RAHTR4 Posted May 23, 2008 Report Share Posted May 23, 2008 I removed one of the rear lamp plastic lenses, it is an original Lucas part and it came off in two peices. The break is at the manufacturered joint between the amber and red sections, thus is behind the stainless steel cover strip. The lense can be fitted in this condition as the centre screw holds it all together. However looking at the lense from the other side this joint is obviously glued together after assembly, presumably to make it water tight. So my question is, does anyone know what type of glue can be used to make a permanent repair? Regards, Richard Quote Link to post Share on other sites
john.r.davies Posted May 23, 2008 Report Share Posted May 23, 2008 Nothing special, Richard. Any epoxy, but make sure the joint is really clean - it'll be dusty by now, if it's been used in a cracked condition. Use sellotape to hold the parts together until set. John Quote Link to post Share on other sites
RogerH Posted May 23, 2008 Report Share Posted May 23, 2008 Hi Richard, Johns idea is the straightforward solution that will work, however acetone (nail varnish remover) may be a solvent for this form of plastic and if so would produce a seamless repair. Roger Quote Link to post Share on other sites
Alec Pringle Posted May 23, 2008 Report Share Posted May 23, 2008 Careful with the acetone ! I tried this years ago with a VW plastic lens, worked brilliantly; tried the same trick with a Lucas lens, and the damn thing went into meltdown . . . Superglue works pretty well, in conjunction with a smidgeon of clear silicone afterwards to seal any tiny gaps. Cheers, Alec Quote Link to post Share on other sites
Alec Pringle Posted May 23, 2008 Report Share Posted May 23, 2008 Afterthought. Maybe the Prince of Darkness just didn't like nail varnish remover . . . presumably he used black nail varnish . . . which just might make him the Proto Goth ? Cheers, Alec Quote Link to post Share on other sites
RAHTR4 Posted May 23, 2008 Author Report Share Posted May 23, 2008 Thanks to all for the advices. The residue of the original glue does appear to be clear. In light of a possible melt down with certain products, I think I will research into the use of a super glue, making sure of course that all is very, very clean. I will post the results in due course. Regards, Richard Quote Link to post Share on other sites
TR 2100 Posted May 24, 2008 Report Share Posted May 24, 2008 In light of a possible melt down with certain products, I think I will research into the use of a super glue, making sure of course that all is very, very clean. I think the most important factor is to achieve a watertight joint. Superglue is water-solvent, I believe, not quickly but over a period of time. I prefer the idea of a plastic solvent glue. AlanR Quote Link to post Share on other sites
vivdownunder Posted May 24, 2008 Report Share Posted May 24, 2008 Hi Richard, The correct adhesive for acrylic products is "Tensol Cement". You should be able to find a supplier under Plastics Products in the Yellow Pages, or take it to a plastics fabricator and they might be able to do the job on the spot cheaper than buying the product. It sets by ultra violet light. Regards, Viv. Quote Link to post Share on other sites
RAHTR4 Posted May 24, 2008 Author Report Share Posted May 24, 2008 Alan, Thanks for the input, I did not realise that super glue degrades in sunlight - best to keep the unit watertight. Viv, I have not heard of this product before but having now looked a various websites regarding Tensol Cement it does seem to be the answer.............but...!!!! It seems to be a bit of a nasty substance to use and quite expensive to buy as I would only really need a very small amount for the job in hand. Thus I shall do as you suggest and try to find a local plastics fabricator to hopefully get it glued up. Many Thanks, Richard Quote Link to post Share on other sites
MikeF Posted May 24, 2008 Report Share Posted May 24, 2008 There are several grades of Tensol, the one recommended for Acrylates is a solvent containing material, (dichloromethane, the same stuff as used in paint strippers). The surfaces you are bonding are dissolved together. When the solvent evaporates you are left with what is effectively a weld. If you ever used model aircraft glue (airfix!!) its the same principal. If you use this stuff naturally be careful not to get any in places you don't want marked. On really old polymer assemblies like the lens lights, which have probably got a little brittle over the years, I personally would not use a solvent based adhesive as there could be some stress crazing or cracking. Superglues come in various qualities/types, and also have a little solvent in them, but the main joining process is hardening of the glue itself by moisture. They aren't permanent in the sense that an epoxy is but if you get a proper quality one such as Loctite, they are OK. I would avoid own brand materials as they tend to be just re-packed low grade commodity stuff. Mike Quote Link to post Share on other sites
RogerH Posted May 24, 2008 Report Share Posted May 24, 2008 Hi Folks, heres an interesting one - when using 'instant' glues - loctite etc - if after applying it you decide to break the bond and redo it, it won't work. The two face will not react with the glue and will not bond. You will have to remove apprx 0.010" of surface material for it to react successfully ( tried on perspex and aluminium) It must cause the atom/molecular strucuture to fill all its empty spaces up, down to a certain depth. Roger Quote Link to post Share on other sites
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