Best epoxy for small pin hole in aluminum exchanger...

john p_2

Has anyone had any luck with an epoxy that works on aluminum exchangers? Not interested in peoples opinion about how this should or should not be done because I do need to nurse this through to warmer weather. I've already tried a product Cotronics RK454. Spoke to the engineer at the company and said they've had great success for my type of repair as well as automotive type of cast aluminum repairs - regarding both high heat, pressurized fluid behind the repair and constantly heating and cooling where the repair is located. But it didn't work even after scuffing up the aluminum, wiping down w/denatured alcohol and allowing a 24 hr. cure time.

I only have a small pin hole - placed a small 6" X 6"X 2" pan under it that requires draining about every 6 hours depending on ODT. Would love to find something with a faster cure time than 24 hrs. due to the extreme cold here in NJ...

RJ_4

Alumiweld check the web site, used it on aluminum condenser coils

icesailor

You've tried everything else and it didn't work.

I'd take a very sharp Awl/icepick and pick at that pin hole. See what it is like for rottenness. If there's meat to it, I would put a #10 stainless steel faucet washer screw and a washer, well slathered with high temp RTV. If there is room in the inside water passage, I'd drill and tap it for a 1/8" brass or stainless plug. Generously covered with Teflon Tape.

Only do if you like to live on the edge, dangerously. The leak will not get better, so what do you have to loose.

There's a reason that bump is there. It had to do with something inside that moved when the block was cast. It might have sand in it.

john p_2

Ice, the bump is a dime sized area where it appears the epoxy didn't take.

icesailor

If you're going to use epoxy, you really need to scratch it up so it has something to stick to.

There's all kinds of things you can put in there. If you get a dental implant, they drill a hole in bone and cement a titanium hut into your head or jaw. Once the bone has set, they screw a post in the nut and hang a fake tooth on it. Not much difference that I can see.

If I was faced with that dilemma, I'd me calling up whomever made that boiler and be asking them about drilling and tapping a plug into that leak.

Unless there were a whole family of leaks developing in the block.

bmwpowere36m3

Have considered having it welded or brazed? Or using a low-temp filler rod like: http://durafix.com

john p_2

Yes, and I am a union pipefitter very familiar with brazing all types of metal. That said, the repair is on a vertical side of the block not horizontal and I'm not sure if the pin hole is a sand defect or caused by bad water quality but feel it is not the latter.

I do like the idea of a low temperature filler but the idea of attempting this and possibly having more holes opening up and leaving me w/o heat altogether does not appeal to me.

Don_197

I'm curious if its an aluminum block exchanger such as the Hydrotherm has or if its a Gionanni ModCon exchanger......

kcopp

JB weld Quick.... What boiler is this?

john p_2

Utica UB 90 - 150

john p_2

JB Kwik Weld looks interesting in that it is only 4 - 6 hr. cure time but not sure how hot that exchanger will get to....300 degrees, I doubt it.

Larry_52

You my friend need to go to the Belzona website and find the product that best matches your disaster. This is what most industrial institutions turn to when they have an oh no moment.

icesailor

I understood that Epoxy was already tried and it didn't work.

Of course, Tech Support isn't going to tell you to go ahead and drill holes in their aluminum casting. They also aren't going to send you a new Warranty block. So, there's the space between the two rocks. What options do you have? If Epoxy didn't work, you either live with the slow leak that will get faster, or you drill out the weep. Its probably a fault in the casting pour. Its doubtful that the defect is all that big. Certainly not more than 1/8" wide.

Extreme situations require extreme measures. They make easily obtainable 10-24 or 10-32 stainless steel bolts (machine screws). Find a spot on the boiler (like somewhere on the base) where a hole isn't going to hit a water passage and drill and tap a hole. Screw in the SS bolt with a heat proof convex faucet washer with a stainless washer to back it up. If it works and you are comfortable, try it on the hole. You have nothing else to loose.

As far as brazing aluminum, it is a really specialized field, that takes a lot of training and experience. I personally, wouldn't want to touch your situation with a 10' pole. But if there are no other choices. it should work. But you have to go at it with the right attitude. If you are positive it will work, it won't. But if you think it won't work, and you do it anyway, it will work.

Successful troubleshooters/repair persons, never believe what they are going to try will work. They just know that somehow, they will make it work, and always have a plan to fall back on. So it works. You tried Epoxy (JB Weld) and it didn't work. What now?

bmwpowere36m3

I like @icesailor plan... if you get access to inside the HX.

Depending on the thickness of the jacket, tapping might not work (if its too thin). However if you can get a nut on the inside you should be golden. Some sort of machine screw/bolt, washer under its head (or a truss head fastener), rubber washer and washer/nut (inside HX). Slap on some automotive RTV (like permatex blue, used on water pumps among other things, 500*F rated) and tighten it up.

icesailor

No nut on the inside. If you have to go to that level, you might as well get a new HX or boiler.

They make commercial products for stopping leaks in tanks like this. Its just a steel self tapping bolt with a washer.

In my Crest faucet washer kit, there were two sizes of stainless steel screws. 3/8" and 1/2". Its no different than drilling out a brass bibb screw that the head rotted off, using a bibb screw replacement drill, drilling out the old screw, tapping the hole with the provided tap, and putting in a new Stainless Steel bibb screw and holding a new heat proof washer in place.

Teflon and RTV on the screw will help seal the hole if you get that far. As my friend Bill says, "Any fool can do it". He's right.

bmwpowere36m3

I was looking at the pic he posted... looks like he applied a thin "skim" coat to a large area of the HX... I think the epoxy failed because it was applied to thin [weak].

Personally I would scuff/sand/scratch an area slightly larger than the bubble and put a "big" dollop of JB Weld (kwik or water weld), like 1/4" thick or more. That should do it. Like this:


No reason to be pretty, just want it to hold. While I haven't used it for this particular application, I've had good results with the product when carefully applied.

john p_2

Funny, stopped in HD to see if they had the JB Kwik Weld in stock....of course they did not. But also most of the packages were in print that I couldn't read, even w/glasses - needed a magnifying glass!

vaporvac

Lowe's carries it. The waterweld is a one hour cure time.

bmwpowere36m3

Lowes, HD, Wally world, autozone, advance...

icesailor

bmwpowere36m3 said:

I was looking at the pic he posted... looks like he applied a thin "skim" coat to a large area of the HX... I think the epoxy failed because it was applied to thin [weak].

Personally I would scuff/sand/scratch an area slightly larger than the bubble and put a "big" dollop of JB Weld (kwik or water weld), like 1/4" thick or more. That should do it. Like this:


No reason to be pretty, just want it to hold. While I haven't used it for this particular application, I've had good results with the product when carefully applied.

That's not the same photo that was posted by the OP on the first post.

If you're going to apply Epoxy, you need to seriously clean the side. It should have been cleaned completely and then scrubbed down with PVC cleaner.

That's not even close to being what was described.

bmwpowere36m3

@icesailor

Yes, that’s just a quick photo I found online to make a point as to how much epoxy to apply. I agree, it needs to be cleaned much better than the photo shows. Again, that is not showing “my work”, just showing the amount of epoxy to apply. His photo shows a "bubble" (water leaking at the center of it) and a large area of the HX he "skim" coated the epoxy. Personally I’d concentrate on applying the epoxy to the area of the bubble and maybe ¼” to 1” beyond it, while keeping the thickness of the epoxy to at least ¼”.

j a_2

Well My first thought was a drilled and tapped hole….I did in my prior life work on comercial airplanes….If you don’t have the wall thickness you can install a pull rivet wet with P R C …There are airplanes flying around with that type of repair….A pull rivet is a high quality pop rivet made of alumnimum or s/s ...

icesailor

""" You really need a grinder and a wire wheel. """

Wire wheels are nice, but tend to polish metals smooth but rough appearing. You need to rough it up some with a sanding block or a burr fitting on a drill to bare and rough metal for good adhesion. The rougher, the better. So the epoxy can "key" in on the roughness.

icesailor

I guess you have more experience with Epoxy that I do. That and soldering severely salt corroded copper tube from salt water or aggressive water leaks. Unless you get the corrosion out of the crevices completely, it won't solder.

When I epoxy'd my skate brackets to the new plank I made for mi Iceboat, it wasn't necessary to sand the coating off the plates before I glues and bolted the brackets to the plank. Like West suggested with 100 grit sand paper.

And like Locktite, the only way to get the plate or bolts out is to heat it all up with a heat gun.

http://www.northwindiceboats.com/?Section=Details&ProductID=37

icesailor

"" I never had to solder deeply salt corroded copper tube, thankfully. I probably would have cut it out and replaced it. ""

Sometimes, you have no other choice. And the piece you cut out might be pitted, as is the remaining piece.

As far as glue. the only function in carpentry framing of a nail is to hold one board in place while the next one is placed, holding that one in place.

In the case of the skate chock. the only functions of the bolts are to hold the chock on place until the epoxy hardens and the skate is perfectly aligned with the other chock. The Epoxy holds the plate in place. Not the other way around or the bolt. If you tighten the bolts too much, you will squeeze all the epoxy out of the joint and the only thing holding the plate on are the bolts. The chocks must be perfectly parallel with each other or else they don't run true without scraping. I use two parallel mirrors. Some use a rifle telescope fixed on some far away object. Or a Jig. The Epoxy has to be soft to make the adjustment and left to harden. It needs to be "scratched" so it keys into place.

Steel framed buildings are the same. Each beam rests on another from the foundation on up. Brackets and bolts only hold things in place for the next members.

john p_2

I am waiting for temps to ease somewhat before shutting the system down to make a new attempt at this repair. The area was cleaned with a flapper a Roto-Zip. I'm almost thinking I should pull a small vacuum when I re-attempt the epoxy.

kcopp

good luck! Let us know how it goes. I do think you should try to make the hole a bit deeper to get some epoxy into the void.

unclejohn

That bump looks too me like a water swell. I would wire brush that lightly and go right back over it. The idea of making the hole bigger does not appeal to me at all.

icesailor

john p said:

I am waiting for temps to ease somewhat before shutting the system down to make a new attempt at this repair. The area was cleaned with a flapper a Roto-Zip. I'm almost thinking I should pull a small vacuum when I re-attempt the epoxy.

Don't pull any vacuum's or pressures. It will either suck in or blow out the epoxy out of the hole. You want to open things for a free flow of atmospheric air into the boiler.

Just like you can't solder e closed pipe with water in it that can boil. You can solder 10 fittings, but when you get to the last one, the solder sprays out and you have a leak.

john p_2

I plan to use my RotoZip with a mini flapper wheel to attempt another repair using epoxy once the temps warm up somewhat. Now that I am finding some epoxies that have shorter cure times than 24hrs. The bump is a water swell and I'm not sure why it didn't take in that dime sized area only. I had the drain open so I can't see how any pressure built up when applying the epoxy. I do not have any of the original RK454 epoxy left over so I cannot just re-apply over what's there.

icesailor

That might work for you. It doesn't always work for everyone, but it might work for you. Just be sure to remove ALL of the old Epoxy. Epoxy is a complex chemical process. Not all Epoxy's are compatible with others. WEST which is considered by woodworkers as the best, does not work well with other brands of Epoxy's. The hardeners are the same within one manufacturer, but the resins are different. The resins all have different temperatures and setting times. Don't even think of trying to put one Epoxy over another. Grind it off and clean with Acetone. Then, if you grind and flap it, be sure that the flapper doesn't leave smooth and shiny peaks. Sand them off. The longer the cure after initial setting, the better the bond.

When I would make a laminated wood spring plank for my iceboat, it was hard and dry in the clamping jig in 8 hours. I still let it cure for a week. If you want to help it along, use heat. I liked using one of those quartz halogen lights placed a few feet away from the spot. Don't let the radiated light get it too hot. Check it regularly by feeling with your hand. If it's too hot, move the light back farther.

If it matters to you.

john p_2

The first two applications were done pretty much exactly the same...mini flapper wheel, scuff up with sandpaper provided by epoxy manufacturer and then clean area with denatured alcohol. Once cleaned I waited 5 or 10 minutes to dry then applied the epoxy. Both attempts I let the epoxy cure for 24 hrs. but still it didn't take in that dime sized area.

unclejohn

Try a little heat from a hair dryer next time to get a better faster cure.

icesailor

Wrong Epoxy?

Those flapper wheels polish the surface. You need aggressive sanding to make the surface rough enough. If the Epoxy blistered after a 24 hour cure, it wasn't mixed properly, or didn't have enough hardener in it. The only way to blister is if the Epoxy was still soft. Is the Epoxy your using rated for the temperatures used? Heat softens Epoxy.

john p_2

The epoxy I used was RK454 by Cotronics out of Brooklyn rated for 500 degrees F. Spoke with an engineer there, told him exactly what I was doing and he told me about using a heat lamp to get it to 250 degrees F for 4 hours the 2nd attempt. I left it on about 5 hours and even bought an infrared thermometer so as to get the temps perfect. I think you may be right about polishing the metal with the flapper wheel but it was perfect for removing the old epoxy from the first attempt. The engineer said they've had great success using it on auto motive and HVAC equipment where it had to seal a liquid under some pressure. It is also made for aluminum based metal use.

icesailor

I guess it isn't working for you then.

john p_2

No, but I am going to try one more time like I said when/if it ever warms up enough to have the boiler off long enough for the cure time of what I use.

Larry_52

As ice sailor mentioned West epoxy is one of the most popular in the marine field followed by System Three. They both offer the best in wide range application epoxy. But when it comes to industrial metal repairs I have never found anything better than Belzona products. We have used it for pump shafts on bearing and seal surface without a hitch. Although I can only imagine it ain't cheap as it won't be found at your local HD.

john p_2

Just called Repair technology who sells the Belzona products. Spoke to a Steve Kitchen there who recommended a Belzona 1221 product which cures in an hour at 77 degrees. I think I'm going to give this product a shot this Sunday since we are supposed to be in the 40's...

hot_rod

could be some moisture gets to the hole before the epoxy goes off?

john p_2

Yes, and I used a mini flapper wheel on a RotoZip to remove the 1st attempt at epoxy, then scuffed it up with 60 grit sand paper and wiped it clean with alcohol.

A couple things could have caused an issue...the alcohol supposedly leaves some sort of film as most recommend acetone. A friend offered to pull a small vacuum on the exchanger and I refused but think I should have taken him up on it. It may have kept any moisture from leaking out and help to keep/pull in the epoxy to the pin hole.

Sunday we are supposed to be in the 40's and will attempt the epoxy for the third time. This Belzona product is supposed to be the equivalent to JB Weld on steroids and best part is it fully cures in one hour at 77 degrees...