Display Cases - Advice on the making of!

[districtgrandmaste]

Although I have made model steam engines for about forty years I have only recently decided to smarten some of them up by putting them in display cases.

This is proving difficult!

My compound mitre joints don't come out at 90 degrees and cutting perspex to fit my rebates leads to lots of scrap!

I've just finished one of Anthony Mount's Crosskill engines. As that is small (and good fun to make!) I wanted to do a display case of persex only (dodging compound mitre joints! : but 'hard plastic glue' goes all over the place!

Anybody know any good technical articles on the subject?

[ron]

Hi
Why not make it out of glass and stick it together with silicon rubber the same way as an aquarium, it makes a very strong unit.
Ron

[dickdastardly40]

I'm afraid I don't know of any technical articles myself but here is my take.

Most mitre saws/boxes are only so close in accuracy, a sanding disc/linisher with an adjustable fence is a great method of getting mitres on picture framing just so, just practise on scrap first.

Perspex can be cut by scribing and snapping similar to a ceramic tile, does not take well to nibbling and needs supporting well along the cut line while you 'snap'. A pair of clamps and a straight edge holding down with the scrap portion over the edge of the bench is what I have used.

It can also be cut with a jigsaw though this leaves a ragged edge which needs sanding if exposed. The edge can be planed with a block plane as long as your blade is sharp, I've never tried a power plane.

Counter-intuitively (for me anyway) it can aslo be cut successfully using a circular saw, best on a bench type and leaves a semi acceptable edge. Use a blade with not to much kerf and don't dwell on the cut to avoid chipping.

If picture framing your display case and the edges of the persex aren't on show, there is no need for the sheet to be the exact same size as the rebate, a loose sliding fit is much easier.

Perspex can be bent successfully, I can't remember the temp required but you can get a quite sharp corner depending on the sheet thickness bending over a former. You could make a 'U' shaped lid and sides in one piece and wooden ends with the end routed with a channel to fit the perspex into and windows on the end rebated in the inside to accept perspex. This would negate the use of mitre joints entirely.

I leave the protective film on for as long as possible to prevent scratching.

Hope this is of use

Al

[chris vine]

Hi,

I have made small display cases from picture framing glass and some adhesive copper tape to stick it all together. Sounds awful but it works very well.

The tape is made for making glass terrariums (terraria?).

C

[hat]

I like Chris Vines idea and done with care could look very professional.
A few thoughts on the use of Perspex: if you really want to mitre it stick masking tape along the line of the saw cuts this helps with spelching, if using a power saw use a small fine blade running top speed of your saw ( if you can adjust the speed that is) keep it moving or at best it will leave rings which will be difficult to remove or it mat even burn or melt the perspex. Protect your eyes as the chips are vicious. You used to be able to buy a special perspex cement for the joints. We used it to make underwater camera cases. You might also cut it with a joiners tenon saw keeping the angle of cut very low. If you want to plane it a sharp block plane is fine because they have a low cutting angle - it must be sharp though. A standard smoothing plane will do the business but make sure that the back iron ( chip Breaker) is a good fit to the back of the cutting iron and its fitted close to the cutting edge (1/16 away)
You might design out the mitre with some clever butt joints and round and polish the exposed edge with Brasso ( or the propriety perspex polish.)

[modeng2000]

I made a case for the ME Jubilee clock using custom made glazed picture frames.
John

[Uzzy]

Here my two pence worth - not much use though. Many moons back my father (Rest His Soul ) built himself a case for underwater photography out of what I think was perspex problem is I was to young to take any notice what he used as glue but I think it was one of the ones that weld the two pieces together. Again sorry not much help!!

[circlip]

If the material IS Perspex - Acrylic - the adhesive that was used a long time ago was chloroform, Oh what fun the elfs will have with that one! More recently the glue used went under the trade name of TENSOL, which leaves a colourless joint, but that is assuming the base material IS acrylic. DIY Supermarkets also sell clear glazing materials which could also be Styrene or Polycarbonate which use different adhesives. For long term clarity and scratch resistance the only glazing material to use is Glass. You just have to teach the grandkids the meaning of the word NO and DON'T TOUCH followed with a short sharp shock if they don't.

[districtgrandmaste]

Thanks for these suggestions which are all very helpful.

On cuttng persex - I am quite satisifed with my 'Burgess Bandsaw'. It delivers a clean cut and for pieces smaller than the table it is easily adjusted. I've made a cutting table for larger sheets and use my circular saw - but my technique there needs some honing!

I'll let you know how I get on - many thanks for now!

CEW

[charles]

hi
Charles here
now this is interesting whether you want to but glue or use small brass angle or aliminum angle the powder coated 1/2 inch material my personal idea is i like the metal angle this tends to set the model of show wise and tends to date the job
which is good also you can use a thinner perspex/acrylic and also can glue with a clear silicone bathroom sealer type to use is neutral cure ,,,, if you use the old aesthetic cure it attacks chrome ( lovely stuff for sniffing ) ,,,,, another thing your edges can be a bit rougher ( hidden by the angle ) really to cut perspex/acrylic,,,,,, small bench saw and a small electric planer
clean edges up....most important if you are going to but glue very tricky (( but easy enough for a joiner)) its a fiddly job everything has to go together dead square and i mean dead square this is why i say use brass angle its very forgiving and your base would haft to be a nice piece of utile / mahogany and rebated to take the case best idea would make that first with the rebate of the thickness of perspex you tend to use reason it will help to hold everything square as you glue then again you could use standard glass i am saying this from a professional point of view as a carpenter/joiner/chippie wood carver now retired Charles

[charles]

Charles returning
drop me a line of forum my e-mail is there and i will try and explain a little better and if you have a camera i will try and talk the way through the job such a simple thing to do but quite involved to get an acceptable job that going to enhance the model i have looked through the wide web and theres nothing plenty of people who want to sell cases but no information
Charles