Hi Simon,

I too have been building a Bentley off and on for far too long and I know just how your father must feel having discovered the rusting.

If it's badly pitted there is nothing you will be able to do to restore the surface finish without recutting. Nickel plating will just plate what is there and in all probability accentuate the problem besides being totally out of character for the engine.

I have always found the coarser Garryflex abrasive blocks used with paraffin as a lubricant ideal for rust removal but even they can't do anything about any deep pitting effect left other than polish out the 'recesses'. The only way in my experience that that can be overcome is, as said, by recutting the metal but if the pitting is not too deep using wet and dry paper of varying grits stuck with doubled sided tape to small blocks of smooth hardwood (model aircraft engine bearer is ideal) and a bit of patience may help even things out a bit before using the Garryflex.

As a matter of interest I have the various steel parts made (all En1a for the case parts) stored for several years coated with a mixture of paraffin and oil and wrapped in waxed paper stored in card boxes. I began it (much to my chagrin) in 1992 and only once has a small amount of rust been found on the rear thrust box which was easily dealt with as above. It occasionally sees the light of day when a quick inspection and re-oil sees it ok for another few months – this is a timely reminder to perhaps have another check

I haven't worked on it for some time now and am not sure when the opportunity will come when that might be again – shame really as there's a lot of work been done so far but neither the time nor the inclination to do so is there at the moment.

Hope you manage to resurrect it sufficiently to meet your 'eyes approval' – it's a lot of time not to mention swarf to make another!

Hope this helps a little

regards – Ramon

Edited By Ramon Wilson on 02/12/2012 23:18:40

One of the best oils for rust protection is Camellia oil – used historically by the Japanese to preserve tools and swords (Also for Sumo Wrestlers hair dressing ). It is expensive to buy for this purpose but is also sold for essential oils use more cheaply. eBay is a good source. I use it on my machine surfaces and can only report good results.

Another oil for rust prevention is of course Lanolin which was used extensively in industry for preventing rust on bright Steel and tubing, it is a by product of wool production – sheeps fleece contain it.

Best regards

Terry

Lampton, please note that the electrolytic method of de-rusting can/will cause hydrogen embrittlement of steels.

Yes this is a possibility with some high strength steels but the effect can be mitigated by limiting the current used and by heating the component at 100 C + for a while after treatment.

The system is perfectly safe on mild steel and cast iron.

Lots of info on hydrogen embrittlement & its prevention/correction on the Internet

There wereare quite a few formulas used by the Japanese to preserve sword blades and the like. One western approximation is a mixture of light mineral oil and clove oil. It's got the advantage of being relatively cheap – but the smell of the cloves might not suit everyone, it's fairly pungent.

A agree with the suggestion of electrolytic rust removal. I was given a 'basket case' half-finished seal, and used it to clean up the very sorry looking crankshaft. The rust was converted to black phosphate.

You would not believe the condition of this before I started:

Don't forget to oil it as soon as it comes out of the bath. I used caustic soda, I understand that even sodium bicarbonate (baking soda) works just as wel as either caustic or washing soda and much better if you spill it!

Neil

I use a tumbler for small pieces using steel media and burnishing powder. It gets rid of all corrosion even in the pits and shines just like polished steel. If you want a matt finish use ceramic shapes, ideal for deburring as well. For larger items I use a large coffee tin in the lathe. I have been restoring a lathe and have cleaned all the headstock and gearbox items using this method. I also use it to restore bits on my m/c's as well. Just load the drum and leave it all day to tumble and get on with something else. I have used this method for 20 plus years with great results. The great thing about it is you are not restricted to any particular material or media. Even crushed walnut shells do a good job on brass and other soft metals.

Lots of good advice given – no response from OP Simon?

JD

Mike,

I bead blast crankcases too – usually ali though – and agree on the lovely uniform finish it gives and that it will soon remove surface rust on steel too. It won't eliminate average tool marks however so I doubt it would disguise the pitting described by the OP.

I notice you use the word Soda – is this using Bi Carbonate ? I have recently been made aware of this but haven't tried it yet. Are you able to comment on how it compares (surface finish) to bead blasting?

Jeff, I guess we have to assume Simon hasn't returned to see the response to his question – otherwise what else could one think

Regards – Ramon

OK Simon, I appreciate your situation but responses on here to a plea for help usually come by return.

From what you say I don't think you have fully appreciated the attempts to help you.

Firstly as a Bentley builder myself I can well appreciate your fathers feeling and can empathise with his situation.

Having made a similar crankcase I can well appreciate the work involved and as someone with a degree of past experience can only offer the advice given so far. However, for what it's worth plating is like painting – the surface finish will only ever be as good as the substrate underneath. In your case this is damaged and to do as you suggest would require either the ability to plate the area damaged and then reclaim it by abrasive means leveling it to the surrounding area before plating it again to get a uniform finish. A bit like trying to paint a surface and reclaiming areas where the paint has flaked off back to the parent surface only in your case theres not the ability to cover that final surface with an opaque colour. I'm sure you can see that's not something that probably most of us on here would recognise as a reasonable way of going about things given the part.

To that end I think your fathers decision to make another is the only effective way to get over the problem as whatever you do to reclaim it will as you say potentially either weaken the part or change it dimensionally at the expense of visual perfection.

I confess to being someone who does not like 'imperfect' things and in this case I would very much follow in your fathers footsteps and make it again – if it's any consolation I made three cam boxes and, as I'm sure he will agree, theres an awful lot of work in them too.

I do wish him luck with it – I only wish I could find the time to finish my own.

Regards – Ramon

"I can't find much info online about plating damaged parts."

Ramon,

You are correct, the media used is Bi Carb of Soda. It comes in many grades and the finish can be as perfect as you want. A coarse grade would be better for a rough surface to accept a painted finish whereas a fine media for a metal component that is seff coloured. If using it over a chilled iron or glass media tha best advantage is the part can be washed in a hot tank and the soda desolves leaving a perfect part ready for assembly. Sometimes trying to get the grit out can be a tricky process and always a small risk that a small piece of media ends up on a bearing surface and causes damage. Recently I soda blasted a TVR front crankcase casting which has the oil pump included in it. In the past I have blanked and masked the openings to stop the ingress of glass madia as they get vapour blasted but with soda, no masking is necessary and the finish is better than new.

Here are a couple of shots of a 92 Fireblade I am doing, the finish is amazing. And it's dead cheap!!

Mike

You should look on my website, you will see many types of finishes and paint work. To be honest the process is so cheap it probably not worth the investment in either the media or the cabinets/compressor etc. For the jobs you are doing perhaps £5 at the most. You can email me directly throught the site, on my profile.

Glad to help if I can.

Mike