7mm Mickoo's Commercial Workbench

mickoo

Western Thunderer
Quick out and back to Yorkshire, delivery of one, collection of another Midland engine to join the Garratt, I'll do both at the same time and flit twixt one and the other in due course.

I still need to tidy some other niff naff up before rebuilding the A2 but here's a couple of teaser shots.

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cmax

Western Thunderer
Irish Elegance, elegance indeed, super build & super paint job.

looking forward to seeing her after the rebuild.

Gary
 

mickoo

Western Thunderer
Small update, few issues along the way with the rebuild, all eventually solved and it now runs sweetly.

One of the sand pipes came off......bahh...... and whilst refitting, noted I'd completely missed the front ones off altogether :eek:; those, the speedo cable and fittings need a touch of paint to complete and I've caught one or two other areas that just need a small dab to blend them in.

Just a few more bits to refit, backhead and drawbar, then secure the doors, fall plate and gauges.

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mickoo

Western Thunderer
Still grinding along on the A2, a case of two steps forward and one back.

Pretty much complete except for the one very big elephant in the room, and, being as we all like to show and tell I shall do so, painful and bad as it is, maybe y'all learn where I didn't.

The final view, looks fine doesn't it.

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The completed cab, sans doors and fall plate., they've been left off as they pose a high damage risk for the next and hopefully final stage.

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Right folks, just to show not everything at castle Mickoo is unicorns and skittle rainbows.

Remember the firebox, sure you do, the one that was too narrow at the crown, and the grafted in slice to rectify, well it's come back to haunt me.

The correct thing to do was to throw it in the bin and make a new one, I didn't, I sliced it, backed it with a large plate and inserted a slice heavily dosed in solder. That was all trimmed back and the last final vestiges of the joint filled with Milliput and sanded smooth, smooth to the touch but sadly not smooth enough for Warrens ultra thin skim of paint he uses to get that lovely smooth finish.

In fairness neither of us spotted it early on, only when it was back lit did it become obvious.

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The image has been processed to highlight the flaw, it also shows that no matter how much you clean the model they attract dust that digital cameras just love to highlight for you :p.

As time has passed it has gotten worse and there is a definite visible joint now showing under most conditions, such that the fix is not going to be easy.

In addition to that, two patches have appeared on the cab roof below the gutter, I suspect there was some flux trapped under the angle and it has seeped out to attack the paint from underneath, that'll have to be cut back to the metal to make good I suspect, pahh.....:rant:

Clearly the safety valves had to come out one way or another and whilst doing so noted that the originals were not right either, actually quite cross I didn't spot that before fitting them.

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The originals are the right diameter but have a big nut mid body, the Thompson ones are like the generic LNER ones with two rings mid body as seen by the spare Finney7 one (temporarily) placed to the rear. Sadly the Finney7 body is slightly small in the girth (0.4mm) and too tall as it's designed to sit recessed.

The slimline waist I can live with, turning down the height might be a chore; it would probably take longer then it would to draw up a correct (waist and height) one in 3D and print a couple off. I may well do that anyway and speak to the client and seek his preference.

Most, if not all valves were a dirty black in regular use, it seems to be a preservation thing to polish them, therefore base material is not a factor.

Not really sure how to deal with the firebox top though, the Viking in me wants to attack it with big files and smooth it back, there's plenty of material underneath to do so without fear of weakening it, but that might make the painters job near impossible to blend in. It's the right (painful) thing to do and looking back at previous build photos it look like it's the Milliput that has/is failed/ing, so it really needs digging out and the joint redoing.

I also need to to fill the small rings around the filled washout plugs that were etched in the wrong place in the kit! Why would you do that, etch holes in the wrong place, know and recognise you've done it and then tell customers to fill and drill new ones, sorry, that's just so wrong on many levels. Do the right thing, pay for new masters and take it on the chin, don't unload your cock up onto the customer.

All in all it's just bad cricket, but come what may, it'll not leave here until that joint is perfectly smooth and I am quite prepared to drop the whole lot in thinners and strip out that whole section for a new one and rebuild, then pay for anew paint job myself.
 

Phil O

Western Thunderer
Water based correction fluid might well work, in getting a smooth finish. Allow it a few hours to dry properly and then wet and dry to cut it back to a finish. I have found it pretty good as a fine filler. It's not my idea, I read or heard about it somewhere.
 

mickoo

Western Thunderer
Phil, could work but not sure how itll react to the final cellulose layer to blend it in.

Anyway the Viking won, probably just as well as it was a country mile out once I began to cut back. Part of the discussion with Warren was to apply more paint and cut back, sadly the marks were too deep and you would had to have laid it on with a yard broom.

There comes a point where you have to go backward to move forward and I now have a nicely polished brass crown with the edges feathered in. Tonight I'll blow some etch primer in and let it key before cutting back.

The remaining joints are so fine that light layers of paint will blend it all in. That's the plan but it may not be as straight forward as I'm hoping/planning :D
 

Yorkshire Dave

Western Thunderer
Not really sure how to deal with the firebox top though, the Viking in me wants to attack it with big files and smooth it back, there's plenty of material underneath to do so without fear of weakening it, but that might make the painters job near impossible to blend in. It's the right (painful) thing to do and looking back at previous build photos it look like it's the Milliput that has/is failed/ing, so it really needs digging out and the joint redoing.

Without teaching teaching you suck eggs etc. Another solution is to cut back to the metal with fine files/emery paper and use superglue and bicarbonate of soda as a filler in the joints. The bicarb acts a 'kicker' to set the superglue.

Let it all set and re-profile with files/emery paper. When you think it's smooth run a fingernail over the joint and you'll be able to feel if it's filled or not. Or alternatively paint the area (use acrylics as this can be scraped off with a fingernail) and let it dry. This will also reveal whether the joint requires further filling.
 

mickoo

Western Thunderer
Dave, right now it's been filed back to bare metal and has been polished smooth (photo later), there is a very very small recess where the solder is, too small for the application of more solder really, it'll just wick in and shrink when it cools; you'll do more damage than good.

I do have one larger (0.2 x 0.4 mm approx) sinkhole though where the superglue/bicarbonate solution will work very well, and no, I didn't know about that little trick, so carry on teaching egg sucking :thumbs:

That little trick will work better than several layers of celly as that'll take ages to dry/harden.

I've also noticed that the safety valves were slightly off centre (0.3 mm) as well, the original holes being kicked slightly offline due to the new section added, now will be the time to move the holes accordingly which will leave a slight gap on one edge.

However, rechecking the A2 clothing drawing last night (with reference to the safety valve shape and sizes) I've seen that there are in fact two circular flange plates on top of the clothing, these I'll make from 5 thou brass and they'll cover the edge of the old hole and add a bit more detail here. In fact on the real engine the safety valves are inset into two circular recesses with the above mentioned flange plate around the edge.

It is very tempting to now replicate that little extra detail. It's a bit of extra work but it'll solve two previous problems, the original offset holes and the trimming back (shortening) of the Finney7 safety valves; the flanges will have to go on until after it's all been smoothed as they'll just get in the way right now.

I'm happier now with the overall smoothness, if before we graded the joint as 0%, then now I'm at about 90-95% smoothness. A paint layer will now reveal if I've managed to keep the radius uniform over the crown, aka, not created a flattened area which is very easy to do on a rounded surface.

The next step will be a good wash in IPA to get rid of any surface oils and then masking the general area to preserve the rest of the model.

Not sure which will be the next best layer of witness paint, acrylic can tend to peel in my experience, especially on a highly polished surface, you may end up actually pulling the paint out of the joint, enamel might be better but again I've had it peel as well, as I have with pure celly paint too which has no etch layer beneath.

I'm heading toward a good strong celly etch layer so that it gets a good bond with the metal and then dress back, carefully! I did a couple celly test etch runs on the motor mount I'd fabricated and the sides of the gear box (they were visible under the mud ring) and it's silly strong.
 

Lancastrian

Western Thunderer
Mick,

You could also try a filler primer once you've put a layer of etch primer on. I do hope you have managed to fix it though.

Ian
 

mickoo

Western Thunderer
Mick,

You could also try a filler primer once you've put a layer of etch primer on. I do hope you have managed to fix it though.

Ian
Hope......not an option....will is a better target to aim for ;)

I've got some Halfords filler primer but I'll not go near the model with a rattle can, I'll simply decant some into the airbrush and thin accordingly, but it's certainly a good option :thumbs:
 

mickoo

Western Thunderer
So, moving on, step one last night was to cut back with the big metal bashing tools and smooth it all off. This evenings task so far is to move and enlarge the safety valve holes. Fair warning to those with a nervous disposition.

Note the two remaining sink holes to the rear left of the rear opening and to the rear right about 4 'o'clock on the front opening. The solder shows up as a darker area but it is smooth, not mirror smooth yet but significantly smoother than 24hrs ago. I will remove the paint off the mid clothing band in due course and as expected, the lining on the boiler rear band has been damaged but I'll deal/worry about that later, right now it's not high on the priority list.

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The second step was to back the holes with a nice thick block of Plasticard held in place with a nice big dollop of double bubble inside. The extra thickness will get a good grip on the safety valve spigots with the adhesive, there is no way any sort of heat is going near this area now so Plasticard is fine.

Next up are the clothing flanges, I had a some spare washers in 10 thou from an etch project ages ago, they're a little small compared to the real thing, but being as the Finney7 valves are a little slim the whole will look much better than small valves and scale flanges. The rear flange needs a little waft taken off the rear flat edge to pull it back the merest fraction and align perfectly with the valve once fitted.

Note that the flanges conveniently cover the sink holes, no need to justify why I need bi carbonate from the domestic authorities.....you want to do what....! Life is much easier the less they know :p

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The flanges are just held on with stiction, no invisible solder here chaps, these will have to be stuck on and then painted.

Finally the test fitting of the new valves, much better in my view.

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They may actually be sat a little too low now but that is easy to fix, just add a thin 5 thou washer underneath the valve to pack it up a little.

All in all, I think the extra effort was worthwhile and now that the easy bit is over we get to the really hard part, blending it all in. That'll be tomorrow now, no rush, slowly slowly catchy monkey as we say at work.
 

dibateg

Western Thunderer
Phew! Well done Mick - its always agonising when you have a problem with a finished loco. Its easy to look back now and think it would have been better to make a complete new firebox.....

Years ago I built a 4mm brass MTK Cravens DMU. The door etch outlines were a scale 3 inches wide... After painting I showed it to my good friend Tony Wright - 'What do you think?' He replied 'Its sh1t!, the doors look terrible'. So we took it up the club, Rob Kinsey came up with an answer - every day paint in the door outlines with some more green enamel, until they are filled. Once they were, I rubbed them down and blended them in and drew the door outlines with a pencil. It looked a treat - apart from the windows on one side being higher than the other! Now you can buy one off the shelf...
MTK-built Cravens 02.jpg

Sorry for hijacking your thread - but we've all been there with finished models.... and I'm sure your resolution will be perfect.

Regards
Tony
 

mickoo

Western Thunderer
Tony, no problems on the hijack, nice Cravens :thumbs:

It's getting there now, first coat of etch on tonight after masking up, quite thick (relatively, as it's still about a 1/3rd of a single pass from a rattle can) to allow it to be cut back, might or might not be a mistake going for an effective double layer in one hit.

As such I'm going to leave it a couple of days to really harden off before smoothing off, but even as it stands now, the thin solder lines are barely visible, another step in the right direction.....and I've double checked I've not left the door ajar for Captain cock up and his crew to visit, if anyone else wants to keep him/them occupied for the next few days.....feel free :p
 

mickoo

Western Thunderer
So, here's where we're at end of play today.

I know I said I'd wait 48 hrs, and I should have done; although the clatter of hooves from Mr CCU and his horsemen could be heard in the distance........ he was thankfully off to visit some one else :eek:

The witness layer was smoothed off and resulted in no joint mark at all, I thought I'd have to do two or three coats, but the first sealed them up.

On the other hand, I ended up with a tide mark twixt old and new layers, on one side (drivers it feathered nicely) on the firemans side it didn't and the new layer 'rolled' up and left a ridge. I was simply smoothing from left side over the top and down the right. In reality I should of smoothed from the top and down each side; but it's not a great issue and so long as I continue with a list of diminishing errors everything is fine.

For the second layer I spaced off the masking by a couple of mm to give a smoother feathered edge, once this layer has set....and yes it will be tackled on Friday now.....then I'll carefully smooth it all off with very fine grade polishing boards. During that process the masking will be removed and set lower on the firebox side to give the green a better/broader blend line.

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You can just see the small ridge line on the rear section in the paint (halfway between the masking and valve openings) from sanding up the left side of the firebox toward the crown, it's also present on the front section as well. This layer is quite dusty (thin) as it was just a blending layer and will have to be smoothed before the top coats.

In other news, the 3D printed balance weights on the 47xx were fitted and sprayed up, pleased to say the resin did not react or melt under cellulose paint.

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There's a couple of sink holes in the leading weights to fill with knifing putty and a small gap twixt one of the spokes and the weight infill, but overall they work and look well.
 
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mickoo

Western Thunderer
Nice work Mick - I think I would have been sweating a bit on this one!
I was, and still am, not out of the woods yet.

The paint is still not hardening off as fast as I expected; I also did a couple of scrap etch test shots at the same time and these are still not hardened off either, possibly because the paint mix was not thinned enough or too many layers on at once. It's cellulose so it should harden rock hard eventually, just have to sit it out.
 

Lancastrian

Western Thunderer
Mick,

Captain cock up and crew are at my place presently, although I am about to kick them out ! Second Schools class frames etc completed to realise I've not fitted a crank and operating lever I made for it ! Tea break I think !

Ian
 
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