Sub-frames protection

Everything that keeps your car in contact with the road, and from contacting other road users.
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torque2me
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Sub-frames protection

#1 Post by torque2me » Fri Oct 22, 2021 12:18 pm

Hello,

Most of us have tried to protect various parts from corrosion and rust :shock:

I've a sub-frame to protect and whilst I automatically thought powder coating I then considered if there were better alternatives, in your opinion, to PC?

Kev

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Re: Sub-frames protection

#2 Post by johnnydog » Fri Oct 22, 2021 11:23 pm

I think the quality and durability of powder coating is relative, as with any finish, to the amount of preparation of the surface of the part.
I had a Freelander front bumper with rust spots powder coated by a different company many years ago, and it rusted again in a short space of time suggesting that the metalwork wasn't prepared properly to remove the rust. Like I said above, heavily rusted Triumph towbars taken off Triumphs I have scrapped, have been shotblasted prior to powder coating, and are now fitted on my S, both PI's and the Mk2 2000 today - the gloss finish is still excellent some 15 years later. It wasn't particularly expensive - much cheaper than me preparing them, buying and applying another form of protective finish.
Maybe the caravan legs weren't prepared properly prior to being powder coated?
Just my thoughts / experiences. It may also depend on whether a 'concours' finish is wanted.
Last edited by johnnydog on Sun Oct 24, 2021 9:46 pm, edited 1 time in total.
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1967 Mk1 2000 in Gunmetal Grey
1969 Mk1 2000 in Royal Blue
1970 Mk2 2000 in Valencia Blue
1972 Mk2 2.5 PI in Triumph White
1973 Mk2 2.5 PI in Sienna Brown
1976 Mk2 2500S in Carmine Red

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david_lall
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Re: Sub-frames protection

#3 Post by david_lall » Sun Oct 24, 2021 7:08 am

In the past I've used powder coating and reached the conclusion that it's a waste of money especially as I've now discovered Rustoleum combi colour.

It's white spirit based and is essentially an enamel paint that when used with decent brushes such as Purdy can be flatted and polished if you want a high gloss finish.

Some suppliers such as Avenue Coatings in Colnbrook can even mix it to any colour you want whereas places like Brewers only do RAL colours.

Just like Hammerite it can be applied to bare metal and rusted surfaces but it's a much superior paint.

There's a hard hat version too and with that over an etch primer stone chips on the PI grille are pretty much a thing of the past - the grille was one of the few places I've used it from a spray can but this is what I've achieved in the engine bay of my MG 1300
20170426_165311.jpg
The bulkhead and inner wings have all been brush painted with Rustoleum, only the rocker cover has been sprayed. And underneath...
20170428_111223.jpg
The Triumph grille was done with the hard hat around 10-years ago
IMG_20210917_160214.jpg
Powder coating on the caravan legs lasted a couple of years, the Rustoleum lasts something like 6 years.

There's one big disadvantage with Rustoleum though, and that's you have to do all the work yourself! 😂
David Lall

1972 Triumph 2.5 PI Estate Royal Blue
1968 MG 1300 Saloon Connaught Green
1978 Carlight Casetta Caravan
http://carlightrestoration.blogspot.co.uk
1995 Lada Riva 1.5 Estate Cherry

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Re: Sub-frames protection

#4 Post by johnnydog » Sun Oct 24, 2021 10:09 pm

johnnydog wrote:
Fri Oct 22, 2021 11:23 pm
I think the quality and durability of powder coating is relative, as with any finish, to the amount of preparation of the surface of the part.
I had a Freelander front bumper with rust spots powder coated by a different company many years ago, and it rusted again in a short space of time suggesting that the metalwork wasn't prepared properly to remove the rust. Like I said above, heavily rusted Triumph towbars taken off Triumphs I have scrapped, have been shotblasted prior to powder coating, and are now fitted on my S, both PI's and the Mk2 2000 today - the gloss finish is still excellent some 15 years later. It wasn't particularly expensive - much cheaper than me preparing them, buying and applying another form of protective finish.
Maybe the caravan legs weren't prepared properly prior to being powder coated?
Just my thoughts / experiences. It may also depend on whether a 'concours' finish is wanted.
Looks like I somehow deleted the wording of my original post.....? :roll: Lesson to myself - shouldn't do it on my mobile.... :roll:

But basically, I referred to the benefits, in my opinion, of powder coating as a protective finish. If heavily rusted, then shot blasting prior to powder coating is important to remove all surface contamination, and protecting the blasted surface from moisture prior to the powder coating being applied. I referred to the difficulties in preparing the surface yourself if considering chassis black or smoothrite etc, and the likelihood of rust reappearing, and the heavily rusted Triumph towbars I have had powder coated which are still as good as the day they were done, some 15 years ago.
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1967 Mk1 2000 in Gunmetal Grey
1969 Mk1 2000 in Royal Blue
1970 Mk2 2000 in Valencia Blue
1972 Mk2 2.5 PI in Triumph White
1973 Mk2 2.5 PI in Sienna Brown
1976 Mk2 2500S in Carmine Red

torque2me
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Re: Sub-frames protection

#5 Post by torque2me » Tue Oct 26, 2021 8:05 pm

Thanks for your replies David and Johnnydog.

How about enamel? Might be too brittle for a sub-frame - a bit like a bath getting a chip and impossible to repair.

Kev

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david_lall
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Re: Sub-frames protection

#6 Post by david_lall » Fri Oct 29, 2021 11:11 am

Rustoleum is essentially an enamel paint.... It's dead simple to get a flat finish with matt, a little care is required with the satin but really it's down to the brush, i use Daler-Rowney System 3 brushes for small areas that Purdy are too big for and you need a bit of skill to get a flat finish with gloss
David Lall

1972 Triumph 2.5 PI Estate Royal Blue
1968 MG 1300 Saloon Connaught Green
1978 Carlight Casetta Caravan
http://carlightrestoration.blogspot.co.uk
1995 Lada Riva 1.5 Estate Cherry

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Re: Sub-frames protection

#7 Post by GinettaG15 » Tue May 02, 2023 10:58 pm

Powdercoating is a very common and durable process for wheels and suspension parts, incl. coils.

but the final result always depends on preparation.

alloy wheels can be sand-blasted and coated straight away.

with steel parts you can do this as well (and most powder coaters do it that way...because its quick, easy and cheap...)...but its NOT the correct way:

so the problem is NOT powder-coat in general: it is the way it has been done

the correct way is removal of old paint /coating (dipping into chemicals or sand-blasing), followed by:

1.Iron phosphating

By spraying on the iron phosphating, the metal surfaces are first cleaned of dirt, such as oils and greases. The insulating property of the phosphate layer protects a damaged coating layer against rust. The workpieces are then rinsed twice in a continuous spraying system and the residual chemicals are removed.

2. Passivate

The passivation follows the iron phosphating and rinsing and creates a defined thin and stable conversion layer on the workpiece. This increases both the adhesive strength and the corrosion resistance of the subsequent powder coating

3. powder

above steps do also cost.

alternative:

galvanizing (hot dip zinc)

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Re: Sub-frames protection

#8 Post by johnfrancis898 » Wed May 03, 2023 12:23 pm

I am currently completing a front suspension rebuild and I have used black gloss Hammerite for most of the bits. The previous owner of my car painted the whole engine in green Hammerite with the hammered finish and it looks really good. I chose Hammerite because it claimed it can be put on to rusty surfaces. I thoroughly prepared all the rusty parts with a wire brush in various forms, by hand and with a drill, so they were more or less bright and after degreasing applied 2 coats. The result so far is good, if not better, than some of the powder coating I have seen. I have also done the front crossmember in it and I am really pleased with the results so far. As mentioned by others I think the preparation is key to whatever finish you go for.
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