Assembling laser cut cabs

Hi forum,

I'm looking for info regarding the assembly of laser cut cabs and tanks... rivetting, soft soldering etc. Any hints? Any youtube clips etc?

I 'm looking for the best way of doing it as we have a RobRoy that will need doing soon, and indeed... eventually, my Juliet build.

I've had a look with a search, but can't find the right search string!

Many thanks

Ian

I cut the cab/bodywork of my shunter out by hand. All 1/32 rivets(!)

Most useful things were:

Using a dolly made out of a length of 3/8" bar with dimples in it and rounded and square edges/corners then held in the vice was essential.

Making supports, just lumps of wood/mdf to support the body when drilling through. I drilled the outer holes accurately in the flat, but spotted through the jigged together body. Even with care I got through a whole packet of ten 1/32" drills.

I used coper rivets as ease of riveting was more important than strength

Half a dozen really in accessible rivets just had their tails bent over.

Neil

Cheers Neil.

So, You riveted the panels together, then did you soft solder?

Apparently, the Model Engineers Laser panels have tabs to aid the assembly. Not got mine yet, but does this mean that they should be soldered while being butted together? This is a whole new world to me as a beginner, but I'm trying to do as much research as I can.

Ta

Greetings, some pre cut cabs can be MIG welded, and as I understand it the one from Model engineer laser are made to be TIG welded, with just enough metal protruding from the take to avoid the use of a filler rod.

If you are nervous of welding, they can be soft soldered, but might need a few angle brackets for strength.

This cab was MIG welded, starting life as a Winson kit.

Regards

BB

Cheers Brian. I doubt I'll be doing any welding on the cabs of my little 3.5 Juliet

So, the suggestion of brass angle? and soft solder? I will need the rivets of course as Neil has stated above. Heating with a torch? Will electrical solder do the job or am I using plumbers type and a separate flux... bearing in mind that this is a small cab.

Ta

I asked a similar question on a 3 1/2" gauge Betty locomotive tender because I was concerned about heat distortion of the platework.

These were the tips I received - by the way, I haven't tried any of them yet;

1. Try and get some lead solder with a low melt point because the newer lead free variety has a higher melting temperature. The higher the temperature, the greater the distortion risk. You can still get hold of it from some suppliers.

2. Tin the parts first and check that brass angle is truly 90 degrees - sometimes it isn't.

3. One tip included assembling the parts, painting it with solder paste and at least pre-warming the assembly in a domestic oven. Take the wrapped parts out of the oven and use an electric iron to run along the joints. Put it back in the oven between sections and return it to the cooling oven after you have finished so the whole assembly cools down at the same rate - hence preventing distortion.

I am also building Rob Roy and the cabs and tanks of the real don't appear to have lines of snap head rivets on the outside. The smokebox and buffer beams appear to be heavily riveted but the platework appears to be flush.

Another tip. Take care if you rivet the plates with the snap heads on the inside of the platework. My Betty tender was done like that in accordance with the so called words and music and a very neat job has been done of it. Unfortunately, even very careful riveting from the previous builder has left a very noticeable 'dimple' on the outside of the platework at every single rivet position. It can probably be put right with car body filler but it is something else to bear in mind.

Phil H

By the way, I thought about buying the laser cut tank kits for Rob Roy but I am thinking of doing them using thicker brass with traditional angle and but joints. I will use the tinned parts and consider the oven tip (when my wife is out - tricky at the moment).

Phil H.

Thanks Phil. Sounds like fun ! I believe the sheets will be 0.9mm half hard cz108. Juliet calls for 16 or 20g sheet, I think the 0.9 is 20G. Hmmmmm. I beginning to think hearth and some weight... and letting it warm gently. AND, plenty of test pieces

Ian

Why is it traditional to make platework from brass? Expensive and not easy to paint. Apart from tanks I've used steel on my locos. Then rivets and angle in the corner joints

Model Engineers Laser will cut the parts in your choice of material and thickness using their 'standard' drawings if you ask. Obviously if you change the thickness then tab slots and corresponding tab thickness will be incorrect.

Regards,

Phil.

A chap from the club just down the road from me has built a superb version of Lion in 7 1/4" gauge. He used steel for the tender tank. When asked about corrosion, he said he would give it a coat of Hammerite to seal and protect it!!

Phil H

Providing you protect the steel properly then there is no issue with using steel for any plate work including tanks, after all the prototype uses it and some of those have been around an awful long time. My Aspinall with the exception of the tender flares all of it is in mild steel. It is all laser cut with slot and tab construction, to my own design and was done at work just before I retired ,being chief designer had its perks!. Assembly is with silver solder using an oxy-propane kit. The tender tank has access plates in the bottom with the whole top plate also removable, which enables it to be properly protected from corrosion. As it cost me nothing rather than £200 plus in brass it was a no brainer.

1st phot shows typical construction. 2nd shows completed tender awaiting painting. 3rd shows some of the loco plate temporarily put together. The splashers are just held by the fit of the tabs in the slot.

Dave