| What plastic welding rods to use? [message #66715] |
Sat, 05 December 2009 18:36  |
LarryInSanDiego
Messages: 336
Registered: September 2006
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So I bought a plastic welding kit at Harbor Freight today, along with a couple bags of welding rods that they carry. The plastic rods listed are grey PVC, green polypropylene, and white ABS. Which of these rods (if any) can I use to repair my fresh and black water tanks? Or should I go to a plastics supply place to get rods?
Thanks.
Larry Engelbrecht
San Diego, CA
'73 26' ex-Glacier
TZE063V100319 03/07/73
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| Re: What plastic welding rods to use? [message #66721 is a reply to message #66715] |
Sat, 05 December 2009 19:33  |
Chr$
Messages: 2690
Registered: January 2004
Location: Scottsdale, AZ
Karma: 1
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None. You will need polyethylene (HDPE). I used the HDPE ones on my black tank. My fresh tank is in a land fill somewhere so I can only guess it was HDPE also.
My custom fresh tank is Polypropylene.
-Chr$: Perpetual SmartAss
Scottsdale, AZ
77 Ex-Kingsley 455 SOLD!
2010 Nomad 24 Ft TT 390W PV W/MPPT, EV4010 and custom cargo door.
Photosite: Chrisc GMC:"It has Begun" TT: "The Other Woman"
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| Re: What plastic welding rods to use? [message #66730 is a reply to message #66715] |
Sat, 05 December 2009 21:32 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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| LarryInSanDiego wrote on Sat, 05 December 2009 19:36 |
So I bought a plastic welding kit at Harbor Freight today, along with a couple bags of welding rods that they carry. The plastic rods listed are grey PVC, green polypropylene, and white ABS. Which of these rods (if any) can I use to repair my fresh and black water tanks? Or should I go to a plastics supply place to get rods?
Thanks.
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Larry,
I didn't do tanks when I worked for Thetford, but I had lots of them modified in our shop.
The guy that did it always used nitrogen and insisted that is was essential to keep oxygen away from either PE or PP during any hot process. I am quite sure that the black tank is PE and you will have to get PE rod for that as to the potable tank, I am not sure and maybe another can help there.
let us know how this works out.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: What plastic welding rods to use? [message #66731 is a reply to message #66723] |
Sat, 05 December 2009 22:22 |
midlf
Messages: 2212
Registered: July 2007
Location: SE Wisc. (Palmyra)
Karma: 1
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| Ron wrote on Sat, 05 December 2009 20:25 |
Guy,s..
Isn't the grill PVC or some such.. Have to do some surgery and gluing on mine>>
Ron
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IIRC the grill is ABS and some have used abs shavings and ABS solvent to make a repair goo that is used like an epoxy or resin repair goo. Info may be in Gene's site but I couldn't fine it.
Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI
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| Re: What plastic welding rods to use? [message #66737 is a reply to message #66731] |
Sun, 06 December 2009 01:54 |
Larry C
Messages: 1168
Registered: July 2004
Location: NE Illinois by the Illino...
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the grill is ABS and some have used abs shavings and ABS solvent to make a repair goo that is used like an epoxy or resin repair goo. Info may be in Gene's site but I couldn't fine it.
_______________________________________________________________
I did the Grill repair with the ABS black pipe shavings and solvent.
How you use this depends on your repair.
My grill had the attachement nubs ground off and holes where screws were bolted through the grill to the vehicle body.
This created undue stress and cracks and some actually had pieces missing. There were a couple other cracks in the grill from stress or some pressure applied on it.
Where you have material missing, you will take the shavings and mix it with the solvent until you have a thick sticky gooo. I suggest gloves and don't breath the vapour.
I used tape to make a surface on the side that is seen and applied the gooo to the back side. ( You want to be as close as level to the original grill surface or you will be sanding it down. I found the ABS very slow to sand down ) Work it in good to the edges where the plastic broke off and overlap a little over the edges on the backside but don't make too much of a build up.
The cracks were a bit different. You may get away with just applying solvent to the crack. If it is a crack that completely separates and you have the room on the back, try to reinforce with a piece of abs glued with solvent to the back of the grill.
With the original attachment system gone, I glued some strips of ABS on the bottom of the grill to form a groove, where the body panel will slip into. I glued an ABS piece on the left and right side where the nubs used to be and two in the top where the nubs used to be. The two top ones have a hole where when inserted in the body, I can slide a couple of nails easily to hold it in place. Since this was a glue job, I also put a piece of wire around the gril ( out of sight ) and attach somewhere to the frame holding the radiator. You probably don't need it, but if the abs broke loose, you won't lose the grill.
A note about the gooo.....
The solvent will take a good long time before it is completely cured. It is dry to touch in about a day and is relatively hard. I thought a week was enough time, then I used bondo, not much, to make the front smooth of any defects and painted.
What I found was as the solvent evaporates to cure, the gooo will shrink slightly. I can see where the gooo continued to cure after my week then paint. I don't think anyone else would see the slight indentations if I did not point it out.
I would suggest letting it cure for two weeks before finishing it. You have to figure where you are replacing material where it was cracked off, the grill is anywhere from 1/8 to 3/16 inch thick and we are using a lot of solvent to make the gooo. Maybe if you tried to really make the gooo thicker with abs chips and as little solvent as possible might help but I thought I had done that. I do, however believe that this is the only way to make a repair on the grill with like materials.
Even though the grill is 30 years old, it seems to be remarkably stable other than where someone weakened it by drilling holes into it. The other cracks appeared to be impact results of some sort. My grill had quite a few cracks but the material was well worth repairing. The repair was done about 3 years ago and I have no new damage and the repairs have held up.
Any questions, just yell but I think I covered it all.
At about $350 for a new grill, it was well worth trying to repair the OEM grill.
LarC ( Keeping the repairs in the budget whenever I can )
Gatsbys' CRUISER  08-18-04
74 GLACIER X, 260/455-APC-4 Bagg'r
Remflex Manifold gaskets
CampGrounds needed, Add yours to "PLACES" />
http://www.gmceast.com/travel
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[Updated on: Sun, 06 December 2009 02:11] Report message to a moderator |
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| Re: What plastic welding rods to use? [message #66743 is a reply to message #66737] |
Sun, 06 December 2009 08:25 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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While you are playing with the grill, put some eyelets in the grill, and use springs to reattach the grill to the body. When you have to work in that area, removing the grill will only take a few minutes and sure helps with it out of the way. Plus, by not being a rigid attachment point, the springs allow the grill to move and this will reduce stress and related cracks to the 30+ year old grill.
Tom Phipps,
75 GMC Ex-Avion
2012 Phoenix Cruiser model 2552
KA4CSG
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| Re: What plastic welding rods to use? [message #66755 is a reply to message #66745] |
Sun, 06 December 2009 14:02 |
Ron
Messages: 250
Registered: February 2004
Location: Conifer, Colorado
Karma: 0
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Larry..
Thanks for the detailed instructions on the grill repair.. And especially thew drying time.. I would have never guessed that long..
Ron
now a P.O.
Conifer, CO
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| Re: What plastic welding rods to use? [message #66770 is a reply to message #66768] |
Sun, 06 December 2009 21:47 |
LarryInSanDiego
Messages: 336
Registered: September 2006
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I haven't tried it yet (mine is model 96712 with the built in air pump). From what I've been reading, I may have to use nitrogen. I'm going to check with a body shop friend of mine to see what equipment he uses for plastic repair and go from there.
Larry Engelbrecht
San Diego, CA
'73 26' ex-Glacier
TZE063V100319 03/07/73
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| Re: What plastic welding rods to use? [message #66795 is a reply to message #66737] |
Mon, 07 December 2009 15:29 |
Mike O'Connell
Messages: 53
Registered: November 2008
Location: Deerfield MA
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I just did some crack repair on my grille and I thought I'd pass this along.
I had done some repair on similar plastic on a broken driving light using good old JB Weld and found that even though the JB was solid as a rock it didn't bond well enough to the plastic. I also had a tube of 2 part epoxy made specially for plastic handy(I don't remember the brand from here but I got it at Walmart) so I used that to glue the built up JB blob to the light housing. That looks like it good and stuck and all is well with the light.
So to fix some cracks on the grille I combined the two and mixed roughly equal parts JB (both parts) and the 2 part epoxy. Judging by the similar smells of the products (oh so scientific) that both smell like a hair perm I figured they stood a chance of being compatible. The results look like it's going to work. I cut a "V" groove along the cracks with a Dremel first and the JB adds enough bulk to let me build up some along the crack and the epoxy adhesive looks like it's bonding the stuff much better than the JB alone would.
Next up is to recreate the bosses/studs on the grill. I Got a handful of nylon spacers and some 2" #12 flat-head screws. I'll countersink the spacers so that the screws go into them flat then apply the JB-Epoxy mixture to glue them to the grille, using the stuff to build up a bead to support the base of the spacers.
Time will tell if it works.
Mike O'Connell
Deerfield, MA
'75 Eleganza
[Updated on: Mon, 07 December 2009 15:32] Report message to a moderator |
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| Re: [GMCnet] What plastic welding rods to use? [message #66829 is a reply to message #66715] |
Sat, 05 December 2009 19:00 |
Carleton Douglas[1]
Messages: 174
Registered: March 2006
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Good luck the air regulator will not reduce the pressure low enough to
weld with it blows the filer rod all over the place, took it out and
used a paint manual reducer, you need very little air pressure.
On Sat, Dec 5, 2009 at 5:36 PM, Larry Engelbrecht
<lengelbrecht@sandi.net> wrote:
>
>
> So I bought a plastic welding kit at Harbor Freight today, along with a couple bags of welding rods that they carry. The plastic rods listed are grey PVC, green polypropylene, and white ABS. Which of these rods (if any) can I use to repair my fresh and black water tanks? Or should I go to a plastics supply place to get rods?
>
> Thanks.
> --
> Larry Engelbrecht
> '73 26' ex-Glacier
> TZE063V100319 030773
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
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>
--
Carleton Douglas
73 custom, by myself
Prescott, AZ
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