Hi my first post, I want to bond / laminate some clear acrylic to a hardwood, any recommendations? I’d like it to be clear of course so the wood can been seen through the acrylic. This is for small pieces 6’ x 9’ maximum.
Hello first question GLUE ?
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Hi and welcome. You don't say what you are making so I'll have to guess about what sort of construction it is.
I imagine you are making some sort of display box where there is a comparatively narrow hardwood frame with glazing panels of acrylic.
The acrylic will probably expand and contract with temperature changes more than the wooden frame will, so you will need something with a bit of give in it. I would use a clear glazing silicon from a reliable brand such as Dow Corning. There was a discussion on here recently about another brand: https://www.ukworkshop.co.uk/forums...r-product-you-ve-used-for-glazing-t64870.html.
However, if you have something else in mind entirely - such as something where you want to glue the entire surface of the acrylic, then none of this will help! (And even if I have guessed right, wouldn't a groove for the plastic be neater?)
I imagine you are making some sort of display box where there is a comparatively narrow hardwood frame with glazing panels of acrylic.
The acrylic will probably expand and contract with temperature changes more than the wooden frame will, so you will need something with a bit of give in it. I would use a clear glazing silicon from a reliable brand such as Dow Corning. There was a discussion on here recently about another brand: https://www.ukworkshop.co.uk/forums...r-product-you-ve-used-for-glazing-t64870.html.
However, if you have something else in mind entirely - such as something where you want to glue the entire surface of the acrylic, then none of this will help! (And even if I have guessed right, wouldn't a groove for the plastic be neater?)
Eric The Viking
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Some thoughts:
1. People like to display the valves.
2. Valves get hot and dusty - you'll need cooling vents and possibly even a fan - wood and Perspex are both good thermal insulators - and you'll get dust staining from convection air currents on the inside top, if it's clear.
It's class A, so will be much less than 50% efficient, so more than half of the power input is wasted as heat that has to be removed.
3. Could you use a high-gloss varnish instead? It might be easier. For example a two-part polyurethane will be really tough and can be polished to a near mirror finish. The quality you get depends on effort+time expended - there isn't really a quick fix.
4. It will need good screening, so there will be metal/foil involved somewhere too.
5. Perspex scratches really easily - could be a problem in manufacture.
6. If you stand one off from the other, wood within perspex, for example, the glue problem goes away, possibly.
7. The best glue for Perspex joints is the special UV-cured stuff that's the same refractive index as the Perspex (so the joints become invisible, if done well). You need special kit to 'zap' the glue though, and getting it bubble-free is a black art.
Try an architectural modelmaker for ideas, if they're willing to talk. They often get similar tasks.
E.
1. People like to display the valves.
2. Valves get hot and dusty - you'll need cooling vents and possibly even a fan - wood and Perspex are both good thermal insulators - and you'll get dust staining from convection air currents on the inside top, if it's clear.
It's class A, so will be much less than 50% efficient, so more than half of the power input is wasted as heat that has to be removed.
3. Could you use a high-gloss varnish instead? It might be easier. For example a two-part polyurethane will be really tough and can be polished to a near mirror finish. The quality you get depends on effort+time expended - there isn't really a quick fix.
4. It will need good screening, so there will be metal/foil involved somewhere too.
5. Perspex scratches really easily - could be a problem in manufacture.
6. If you stand one off from the other, wood within perspex, for example, the glue problem goes away, possibly.
7. The best glue for Perspex joints is the special UV-cured stuff that's the same refractive index as the Perspex (so the joints become invisible, if done well). You need special kit to 'zap' the glue though, and getting it bubble-free is a black art.
Try an architectural modelmaker for ideas, if they're willing to talk. They often get similar tasks.
E.
Eric, your post has just reminded me of some other information about gluing perspex that I had almost forgotten.
Some time about 40 years ago when I was a lad, I borrowed a book from the public library about how to make your own transistors. Not how to use transistors, but how to dismantle a germanium diode, add an extra contact to it and make one of your own. The recommended way of holding it all together was to use a block of perspex and stick extra bits of perspex on. It said that the best way to stick the perspex was to dissolve some of it in chloroform, which you could buy from your local chemist if you explained what it was for!
I never did make my own transistors...
Some time about 40 years ago when I was a lad, I borrowed a book from the public library about how to make your own transistors. Not how to use transistors, but how to dismantle a germanium diode, add an extra contact to it and make one of your own. The recommended way of holding it all together was to use a block of perspex and stick extra bits of perspex on. It said that the best way to stick the perspex was to dissolve some of it in chloroform, which you could buy from your local chemist if you explained what it was for!
I never did make my own transistors...
Eric The Viking
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Yup.
One common perspex glue is perspex chip dissolved in chloroform.
There are two problems with this: Chloroform is hard to get legally, and it degrades, IIRC in sunlight, and certainly over time, giving the glue a limited shelf life.
I've been trying to get some to mend a motorbike screen for ages, and pretty much given up hope now. The UV curing stuff is really good, but not quite strong enough for the application. I have, however used it for display cases for equipment at trade shows, where it was carrying quite a bit of weight on the glued joints and got quite a hammering in transit.
E.
PS: in the old days Trich was also a good solvent for 'welded' joints, but that's now unavailable too.
One common perspex glue is perspex chip dissolved in chloroform.
There are two problems with this: Chloroform is hard to get legally, and it degrades, IIRC in sunlight, and certainly over time, giving the glue a limited shelf life.
I've been trying to get some to mend a motorbike screen for ages, and pretty much given up hope now. The UV curing stuff is really good, but not quite strong enough for the application. I have, however used it for display cases for equipment at trade shows, where it was carrying quite a bit of weight on the glued joints and got quite a hammering in transit.
E.
PS: in the old days Trich was also a good solvent for 'welded' joints, but that's now unavailable too.
Hi Eric , you have raised some good points, the amp I’m starting with is a low power, with TV tubes and small http://www.pmillett.com/midget.htm. The idea is to glue the veneer to a 5 to 6mm Perspex sheet, I want to combine the wood and plastic as a medium both good looking and rigid to make parts of the case, the front panel and maybe the top plate. It does not produce large amounts of heat even in an alloy case, but I could vent the sides or rear. So basically I need a strong, clear drying glue. I do have a very strong polyurethane crystal clear resin that might work I’ll experiment but it’s extremely expensive, it dries like glass, and it’s not the stuff you can buy off the shelf from eBay. But the results are very impressive, I have to first vacuum it and then pressure pot to get it perfectly clear, but once cured it’s like glass slightly flexible but tough.
Steve Maskery
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I bought some chloroform over the counter. 50p for 100ml, IIRC. That was in about 1975.
The next time I went it was banned. So I said to the pharmacist, "I suppose that's the case for dichloromethane too, is it?"
"Oh, no," was his reply, "You can have some of that!".
So no to trichloromethane but yes to dichloromethane. Bonkers.
Dichloromethane is chemically very similar indeed. Worth a try.
S
The next time I went it was banned. So I said to the pharmacist, "I suppose that's the case for dichloromethane too, is it?"
"Oh, no," was his reply, "You can have some of that!".
So no to trichloromethane but yes to dichloromethane. Bonkers.
Dichloromethane is chemically very similar indeed. Worth a try.
S
So I will need a bottle of Chloroform, a rag, some gloves and a mask? I’m thinking I’ll have less than 8 minutes after I ask the chemist to fill my shopping list before the police turn up ? Give traffic and time of day 
Eric The Viking
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If you don't ask for the rag it'll confuse 'em.
AndyT":crncg24f said:
That takes me back too! I had the same book, though it was probably at least 50 years ago. (Yes, transistors had been invented then!) Can still remember some of the pics - didn't the book also say that pieces of razor blade were as good/better than the reclaimed point contacts? But like yourself, I never actually got round to making a transistor - out of spec manufactured ones became available pretty cheaply about then.
But to go back to the original query, doesn't solvent for welding plumbing fittings work well with acrylics?
Eric The Viking
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On plumbing solvent: sadly, it doesn't seem to work on Perspex, leastways not the stuff I buy (there are different formulae though).
E.
E.
