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Acrylic (Perspex) display case for stationary model

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JCvdW:
I recently completed building a MEM Corliss steam engine and decided it needs a display case.

So an acrylic display case had to be made. I found this very informative youtube video on the subject:
 [youtube1]https://youtu.be/ufwUaZaM0ig[/youtube1]

Methylene chloride melts acrylic. It is hazardous, so take all necessary health precautions! It has a very low viscosity and when applied to an acrylic joint with a syringe needle, capillary action spreads the solvent, resulting in the two pieces of acrylic being welded together. After 24 hours, the joint is as strong as the parent material.

I bought some methylene chloride from a perspex fabricator and practised joining some scrap pieces of acrylic using a syringe needle. The two faces to be joined must be perfectly smooth and flat, as the methylene chloride has no gap filling properties. Milling the edges on a milling machine produced the best results.

I also found that the joint must not touch any other surface (such as a vertical backing plate).  Capillary action will pull the solvent between the backing surface and the acrylic, damaging the acrylic in the process. It works best to hold the pieces together with masking tape when applying the solvent.

I bought 3mm acrylic sheets for the four sides and the top of the case. These were ordered slightly oversize, to allow the edges to be accurately milled on the milling machine.



The protective covering was removed and all the milled edges deburred. The case was then assembled with masking tape and all joints were checked for a good fit.



A test fit on the model base was also done.



The corners were first tacked as described in the video. Then all the edges were glued by running the syringe along the inside corner of each edge, taking care to apply only the required amount of solvent (i.e. very little!). After a few minutes, the case can be handled and the tape removed. 24 hours later the joints are fully cured.

The neatness of the resulting joints is quite surprising, and I am very pleased with the final result.

propforward:
That is very nicely done - a great way to display the model.

vcutajar:
WOW.
I like.

Vince

Bearcar1:
That certainly is SWEET! And it will keep airborne dust and particulates from ever reaching the surfaces of that fine model. I have wondered about undertaking such a project, but have always passed as I thought it to be too tedious and that I would get the chloride were I did not want it and form a blemish thus ruining hours of work.. You have made it look so very easy...


BC1
Jim

crueby:
Very nice!  Back when I was much younger my mother made up several cases that way, there was a local glass shop that sold the sheet plexi and would cut/polish the edges to the sizes we gave. As you say, the trick is to use just a little of the solvent, it wicks in a long way. We were able to buy it with a little squeeze bottle with a needle tip applicator. Still have some of those cases with my ship models in them. Sometimes you can find a local store that will make them to order - beware of ordering them and having them shipped, tried that with some larger ones and fortunately was able to get a refund when they were cracked in transit, the way boxes go through conveyor lines and tossed around. Small ones are quite sturdy. Dont recall if they still do, some of the train suppliers and catalogs like MicroMark here in US used to do custom sizes.

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