Priming and Painting Laser Cut Card

[justin1985]

Hi all,

 

I've got some laser cut kits on order from MBZ in Germany, for a little Black Forest themed project I'm doing. By all accounts these kits are very fine quality - they're the ones created for Josef Brandl's famous Hochschwarzwald layout. 

 

 

They only have a minimal amount of info available in English, so I've been scratching together what I can understand with my schoolboy level German\Google Translate's attempts. I've never used a laser cut kit before - I'm more used to scratchbuilding with brick papers or plasticard etc. It looks like they recommend a rather odd painting method, so I'd be interested to hear how others paint laser cut card buildings in general?

 

The method described in the official instructions (brief English version here) and a video from their American distributors, Reynolds Imports, shows first brushing the whole fret with their proprietary "primer", which looks like a clear varnish. Then the method recommended seems to be to make up a paste from their proprietary pigment powder and proprietary solution, and apply with a sponge. 

 

 

I'm guessing the "primer" is a form of artist's varnish, and the pigment and solution are equivalent to weathering powders and pigment fixer in the military armour weathering ranges (e.g. MIG)? Has anyone used that kind of process on card kits before? 

 

I'm guessing it would be equally possible to use conventional acrylic paints and then drybrush weathering on a card kit of this type? (after priming?)

 

Cheers

Justin

[Chubber]

I can't comment on the kits in question, but several years ago I built a lasered wooden signal box kit for a magazine review which included interior detailing in lasered card. I should have realised when pushing the 'levers' into the slots with difficulty that the PVA glue I was using was making them swell up, and when I used water based acrylic paint on them they swelled up to a scale 4" square!

I suspect the 'primer' may indeed be a type of varnish designed to minimise the uptake of moisture from finishing paints. Perhaps it might be wise to try out your finish on a scrap bit of card first, or, take a copy of the German instructions to your nearest foreign language night school, and follow an attractive young lady into the Modern German class with a request for a translation!

Good luck,

Doug

Edited February 7, 2018 by Chubber

[ROSSPOP]

This is a UK laser cut 7mm kit .....comprising of mdf and thick card........

 

 

I used Halfords Acrylic spray can primers.

 

 

And then assembled with quality un-thinned PVA glue.  Painted with enamel paints.

 

 

 

Cheers

 

John

[justin1985]

Thanks - it certainly seems like something that seals against moisture is what's needed. I guess either varnish or traditional spray primer would do the job.

 

I think the question is less about translation, and more the fact that the instructions in either language just refer to their specific proprietary paints etc. I was very reluctant to buy these as well, considering I've got a pretty good stock of other brands of these kinds of things. It's just knowing what type of paint etc would be best!

 

It's good to see what the Halfords primer and enamels work fine Any experience with acrylics?

 

J

[ROSSPOP]

Just a thought.........

 

To stiffen and prime paper and card....... good old ,but effective,..........      SHELLAC.....

 

 

John

[Marly51]

Very interesting topic and lots of technical advice! Hope you had success with the kits?

 

Marlyn

Edited January 30, 2018 by Marly51

[justin1985]

Hi Marlyn,

Funnily enough I was just looking at your textures thread. I haven't started any of these kits yet, but I'm tempted to try the shellac method of sealing the card, as discussed on your thread too. I hadn't realised "knotting solution" was the same thing! I hadn't fancied mixing the old stuff up, so this is an attractive solution. Does anyone know if "knotting" is always just "knotting", or should I look for any particular formulation for this kind of use?

 

I think the first step will be to try a few different things to seal the card on the waste areas of one of the kits. Planning to try knotting, Klear floor varnish, and enamel varnish (probably the ready thinned airbrush version?) 

 

Best

 

J

[Chubber]

There are modern knotting mediums, (in case someone is wondering what it is for, it is used to paint over knots in joinery softwoods so that the resin (think turpentine) doesn't find its way through subsequent coatings of oil-based paint finishes) which are a clear plastic like coating.You need an alcohol based preparation of lac beetle wing cases or the modern equivalent. Knotting is generally brown in colour, but French Polish of similar formulation may be had in colours as pale as cream, wherein the particles are bleached before use. 'Button Polish' is another stable formulation, once available in appropriately small bottles!

 

 

. Doug

[BrushType4]

This may help too.

 

http://intentio.co.uk/painting-tips/

[justin1985]

Thanks for the tips! 

 

I happened to be passing an old fashioned ironmongers type shop in Purley yesterday, noticed it while I was waiting to cross the road, and decided to pop in. They had some small bottles of Button Polish with the caption "only pure shellac", so I bought one at £7. I'll try and get around to testing this, and some of the other suggestions, on some of the scrap "fret" of the kit over the weekend.

 

Its the fact that all the parts are card, rather than MDF etc, that makes me a little anxious about over-saturating with anything water based.  

 

Justin

[Marly51]

Thanks for the tips! 

 

I happened to be passing an old fashioned ironmongers type shop in Purley yesterday, noticed it while I was waiting to cross the road, and decided to pop in. They had some small bottles of Button Polish with the caption "only pure shellac", so I bought one at £7. I'll try and get around to testing this, and some of the other suggestions, on some of the scrap "fret" of the kit over the weekend.

 

Its the fact that all the parts are card, rather than MDF etc, that makes me a little anxious about over-saturating with anything water based.  

 

Justin

Look forward to seeing your results, Justin. I still need to buy some knotting to experiment with.

 

Marlyn

[BrushType4]

For the card, Halfords acrylic primer is fine as long as you don’t use to much. Several light costs are better if it’s needed. The white primer is particularly good for window frames.

[Norski]

Hi Marlyn,

Funnily enough I was just looking at your textures thread. I haven't started any of these kits yet, but I'm tempted to try the shellac method of sealing the card, as discussed on your thread too. I hadn't realised "knotting solution" was the same thing! I hadn't fancied mixing the old stuff up, so this is an attractive solution. Does anyone know if "knotting" is always just "knotting", or should I look for any particular formulation for this kind of use?

 

I think the first step will be to try a few different things to seal the card on the waste areas of one of the kits. Planning to try knotting, Klear floor varnish, and enamel varnish (probably the ready thinned airbrush version?) 

 

Best

 

J

 

Hi - not sure if this would be of any use but last year I spent months priming badly varnished pine skirting and door frames (a lot of it !!) - i used a shellac primer called Zinnser BIN. It was very much recommended by the trade decorators on screwfix as the best there was to cover knots, stains etc. It is bonkers expensive but i can vouch for it. Like I said, may be of no use  - new to model railways but I could take a degree course on painting skirting LOL (I'm never doing it again).

 

Steve

[Chubber]

Thanks for the tips! 

 

I happened to be passing an old fashioned ironmongers type shop in Purley yesterday, noticed it while I was waiting to cross the road, and decided to pop in. They had some small bottles of Button Polish with the caption "only pure shellac", so I bought one at £7. I'll try and get around to testing this, and some of the other suggestions, on some of the scrap "fret" of the kit over the weekend.

 

Its the fact that all the parts are card, rather than MDF etc, that makes me a little anxious about over-saturating with anything water based.  

 

Justin

 

I'm sure you have cottoned on, but hope you had some methylated spirit to hand to wash out your brushes.....

 

Doug

Edited February 7, 2018 by Chubber

[justin1985]

I'm sure you have cottoned on, but hope you had some methylated spirit to hand to wash out your brushes.....

 

Doug

 

Haha, yes I did get a bit of a shock when I realised normal white spirit didn't shift the button polish from the brush I used. Sorted in the end with different cleaner as you suggest, but now I see why the bottle recommends applying it with a rag!

 

The button polish was the only thing that sealed the card, made it rigid, and didn't show any sign of lifting or swelling the softer textured card. I now want to just check how well it takes acrylic paint before I apply it to the kit.

 

J

[Chubber]

Oh Justin!

Sorry I didn't get back to you sooner. I have rubbed my shellac'd surfaces with a green pan scourer to give a little 'key' for gluing, etc.

 

Look here... https://thechelseascrolls.com/tag/lac-beetle/

 

More power to beetle poo!

 

Doug

[michl080]

 

I've got some laser cut kits on order from MBZ in Germany, for a little Black Forest themed project I'm doing. By all accounts these kits are very fine quality - they're the ones created for Josef Brandl's famous Hochschwarzwald layout.

 

Justin,

 

I just discovered this thread. I am sure you already found your way to build these kits, nevertheless, let me comment how I built them.

IAs a first step, I  have treated the cardboard With "Tiefgrund", which is an acrylic binder that is used to fix loose plaster before painting. I am not sure about the translation, but I think it might be called "pentrating primer".

I treated the complete board before removing any of the parts. The primer is applied two or three times within a few minutes. The primer is absorbed very quickly.

 

Next step is to build a layer of plastic foil (Polybags) and board and press the whole pack with some heavy books until they are dry. This is necessary because the primer would cause the board to crumple.

Polybags are from Polyethylen do not stick to the primer.

 

After this treatment, the parts are very stiff and can be handled easily. The surface is sealed and can be painted with brush or airbrush. See this example:

 

 

regards,

Michael

Edited February 25, 2018 by michl080

[justin1985]

Hi Michael, many thanks for this insight! I'm really impressed by your beautiful barn. I hope I can do justice to the MBZ kit as well as you have! I got distracted with other projects in other scales recently (see my thread in 2mm Finescale area on here) so haven't made any progress on these yet. 

 

The tiefgrund primer looks really good - I can think of several decorating jobs around my house that it would have made a lot simpler! British builders and decorators don't seem to often use this type of product - and I think most would use simple diluted PVA, or diluted cheap emulsion paint ("misting") for this kind of job. I did find this similar product from Bostik "Cementone Universal Primer" but it doesn't seem to be very widely used. (This reminds me of a frequent conversation with a Czech\Irish friend about how bad workmanship is in British buildings!)

 

The shellac based polish that I tried before seems to work pretty well at being rapidly absorbed by the card, drying quickly, and making the card very rigid. So I might press ahead with that on one of the kits.

 

Justin

[justin1985]

I finally finished one of the kits - the smallest - the crossing keeper's cottage.

 

I used the button polish type shellac to harden up the card, which seemed to work pretty well. Then I assembled with UHU Hart (found this at the 4D Modelshop in London) and painted with Vallejo acrylics. 

 

It did need some extra bracing here and there - the card wasn't totally rigid even with the button polish. No problems with the card swelling at any stage though, which is what I was worried about.

 

 

 

Really pleased with this - especially the engraved texture - hard to believe it is Z (1:220) ! I've left the stair handrail off for now, even though its cut from thin ply rather than card, it would still be exceptionally vulnerable until installed on the layout.

 

Justin

[michl080]

Justin,

 

that looks fantastic. Z would be a nightmare for me and my eyesight.

 

I agree that the texture of the MBZ kits is very special. I never saw anything comparable at other laser cut manufacturers.

 

Michael

[jonny777]

Thanks for all the advice regarding acrylic paints. I might try them on my tiny signal box that I have recently bought from L-Cut

 

http://lcut.co.uk/index.php?page=pages/products&title=4mm%20scale

 

I have to say that the card parts are very finely cut out, and I am well impressed by the thought and design work which must have gone into the initial design. The parts seem to fit together very well.