| Author | Message | ||
| Gary Stadler (Boogiethecat)
Rating: N/A |
I've messed with spin welding with fair success fixing meltdown holes in two of my T-105 batteries (I got em cheap because the prior owner melted a few terminals and left some holes in the top) but having never seen it done or been told how to, I'm wondering if anyone has done it and knows what he's doing... want to share? I'm about to put fittings into two poly water tanks and two black tanks. The only local guy around here is 50 miles away and won't do it "while you wait" so the driving is too much for me. I'd rather learn and do it myself, and I'd rather not get "all wet" when I don't expect it later on... So..... tell me... whadddya know about it? | ||
| Marc Bourget Rating: N/A |
One method, the only one I've seen described on the BBs, is to use a (plunge,I guess) router with a special threaded adaptor. Spin'er up, push her down till friction generates enough heat (look for color change or a bead to show ???) Stop the router and let sit. Never googled for a spin adaptor source, I have a lathe to make one. I planned on using Gumpy's weld 'em in approach. | ||
| Frank Allen (Frank66)
Rating: N/A |
i put the fittings in mine, the router is a 1/2 inch and 25000 rpm or more, the adapter goes in the router and it spins the fitting, you first cut the hole and put the fitting in, as soon as it gets hot from friction a bead will appear and its time to stop. fairly easy but need to stop at the right time Frank Allen 4106 | ||
| Dale Fleener (Dale_mc8)
Rating: N/A |
The fittings I got have pipe threads in the top. I got some brass plugs at the local hardware store and had a machine shop (I don't have a lathe) drill and tap a hole in them to accept a threaded shaft (bolt.) Screwed the fitting on this adapter and installed them as above. Had a little trouble with the 3" fittings but none with any of the others. Dale MC8 | ||
| Brian Brown (Blue_velvet)
Rating: N/A |
Gary, If you haven't seen it already, Craig "Gumpy" Shepard has some good info on plastic welding on his uber bus-conversion site: http://www.gumpydog.com/bus/MC9_WIP/Plumbing/Holding_Tank_Fabrication/holding_tank_fabrica tion.htm HTH, Brian | ||
| John H. Dodge Rating: N/A |
Gary, I purchased the bungs of the size I needed 1/2", 1 1/2", 2", and 3". I bought 1 extra of each for practice purposes and found an old polyethylene tank and did the practice on it before doing the tanks to go in the bus. I got pipe plugs to fit all bungs and then drilled 3/8" holes in the tops in the center and placed a 3/8" bolt thru from the under side and tightened a nut down on the top with about 1 1/2" projecting out of the nut. Tighten very securely. Then place the threaded portion of the bolt in a 3/8" drill, screw the bung onto the pipe cap, start the drill and contact the tank in the location marked. Hold drill against the tank untill the plastic on the tank and bung melt. When it shows liquid plastic let go of drill switch. As the plastic cools, the drill will stop (quickly, I might add). Hold drill still and wait until the bung and tank are at room temp. Then either reverse drill or unscrew the pipe plug with a wrench. You will find that the 3/8" drill will not do the 3" bung. The way I did it was to borrow a MIlwaukee 7" or 7 1/4" angle grinder and remove the disc. I believe it has a 1/2" threaded shaft and I drilled a 1/2" hole in that plug. Also only let a little bolt stick out from the nut. Next, I took two 1/2" nuts and welded them together stacked one on top of the other. Then screw one side of the double nut onto the bolt and the other side onto the grinder. USE CAUTION, WEAR GLOVES, AND GOGGLES. MAKE SURE NO ONE IS CLOSE. Use the same procedure, and hold the grinder with plug and bung very close to position on tank before starting. Again, after starting and contact, when melting occurs let go of switch on grinder and let plastic cool. 7000 rpm stops prety quick. Then unscrew the plug with a wrench. Next get a drill with a 3/8" bit and a saber saw. Drill a hole in th middle of the bung and carefully cut out the remaining plastic. You may want to file the rough edges inside the bung also. This worked for me and has lasted so far 9 years and still holding. I might add that you may want to buy a few more bungs and practice several times before you do the good tank. Hope this helps. John Dodge | ||
| John MC9 Rating: N/A |
Uhh... or, bring it to an RV shop and let them do it? They screw it up, and you don't lose a penny. | ||
| Gary Stadler (Boogiethecat)
Rating: N/A |
John (MC9): Read my first post.. "The only local guy around here is 50 miles away and won't do it "while you wait" so the driving is too much for me. I'd rather learn and do it myself" That's why... So John H, I'm about ready to do mine. If I'm reading you correctly, I'm getting that you did not cut a hole in the tank first? Even a pilot hole? I was under the impression that you needed to drill a hole in the tank first, BUT it makes a lot of sense that you would do the hole last, as that would give the bung better contact during the 'spin'. If this is correct, that would have been the last mystery!! I did take a look at a tool used for doing this professionally, and at the time I thought it odd that it had a 1/4" drill bit for a center. Now it makes perfect sense! Ok, I'm ready now!!! Thanks Gary | ||
| FAST FRED Rating: N/A |
Having had my tanks done while I waited at Duracast , they used a similar but different technique. The hole for the bung was drilled with a std hole cutter of the right size , the tank was stood so the girl could push down and a big (2 or 3hp) router turned the bung which was held with a wooden mandril attached to the router. The bung had a lip thru the tankwall which helped the bung stay centered. No more than 5 or 6 seconds of router and the unit was stopped , spin welding complete. If you can,be sure to install a low point tank drain , as sometimes you will wish to dump all the FW when a less tasty spource becomes avilable. It is also easier to flush tanks , or chlorinate them with a nice 2 inch dump plug. FAST FRED | ||
| Dale Fleener (Dale_mc8)
Rating: N/A |
Gary, yes, you need to use a hole cutter to make the right size opening to fit the fitting. The welding takes place between the tank and the flange on the fitting. Easier to do than explain. Dale MC8 | ||
| Gary Stadler (Boogiethecat)
Rating: N/A |
Hmmm. But it seems that if you don't cut the hole first, and only use a centering bit in your "tool" then the lip of the bung would contact the tank first and dig itself deeper in due to the concentrated frictional area, then when it (the lip) melted and sank down, the flange would make contact and weld. Then after it's all cooled off, drill out the hole with a paddle bit (or a hole cutter in the case of the big bungs)... This seems like it'd make one heck of a better weld since if nothing else there'd be more material welded (the lip as well as the flange surface) That is apparently what the pros at the shop here do. Their tool looks a lot like a hole-saw without teeth, but with two vertical notches that match the bung's keys to transmit power... I'm tending to want to go that way. I'll probably have it done by sunset and I'll report in with some photos I agree with Fred about extra ports, especially in the poop tank for cleaning. On my first bus I once ended up sitting for a week and my guests used too little water while doing their #2 duties... the tank ended up with a "mount poo-lympus" that plugged the inlet pipe and try as I might I couldn't break it. Ended up drilling a side hole in the tank and taking the mountain down with a high pressure sprayer. Not fun. Having the port already in there would have been a lot less scary than drilling into a black tank that you don't know how full it is....  | ||
| John H Dodge Rating: N/A |
Gary, I did not drill a hole. I let the bung cut/melt its way in till the flange was even with the tank. Also I used metal bung plugs, not plastic. Be sure where you want the bung before starting and hold tool steady. That's how I did it and wish you luck. Practice on a throwaway piece of plastic first. Not too difficult if I can do it. John |