Bonding thin alum- JB Weld?

[ToddT]

I'm fabricating a heat exchanger to be mounted through a 2" npt drum opening. My welder said the .035 alum. tubing is a bit small to weld, particularly with more than one piece of tubing coming through. What about using JB Weld or some other two-part type epoxy glue or filler?

I've heard about copper bond. Do they make an aluminum bond?

This will be for the coolant feed (low pressure) and fuel supply (under vacuum). Using new parts, we should get a good bond.

Will it work? Options?

Todd

[danster]

What about those aluminum rods that you just use a propane torch to weld. Just heat the surface and stick the rod on it till it melts without putting the torch on the rod. I don't know what they are called but they work great. Used it a couple of time. When I first saw it the guy doing the demonstration was welding Pepsi cans together, don't think you can go thinner than that.

You can get these rods at most welding supply stores. I got mine at a fair and of course I got screwed on the price, it was the first time I had ever seen them, but the demo was very interesting.

Dan

[dssamp]

aluminum rods....saw them at local Harbor Freight...didn't know what they were for. Thanks.....

[bork]

I have them & they work great.But there are copies & are much harder to work with, due to impurities. I'll try to get the name of the ones that work. I think they are based in the Carolina's.

[tduncklee]

JB Weld is not an option. It gets soft after contact with the oil a while. I'm also looking for something that will stand up to the oil. Was going to mix up some Marine Tex (Similar to JB) and see if it gets soft also.

[danster]

If you go on Ebay and do a search for "aluminum welding rods" you will see what I meant. You just clean the surface to be welded with sandpaper or wire brush. Heat with a propane torch the area to be welded taking care not to melt the aluminum (melts at 1200 deg Far), just run torch on it and touch it with the rod once in a while till the surface is warm enough to melt the rod. The rod melts at a lower temp. than aluminum and don't use the torch to melt the rod, use the heat from the surface.

It works great, they claim the repair area is stronger than the actual aluminum once its cooled. At the demo I saw the guy welded two aluminum plates together and then banged it with a hammer to try to break the weld, it never did.

Thought it might help you .

Dan

[ToddT]

That's what I was thinking about... alum rods. Is this what they consider 'brazing'? Do you think there is any difference between these eBay rods and others found in a Google search? Big price difference just to get an instructional video.

Any suggestions on learning how to do this? Sounds easy enough.

Todd T

[JOAT]

I used these type rods (welder father in law gave me) where my aluminum tubing goes thru the aluminum plate that is mounted on my plastic tank. Very easy to use and as far as I know these type rods are pretty much all the same. If you hit a spot where the rod isn't sticking pull the torch back and use the rod to scratch the area and then reaply heat. They are really easy to use. Much easier and forgiving than soldering or other brazing. I'm told a welder supply guy demos these rods by brazing two aluminum cans together without any surface prep at all.

[bork]

They are NOT all the same ! I had some that would bead up too much . I did as instructions say to the T. Would not flow like should. Then about a year latter ,I was at a boat swap meet and a guy was demo-ing rods. So me and another skeptical guy said "ok" let us try & let us pull out a random rod outta one of the for sales packs. (I know how to solder) Soooo , I proceeded to alum solder the cans together & even thermostat housing(cast alum) . Me and skeptical guy bought packs. I asked vender why batch at home didn't work ? he said " there are copy cats with a lot of impurities and it probably didn't flow & alum would melt before good flow. I repied " Yup" . since I have used with no problem. I carry a few sticks in van tool box, dirt bike tool box, & at house & in plumbing truck. THE big must is ; to have a stainless steel brush for cleaning both surfaces real good & brush is for aluminum only. (no other ! Steel will get rust carbon dust in pores and cause havock !) I think instruction sheet with brand name is on rods at vacation home,(not accessable) But I'll keep searching for you though.

[JOAT]

I'm curious now which one you have. I searched and there are quite a few different brands. Most said they work with aluminum alloys, but one called alo-weld says it works with most non-ferrous including copper. Could be handy for making cheap HIH fittings with copper pipe and aluminum tubing. I'll have to try it with whatever rod it is I have at home.

[bork]

all non-ferris metals is true, except stainless steel.

[rcdallas]

When installing the hot water heater element into my main settling tank; I used JB Weld. It's been about 5 months now and still does not leak.

I used the overnight stuff, not the 5 minute one.

So far so good [img]/ubbthreads/images/graemlins/shrug.gif[/img]

[bork]

I think the overnight is better on all the epoxies if you can wait .My .o2