ADVrider

Go Back   ADVrider > Gear > The Garage
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 05-15-2010, 07:14 PM   #1
wontco OP
B00n
 
wontco's Avatar
 
Joined: Sep 2005
Location: Huddled Masses
Oddometer: 27
Eh? Plastic Welding (?) on an Intake Manifold

I'm a lurker over in the sandbox (now that I'm displaced up North) and I'm Posting here on the recommendation of my bud Mugwest:

I traced a massive coolant leak in my fiance's 02 Saturn SL2 to a crack on what I discovered was a plastic (composite? whatever, it feels and looks like plastic to me - composite would be giving it too much credit) intake manifold where the heater hose goes from the manifold to the firewall. Comments on the Quality/Lack Thereof of Saturns and the wisdom of plastic intake manifolds aside, I could use some input.

Here's the crack in these photos; Engine side is to the left, firewall is on the right. You should be able to see that the crack is about 3" to 4" long and runs above the seam. I'm squeezing a radiator hose in these shots to force some coolant through the crack to make it more visible, but you can see how wide the crack has gotten. I'm sure there's hairline on other side of the visible crack as well.




Now I know the most sure fire repair is to just replace the intake manifold, But -there's always a but- that's at least $300-$350 on a veh. that has almost 210K miles on it, plus I don't really have the facilities in my current digs for such labor intensive operation.

I would think it's too high pressure to bother wasting attempts with JB weld or epoxy (although I think there's a VersaChem application that might be caustic enuogh to work), so my big question is: Who has had experience welding plastic? Will it hold? Is it only a temporary fix? Does it take an experienced hand to do a weld without FUBARing the the whole job? Can I use the cheap $15 Harbor Freight welding iron, or do I need to spend the extra $$ for a variable temp iron? These are the unknowns that are keeping me from just diving in filling the thing.

Any experience repairing these kinds of intake manifolds, or with plastic welding in general is greatly appreciated. Thanks!

wontco screwed with this post 05-15-2010 at 07:22 PM
wontco is offline   Reply With Quote
Old 05-15-2010, 07:30 PM   #2
P B G
Beastly Adventurer
 
Joined: Mar 2008
Location: Greater Chicago
Oddometer: 9,996
Plastic weld could work, its tricky though. If it were me I'd price the part at a junk yard and replace it, or wrap it with really good electrical tape.
P B G is offline   Reply With Quote
Old 05-15-2010, 07:37 PM   #3
wontco OP
B00n
 
wontco's Avatar
 
Joined: Sep 2005
Location: Huddled Masses
Oddometer: 27
Quote:
Originally Posted by P B G
Plastic weld could work, its tricky though. If it were me I'd price the part at a junk yard and replace it, or wrap it with really good electrical tape.
Thanks for the quick input.

Thought about a tight wrap with some Gorilla tape, but it's a no go. What you cant see is that the tubular section in the photo is actually connected to the larger intake body by a wide, flat strength/support spine that runs almost the full length on the opposite side. So although it looks like a cylinder it isn't - there's just no way to get a practical tight wrap on it.
wontco is offline   Reply With Quote
Old 05-15-2010, 08:03 PM   #4
Jonex
zipper suited sun god
 
Jonex's Avatar
 
Joined: Mar 2006
Location: Central Wisconsin
Oddometer: 1,357
I think heating the plastic to melt it shut is going to change its chemistry and you'll end up with a new crack adjacent the fix.

I've had good luck with two part epoxy on plastic, and that's what I'd try in your situation.
I had to fix a cracked polycarbonate sight tube on the reverse osmosis system at work and I used some Hercules brand epoxy that worked great.

I fixed a hole in the crankcase on my snowblower with JB Weld, too, so you might be surprised at how good it can work.
Jonex is offline   Reply With Quote
Old 05-15-2010, 08:45 PM   #5
wontco OP
B00n
 
wontco's Avatar
 
Joined: Sep 2005
Location: Huddled Masses
Oddometer: 27
Quote:
Originally Posted by Sonex522
I think heating the plastic to melt it shut is going to change its chemistry and you'll end up with a new crack adjacent the fix.

I've had good luck with two part epoxy on plastic, and that's what I'd try in your situation.
I had to fix a cracked polycarbonate sight tube on the reverse osmosis system at work and I used some Hercules brand epoxy that worked great.

I fixed a hole in the crankcase on my snowblower with JB Weld, too, so you might be surprised at how good it can work.
Yeah, I suppose it wouldn't hurt anything to try an epoxy first, it's just that it's exposed to the extreme high pressure of the expanding coolant, so I'm less than confident in a patch repair. Still if it fails, I suppose I haven't wasted too much. I have to sand down to prep for weld anyway, so I could just clean off the remnants

Although I haven't ever actually done it, with a plastic weld you fill with a nylon stock rod as you melt the outside material as well, so it's not a pure surface melt, it's more of a bonding. In theory it should be as strong as the original material, but I still haven managed to find anyone who has experience welding anything heavier than a plastic bumper.
wontco is offline   Reply With Quote
Old 05-15-2010, 09:16 PM   #6
Mugwest
.
 
Mugwest's Avatar
 
Joined: Oct 2005
Location: 3rd Ring of Buzztopia
Oddometer: 5,771
Keb, after reading here i'm thinking the 2-part epoxy treatment should be the first course.
Drain that part of the syst of coolant (already drained, right? ) soap-wash/Simple Green the area to get any coolant residue off, let dry thoroughly, then fill in/around the crack with a tough 2-part epoxy-- the Loctite twin-syringe stuff i used to attach the heated grip elements to the DR handlebars should be fine, avail anywhere. It goes on quite sticky after you mix it, and cures hard as hell in 24-ish hours depending on ambient T/humidity.

JB could do as well but it cures hard as metal-- the epoxy might be a better fit here i'm thinking, as it'll creep a bit better into the Void, cure hard, but still be 'plastic'


I'm always in the Void. I knows about some Void

good luck bro
__________________
.
Mugwest is offline   Reply With Quote
Old 05-16-2010, 09:56 AM   #7
the_gr8t_waldo
Beastly Adventurer
 
Joined: Feb 2006
Location: tacoma warshington
Oddometer: 2,024
i ditto for trying clean'n and epoxy wrap. i'd also wrap it with some fiberglass tape to hold it all together. if done right you should see another 200k
the_gr8t_waldo is offline   Reply With Quote
Old 05-16-2010, 11:16 AM   #8
wontco OP
B00n
 
wontco's Avatar
 
Joined: Sep 2005
Location: Huddled Masses
Oddometer: 27
Quote:
Originally Posted by Mugwest
Keb, after reading here i'm thinking the 2-part epoxy treatment should be the first course.
Drain that part of the syst of coolant (already drained, right? ) soap-wash/Simple Green the area to get any coolant residue off, let dry thoroughly, then fill in/around the crack with a tough 2-part epoxy-- the Loctite twin-syringe stuff i used to attach the heated grip elements to the DR handlebars should be fine, avail anywhere. It goes on quite sticky after you mix it, and cures hard as hell in 24-ish hours depending on ambient T/humidity.

JB could do as well but it cures hard as metal-- the epoxy might be a better fit here i'm thinking, as it'll creep a bit better into the Void, cure hard, but still be 'plastic'


I'm always in the Void. I knows about some Void

good luck bro
Gonna, try the epoxy route, can't hurt, unless it let's the crack get bigger. Mug, it's the highest point in the system, so I won't have to drain it completely. And, yeah, it's mostly already done that for me. Was gonna prep with Acetone or isopropyl too along with a a little sanding.

Now I'm wondering if I should drill out the ends with the smallest bit I can get my hands on too - that might just be makin' more holes though. I'm hoping a heavy clamp will get it closed enough that the hairlines won't continue. If the crack makes it to the head -if it hasn't yet already- then I'm dealing with compromised gasket too. Man, just more shit I gotta do....
wontco is offline   Reply With Quote
Old 05-16-2010, 11:40 AM   #9
Ratski
Studly Adventurer
 
Ratski's Avatar
 
Joined: Dec 2009
Location: Eastern WI
Oddometer: 730
Keep in mind most cooling systems only see 15 to 17psi depending on when the rad cap vents.
Ratski is offline   Reply With Quote
Old 05-16-2010, 01:17 PM   #10
wontco OP
B00n
 
wontco's Avatar
 
Joined: Sep 2005
Location: Huddled Masses
Oddometer: 27
Looks like my best bet is going to be Permatex PermaPoxy Plastic Weld . I wrote to them to see what they have to say about the application, but I'm not holding my breath for a response.

New concern isn't pressure - this is rated to 3500 PSI and as Ratski points out it's not really as high pressure as I thought (manual sez 13) - but the temp rating for this is 250 F, and that's the highest I could find in any consumer available brand. (Mug, The Loctite epoxies are only rated up to 200 F). Repair manual indicates the thermostat full open at 211 F - - That's cutting it close. JB weld products have a higher temp rating at 300 F, but nothing they make is really intended for plastic applications, and honestly, I've never had JB Weld hold on anything, so my confidence in it isn't high.

wontco screwed with this post 05-16-2010 at 03:35 PM
wontco is offline   Reply With Quote
Old 05-16-2010, 03:38 PM   #11
GreaseMonkey
Preshrunk & Cottony
 
GreaseMonkey's Avatar
 
Joined: Jun 2006
Location: The only county in Illinois with no train tracks
Oddometer: 5,183
I'd use this stuff:


Believe it or not, but this stuff was first recommended to me to use for bonding brake disk linings to the backings! It is pretty good stuff and you can buy it at many auto parts stores. I'd roughen the pipe first with some 80 grit sandpaper and then clean it with PVC plastic pipe primer, then apply the epoxy. (in general, I prefer to keep 5 minute types of epoxy in reserve for emergency repairs where time does matter over a permanent solution. The longer an epoxy takes to cure the better the bond with the base material IMHO)
GreaseMonkey is offline   Reply With Quote
Old 05-17-2010, 04:00 PM   #12
Anorak
Woolf Barnato
 
Anorak's Avatar
 
Joined: Jul 2004
Location: OAK
Oddometer: 32,384
How about this? You're going to epoxy it and it will appear to hold. Your fiancè will be driving along on the highway and it will let go spectacularly. She will be stranded and the engine will have fatally overheated. How much is a new intake? Here is the deal, there is more too that crack than what is visible, heat and pressure cycles will just cause it to progress. The pressure is going to find the weakest point and rupture it.
__________________
'Gonna get me a six pack...push people off the highway!'

"they live off the carrion of our mutual distrust and bribe us with symbols that equate hatred with manhood."

"I mean at the end of the day, I was addicted to Starting Fluid for Christ's sake!"

"Yeah, that guy sure is terrible at touching moms"
Anorak is offline   Reply With Quote
Old 05-17-2010, 04:06 PM   #13
H96669
A proud pragmatist.
 
H96669's Avatar
 
Joined: Nov 2009
Location: Hiding off Hwy 6, B.C.
Oddometer: 4,379
Check the marine products, they use them on my leaky old tub/ship with very good results. Rated for pretty high temperatures and pressures.

Here is one,that one is even rated to fix mufflers.
http://www.epoxyproducts.com/g_otherprod.html
__________________
Have tools, will travel!
H96669 is offline   Reply With Quote
Old 05-17-2010, 06:59 PM   #14
Parepin
The Filthy Nomad
 
Parepin's Avatar
 
Joined: Dec 2007
Location: That's... a tough one to answer
Oddometer: 1,078
I tried patching a 6 inch crack in a plastic tank to the radiator in my Ford Ranger. It slowed down the leak, but never sealed it completely. I even ground down the fins, roughed it up, layed fiberglass tape over the crack and slathered JB weld over the whole shebang. Even then, I'd find on several occasions that I was leaving puddles of coolant where I parked. I must have slathered JB weld and JB quick weld on the patch three or four times before finally tracking down a radiator at a junk yard. You might be better off just getting a new used part.
Parepin is offline   Reply With Quote
Old 05-18-2010, 10:02 AM   #15
capeklr
Gnarly Adventurer
 
capeklr's Avatar
 
Joined: Dec 2009
Location: Cape Town
Oddometer: 309
If you want the car to be reliable then get a new one, even a good used one has years on it and they get brittle with time.
If it was my car I would not even bother to fix it or look for a used part.
capeklr is online now   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 10:20 AM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014