap. Given pistons are made of alloy and have been for many a year as is much else on a modern engine. And the pressure inside a cylinder is far higher than in a tyre. If a steel wheel is rusty where the tyre meets it, that will leak too. -- *Is it true that cannibals don't eat clowns because they taste funny? Dave Plowman London SW To e-mail, change noise into sound. |
Alloy porosity
Michael Chare wrote:
[...] The annoying thing is that you can't fit an inner tube to the things. Why not? You can't use inner tubes with most tyres now, regardless of wheel type. The inside of the tyre is not smooth enough, plus the tube shape isn't designed for the low profiles currently in vogue. Chris -- Remove prejudice to reply. |
Alloy porosity
Dave Plowman (News) wrote:
In article , Bill wrote: I have always wondered whether this is a standard get-rid-of-him phrase taught as part of the Car Mechanics PhD (Hons) course, or whether alloy does actually start to leak. Just the usual meja ********. If alloy really did go porous, your engine would soon be scrap. Given pistons are made of alloy and have been for many a year as is much else on a modern engine. And the pressure inside a cylinder is far higher than in a tyre. If a steel wheel is rusty where the tyre meets it, that will leak too. ISTR way back when I was a lad, that some Norton crankcases were found to be porous. They had to paint the inside with something-or-other to stop them leaking. |
Alloy porosity
On Mon, 2 Oct 2017 11:28:06 +0100, "Dan S. MacAbre"
wrote: Just the usual meja ********. If alloy really did go porous, your engine would soon be scrap. Given pistons are made of alloy and have been for many a year as is much else on a modern engine. And the pressure inside a cylinder is far higher than in a tyre. While I may actually agree with the gist of your argument how many tyres are repressurized a thousand or more times a minute. G.Harman |
Alloy porosity
On Monday, 2 October 2017 11:37:37 UTC+1, wrote:
On Mon, 2 Oct 2017 11:28:06 +0100, "Dan S. MacAbre" wrote: Just the usual meja ********. If alloy really did go porous, your engine would soon be scrap. Given pistons are made of alloy and have been for many a year as is much else on a modern engine. And the pressure inside a cylinder is far higher than in a tyre. While I may actually agree with the gist of your argument how many tyres are repressurized a thousand or more times a minute. G.Harman With alloy engine parts, the holes/pores soon block with dirt/carbon particles. In any event any leakage is made up in the next fraction of a second. Which doesn't happen with wheels. |
Alloy porosity
In article ,
harry wrote: On Monday, 2 October 2017 11:37:37 UTC+1, wrote: On Mon, 2 Oct 2017 11:28:06 +0100, "Dan S. MacAbre" wrote: Just the usual meja ********. If alloy really did go porous, your engine would soon be scrap. Given pistons are made of alloy and have been for many a year as is much else on a modern engine. And the pressure inside a cylinder is far higher than in a tyre. While I may actually agree with the gist of your argument how many tyres are repressurized a thousand or more times a minute. G.Harman With alloy engine parts, the holes/pores soon block with dirt/carbon particles. You have carbon/dirt in your cooling system? In which case something is porous. In any event any leakage is made up in the next fraction of a second. Which doesn't happen with wheels. No it doesn't. But I'd love to hear of a wheel which was genuinely porous, rather than just a poor seal between tyre and rim. And somehow I doubt you've ever changed a tyre yourself. -- *If a pig loses its voice, is it disgruntled? Dave Plowman London SW To e-mail, change noise into sound. |
Alloy porosity
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Alloy porosity
On 02/10/2017 11:15, Dave Plowman (News) wrote:
In article , Bill wrote: I have always wondered whether this is a standard get-rid-of-him phrase taught as part of the Car Mechanics PhD (Hons) course, or whether alloy does actually start to leak. Just the usual meja ********. If alloy really did go porous, your engine would soon be scrap. Given pistons are made of alloy and have been for many a year as is much else on a modern engine. And the pressure inside a cylinder is far higher than in a tyre. If my pistons lose 0.1% of the gas on every stroke I won't notice. They are typically running about 25 power strokes a second. If my tyre lost 0.1% of its contents every 25th of a second I think I'd notice... If a steel wheel is rusty where the tyre meets it, that will leak too. Agree there. Andy |
Alloy porosity
In article ,
Vir Campestris wrote: On 02/10/2017 11:15, Dave Plowman (News) wrote: In article , Bill wrote: I have always wondered whether this is a standard get-rid-of-him phrase taught as part of the Car Mechanics PhD (Hons) course, or whether alloy does actually start to leak. Just the usual meja ********. If alloy really did go porous, your engine would soon be scrap. Given pistons are made of alloy and have been for many a year as is much else on a modern engine. And the pressure inside a cylinder is far higher than in a tyre. If my pistons lose 0.1% of the gas on every stroke I won't notice. They are typically running about 25 power strokes a second. If my tyre lost 0.1% of its contents every 25th of a second I think I'd notice... How about the cooling system often made of alloy these days. If that were porous, it wouldn't hold pressure. If a steel wheel is rusty where the tyre meets it, that will leak too. Agree there. Andy -- *Shin: a device for finding furniture in the dark * Dave Plowman London SW To e-mail, change noise into sound. |
Alloy porosity
On 03-Oct-17 11:36 PM, Dave Plowman (News) wrote:
In article , Vir Campestris wrote: On 02/10/2017 11:15, Dave Plowman (News) wrote: In article , Bill wrote: I have always wondered whether this is a standard get-rid-of-him phrase taught as part of the Car Mechanics PhD (Hons) course, or whether alloy does actually start to leak. Just the usual meja ********. If alloy really did go porous, your engine would soon be scrap. Given pistons are made of alloy and have been for many a year as is much else on a modern engine. And the pressure inside a cylinder is far higher than in a tyre. If my pistons lose 0.1% of the gas on every stroke I won't notice. They are typically running about 25 power strokes a second. If my tyre lost 0.1% of its contents every 25th of a second I think I'd notice... How about the cooling system often made of alloy these days. If that were porous, it wouldn't hold pressure. The tubes of an alloy radiator are wrought and not cast. The process that makes the tubes compacts the alloy, distorts the crystal grain structure and removes (most) porosity. Casting process can entrain gas and that results porosity. So cast blocks and heads can be porous but drawn tubes and rolled sheet won't be porous. In part the thicker walls of castings prevent porosity as all the holes have to line up and join up for it to leak. Aero grade alloys for large cast structures (jet engine intercase) are vacuum melted to remove gas and vacuum cast. They can still suffer from strain induced porosity, where voids open up between the crystal grain. Unlike a crack that will go though a grain. |
Alloy porosity
In article ,
Peter Hill wrote: How about the cooling system often made of alloy these days. If that were porous, it wouldn't hold pressure. The tubes of an alloy radiator are wrought and not cast. The process that makes the tubes compacts the alloy, distorts the crystal grain structure and removes (most) porosity. But loads of the rest of the engine, cast. Many engines these days have an alloy block and heads. -- *Filthy stinking rich -- well, two out of three ain't bad Dave Plowman London SW To e-mail, change noise into sound. |
Alloy porosity
On Tuesday, 3 October 2017 11:02:25 UTC+1, Dave Plowman (News) wrote:
In article , harry wrote: On Monday, 2 October 2017 11:37:37 UTC+1, wrote: On Mon, 2 Oct 2017 11:28:06 +0100, "Dan S. MacAbre" wrote: Just the usual meja ********. If alloy really did go porous, your engine would soon be scrap. Given pistons are made of alloy and have been for many a year as is much else on a modern engine. And the pressure inside a cylinder is far higher than in a tyre. While I may actually agree with the gist of your argument how many tyres are repressurized a thousand or more times a minute. G.Harman With alloy engine parts, the holes/pores soon block with dirt/carbon particles. You have carbon/dirt in your cooling system? In which case something is porous. In any event any leakage is made up in the next fraction of a second. Which doesn't happen with wheels. No it doesn't. But I'd love to hear of a wheel which was genuinely porous, rather than just a poor seal between tyre and rim. And somehow I doubt you've ever changed a tyre yourself. I have built cars from the ground up. How a bout you? |
Alloy porosity
In article ,
harry wrote: And somehow I doubt you've ever changed a tyre yourself. I have built cars from the ground up. That I very much doubt. How a bout you? Very well, thanks. -- *You're never too old to learn something stupid. Dave Plowman London SW To e-mail, change noise into sound. |
Alloy porosity
On 01/10/2017 20:37, MrCheerful wrote:
On 01/10/2017 20:15, Harry Bloomfield wrote: Bill laid this down on his screen : When you say paint, what with and inside or outside the wheel? Or is this referring to painting the edges, or more, with sealant. No point to adding it to the outside, it needs to be inside. The problem with alloy rims, is that the salt and water corrodes the alloy, causing a poor seal to develop between tyre and wheel rim. The corrosion needs to be cleaned off down to bare metal, then the bare metal painted to protect it. There are plenty of places that will refurbish wheels to better than new, but it is not cheap and takes a few days or so.* One of my customers had his Lexus wheels refurbed because they leaked extensively and they were fine afterwards, iirc it was about 200 for all five. For my wheels I strip the tyre, clean the inner rim up, and use a belt sander on the important seal area around the edge, then spray them with etch primer, then some silver wheel paint, works fine, even if you miss out the etch primer. Can you see the corrosion if you take the tyre off. i.e. is it obvious to repair. -- Michael Chare |
Alloy porosity
On 08/10/2017 20:33, Michael Chare wrote:
On 01/10/2017 20:37, MrCheerful wrote: On 01/10/2017 20:15, Harry Bloomfield wrote: Bill laid this down on his screen : When you say paint, what with and inside or outside the wheel? Or is this referring to painting the edges, or more, with sealant. No point to adding it to the outside, it needs to be inside. The problem with alloy rims, is that the salt and water corrodes the alloy, causing a poor seal to develop between tyre and wheel rim. The corrosion needs to be cleaned off down to bare metal, then the bare metal painted to protect it. There are plenty of places that will refurbish wheels to better than new, but it is not cheap and takes a few days or so.* One of my customers had his Lexus wheels refurbed because they leaked extensively and they were fine afterwards, iirc it was about 200 for all five. For my wheels I strip the tyre, clean the inner rim up, and use a belt sander on the important seal area around the edge, then spray them with etch primer, then some silver wheel paint, works fine, even if you miss out the etch primer. Can you see the corrosion if you take the tyre off. i.e. is it obvious to repair. yes, but I would usually put detergent around the tyre first to confirm the leaking side/area. |
Alloy porosity
On Sunday, 1 October 2017 19:23:23 UTC+1, Retro Futurist ... wrote:
"Bill" wrote in message ... I may be about to buy, from a scrapyard, a set of 5 replacement wheels for the recently purchased car to get a spare wheel, proper sized tyres and wheels that fit the wheel nuts. In the past, I've often been told that the reason for a slow puncture was that the alloy wheels had gone porous. More recently, I've been told that the cylinder head on a certain vehicle had gone porous and that was why it chuffed when cold. I have always wondered whether this is a standard get-rid-of-him phrase taught as part of the Car Mechanics PhD (Hons) course, or whether alloy does actually start to leak. Does anyone know? Is there any sort of standard test, like wheel tapping, that can detect this sort of rot? I have found them to leak and the seal goes at the rim ...... I had mine resealed they just spun them on a jig then applied some magic to the milled surface and they were excellent afterwards. 20 quid. |
Alloy porosity
On Sunday, 1 October 2017 20:15:20 UTC+1, Harry Bloomfield wrote:
Bill laid this down on his screen : When you say paint, what with and inside or outside the wheel? Or is this referring to painting the edges, or more, with sealant. No point to adding it to the outside, it needs to be inside. The problem with alloy rims, is that the salt and water corrodes the alloy, causing a poor seal to develop between tyre and wheel rim. The corrosion needs to be cleaned off down to bare metal, then the bare metal painted to protect it. I doubt that is the problem as the tryes need to be leaking to allow ingress. |
Alloy porosity
In article ,
Weatherlawyer wrote: I have found them to leak and the seal goes at the rim ...... I had mine resealed they just spun them on a jig then applied some magic to the milled surface and they were excellent afterwards. 20 quid. They seem to use some form of sealer these days. I was having two new tyres fitted to the old car when the fitter took a phone call after applying it to one wheel. And was on the phone for ages. He didn't apply more, and that tyre leaked. The other OK. Had it re-done and it was fine. -- *If Barbie is so popular, why do you have to buy her friends? * Dave Plowman London SW To e-mail, change noise into sound. |
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