Using Solution Welding Rod For Boat Fabrication

Hi,

New member here. I am starting on a 25 ft catamaran and have TIG/MIG capability. I ran across "Solution Welding Rod" it is low temp brazed, low material distortion but 45 psi tensile strength, has anyone tried complete boat fabrication with this rod? It seems to be a nice boat building alternative but I cant find any info. Maybe the cost is too high for production.

Thanks in advance,
Pete

Sounds like this is an aluminum brazing rod instead of a traditional electric arc welding rod.

I've used aluminum brazing rods with success but not this brand. However, there are some issues.

1) Unlike steel, aluminum does not change color as the temperature changes. Steel will get yellow, orange, red, and white before it completely melts. Aluminum just melts with no warning. There is danger of overheating the aluminum base metal with your torch and having the metal collapse in a puddle leaving a big hole. I have done this.
2) Aluminum brazing rod melts at a temperature close to the base metal melting point. This means that once you get your base metal hot enough for the rod to bond well, you're dangerously close to melting the base metal - see #1.
3) I suspect the tensile strength of the brazing rod is not really 45psi. There lots of aluminum alloys but the most common ones have tensile strengths between 18,000 psi and 45,000 psi. A 45psi tensile strength is probably closer to duct tape. Is it possible it's 45 ksi?
4) If I was building a whole boat, I would buy a tig welder and learn to tig for this project. Even mig leaves imperfections in the welds.

TIG welds are good but for me, painfully slow.

A MIG welder with spool gun is way to go in my opinion. Can be had for around a thou but if you are building a boat, it will pay for itself. Plus you could sell it afterwards if you like. The learning curve is pretty easy on MIG welding. Biggest factor is to have the metal super clean & wire brushed.

Building a boat with that stuff is an exercise in frustration. It's expensive, slow, and torch gas is not cheap.

I bought a MIG for aluminum boat construction and let me tell ya, there's a learning curve to it. Welding takes a lot of practice to do it correctly to get good penetration without the inclusions and contaminants that cause porosity and other welding imperfections. Now TIG is another animal and to even try to do a whole boat with it would take you for ever and a day to do, even with lots of welding experience. If you're a beginner it would take you even longer, not to mention the learning curve with it. Cleanliness is paramount with MIG and aluminum. Personally I'd start with something easier.

MrGiggles said:

Building a boat with that stuff is an exercise in frustration. It's expensive, slow, and torch gas is not cheap.

Click to expand...

And at 45psi a death sentence. [-X

Typically the filler metal itself doesn't fail, it is the bond to the base metal that will tear loose.

I'm unsure of terminology or manufacturers names for stuff, so I'll be a bit cautious here.

Some years ago, an aluminum "welding" rod was pushed hard at boat shows and such like, where the salesperson would stab a hole in the bottom of a beer can, then seal it up with his product, using a propane torch. It was actually more of a brazing or soldering rod. Then he'd stab at the repair with an ice pick and the repair was far stronger than the can. They did several similar displays.

I was impressed; bought a package of it and for the most part it did work very well and made a very strong join, tho' it's not all as simple as the sales guy made it look. There Is a learning curve. I was learning refrigeration and appliance repair in a small rural community at the time and getting calls for refrigerators with holes stabbed in the aluminum evaporators by owners trying to fast defrost them was common. (this was 40 years ago)

With proper, careful prep, the rods welded up those evaporators beautifully - smooth, strong repairs that looked great....but they leaked.

Pressurizing the system, then spreading soap bubbles on the repair quickly showed that the weld itself was porous - the gas oozed right out of microscopic holes in the repair metal - the soap bubbles would actually foam over the repair, but visually the repair looked beautiful. I don't know how that would work with water and don't know if it's the same product you're asking about.

As others have said, "weld" is a strong word. I have to think these are brazing rods. Find for plugging a leak, but I wouldn't use for anything structural.

You you have MIG capability, do you have a spool gun? With that and some 100% argon (vs 75/25 for steel) you're good to go.

Go to Youtube and look for videos by "Project Farm" He does testing of products. Just this week he tested several brands of Aluminum welding rods. Some were crap but a few worked very well in the test he did.

don't ever use those brazing rods to attach two pieces of structural materials--and yes any part of a hull is considered structural

those "rods" are brazing rods. Brazing is adding a filler material without actually joining them mechanically all you are doing is making a filler material stick to both without actually joining them; similar to soldering actually

welding is joining of two materials by melting the parts that are to be attached and adding a filler to join them. Sometimes parts can be welded without filler but for this discussion it's not really a consideration (aluminum)

with those soldering rods and a handheld torch you will never be able to focus enough heat to actually weld. Aluminum is an excellent conductor of heat, thus it generally takes more heat to weld a given thickness as it would if you were welding the same thickness stainless or even mild steel alloys. A 1/4" thick piece of aluminum sometimes need 200A of current to weld it, where a steel alloy can usually be done with 150-ish, stainless 125 or thereabouts. You get the idea. A torch will never focus the heat where it needs to be and it won't get it hot enough, if it could get it hot enough it will melt a large area and it falls out. Lastly, welding with a torch introduces gases into the base metal; those gases come from the combustion of the oxygen and acetylene (if using oxy-acet torch), or from the air and whatever gas (Propane?) is used in a hand torch. They have no shielding gas that keeps the oxygen and other impurities out. That's where MIG and TIG come in, using a noble gas (usually Helium or Argon, or a mix of the two in some cases)--both of those gases will help dramatically to keep oxygen/air out of the weld. Oftentimes a good aluminum weld will be much stronger than the base material.

spool gun works pretty good but with aluminum, cleanliness is of absolute importance. Any impurities in the metals being welded will hinder aluminum's ability to be welded properly, and many times introduce porosity, leaks, holes, burn-through situation, etc. Aluminum welding is not for the beginner for sure! TIG is the way to go, but it is a slower process and even more finicky than MIG/spool gun. With the spool gun, you are now introducing a few more ways for the alum filler to become contaminated such as through the drive rollers, the wire itself, through the gun, etc. Everything has to be clean!!

I have seen rolls of alum filler wire (4043, etc) sitting on store shelves, oxidized. And people buy the stuff thinking its' gonna work through a spool gun, and it never does if it's oxidized. Ever.

I have had pretty good success in welding with a spool gun but the spool gun itself is a pain to deal with, heavy, bulky, etc. I have also used a regular 1lb spool of alum wire in a standard mig gun (not spool gun) with a teflon liner and that has worked decent in the past. The problem there is once the wire balls up on the end of the tip, the drive roller will keep forcing it in and it birdnests, then you pull out about 6 1/2 foot of wire, start over, do it again....pretty soon you've gone through the whole spool to make 5 beads 6" long each. BTDT!