Blue lacquer for hi temp halogen lights....................

Both Rosco and Lee make hi-temp gels which will hopefully do the job. If not then you could go with an appropriately coloured dichroic glass but it will probably cost you more than the buying a set of lights similar to those that Jeff has. Failing that, I have successfully used the 500w bunnings floods with standard gels by mounting the gel outside the wire grille and cutting it oversize so you don't get open white spill. I am surprised that it makes any difference to the melting point when you sandwich the gel between glass. Most glass won't absorb much infra-red radiation (compared to a blue gel which absorbs a lot) and sandwiching it only cuts down on airflow which is the primary method of cooling for a gel. Be aware that the cheapo 'gels' that you can get are often just cellophane which will melt in no time. And yes Jeff, there does seem to be an echo around here.