Discussion
kit car components so poorly coated?
Over the years I've a a fair amount of exposure to kit-cars (through ownership and through friends cars) and the one thing that has struck me is how shocking the coating processes are from the likes of Caterham, Westfield, etc. Even TVR chassis are poorly coated IMO. It just seems like a false economy to me.
Why, when the chassis is the most difficult bit to get at, do the manufactures use such poor quality coatings? I'm sure everyone would be willing to pay an additional few hundred pounds for the piece of mind of not having to do a bare metal strip down of their chassis after a few years of ownership. The only kits I've seen that seem to get this right are from Z-Cars which have superb (and robust) coatings. I've yet to see a LS7 type car that is over 2 years old and doesn't have rusty front suspension and steering arms.
Over the years I've a a fair amount of exposure to kit-cars (through ownership and through friends cars) and the one thing that has struck me is how shocking the coating processes are from the likes of Caterham, Westfield, etc. Even TVR chassis are poorly coated IMO. It just seems like a false economy to me.
Why, when the chassis is the most difficult bit to get at, do the manufactures use such poor quality coatings? I'm sure everyone would be willing to pay an additional few hundred pounds for the piece of mind of not having to do a bare metal strip down of their chassis after a few years of ownership. The only kits I've seen that seem to get this right are from Z-Cars which have superb (and robust) coatings. I've yet to see a LS7 type car that is over 2 years old and doesn't have rusty front suspension and steering arms.
Jon Ison said:
I can think of a few reasons, LS 7 type cars have their suspension components exposed to the elements (and stone chips) been the main one.
You missed my point. That's why they get chipped, not why the coatings are so rubbish. Chassis that are not subject to the same chipping also go rusty very quickly. Why are some thread titles so uninformative?
Give the chassis a good degrease (I use white spirit) wire brush any rusty bits, then use two coats of hammerite (I use the Wickes equivalent (brush washes out in water)) and use a different colour for the bottom coat.
The reason so much powder coating fails is that they don't degrease the metal properly first.
Give the chassis a good degrease (I use white spirit) wire brush any rusty bits, then use two coats of hammerite (I use the Wickes equivalent (brush washes out in water)) and use a different colour for the bottom coat.
The reason so much powder coating fails is that they don't degrease the metal properly first.
singlecoil said:
Why are some thread titles so uninformative?
Give the chassis a good degrease (I use white spirit) wire brush any rusty bits, then use two coats of hammerite (I use the Wickes equivalent (brush washes out in water)) and use a different colour for the bottom coat.
The reason so much powder coating fails is that they don't degrease the metal properly first.
SorryGive the chassis a good degrease (I use white spirit) wire brush any rusty bits, then use two coats of hammerite (I use the Wickes equivalent (brush washes out in water)) and use a different colour for the bottom coat.
The reason so much powder coating fails is that they don't degrease the metal properly first.
But we shouldn't have to though should we. The manufacturers should do a proper job in the first place.
One of my friends is rebuilding his Fisher Fury, and is using a chassis powdercoating process which is used in the Aircraft Industry. it is £300 MORE that a usal chassis powdercoat, but is supposed to last at least 25 years. He gets the chassis back in a couple of weeks, will let you know what it is called if it turns out OK. Agree that it is not normally the powdercoat process that is at fault, it is purely sub-standard preperation of the metal first.
do you know how westfield, sylva, fisher or whatever they are called produce their cars (cars components)?
external companies do everything....there is one guy in a workshop (garden shed) who is welding the chassis, the other companies care about suspension parts etc.
so no control from the constructors, low payment for the sub-contracotrs, no quality control there and it ends at a powder-coating company who is underpayed, therefore saves powder, chassis maybe already arrive rusy, anohter sand-blasting cost money (therefore it wont be done) and after a few years the end-consumer will have the problem with a rusty chassis.
with TVR it was another story:
when TVR started with powder coating (first done on their tasmin-models), it was done by a company, well known and specialized in this kind of process. after a few years TVR decided that they will do themselves...and the coating of these cars starts flaking very soon.
have seen pictures of completed-chassis, waiting on the coating, stored outside on the factory yard and getting rusty.
external companies do everything....there is one guy in a workshop (garden shed) who is welding the chassis, the other companies care about suspension parts etc.
so no control from the constructors, low payment for the sub-contracotrs, no quality control there and it ends at a powder-coating company who is underpayed, therefore saves powder, chassis maybe already arrive rusy, anohter sand-blasting cost money (therefore it wont be done) and after a few years the end-consumer will have the problem with a rusty chassis.
with TVR it was another story:
when TVR started with powder coating (first done on their tasmin-models), it was done by a company, well known and specialized in this kind of process. after a few years TVR decided that they will do themselves...and the coating of these cars starts flaking very soon.
have seen pictures of completed-chassis, waiting on the coating, stored outside on the factory yard and getting rusty.
Having built and ran a Caterham in 1990 to 2002, the most depressing thing about the car was looking at the beautifully built car deteriorating before my eyes. Despite taking car, repainting suspension etc, the chassis frame corroded badly. A small chip in the powder coat didn't show up until the water has penetrated about 30mm or more behind the coating and the coating then dropped off.
Now as for TVR, had one of them too, a 94 Chimaera and there was very little protection to the more exposed chassis sections which is why the dealer I purchased it from used to Waxoyl it every time it went in for a service. Read the Chim/Griff threads on PH and you will see plenty of discussion about body off/full restoration jobs where sections of the chassis have rotted and need replacing. Scary on a high performance, high price car.
Now as for TVR, had one of them too, a 94 Chimaera and there was very little protection to the more exposed chassis sections which is why the dealer I purchased it from used to Waxoyl it every time it went in for a service. Read the Chim/Griff threads on PH and you will see plenty of discussion about body off/full restoration jobs where sections of the chassis have rotted and need replacing. Scary on a high performance, high price car.
Comadis said:
do you know how westfield, sylva, fisher or whatever they are called produce their cars (cars components)?
You have clearly never visited some of the companies you are talking about, Comadis. Westfield, in particular, have quite a sophisticated set-up and fabricate all their own chassis in-house.Certainly, there is sub-contracting from almost every kit-car manufacturer, but suggesting that it is done by men in garden sheds is doing a great disservice to both the industry as a whole and specialist sub-contractors like Caged, Midas Metalcraft etc.
Both the Westfield SE and the Caterham I have owned had pretty good powder coating (and both lived outside without ill effects), thogh ironically the best protected chassis I have come across was the beautifully stove-enamelled chassis on my Raffo Tipo 12, which probably was fabricated by one man (John Raffo) in his garden shed.
I think they tend not to bother with better coating mainly because a tubular chassis will go from the inside-out if left long enough, so there's not much point in getting the outside really good. It's pretty much impossible to protect the insides of all the tubes in something like a TVR chassis adequately. They were regarded as a "service" item with a lifetime of about 10 years under normal use. Also, I think economics comes into it a bit. If they spent more on the coating they probably feel they wouldn't get their money back in terms of higher residual values. By the time a car needs a new chassis, it's very often changed hands several times and there's not much money in it for the factory compared to the income from selling a new chassis.
As far as I can remember, the early TVR chassis referred to were coated in an epoxy powder which bonded very well to the steel. I think later cars used and epoxy-polyester mix, getting progressively more ployester in it (which was cheaper but doesn't really stick to steel).
As far as I can remember, the early TVR chassis referred to were coated in an epoxy powder which bonded very well to the steel. I think later cars used and epoxy-polyester mix, getting progressively more ployester in it (which was cheaper but doesn't really stick to steel).
I have to admit i agree with the OP (and the people who think the thread title is s
t).
One thing i dont get as well is the obesssion with powder coating as the bench-mark 'be all and end all' of coatings.
- As mentioned before, a coating is only as good as the prep, and for powder coat thats ive more so.
Personaly i have a chassis built i would have it shot blasted (well) and follw that on with blast primmer (get it on within half an hour of blasting) then a build coat of epoxyzinc/epoxyaluminum. Followed by two coats of twopack polyerothene of a colour of my choice. Brushed on, or sprayed if i had the gear.
This is what we use on are narrowboat, inside and our, and it works a treated.
Cabin did 10 years or more outside being bashing round the canal, being walked on, rocks thrown at us, and one section of roof being bent at 45degrees and strighted out (long story) and the only rust at all is on the two leading edges where all the paint was taken off to bright steel on a very narrow tunnel and left. No paint has loosened/cracked/flaked/peeled/worn at all even round the gashed corners. And it was only repainted because it had lost is shine, due mainly to the walking on, and being in the sun. The boat is now 17yo.
But yeah, im looking at a 1995 westy, and the surface rust down all of the chassis members, in the engine room, of all places.
- The recomendation is just to 'paint some rust proofing over it' and waxoyl the bottom, and when i ask about all bits i cant get to or even check for rust due to interia pannels i get a funny look!
Chassis shouldnt rust from the inside eather, becuase as far as im aware all the tubes should be sealed? no?
Daniel
t).One thing i dont get as well is the obesssion with powder coating as the bench-mark 'be all and end all' of coatings.
- As mentioned before, a coating is only as good as the prep, and for powder coat thats ive more so.
Personaly i have a chassis built i would have it shot blasted (well) and follw that on with blast primmer (get it on within half an hour of blasting) then a build coat of epoxyzinc/epoxyaluminum. Followed by two coats of twopack polyerothene of a colour of my choice. Brushed on, or sprayed if i had the gear.
This is what we use on are narrowboat, inside and our, and it works a treated.
Cabin did 10 years or more outside being bashing round the canal, being walked on, rocks thrown at us, and one section of roof being bent at 45degrees and strighted out (long story) and the only rust at all is on the two leading edges where all the paint was taken off to bright steel on a very narrow tunnel and left. No paint has loosened/cracked/flaked/peeled/worn at all even round the gashed corners. And it was only repainted because it had lost is shine, due mainly to the walking on, and being in the sun. The boat is now 17yo.
But yeah, im looking at a 1995 westy, and the surface rust down all of the chassis members, in the engine room, of all places.
- The recomendation is just to 'paint some rust proofing over it' and waxoyl the bottom, and when i ask about all bits i cant get to or even check for rust due to interia pannels i get a funny look!
Chassis shouldnt rust from the inside eather, becuase as far as im aware all the tubes should be sealed? no?
Daniel
chassis tubes do not extensively rust from inside and this is definately sure not the reason that the powder-coating is flaking.
preparation of the chassis in advance is the most important thing.
ok..maybe i was wrong with westfield about the chassis, but i know it from sylva, fisher and when i spoke with ginetta 3 weeks ago about some parts for my 1991 G4 i was told to aks the guy who did all the metal-work for them in the past
a friend of mine picked up the refurbished chassis for his Lotus23...and the guy who did the accident damage-repair and the refurb was one of these garden-shed companies.
preparation of the chassis in advance is the most important thing.
ok..maybe i was wrong with westfield about the chassis, but i know it from sylva, fisher and when i spoke with ginetta 3 weeks ago about some parts for my 1991 G4 i was told to aks the guy who did all the metal-work for them in the past
a friend of mine picked up the refurbished chassis for his Lotus23...and the guy who did the accident damage-repair and the refurb was one of these garden-shed companies.
Comadis said:
ok..maybe i was wrong with westfield about the chassis, but i know it from sylva, fisher and when i spoke with ginetta 3 weeks ago about some parts for my 1991 G4 i was told to aks the guy who did all the metal-work for them in the past
Sylva has gone through phases; I've visited the factory at times when Jeremy employed guys to do the welding in-house, and times when there was just him and an assistant and everything was farmed out.But if you've ever seen spaceframes being series manufactured on jigs, you'll know it's not the sort of operation you can carry out within a 'garden shed'.
Why can't the chassis tubes rust from the inside? There might be some designs where SOME of the tubes are sealed, but there are often holes for brake pipe clips, captive nuts, etc in them which will allow oxygen inside. I've certainly seen plenty of TVR chassis that have rusted from the inside AND the outside as well!
I absolutely agree that the rusting from the inside is NOT what causes the powder coating to fall off and I hope nothing I said suggested that was the case! (well, not until the internal corrosion breaks through anyway)! I also agree that with better preparation, the coating would adhere better. That said, polyester is not the best stuff to use (but it IS cheap)!
The barge analogy needs, I think, treating with care because barges are generally made of thicker steel than tubular chassis so they've got more "spare" electrons to help resist the oxidation process. If I left a piece of completely uncoated 5mm mild steel strip and a completely uncoated piece of 1.6mm strip out in the rain, the thicker steel would form an oxide layer all over itself and then continue to deteriorate slowly. The thinner steel would do the same but the oxide layers on each side would obviously "meet" much sooner than on the thick steel. I don't know if that makes sense, but what I'm trying to say is that I'd expect the 5mm to last more than three times as long as the 1.6mm piece.
I absolutely agree that the rusting from the inside is NOT what causes the powder coating to fall off and I hope nothing I said suggested that was the case! (well, not until the internal corrosion breaks through anyway)! I also agree that with better preparation, the coating would adhere better. That said, polyester is not the best stuff to use (but it IS cheap)!
The barge analogy needs, I think, treating with care because barges are generally made of thicker steel than tubular chassis so they've got more "spare" electrons to help resist the oxidation process. If I left a piece of completely uncoated 5mm mild steel strip and a completely uncoated piece of 1.6mm strip out in the rain, the thicker steel would form an oxide layer all over itself and then continue to deteriorate slowly. The thinner steel would do the same but the oxide layers on each side would obviously "meet" much sooner than on the thick steel. I don't know if that makes sense, but what I'm trying to say is that I'd expect the 5mm to last more than three times as long as the 1.6mm piece.
Avocet said:
The barge analogy needs, I think, treating with care because barges are generally made of thicker steel than tubular chassis so they've got more "spare" electrons to help resist the oxidation process. If I left a piece of completely uncoated 5mm mild steel strip and a completely uncoated piece of 1.6mm strip out in the rain, the thicker steel would form an oxide layer all over itself and then continue to deteriorate slowly. The thinner steel would do the same but the oxide layers on each side would obviously "meet" much sooner than on the thick steel. I don't know if that makes sense, but what I'm trying to say is that I'd expect the 5mm to last more than three times as long as the 1.6mm piece.
Narrowboat....However, i dont really see why the thickness of the steel has anything to do with how long it takes a free surface to oxidise.
- Certainly it doesnt answer the bonding/flaking issue.
Daniel
No, I'm not saying that the thicker stuff won't form an oxide layer on its surface any slower - it's what happens after that which makes the difference. Man hole covers are very thick (and uncoated) and last for hundreds of years. OK, they're also cast iron rather than steel so it's not the best example, but I think the surface oxide layer protects what's underneath in a what that a thin section can't.
As for the poor adhesion of the powder coating, I think I have already agreed that this (in my view) is mainly down to poor surface preparation and poor quality coating materials.
As for the poor adhesion of the powder coating, I think I have already agreed that this (in my view) is mainly down to poor surface preparation and poor quality coating materials.
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