Repair crack in plastic

Discussion in 'Materials' started by rasorinc, May 22, 2012.

  1. rasorinc
    Joined: Nov 2007
    Posts: 1,854
    Likes: 71, Points: 48, Legacy Rep: 896
    Location: OREGON

    rasorinc Senior Member

    I'm hoping somebody camn help me with this. My 1992 Subaru SVX has a plastic top to the radiator which I cracked getting the alternator off. It runs left to righe and does not leat with the cap on loose but does when pressurized. A new one is $ 520.00 plus tax and shipping. Ouch... I have 2 thoughts, one is melt it back together with a sodering iron, and 2 is a chemical weld but what chemical? You cannot get just a new top. I want to sell this car but must find a fix to this problem. Thank much for any ideas.
    Stan
     
  2. hoytedow
    Joined: Sep 2009
    Posts: 5,669
    Likes: 285, Points: 93, Legacy Rep: 2489
    Location: North of Cuba

    hoytedow Wood Butcher

    That's aa tough break, Stan. I would find out what kind of plastic it is and have some sticks ready before I tried "welding" it with a hot iron, laying up some extra plastic to thicken the area as I "welded" it back together. You have to be careful not to drop hot plastic into the plumbing though or you will magnify your troubles.
     
  3. CatBuilder

    CatBuilder Previous Member

    What Hoyt said... or... just go to the junkyard and pull a used radiator.
     
  4. hoytedow
    Joined: Sep 2009
    Posts: 5,669
    Likes: 285, Points: 93, Legacy Rep: 2489
    Location: North of Cuba

    hoytedow Wood Butcher

    CatBuilder probably has the better idea, assuming there is a 20 year old radiator to be found.
     
  5. rasorinc
    Joined: Nov 2007
    Posts: 1,854
    Likes: 71, Points: 48, Legacy Rep: 896
    Location: OREGON

    rasorinc Senior Member

  6. SamSam
    Joined: Feb 2005
    Posts: 3,900
    Likes: 196, Points: 63, Legacy Rep: 971
    Location: Coastal Georgia

    SamSam Senior Member

  7. Petros
    Joined: Oct 2007
    Posts: 2,936
    Likes: 140, Points: 63, Legacy Rep: 1593
    Location: Arlington, WA-USA

    Petros Senior Member

    The plastic gets more brittle as the car ages, often they will crumble apart at about 20-25 years even when not struck.

    But I understand your problem, your best and safest bet is to go to a self service wrecking yard (one where you bring your own tools) and get one. There should be one near you, call to see if they have a car like yours in inventory. That model of radiator might be common to other models of Subarus as well (usually with the same engine). The self service wrecking yards you have to bring your own tools, but they are cheap, radiators usually only about $35. Pick-and-Pull, U-pull-it and Pick-your-part and similar names.

    I am pretty sure those plastic radiator tanks are made of ABS plastic, you could try using epoxy or ABS cement with a strip or patch of plastic over the crack. If all else fails I have actually seen the radiator stop leak work on cracked header tanks. I have even seen black pepper work too.

    A friends VW jetta had a crack in his header tank that also leaked only when warm, he stopped by my placed and asked if I had any black pepper he could have. He showed me the leak, put the ground black pepper into the radiator, put the cap on it, and we watched as the leak got less and less, and than stopped. He drove it that way for another year, and than sold the car.

    Good luck.
     
  8. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 476, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Heat treat the surface (oxidize) the surface, then epoxy it. Don't answer the phone for a week after you sell it . . .
     
  9. tunnels

    tunnels Previous Member

    Plastic weld it !!

    Find some one that does hot air welding on plastics . usually bumpers and front grills etc they could can possibly hot air weld it like new again !!
    Plastic can be welded much better than using some sort of sticky crap .:D

    Some plstics nothing sticks to it so hot air is all there is . the rods they use are usually the same color so once its done you probably wont hardly see it !!
     
    1 person likes this.
  10. rasorinc
    Joined: Nov 2007
    Posts: 1,854
    Likes: 71, Points: 48, Legacy Rep: 896
    Location: OREGON

    rasorinc Senior Member

    I want to thank all of you for your time and suggestions. tunnels, I'm going to try your method first. If that doesn't work I'll try the others. Par, I will take your suggestion and not answer my phone for a week. That is good practice when selling anything that is used. Again, thanks much to all of you. Stan
     
  11. Sand crab
    Joined: Feb 2011
    Posts: 92
    Likes: 3, Points: 0, Legacy Rep: 23
    Location: Montana

    Sand crab Junior Member

  12. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 476, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    I've done some plastics welding and it's not as easy as buying a gun and some sticks, trust me. It's just as hard as laying a good, clean, tight bead on metal and requires lots of practice, if you expect it to hold pressure.
     

  13. Herman
    Joined: Oct 2004
    Posts: 1,618
    Likes: 89, Points: 48, Legacy Rep: 1240
    Location: The Netherlands

    Herman Senior Member

    Fix it up with Plexus MA310. This is a very agressive plastic / aluminium / stainless / composite glue. Make sure the glue thickness is 1mm and you are fine. Can even answer the phone.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.