Scalefour Forum

David Barham wrote "I think the problem with standard plasticard is that it gives off chlorine gas when it is burned by the laser. Doesn't damage the laser - just the operators!"

My understanding is that plasticard is polystyrene sheet and polystyrene contains no chlorine, just carbon and hydrogen. So where would the chlorine come from?

This apart, I am constantly amazed at what may be achieved by the laser cutting process.

Joe Newman

My comment was based on looking at laser cut plastic items by some of the firms that offer this service and pictures of those that have been posted in other places. It looks like stryene - i.e platsticard, but of course it may not be stryene.

All laser cutters need to have the fumes caused by the cutting process controlled, even if it is MDF that is being cut. Machines may have a filter system attach which will absorb the fumes. The filters have to be changed when required and the better machines won't work without the filter being effective. Some machines have a full blown extraction system which is even better.

PVC and polyurethane are two materials that should never be cut on a laser cutter. PVC will generate vinyl chloride and polyurethane foam will give off hgdrogen cyanide. These materials should not even be cut if there is an extraction system. The problem with plastics is that some of them look very similar but the chemical make-up is different which is why you need to make sure that you know what it is that you are intending to cut.

Terry Bendall

John McAleely wrote:

barhamd wrote:This was my first attempt with the cutter Makespace in Cambridge had delivered last week.

I see the Cambridge Makespace has an open evening tonight. I shall go along - anyone else from this forum likely to be there?

I'm afraid not. I'm sat at home doing my tax return, amongst other things

Do report back about the facilities!

Flymo

Flymo748 wrote:

John McAleely wrote:
I see the Cambridge Makespace has an open evening tonight. I shall go along - anyone else from this forum likely to be there?

I'm afraid not. I'm sat at home doing my tax return, amongst other things

Do report back about the facilities!

Flymo

I miss that entries completely. Anyway it was my son's birthaday, so a busy evening... Maybe next time (but please John, report)

Carlos

Just a very quick (5 minutes) test sample of painting the MDF to see if the red primer has made it stable enough to use acrylics and enamel paints. All looks ok so far . .

Need to readjust the door measurements and use my maginfiers to paint the proper version, but all looking ok so far



Cheers
Tim

That does beat sticking computer chads on doesn't it? It looks very good (if rather drafty around the door!).

Yeah, the doors a bit of a fail at the moment Need to have another go, hadn't taken into account the laser line!

Quite pleased at how easy the mortar was to do, and how it's made the bricks even better.

Terry Bendall wrote:PVC and polyurethane are two materials that should never be cut on a laser cutter. PVC will generate vinyl chloride and polyurethane foam will give off hydrogen cyanide. These materials should not even be cut if there is an extraction system. The problem with plastics is that some of them look very similar but the chemical make-up is different which is why you need to make sure that you know what it is that you are intending to cut.
Terry Bendall

Buried among the twenty thousand or so posts on this Forum I recall several gems like this, including the hazards of various chemical blackeners, fire risks, getting mains and low voltages mixed up, risks of different soldering fluxes, etc. How about putting these in a top-level thread titled something like "Staying Alive Long Enough to Finish Your Models"? for the benefit of comparative newcomers?

Regards
Chris

I've managed to crack the interlocking today, so I can update the rest of the drawings and get on with the proper job

That is simply awesome! What did you change to achieve this fit? Wish we had one of these Make space projects somewhere near me. In total awe of this type of stuff, most definitely the way forward.

What would be really good would be a central repository for people to upload designs to (I'm assuming this is a DWG/DXF file format), in order for others to use/change for similar projects, which in turn would be up loaded. That's assuming people such as your good self would want to share their hard work...just a thought. Designs on an exchange basis...

Mike

Yes, I've been wondering about trying to create some kind of shared resource for designs. The Open Source software community have things like Sourceforge where developers can share code usually under the terms of what is known as the GPL. This is basically a license that says (and please nobody shout at me for incorrect paraphrasing and putting into the terms of a CAD drawing).
- You can use this drawing for your own use for nothing
- You can make something with it and sell the result for the cost of distribution and materials but not charge for the time producing the artwork
- If you modify the drawing you must make it available again under the same terms

I'd love to see drawings start to appear and then get improved and modified by others. Particularly once you get into things like lasercutting and 3D printing it could be really beneficial.

David Barham

Thanks Mike,

The simplest description is that I've used a different cutting line to the mortar line, just inside the bricks to interlock. Basically cutting out the header brick, but leaving the mortar line in. Quite simple when the penny drops!

Cheers,
Tim

Awesome. It looks exceptionally convincing. It's something rarely seen in modelling so hopefully this can be the start of yet more bar raising of standards. I might try to replicate it by cutting small chunks iut of brick plastic card but I highly doubt it will look very good!

barhamd wrote:Yes, I've been wondering about trying to create some kind of shared resource for designs. The Open Source software community have things like Sourceforge where developers can share code usually under the terms of what is known as the GPL. This is basically a license that says (and please nobody shout at me for incorrect paraphrasing and putting into the terms of a CAD drawing).
- You can use this drawing for your own use for nothing
- You can make something with it and sell the result for the cost of distribution and materials but not charge for the time producing the artwork
- If you modify the drawing you must make it available again under the same terms

I'd love to see drawings start to appear and then get improved and modified by others. Particularly once you get into things like lasercutting and 3D printing it could be really beneficial.

David Barham

Ok, how do we go about this? Would the Society want to get involved in such a venture? Could the file sharing be just another part of this site? Given the above caveat on the sharing of files, should this just be for members of the society...would certainly be another good reason to join. I have drawings I should like to share as I have no intention of marketing the etches I've designed. But there may be others who would like to use them.

Mike

Probably time for a new thread, we've hijacked this one for long enough!

David

Mike Garwood wrote:That is simply awesome! What did you change to achieve this fit? Wish we had one of these Make space projects somewhere near me. In total awe of this type of stuff, most definitely the way forward.

What would be really good would be a central repository for people to upload designs to (I'm assuming this is a DWG/DXF file format), in order for others to use/change for similar projects, which in turn would be up loaded. That's assuming people such as your good self would want to share their hard work...just a thought. Designs on an exchange basis...

Mike

File format is an interesting topic. I recently got access to a Laser cutter and was told I needed to provide a DXF for the cutter software. Disaster! The software added extra lines and made a right mess of it. I found that a PLT file gave perfect results, which is probably not suprising as the Laser native software will almost certainly be using HPGL.

I use CorelDraw and can save to PLT format.

regards

Alan

Just a quick assemble of the sides I'd cut out a few days ago. Not happy with the depth of the lines on this one, will need to go back to the original laser settings on the first cuts. All is not lost though, as this model has been used to test the painting and assembly and work on the roof measurements. Just need to find the correct brick colour as my colour blindness is being a pain!

Cheers
Tim

That is seriously impressive Tim.

I posed this question on another forum...I was told that when building, buildings it was always wise to use the 3 layer approach to avoid warping of the model. Do you think that with the advent of different materials now available in this process that we've seen the 'death' of this approach. or is it too early to make an informed judgement?

Mike

I still follow 'the Law of Laminations' wherever possible, especially when using styrene sheet/strip. The same would apply if I used card, but I have gone for plastics throughout in the buildings on my present layout. Walls I have built this way have stayed put, whereas bowing can occur where only one or two layers are used.

One exception is walls built of Wills scenic sheet which is thick enough and sufficiently rigid to need no bracing.

The middle layer does not need to be continuous. It can consist of strips. The essential point is that the two outside layers should be the same material and of identical thickness.

Distortion is not inevitable if you only use a single layer or two layers, but you run the risk of it occurring in time.

By the way, the brickwork on display in this thread is amazing. Impressive and inspiring.

Yes, I’d follow the odd number layers of lamination where possible to. The MDF stuff is ok, but I try and let it dry flat, painted or glued, to minimise the risk of bending. I know that I've going to build some internal walls to help straighten the model up, but it's not that noticeable at the moment so I think it will be ok.

I've been working on the fiddly bits the last few days, roofing and doors and windows. I try to do everything to near scale as possible, may or may not work, but it's worth a try

Thanks for the kind comments!

Cheers
Tim

Had another go at the small door today, and with the windows, which although a pain to glue, worked out quite well. 160 gsm card with .25mm glazing and a 1mm MDF frame.

Got to up the neatness when installing though

Cheers
Tim

Those sash windows do look good.
(As does the door!)
Keith

Very nice, and many times faster than cutting/fabricating all of those trusses by hand.

This really is starting to look like the future of architectural modelling.

Flymo

Tim

That's incredible, wouldn't etching the window frames and doors make for a finer fit? No criticism intended. Or is this a case of getting everything done by one tool. Have to say it's really moved making buildings to another level of realism altogether. How are the roof tiles going to be done?

Just love this project

Mike

Thanks again for the kind comments, being the first full lasercut building it is a big learning curve at the moment but I'm quite pleased at the results so far.

Mike, I'm cool with comments, good and bad. I think the poor fit is down to me trying to get away with stuff like not sanding the outer brick work and not spending enough time gluing the windows and frames up neatly. It's all a test at the moment and trying to learn what I can get away with. Comes down to most things we do, if we put the time in, usually we get the results we want to achieve I haven't got any experience with etching, so it’s easy for me to bang a few drawings into the laser cutter and see what comes out. I think I’ve adjusted the frames over ten times to get them to fit almost properly, but it comes down to me not fudging up the installation

I've got a few ideas for the slates and lead flashing, but I'm mostly thinking about guttering at the moment. I think I've got everything else covered in my head so I just need to crack on and get the real model started.

Thanks for the interest so far, I think it will improve my buildings in the future, and speed them up too.

Cheers
Tim