RMweb Premium MJI Posted January 27, 2021 RMweb Premium Share Posted January 27, 2021 I may be getting some sideframes, if I do I may try and cast a few off. Of my next few projects most use AEC engines and Swindon bogies. Another will be a Lima DMU conversion to Derby long DMU. 1 Link to post Share on other sites More sharing options...
AlfaZagato Posted January 27, 2021 Share Posted January 27, 2021 Have you considered lead or whitemetal casting? I don't know that you're currently equipped for either. Both are entirely doable at home - or at least in the yard or garage. Link to post Share on other sites More sharing options...
RMweb Premium MJI Posted January 27, 2021 RMweb Premium Share Posted January 27, 2021 Cutting machines My 120 took 45 minutes to cut the 10 thou, and just over 20 to score the 20 thou. The WR IC sides took me 90 minutes to draw up based on the 120 components. Now need to see how similar a 123 is just because. 1 1 Link to post Share on other sites More sharing options...
Bedlington North Posted January 27, 2021 Share Posted January 27, 2021 32 minutes ago, leopardml2341 said: I bow to your better knowledge. Is polyurethane less susceptible to air entrapment? It is sold as a casting resin unlike polyester and is water-thin. One tip I like is to put the filled mould on a washing machine on spin cycle. It helps to encourage any air bubbles out of crevasses. Also painting a thin coat of resin into the mould where possible. I've not needed to do that though. I resin cast my own exhaust stacks for my Hurricane model with no air bubbles. 4 2 Link to post Share on other sites More sharing options...
RMweb Premium MJI Posted January 27, 2021 RMweb Premium Share Posted January 27, 2021 Just now, AlfaZagato said: Have you considered lead or whitemetal casting? I don't know that you're currently equipped for either. Both are entirely doable at home - or at least in the yard or garage. Got a tub of moulding rubber and a lot of casting resin. I have a Derby mould I use for that style cab roof as used on 116 and 119, make sure edges are rough and quite a bit of plastic glued across the gap so the resin will stay in place. Oh and I also need some Leyland 680s for the 120 1 Link to post Share on other sites More sharing options...
Signaller69 Posted January 27, 2021 Author Share Posted January 27, 2021 20 minutes ago, AlfaZagato said: Have you considered lead or whitemetal casting? I don't know that you're currently equipped for either. Both are entirely doable at home - or at least in the yard or garage. Not something I have considered doing to be honest. I expect the start up costs would be quite substantial? Link to post Share on other sites More sharing options...
Bedlington North Posted January 27, 2021 Share Posted January 27, 2021 I have found that the temperature resistant silicon needed to make the mould and the whitemetal are more costly that the equivalents used in resin casting - plus you need a way to safely melt the metal. 2 Link to post Share on other sites More sharing options...
RMweb Premium MJI Posted January 27, 2021 RMweb Premium Share Posted January 27, 2021 I for years assumed a 119 and 120 were the same minus cabs. Window layout is very similar but the underframes are different. 119 is basic Derby 150 long layout like 116 117 118 121 122. 120 is more like the IC sets 2 Link to post Share on other sites More sharing options...
Bedlington North Posted January 27, 2021 Share Posted January 27, 2021 I have successfully cast PU resin seats for 4mm scale DMUs, but no pics at the moment as I'm at work and the seats are at home. The mould was a deep, blind cavity with undercuts which should theoretically be prone to bubbles, but they were good. I will shove a pic or 2 on later. 2 Link to post Share on other sites More sharing options...
Bedlington North Posted January 27, 2021 Share Posted January 27, 2021 Various views of a DMU seat cast in PU. As it came out of the mould, no clean up. 1 3 Link to post Share on other sites More sharing options...
Signaller69 Posted January 27, 2021 Author Share Posted January 27, 2021 1 hour ago, Bedlington North said: Various views of a DMU seat cast in PU. As it came out of the mould, no clean up. That is great, an idea I might add to the list for casting thanks. 1 Link to post Share on other sites More sharing options...
RMweb Premium MJI Posted January 27, 2021 RMweb Premium Share Posted January 27, 2021 I did them like that for my 119 1 Link to post Share on other sites More sharing options...
Signaller69 Posted January 29, 2021 Author Share Posted January 29, 2021 The roof of the DMBS has been sanded. As I have also been working on making the backscene for the stabling point micro I couldn't resist a quick photo of the unit! And a 126 that also called in..... The class 100 DMBS roof has just had a coat of primer to show up any issues and progress is being made on the battery box master. I could just use Replica ones but I always seem to run out of them before any other parts, and they always look a bit shallow to my eye. 9 3 Link to post Share on other sites More sharing options...
Signaller69 Posted January 30, 2021 Author Share Posted January 30, 2021 Off at another tangent! Finding a spare Replica interior prompted much cutting to produce a new interior for the DMBS. The spare MTK control desk (still loose) was another timely find. Interior partitions still to be added. The new seating unit is wider, meaning it sits much closer to the coach side than the bodged Hornby 110 interior, which sits noticeably inboard. The DTCL will have some similar work done. 9 1 Link to post Share on other sites More sharing options...
Signaller69 Posted January 30, 2021 Author Share Posted January 30, 2021 (edited) The casting masters are progressing with the battery box and air intake (radiator?) Done. A few small electrical boxes are needed to complete the set for the class 100. Slightly cruel photo! Edited January 30, 2021 by Signaller69 9 3 Link to post Share on other sites More sharing options...
RMweb Premium MJI Posted January 30, 2021 RMweb Premium Share Posted January 30, 2021 I have just drawn another layer for my 120 of last layer before outside. Now 4 layers of 20 thou then 10 thou outside. Currently running off a few WR IC DMU sides, need 6 cars, first 3. Also will have 4 inside layers but unlike 120 all will be machine cut. 2 normal with +1mm alround window holes 1 shallow with the bottom +1 removed and 10mm removed from bottom, and 2mm from top 1 shallow with the bottom +1 removed and 10mm removed from bottom , and 1.5mm added to the top Not started on the WR IC internal sides yet 2 Link to post Share on other sites More sharing options...
Signaller69 Posted January 30, 2021 Author Share Posted January 30, 2021 1 hour ago, MJI said: I have just drawn another layer for my 120 of last layer before outside. Now 4 layers of 20 thou then 10 thou outside. Currently running off a few WR IC DMU sides, need 6 cars, first 3. Also will have 4 inside layers but unlike 120 all will be machine cut. 2 normal with +1mm alround window holes 1 shallow with the bottom +1 removed and 10mm removed from bottom, and 2mm from top 1 shallow with the bottom +1 removed and 10mm removed from bottom , and 1.5mm added to the top Not started on the WR IC internal sides yet Looking forward to seeing the results. I take it the glazing will be laminated as one of the layers? Link to post Share on other sites More sharing options...
Signaller69 Posted January 30, 2021 Author Share Posted January 30, 2021 I have done a quick, loose positioning test of the various bits. From photos, everything looks in more or less the right place, albeit upside down here. There are some small bits to go between the battery box and the air intake/ radiator, which will largely hide the back of the engine (to do with heating I think, but which are different on either side). As these are also present on the DMCL (along with the battery boxes and electrical fuse box gubbins) these will need masters making too. 6 4 Link to post Share on other sites More sharing options...
RMweb Premium MJI Posted January 31, 2021 RMweb Premium Share Posted January 31, 2021 120 on top of book Layered sides under book WR Intercity 3 cars of below Next cut will be three more power cars Then I will have to work out Swindon cabs 4 off. 3 2 Link to post Share on other sites More sharing options...
RMweb Premium MJI Posted January 31, 2021 RMweb Premium Share Posted January 31, 2021 The glazing will be placed behind the windows once painted. Hopefully very gentle airbrush coats will avoid warpage. 1 1 Link to post Share on other sites More sharing options...
leopardml2341 Posted January 31, 2021 Share Posted January 31, 2021 What did you use to cut those please, Martin? Link to post Share on other sites More sharing options...
RMweb Premium MJI Posted January 31, 2021 RMweb Premium Share Posted January 31, 2021 22 minutes ago, leopardml2341 said: What did you use to cut those please, Martin? https://www.hobbycraft.co.uk/silhouette-cameo-4-digital-cutting-tool/648686-1000 1 1 1 Link to post Share on other sites More sharing options...
Signaller69 Posted January 31, 2021 Author Share Posted January 31, 2021 A mould has been formed with the various parts plus a control panel as I could do with a few extras. Silicon rubber was then mixed...... And slowly poured into the mould at one corner, until it had flowed around and over all the parts and filled the mould completely. A piece of handrail wire was used to try to trace the (now invisible) parts in the hope that any air bubbles were removed. Digital ingredient scales are a big help for mixing the silicon rubber due to the 10:1 mixing ratio (by weight) with the catalyst. Just need to leave the mould to cure now, the instructions say it cures in about 12 hours, but ideally should be left for 24-36 hours as the extra curing time apparently prolongs the mould life, so will come back to it on Tuesday morning. 4 1 Link to post Share on other sites More sharing options...
RMweb Gold john new Posted January 31, 2021 RMweb Gold Share Posted January 31, 2021 2 hours ago, MJI said: https://www.hobbycraft.co.uk/silhouette-cameo-4-digital-cutting-tool/648686-1000 How do you programme it? Does it use a form of 2D CAD? Link to post Share on other sites More sharing options...
leopardml2341 Posted January 31, 2021 Share Posted January 31, 2021 19 minutes ago, john new said: How do you programme it? Does it use a form of 2D CAD? Accepts .dxf files, easily exported from a CAD software suite. I use Libre CAD which is a free open source 2D CAD software. No connection other than a user 3 Link to post Share on other sites More sharing options...
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