WWII fighter planes

Discussion in 'General foundry chat' started by Peedee, Aug 14, 2020.

  1. Jim Edgeworth

    Jim Edgeworth Silver

    I used MEK as a plastic solvent to make prototype electronic cases from sheet ABS & Polystyrene, but in very small quantities with a tiny artists paintbrush and yes, You need to be careful with the fumes, it’s evil stuff.
     
  2. Jim Edgeworth

    Jim Edgeworth Silver

    I know “that look”, I get it all of the time. People just don’t understand that “A guys got to do what a guys got to do”:rolleyes:
     
  3. PVC plastic pipe "Primer solution" for gluing joins is MEK solvent, I was going to get some to try it as a solvent for nitrocellulose spot putty used on patterns. MEK figured prominently in a compensation claim for RAAF maintenance workers who were resealing F-111 fuel tanks that had to have sealant applied to the internal joins of alodined aluminium surfaces of the fuel tanks. Workers were climbing into the tanks and the protective gear wasn't enough for the chemical exposure, one base maintenance facility was using 13000 litres of MEK per year. https://www.airforce.gov.au/sites/default/files/report_of_the_board_-_volume_2.pdf


    So it's not too bad in small doses but in chronic exposure it can cause nervous system disease when used with other solvents. From page 136 of the link above:

    F-111 Deseal/Reseal Board of Inquiry
    Methyl Ethyl Ketone (MEK).MEK has moderate toxicity following both acute and chronic exposures. The major route of occupational exposure to MEK is by inhalation, but absorption can also occur through the skin. Eye contact with the liquid can produce pain, irritation, and corneal injury.Slight nose and throat irritation may occur at 100 ppm, mild eye irritation at 200 ppm, and at 300 ppm the vapour is objectionable, with headache and throat irritation. Prolonged exposure to high atmospheric concentrations (350 ppm) may produce central nervous system depression and narcosis.Prolonged skin contact may defat the skin and produce dermatitis. No untoward effects have been reported for chronic exposure to low concentrations. IDLH Value (Immediately Dangerous to Life orHealth): 3000 ppm.

    MEK may enhance the neurotoxicity of n-hexane, but MEK has been found not to cause peripheral neuropathies itself. When present simultaneously with n-hexane, MEK can potentiate the neurotoxic effects of these compounds by an unknown mechanism. The neurological effects found from MEK, together with these other chemicals, include peripheral neuropathy (numbness, weakness,or tingling of the extremities) and central nervous system (CNS) depression (dizziness,unconsciousness, and loss of vision). Numbness of the fingers, arms and legs have been reported inworkers exposed to 300 to 600 ppm, and polyneuropathy (a number of disease conditions of the nervous system) has occurred in workers exposed to MEK along with other substances.
     
  4. Peedee

    Peedee Silver

    MEK is great stuff, get it in a cut on your hands and you know about it! I approach it with caution.

    My daughter got to be one of very few people to sit and play in the pilot seat of the dual control hurricane yesterday (in the hanger!). As a 17 year old technology addict I think she was slighty overwhelmed by the ancient instruments, knobs levers switches and such.

    Me, I had a good run of rivets then chopped three in a row leading to an early tea break and much swearing/throwing blocks etc.!! Monday is a fresh start (after a few drill outs)
     
    dennis likes this.
  5. Jim Edgeworth

    Jim Edgeworth Silver

    I’ve got that Tee shirt Peedee, it’s all going great, you’ve got into a rhythm and the shop heads all look like identical little cheese wheels - and then it all goes pear shaped. That’s why we Brits have so many tea breaks:D
     
    Peedee likes this.
  6. Peedee

    Peedee Silver

    Jim, when it all goes right the all goes wrong it's nothing short of a heartbreak.

    These ones are near impossible to block (3/16 tails holding you off, no room between bulkhead and spars....) I was gunning and Graham managed to block them and get a perfect cheese tail and I'd bounced and chopped with the snap! 3 Times, I feel bad for him that he actually managed to block it and then I'd screwed the head.

    It's one thing assembling these damn wings in a factory from parts up in 1939 but trying to re-skin them after repairs (we have a manual for official Hawker repairs would you believe)

    I shall spend the weekend having bad dreams about rivets then start again.

    Onwards and sideways as it were (Or as Churchill said... keep bugg**ring on)

    EDIT: you are spot on with the rythym when they run well it's a dream.
     
    Last edited: Jan 9, 2021
  7. Jim Edgeworth

    Jim Edgeworth Silver

    While I was building the Sportsman, somehow I missed a run of 5 rivets on the rear spar of a wing. By the time I noticed it, I had fitted pulley brackets to the spar and riveted the top skins on. I lost so much time grinding a lump of steel into the weirdest shaped bucking bar you’ve ever seen, but it got the job done. Of course some smartass then suggested that I could have got away with using Cherrymax pull rivets:)
     
  8. GTS225

    GTS225 Silver

    Sounds like "Murphy" escaped from the hurt locker again. PeeDee, when you get back to the shop.....double check the lock on that hurt locker, and make sure Murphy and his damn laws are secured.:D;)

    Roger
     
  9. DavidF

    DavidF Administrator Staff Member Banner Member

    Mek is ok, but for really tough jobs methylene chloride is the way to go.
    Back when I did composites I was loaned out to another shop. When I got there I found their tools so loaded up with cured resin I couldn't even use them. So I went out to my truck and grabbed a pail of meth and threw all their tools into it for 30 minutes. You should have seen the look on their faces when I pulled them out and they were nice and new again....
     
  10. Jim Edgeworth

    Jim Edgeworth Silver

    David, I haven’t come across methylene chloride before , does it work on epoxy and polyester resins?
     
  11. DavidF

    DavidF Administrator Staff Member Banner Member

    Oh yea...
     
  12. Some gel paint strippers have a few percent of it: works on live human skin too, like a million mosquito bites :eek:.
     
  13. Peedee

    Peedee Silver

    I'm going to have to look at that because very little is even getting close to the glue on the tank! All I can do now is budget thinners and scrape the softened glue until it's removed enough to take a soaked scotch pad to it.

    The paint stripper we use is nasty (I have permanant scars on my arms from the first time I used it) but it still won't touch this damn glue!
     
  14. Peedee

    Peedee Silver

    Jim, if a historian digs up our massive tool chest of blocks in 1000 years time they are never going to work out what the hell they are! Most of them look like abstract sculpture, they'll probably think we worshiped a contorted god with a very odd nose ;)
     
  15. Jim Edgeworth

    Jim Edgeworth Silver

    The daft thing is, we make them for a very specific job which will never be seen again in our lifetime, but we keep them, Just in case:D
     
    Peedee likes this.
  16. Peedee

    Peedee Silver

    Jim, Just a few of the blocks, that case must run into hundreds of odd-ball shapes..
     
  17. Peedee

    Peedee Silver

  18. Peedee

    Peedee Silver

    I'm having to adapt back into having a fully equiped machine shop at hand, a bracket that would have recently taken me five minutes to hack out grind and cover with paint now takes me half a day with TIG welding lathe turning and milling followed by a trip to the spray booth for an etch/primer/top coat...........it was a steady to stop the balustrade wobbling on the stairs to the kitchen/mess room :)
     
    Tobho Mott likes this.
  19. Peedee

    Peedee Silver

    Well... if you've never sat in the cockpit of one of these warbirds and done an engine test (the plane strapped down to the apron) you haven't lived!!!

    Full chat on that Rolls Merlin running 4 bar boost and full pitch on the props and it wants to be airborne and take the concrete with it, noise and vibrations are unreal.

    I feel absolutely blessed to be allowed in the plane to do it and slightly humbled looking back at what those new pilots did 80 years ago.

    For anyone in the UK we are on CH4 on Sunday 9:00PM and then again the following Sunday, the plane was in the centre spread of the sun newspaper (If you call that rag a paper!) yesterday and there's another program coming out on the discovery channel.
     
    Tobho Mott likes this.
  20. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Let us know when that is scheduled to hit the airwaves Peedee.

    Best,
    Kelly
     

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