Class 22 Diesel (next project)

I don't know about contact glue by I've recently started using a clear Gorilla Glue which is available in quite large bottles, and it is amazing!

We all know MDF but is anyone familiar with HDF.

Apparently HDF is denser and stronger than MDF, hardboard is a HDF and available in 8ft x 4ft x 1/8" thick. I have read that HDF is produced in a range of thickness but apart from the 1/8" the other sizes don't seem to be stocked in the UK ?

Wondered if anyone knows anything of it.

18mm high density MDF is stocked by the panel specialists such as Spanolux Deep Rout this has a density a bit higher than HDF at 960kg/m3 but its not something you will find in a DIY shed being used more commercially for things like kitchen cabinet doors that would have a decorative panel routed into then before being foil or vinyl covered as it has a smoother surface and cut ends less plecking (fluffynesss).

Same panel specialists will also have nominal 6mm hardboard/HDF but mostly only smooth on one face as well as 6mm melamine faced MDF which is quite a high density., I often use the later for knocking up quick templates.

Thanks Jason that's helpful.

Happy New Year,

Just seen your build thread, looking good.

I have been in joinery manufacture for about 40 years, and had my own business for about 30 years, so this is my opinion on MDF etc.

MDF is available in standard, moisture resistant, exterior and fire resistant grades.

There is no noticeable difference in density in any of these grades. The moisture resistant, (mr), grade is always dyed green, either right through, or just the core for identification purposes. The standard and mr version soon swell and disintegrate if they get wet for any prolonged time. The more expensive exterior grade also requires all edges to be sealed if it is to survive prolonged exposure to water. There is a new kid on the block, which is described as extremely durable, and sold as Tricoya, not cheap but with a claimed durability, guaranteed for 50 years.

I have only ever seen HDF sold in 3mm thick sheets with a white/black or cream coloured finish on one face, it is used as a replacement for white faced hardboard. The denser deep rout MDF is, I think, only available in thicker boards. It is used because the “normal” thicker MDF boards can have an inner core made up of larger fibres, which don't leave a good finish when routered into.

All MDF is abrasive and blunts hand tools and HSS type spindle moulder tooling very quickly, TCT or even diamond coated tooling is required. TCT router cutters are ok to use, but do blunt quicker than when used on timber.

Thin Birch plywood is nice to use, but I think it is interior grade only, in thin sheets, and not moisture resistant or exterior grade.

Lawcris, Arnold Laver, Timbmet and Lathams are all good suppliers of MDF and Ply, depending where you live.

Solvent based contact adhesive is still available, not seen the really small tins or tubes for years, I think shops stopped selling them during the glue sniffing era in the 80's.

I have been using this solvent based, Link , own brand from, “Construction Chemicals”, the big name EVO-STICK is also available, but I am not convinced it is the same formulation as it used to be. It all goes off in the tin after its been opened, but sometimes it's still ok after a year or so! Water based is also available, but I haven't tried it. The red plastic spreaders are also a thing of the past.

Polyurethane glues, such as Gorilla glue, stick well, they don't care about a freezing cold workshop, (unlike PVA types), and are waterproof, but also messy, and possibly carcinogenic, via prolonged skin contact.

Hope some of this may be of interest. I am in East Yorkshire, if I can help by ordering anything for you, or cutting anything.

Mark.

Edited By Mark Easingwood on 05/01/2020 17:53:38

Thanks Mark, information appreciated.

We have a couple of local firms which make bespoke kitchens so I will pop in and see what material they carry and if suitable if I can purchase some.

Ron

I took a gamble and bought a cheap Chinese set of 4 radius edge cutters, cost £8 for the set 1/8, 1/4, 3/8 and 1/2 inch rads.

The 20mm thick loco body cab/end plates have radiused edges which I was planning to cut and shape by hand but then thought it better and more accurate if I could machine to the basic shape and then hand finish. I didnt want anything expensive as the cutters will be seldom used if at all.

I know router cutters are run at high speed and I only have a top speed on the mill of 2500 so that was the main worry, would they work at the lower speed..? Need not have worried as they work and cut just fine, tried some test cuts on a piece of Pine, unknown hardwood and MDF and they left a very clean finish even on the MDF which surprised me. So in this instance £8 well spent.

1/2 inch cutter below.

Our club track is open again (with restrictions and limited numbers) so I thought I would put a few hours in and make a start on the body. A picture below of one of the side panels in its early stages, base material 6mm MDF faced with 1.5mm birch ply. The top third of the panel is angled inboard by 5 degrees and the apertures cut for the numerous louvered vent panels and doors, 20 vent panels, 4 double engine bay doors and 4 cab doors on a class 22.

I considered fitting the 1.5mm facing as a one piece but went with cutting it into three and added one at a time, used 4 parts PVA / 1 part water to allow it to spread a bit easier when clamped and weighted down.

I found an old tin of cellulose sanding sealer which I tried on some MDF off cuts, 2 or 3 coats with a light sanding in between seems to work really well especially on the edges it soaks well in and seals the surface.

Edited By Ron Laden on 10/09/2020 13:41:02

The body slowly coming together, the sides, base plate, bulkheads and cab end plates all connected and aligned.

Click twice to enlarge.

Edited By Ron Laden on 18/09/2020 19:42:27

Does that turn a 5in to a 7 1/4in gauge?

Looks a good way of getting the surface panel relief.

Haven't had much shop time of late but started modelling up the cab glazing frame in card at the moment.

Starting to look a bit more like a class 22 now.

A bit more done, just needs a tad more filler to lose a couple of divots. It then needs repeating at the other end and then the side window frames to make and fit.

Edited By Ron Laden on 10/10/2020 10:46:55

I have both cab ends fitted and faired in, spent hours on them but they have turned out quite well.... thank goodness for filler primer ​​​​​​

The roof is next but still deciding if I should make it one piece or split into two it's 36 inches long.

Looking good Ron

Thanks Jason

Thats looking like its going to be superb example

I dont know about superb Bernie it certainly wont be a scale exhibition piece, I know I,m not capable of that. The aim is for a practical reliable model which I can run at the club track, I hope it turns out a reasonable representation of a class 22 and should people recognise it as a 22 then I will be more than happy.

A quick mono picture of the body on the chassis complete with bogies, it's beginning to get there I think but there is a ton of detailing to do yet.

Working on the loco roof which will be removable for access. You can probably see the roof formers have been laser cut, a forum member very kindly offered to cut them for me which saved a lot of work. The longerons will be 6mm square bass wood and the roof skinned in 1mm birch ply.

It's looking great Ron! I think you must have built some balsa airplane model kits at some point, didn't you? when I was a young kid I built lots of Guillow balsa airplane kits from the USA, the fuselage formers and longerons were just like the top of your loco body (but die cut rather than laser cut). This construction should make a very sturdy top cover on your engine.