Thursday 27 March 2014

Achilles Report No51: Smokebox Success at Last!...

Hi there. Regular readers will probably have been keeping up with the steady progress on my locomotive "Achilles". She has been under-going a repaint as well as some repairs for the last three months now, off & on. One of the biggest problems has been the smokebox as the various paint types and manufacturers I've tried so far have not worked. The last post on this blog regarding the loco saw the smokebox in a grey Exhaust Spray paint, designed for high temperature applications. However, the finish was very powdery. As you rubbed your hand across it, even when totally cured, the effect was dusty at best. The paint also had pretty poor coverage for a spray paint and so, enraged as one gets with these constant irritations, the smokebox again found itself under paint stripper. The paint blistered like mad as it was sanded away from whence it came. White spirit was then used to clean away the debry and the remaining paint stripper. What was then revealed was probably the cleanest paint-free finish yet on the smokebox. The new brand of paint: another high-heat type: is Hammerite Matt Black. This stuff was applied yesterday. It has much better coverage, settles much more nicely and dries quickly. It also cures without heating which is a bonus. However, even with a much better finish than had yet been achieved, the paint still reacted with the final remnants of the old paint underneath. After pondering it over a cuppa', I decided that there was only one course of action left. As paint stripper would not even think about touching some of the 27-year old paint, it would have to be lightly chipped off until bare metal was found. So, with a sharp straight edge and lots of care, I set to work. One of the worst areas of reaction was at the foot of the smokebox near the running board...
From the front running board I worked my way up the smokebox face, following the trails of the reaction. Eventually, the smokebox face was fairly clean and was then sanded to become as flat as possible. This was the result...
"The Greatest Struggle Ever!"
With the best possible finish achieved, I tried the paint again with much better success. The paint took to the smokebox face beautifully with no reaction. The only remaining parts of reaction are some very small spots around the snifting valve (probably oil residue) which can easily be chipped off, sanded and repainted. The smokebox will need a final coat anyway. The smokebox door also later received a coat of matt black ready to join its counterpart in the near future. Thank goodness for that...
It was then time to head off the job until this morning when work recommenced. So, today, the job continued with the rubbing down of the chimney ready for spraying. The brass area was heavily masked for protection and then the black liveried areas rubbed down. It will also be sprayed with the Hammerite high-heat so as to match the smokebox when time allows...
Meanwhile, the expansion links and their trunnion bearings have also received attention. The old, worn bearings have been replaced with new ones which we turned from phospher bronze bar. The holes in the centre are completely central but have not been made to drawing, instead they've been made to a good running-fit with the trunnion pins. This is to save replacement of the trunnion pins themselves as they are still in fairly good condition. Obviously any wear on the pins themselves will be taken in account by the new bore in the new bearings, rather than worrying about replacing both. The engine will still work just the same. The new bearings look fairly smart and just need to be pressed into their housings before having the oil-way hole drilled. These simple tasks will take place once the housings have been painted which is being done in due course...
"More New Bearings!"
A close up of one of the expansion links with the new trunnion bearings...
The smokebox paint had fully cured by this morning and is beginning to look rather smart. I just have some more tiny bits of reaction to remove and then she can have her top coat and the door replaced. I will then lag the boiler...
"Smokebox Nearly Done"
The new whistle valve was tried today with the pipework to the whistle itself. Eddie kindly did some modifications to the whistle as it did not fit the manifold when it arrived. The smart-looking valve is a Reeves product, much like the loco, and should look well when fitted to the engine...
The final task of today was to sand and prime the four trunnion bearing housings. The four received their first coat of primer just before I stopped play for today. They'll just need a final coat of primer (or maybe not if it has settled well) and then a coat of matt black. It will then be time to press the bearings in and drill the oil-ways before painting the slide-bar hangers from which these housings also hang. Once those jobs are complete, the expansion links can be refitted ready for action...
"Trunnion Bearings in Primer"
As you can see guys "Achilles" is now marching along quite nicely. Most things are progressing well and I am quite enjoying the various tasks at present. I am so relieved that the smokebox has now settled as that was becoming quite a worry. Best Regards, Sam...

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