Jump to content

3x PRMRP TTA Tanks Build


Recommended Posts

  • RMweb Gold

Hi,

 

From the evidence presented on this thread you look to be a dab hand at this.

 

I'm new to O gauge and new to soldering (other than track feeds) and kit bashing. I have some RTR O gauge stuff and a couple of donor big big train hymeks (my favourite loco).

 

I realise it is difficult to look on something with someone else's eyes (and hands), but did you find the conversion using the PRMRP kit a straightforward one? Or should I practice a bit more on other projects first?

 

Regards,

James

Link to post
Share on other sites

Hi James, 

The main job to tackle with the PRMRP conversion is the chassis and making sure it's nice and square. This is the only part that really needs to be soldered. It's really just a matter of taking your time and sticking to the basic principles:

Clean surfaces, hot iron, steadied work and plenty of flux. 

PRMRP chassis are a generic build and the 37 ones i've described above is the same as for the Hymek, just a bo-bo rather than co-co type. 

The rest of the conversion reminds me a lot of the 4mm superdetailing we used to do on Lima diesels. 

The major issue (to my eye) with the BigBig train body is the cab roof profile was too shallow. I built mine up using layers of plastic sheet and filler and then sanded to shape. TBH i've seen really good conversion efforts on here that haven't had this done. 

The PRMRP instructions aren't great and for a job like this lots of images should be referred to. The supplied castings vary in quality too. I replaced the cast pipework with silicon tube and sctrachbuilt some other details to suit. 

There a great project to take on with a decent sense of satisfaction at the end. I sourced the cast numbers from Fox transfers. 

 

Cheers and thanks for your kind words. 

  • Thanks 1
Link to post
Share on other sites
  • RMweb Gold

Thanks for the tips - I'll also be interested in your 108 build....so I will be staying tuned!

 

Hopefully I'll have a Dapol 122 DMU soon (which will require much less effort)!

 

Regards,

James

  • Like 1
Link to post
Share on other sites
3 hours ago, pwr said:

I am very impressed with how tidy your workbench is!

 

Paul R

I'm very well house trained! If it's a mess such privileges as a dedicated space and bench may face withdrawal by the Overseeing Authority! 

I've adapted a cheap computer desk with bespoke storage for all tools using sheets of foam cut n glued. I tidy after every session. 

IMG_20201009_171957.jpg.ecd3af2660705dd82b3db0859b5b2ff2.jpg

 

Anyway a start has been made on the 37 body. There are strengthening strips that need cutting to 385mm and folding to 90deg. These are soldered to the inside just above the the long fold for the tumble home. 

IMG_20201009_163010.jpg.bd033b8856c95dc8a0bda10e1c87ae9f.jpg

 

Cheers

  • Like 3
  • Round of applause 1
Link to post
Share on other sites

The 37 as had the doors fitted with hand rails and door handles too. All soldered from the rear so it looks neat. 

IMG_20201010_160239.jpg.b541e86d32160ae688671c0590e6972d.jpg

 

Next will be the bodyside sand box fillers recesses. These are a bit 'flat' compared to the prototype so they'll be detailed with plastic later. IMG_20201010_100846.jpg.b8a1fa2cddc3290fcc54033ddbecc4ef.jpg

 

The flatter profile etches are the onrs required. The curved profiled ones are for the nose ends. 

One fiddly job is to orientate the side grills to a realistic angle. I'll probably cut two shims of thin metal to gently turn each blade. Not easy though! 

IMG_20201010_160309.jpg.99481a689bc1ac3601a7b7d38c4a5d0b.jpg

 

Cheers

  • Like 2
Link to post
Share on other sites

The grills have been angled and soldered in along with the sandbox filler caps and surrounds. 

IMG_20201011_105818.jpg.87ec0f071ca412ff40a2c5759fc91155.jpg

 

The instructions say to now sort the fan mesh and fan assembly then the nose ends, bonnets and windscreens and bogie mounting brackets. All of these will bring the sides together and create the correct profile for the bodyshell. I will note at this point that my original plan of installing frames into the body to give support, additional rigidity and good profile has been abandoned. The test fit proved too unreliable and hopefully unnecessary. The finished model wil be vulnerable to careless handling if grabbed on the bodysides but i'll just have to be careful! 

Anyway, in order to get a correct setting of the bogie centres and a free bogie swing to a decent minimum radius (around 1600mm minimum radius curves) for my purposes, i need to build the fuel tank group next. 

 

Cheers

  • Like 6
Link to post
Share on other sites

Fuel tanks - these are brilliantly puzzling etches at first glance. You need to plan which folds to perform in a particular order - there are folds both ways and thin zones to encourage a curved profile:

IMG_20201011_171539.jpg.b47a2adaa1eec8fce1b0aba78b778e1d.jpg

 

And here's the first side folded up with joins and some folds sildered up:

IMG_20201011_173906.jpg.b0d5591b93967893b3f0ea3fbaf0bb02.jpg

 

And from the inside:

IMG_20201011_173918.jpg.636d09f85d30e301cb2b8a9efbcc11ae.jpg

 

Now to repeat for the other side and then tidy and clean. 

 

Cheers

  • Like 5
Link to post
Share on other sites

Lots done on the 37 today. To begin i made up the bogie pivots with captive nuts soldered in. These are always a tricky task needing accuracy and the complication of soldering brass and steel together. I always file both surfaces to a rough finish and use lots of heat, flux and solder and pre-clean with IPA. Here they are completed:

IMG_20201013_161133.jpg.a5ad1c22aaee95340c59827e0320fbac.jpg

The nut sits inside the made up box and these are soldered to the loco body. Nylon bolts then hold the bogies upto the body. The spacing of the pivots has to be carefully considered to allow swing without fouling the beams and tanks. Here is the body with pivots soldered in. 

IMG_20201013_162545.jpg.64a892cba5a7593399ef95f1637db272.jpg

 

And finally mounted on the bogies! IMG_20201013_163441.jpg.abba6db2693a5bd750263f4b6dfd47ae.jpg

 

There are no pick ups on the wheels. PRMRP use the live chassis principle and so you have to be pretty exact with measures to avoid shorts. The loco runs OK in a straight line so far. Once i get tanks and beams fitted, I will test it on curves and adjust as necessary. 

Next tanks and nose ends fitted. 

Cheers

  • Like 6
Link to post
Share on other sites

The next phase of the build, fixing in the nose end etches and bonnet castings will highlight the single significant flaw in the kit - the lack of a roof taper from the rear cab line to the point above the windscreen. The kit is designed to follow the taper of the sides from cab doors to nose, but not the roof taper. In fact, once the nose ends are fitted the proper narrowing here highlights further the deficiency by increasing the arch of the roof and pushing out the cab side diagonal window frames. Some of the few images of completed kits of the PRMRP 37 shows this effect. 

For me, this will be an elephant in the room when i look at it so drastic action is required! 

The solution will be to fit the nose ends first. This will maximise the effect of the fault. Then, i'll cut a line from the cab roof front to the cab roof rear. Then i can determine the amount of material to be removed (filed out). If my study of the geometrics is right, this will leave a triangular shaped gap in the cab roofs. The opening can be brought together and, hopefully, a more prototypical profile will be achieved! 

 

Apologies for the waffle, but images of the butchery to come will make it clear.. 

Cheers

Link to post
Share on other sites

I think similar problems affect their 56 in that the shape of the roof is not right - too shallow. I have heard some modellers cut the roof in too and insert a brass strip of a few mm to correct. 

 

The problem with these kits is that they have passed from parkin to RJH to PRMRP and the error is perpetuated.

 

David Parkin was supposedly producing some to a new design but I think with the advent of models from Heljan he has given up on that. Not sure the 56 profile on the new Heljan model is right either but we have not seen the second EP yet. According to the interview on the Hornby Virtual Exhibition they have corrected some faults and the model is not due now until the back end of 2021

 

Paul R

Link to post
Share on other sites
1 hour ago, pwr said:

I think similar problems affect their 56 in that the shape of the roof is not right - too shallow. I have heard some modellers cut the roof in too and insert a brass strip of a few mm to correct. 

 

The problem with these kits is that they have passed from parkin to RJH to PRMRP and the error is perpetuated.

 

David Parkin was supposedly producing some to a new design but I think with the advent of models from Heljan he has given up on that. Not sure the 56 profile on the new Heljan model is right either but we have not seen the second EP yet. According to the interview on the Hornby Virtual Exhibition they have corrected some faults and the model is not due now until the back end of 2021

 

Paul R

Hi Paul, 

Yes the kits are a bit dated compared to the RTR stuff available now. But, i love a challenge and the sense of achievement when a half decent model is produced. With these kits you need patience and plenty of filler! 

Cheers

Link to post
Share on other sites

Ah well some fine afternoon surgery! Those of a nervous and sensitive dispostion look away, those who have never watched Alien vs Predator because they hate chick-flicks, read on... 

 

First nose ends:

IMG_20201014_144758.jpg.6c1868f106c825f6ec0864229555aa59.jpg

End fitted and sides tinned for the white metal bonnets to be soldered in. These need a little fettling. 

IMG_20201014_145753.jpg.574deaedfbd54c1707b13fde19dce3b8.jpg

 

Bonnet soldered in. There will be filler and sanding aplenty here to get a good, neat finish. It's also now really noticeable how the cab roof profile is wrong and how the side windows bow out. 

Now for the solution!...... 

 

First, slitting disc and mini-drill to cut a big T in the cab roof:

IMG_20201014_153653.jpg.b86e9d3d22443bbbc567723c066f0fed.jpg

The blue marker pen shows the degree of overlap/material to remove to get a better profile. 

IMG_20201014_154355.jpg.ad4fe2c047f4003cf2ff5e4ecbfddead.jpg

I have used some thin scrap brass (actually DJH Brush 2 welded front doors not used on my model) and rolled these to the profile of the window frames so the cab roof profile will be right.. 

The brass is soldered to the cab ceiling on one side first then the two parts are brought together and the profiled is gauged to be about right.. 

Then the other side is soldered. 

IMG_20201014_160212.jpg.38994115ac25e8daaaafdcf03a2898f3.jpg

The result is a lower arc profiled cab roof with the correct interface between roof arc and cab windows and non-bulging side windows. IMG_20201014_160144.jpg.f7da9cbc0d1b17fba30d40456d948edb.jpg

The next job is to do the other end the same then create the slight slope using plastic sheet and filler with lots of sanding. 

 

Cheers

  • Round of applause 1
Link to post
Share on other sites
40 minutes ago, Hal Nail said:

Doesn't this all make the side window area bulge out even more now?

 

I'm feeling better about my plan to hack up a Heljan 47 and see if i can correct it now!

No because material is removed from the cut area so when it's pulled back in the windows pull in too but nearer the bonnet end where it's needed. The whole post-op scarring looks a mess but packing anf filler will transform it........... Hopefully...! Good luck with the 47! Brass is very forgiving compared to plastic! 

  • Like 1
  • Craftsmanship/clever 1
Link to post
Share on other sites
11 hours ago, pwr said:

I think similar problems affect their 56 in that the shape of the roof is not right - too shallow. I have heard some modellers cut the roof in too and insert a brass strip of a few mm to correct. 

 

The problem with these kits is that they have passed from parkin to RJH to PRMRP and the error is perpetuated.

 

David Parkin was supposedly producing some to a new design but I think with the advent of models from Heljan he has given up on that. Not sure the 56 profile on the new Heljan model is right either but we have not seen the second EP yet. According to the interview on the Hornby Virtual Exhibition they have corrected some faults and the model is not due now until the back end of 2021

 

Paul R

 

Not sure who David Parkin is but I imagine it must be me!


The following relates to Class 56 kits - but could be about several other subjects in both my original PWP diesel range, and my later MMP range.

 

A Class 56 was introduced by me in 1980 in the Post-War Prototypes range, which I sold to RJH in 1988 and now resides with PRMRP. Same with the Class 37 and about 28 other loco kits. When we introduced these kits they were all priced around the £50 mark, and they sold in their hundreds as cheapo kits that you could very much make what you wanted out of. That was the whole ethos behind them until, when under the ownership of RJH, they took it upon themselves to increase the prices by arounds 250% without upgrading them! But it is nice to see the OP of this thread getting stuck in and making something out of them.

 

We did a Class 56 in the Modern Motive Power range, along with several other diesel kits - a totally different kit to that first one we did in 1980. It came out in 1999 and was withdrawn about ten years back. This I assume is one of the models you say I didn't produce. It's withdrawal along with the rest of my diesel range at that time had nothing to do with Heljan. It was due to the very original and quite bizarre criticisms made of all these diesel kits, including on this forum - that they had too much detail in them and that the box contained too much for the money!

 

I certainly haven't given up on anything, and assumptions are often unsafe things to make. I still hold all these masters and other tooling, and also ones for several more diesel and electric loco subjects I have not yet produced. I may revisit them if that big bad hungry wolf ever comes knocking - who knows?

 

The above is just by way of a little history for the sake of accuracy, though I do of course realise that us old geezers who are still manufacturers [and who might still be suffering from 'not being there' in the 1960s!], know less about our own businesses and kit-ographies, than others seem to!

 

David ParkinS

Modern Motive Power

www.djparkins.com

Edited by djparkins
typo
  • Like 3
Link to post
Share on other sites

Hi David, 

Yes, the kits must be viewed and tackled in the context of their heritage (do you ever get tired repeating the above?) however, some of the etches (37 fuel group as an example) remind us of the level of care and skill that went into their design. Some castings are tired looking now and the moulds are possibly in need of a rework. 

I build these because it's a satisfying to achievement when complete and they're adaptable to what you want them to be. I also value that rapidly withering mental stance of patience. I put no time limit on completion. It is the joy of the journey rather than the speed of arrival at 'point b' that should matter. 

Cheers

Edited by woodyfox
Typo
Link to post
Share on other sites
4 hours ago, woodyfox said:

Hi David, 

Yes, the kits must be viewed and tackled in the context of their heritage (do you ever get tired repeating the above?) however, some of the etches (37 fuel group as an example) remind us of the level of care and skill that went into their design. Some castings are tired looking now and the moulds are possibly in need of a rework. 

I build these because it's a satisfying to achievement when complete and they're adaptable to what you want them to be. I also value that rapidly withering mental stance of patience. I put no time limit on completion. It is the joy of the journey rather than the speed of arrival at 'point b' that should matter. 

Cheers

 

Hello Mr Woodyfox

 

Yes - well thereby hangs a tail! Back in the 1980s my white metal casting was done by the [now late] Adrian Swain.

 

When RJH took over they didn't want to use him, and so so something of a stand-off ensued over the casting moulds, as I recall. Despite having all the original brass masters, RJH made new moulds [very badly], but in the main used second-generation castings for the masters! The results you will be able to guess at - differential shrinkage, distortion and pitting. The clamp pressures they were casting at were incredible so they then had to start making additional 'panic' feeds into the mould cavities. All the above is the reason why your tank wagon ends look like a moonscape!

 

I do totally agree with your comments about the mental processes involved in building.

 

Best regards

 

David Parkins

 

 

  • Like 1
Link to post
Share on other sites
12 hours ago, djparkins said:

 

Not sure who David Parkin is but I imagine it must be me!


The following relates to Class 56 kits - but could be about several other subjects in both my original PWP diesel range, and my later MMP range.

 

A Class 56 was introduced by me in 1980 in the Post-War Prototypes range, which I sold to RJH in 1988 and now resides with PRMRP. Same with the Class 37 and about 28 other loco kits. When we introduced these kits they were all priced around the £50 mark, and they sold in their hundreds as cheapo kits that you could very much make what you wanted out of. That was the whole ethos behind them until, when under the ownership of RJH, they took it upon themselves to increase the prices by arounds 250% without upgrading them! But it is nice to see the OP of this thread getting stuck in and making something out of them.

 

We did a Class 56 in the Modern Motive Power range, along with several other diesel kits - a totally different kit to that first one we did in 1980. It came out in 1999 and was withdrawn about ten years back. This I assume is one of the models you say I didn't produce. It's withdrawal along with the rest of my diesel range at that time had nothing to do with Heljan. It was due to the very original and quite bizarre criticisms made of all these diesel kits, including on this forum - that they had too much detail in them and that the box contained too much for the money!

 

I certainly haven't given up on anything, and assumptions are often unsafe things to make. I still hold all these masters and other tooling, and also ones for several more diesel and electric loco subjects I have not yet produced. I may revisit them if that big bad hungry wolf ever comes knocking - who knows?

 

The above is just by way of a little history for the sake of accuracy, though I do of course realise that us old geezers who are still manufacturers [and who might still be suffering from 'not being there' in the 1960s!], know less about our own businesses and kit-ographies, than others seem to!

 

David ParkinS

Modern Motive Power

www.djparkins.com

 

 

David thank you for then update and correcting my earlier post. Good to know you are still active. I still think your MK1 coaches were the best things you ever did. 

 

I do have one of your original 56's that I got off the second hand stall at  GOG convention back in the day and commissioned a motor bogie from Cherry Scale models to power it but I never got any further. I will finish it but I suspect not before the Heljan Model is about!

 

I also have a number of your Mk2 coach kits with your name on the packaging!

 

Paul R

Link to post
Share on other sites
21 hours ago, woodyfox said:

Hi Paul, 

Yes the kits are a bit dated compared to the RTR stuff available now. But, i love a challenge and the sense of achievement when a half decent model is produced. With these kits you need patience and plenty of filler! 

Cheers

 

 

Do you remember the El Crappo kits!  You were better off throwing the kit away and carving the model from solid filler. I still have a class 15 which was passable in its time and which I think I may ditch now. The motor bogie that i have can be used in something else.  I have 4 of the Little Loco models which are at a whole different level.

 

Paul R

Link to post
Share on other sites
3 hours ago, djparkins said:

 

Hello Mr Woodyfox

 

Yes - well thereby hangs a tail! Back in the 1980s my white metal casting was done by the [now late] Adrian Swain.

 

When RJH took over they didn't want to use him, and so so something of a stand-off ensued over the casting moulds, as I recall. Despite having all the original brass masters, RJH made new moulds [very badly], but in the main used second-generation castings for the masters! The results you will be able to guess at - differential shrinkage, distortion and pitting. The clamp pressures they were casting at were incredible so they then had to start making additional 'panic' feeds into the mould cavities. All the above is the reason why your tank wagon ends look like a moonscape!

 

I do totally agree with your comments about the mental processes involved in building.

 

Best regards

 

David Parkins

 

 

Thanks David, 

The castings do let the kits down now. It's a simple smooth over with filler and sanding remedy though in the parts i've encountered. By kit/scratchbuilding suppose i'll know what the limitations of my models are and that they won't have a gearing failure rate akin to a 1970's Lada estate car like the recent Chinese RTR offerings appear to have! 

 

Link to post
Share on other sites

Hi, 

Work on the 37 body has moved on to applying packing and filler to the cab roofs and bonnets. IMG_20201016_143407.jpg.0f297b9c8bd84f71b9063d9a9ed50019.jpg

Here's the packing on one roof. The brass roof is roughed up with a file and washed over with IPA on a cotton bud. The plastic sheet is cleaned on both sides with IPA. I've found this softens the plastic and makes it easy to bend. Using superglue gel, the plastic bonds really well to the brass.

IMG_20201016_152412.jpg.c5adc0961f37d23292ed2d952c3d7d2c.jpg

The roof and bonnet are then coated in the first application of filler. I use Squadron white putty. It sets pretty quickly and hardens in about 24 hours. I found wiping all surfaces prior to application with IPA makes it bond really well, even in really thin smears. 

IMG_20201016_153423.jpg.3d7e813d3af690c509ec67b490d92253.jpg

A thin smear has been applied to the bonnet top. I haven't done the central area as access doors are fitted here. 

 

While all this is setting, work will now begin on two more projects:

The Easy Build 108 DMU and a Slater's Vanwide. 

 

Cheers

Edited by woodyfox
  • Like 3
  • Craftsmanship/clever 1
Link to post
Share on other sites

Hi, 

I have researched and decided on prototypes for my 108 DMU. The DMBS will be E50601 to dia 543 and the DTC(L) will be E56192 to dia 640. They will be modelled to represent a Hammerton based set around 07/75. As far as i can tell (and the whole thing is a minefield), the vehicles were refurbished in 06/75 and they'll be in fresh white/blue stripe livery. 

The internal fittings will include a dark blue seating (2nd) and orange/brown seating (1st), strip lighting (not working) and light grey and tan pannelling as appropriate. External differences (as far as i can tell) will be the addition of a small vent under a window on the s/man's side on the DMBS and abolition of the train route indicator box below the centre cab window. The vehicles are to the early ER allocated sets and will have buffer beam mounted pipework and small destination blind boxes on the cab roofs. 

I've washed all the plastic parts in warm soapy water and these have been drying over the weekend. 

First job is to prep the sides and ends. I'm starting with the DMBS. All flash and injection pips are sanded away and then the first side and cab are checked for squareness. I use simple PSE screwed to MDF as a jig to get a good square edge on a decent flat surface. The door top needs a slight angle filing across the top so it sits square with the cab. Once this is achieved i sand about half a mm off the bottom of the vehicle doors and sand a 45 deg angle in the door tops. This adds to the impression they are capable of opening. 

IMG_20201019_154329.jpg.c6f9cd5eed813939a5281bbb4cc2bbca.jpg

 

IMG_20201019_154802.jpg.88a2fcb1a0f09a55a2f932cf77a409e5.jpg

 

The cab and first side sit nice and square. 

Now i need to measure and cut holes in the sides for the coolant filler points. Easy Build don't mention these in the instructions, but they are a very obvious feature of a 108 motored car. 

Cheers 

  • Like 4
Link to post
Share on other sites

Bit more work on the DMBS sides. I've fitted coolant filler points and a vent. For the fillers the sides were marked using masking tape and then the squares were chain drilled out. I found some suitable brass castings in the scrap box and these were modified to sit on squares of plastic sheet. There were glued in from the inside. 

IMG_20201021_150503.jpg.45cefbf07688d3d61bd13df132867149.jpg

IMG_20201021_150448.jpg.49d979c58f5e734c54a0ccbe040559b1.jpg

IMG_20201021_152221.jpg.3144da14ffd60f5e5a8bef3c31ded47a.jpg

 

The vent was from a scrap etch. I need to make a surround for the fillers points now as per prototype images and then fit hinges and door bangs. 

The sides have been rubbed down with 400 then 1200 grit wet and dry prior to adding fittings. 

 

Cheers 

  • Like 5
Link to post
Share on other sites
  • woodyfox changed the title to 3x PRMRP TTA Tanks Build

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.