Fire & Flame Guard
It's a cliché but also true that there’s nothing as scary as a fire on a boat, or anywhere else for that matter. You’re in close quarters where a stove or kerosene lamp fire can spread quickly to such flammable materials as cushion covers, bedding, carpets, and curtains. So when a group called The Kelly Companies sent us a sample of its Fire & Flame Guard spray, we thought it was worth a test.
The spray is biodegradable and safe for discharge in sewers, as well as an effective preventative against “flame ignition and promotion of fire over a surface,” according to company literature. We weren’t sure exactly what that meant so we decided to spray a number of flammable materials (cited by the company) with the Flame Guard and set them on fire. We collected some dry wood, some aged branches from an old Christmas tree, some cotton, and some Sunbrella furniture fabric. We then tried lighting them on fire, first in an untreated state.
Next we sprayed several samples each of the various recommended materials, allowing them to dry overnight. If you apply too much, company president Barry Feinman says, you’ll get a white, powdery residue that can be brushed off. He said the spray won’t hurt fabrics, and we noticed no adverse effects, such as staining or discoloration. Nevertheless, a spokesperson for Glen Raven Mills, which makes Sunbrella, said the company does not endorse any spray-on flame retardants. (Sunbrella, incidentally, sells its own flame-proof fabric, called Firesist.)
Feinman prefers to keep the active ingredients of Fire & Flame Guard proprietary, but we saw the MSDS (material safety data sheet) for the spray and it consists of some fairly harmless chemical compounds in a distilled water solution.
All the untreated materials—wood, cotton, Sunbrella—caught fire and burned, which we expected. The treated materials, however, scorched, but did not burst into flames. Each test was repeated several times to ensure we got consistent results, which we did. We weren’t sure whether the scorching was a failure, but Feinman told us that the spray is intended to block an actual fire, not provide complete protection for the treated material. “It will not promote a flame," he said. "It goes cold as soon as the flame source is removed.”
Feinman says the spray can also be used to pretreat such potential trouble areas as fire walls, fuse boxes, and wood veneer. Because it will wash off—fabrics will need to be resprayed after two or three washings—it should be applied to the underside of materials rather than both sides.
Fire & Flame Guard comes in a 16-ounce spray bottle with a suggested retail price of $17.95. It can also be used to spray “fire towels” for use in dampening flames, or kept on hand as a fire extinguisher for such things as stovetop grease fires. You can probably find a lot of uses for it around the home as well, where few things are fire retardant. From our tests, the spray does what it says it will, and what it does is an important safety precaution. We recommend it. (The Kelly Companies, 4344 Ute Dr., San Diego, CA 92117; 619/483-1233; fax 619/483-1166.)
Welding Aluminum With a Torch?
The last time we needed any serious aluminum welding done was on a broken fitting on a mast base. We hired a professional. He arrived with a slew of equipment and a big grin. The grin translated into money. He was good at what he did and he knew it. He handled the task like a surgeon.
Aluminum is a unique metal. It is light and strong and has the odd ability of protecting itself from corrosion by forming a surface oxide that seals the bulk from further oxidation.This property is what makes it suitable for the marine environment.
However, welding aluminum can be a nightmare. It melts at about 1225°F without ever changing color. And, right at the melting point, it tends to oxidize rapidly, which turns it into a kind of slag which is brittle and weak.
To compensate for this, the welder creates an atmosphere around the weld point that keeps the oxygen away. He does this by flooding the area with helium during the arc-welding process and hence we have the term heli-arc. Helium is not cheap and neither is the welder who has to spend many hours perfecting his craft. He must learn how to keep the metal molten while applying the welding rod and still not let the seam splash away like a big glob of liquid solder.
A Better Idea
Born from a process used in Vietnam to fill bullet holes in airplanes, Randy Weeks of Weeks Distributors in South Carolina came up with a formula of metals to create what amounts to a very effective brazing product for welding aluminum and other non-ferrous metals. Called Dura-Fix, it comes in 1/8" diameter inch rods 18" long and melts at 732°F.
It applies very much like lead-tin solder does on copper except no flux is necessary. The bonding mechanism is also like solder in which the solder bonds to the pores of the metal, making it impossible to separate. A Dura-Fix weld is stronger than the parent pieces. If the user has experience with soldering copper pipe, applying Dura-Fix is easy after a little practice. If the user has experience brazing cast-iron with brazing rod or silver-solder, applying Dura-Fix is a no-brainer.
What We Did
We collected some aluminum sheet, 3/4" tubing and channel pieces and set out to create some butt welds, T-welds and sheet edge-to-edge welds (see photograph).
The Dura-Fix kit arrived with a bunch of rods and a small stainless-steel brush which is used for preparation of the surface. It turns out that this brush was the only method that yielded a proper surface. Sanding with silica grit or aluminum oxide paper doesn’t work even though the surface looks good—the welds we attempted failed. Randy Weeks says the microscopic pores get clogged and they can only be cleared using the stainless steel brush. Pre-heating helps.
He also cautions to stay well clear of any ferrous cleaners such as a plain steel brush or a steel wool pad because the iron particles will contaminate the weld. We also discovered that even the hint of oils left behind—including skin oils—will corrupt a weld. Oils can be cleaned away with acetone; the key is to brush it and not touch it.
The Tricky Part
When soldering copper pipe, the process is simple. Clean it, apply flux and heat. Typically, the copper is heated and the solder is melted on the copper and the solder flows. Experience teaches that if the heat is applied close to where the solder touches the copper, one can sometimes accelerate the flow process and then wipe away the excess with a rag.
This technique does not work when welding aluminum with Dura-Fix because it is very easy to get a “cold” weld. It is imperative that the aluminum stock be heated well away from where the Dura-Fix rod is placed and that the melting of the rod be caused by the heat of the aluminum and not the propane torch. This heating process is tricky because both pieces of aluminum have to be heated when connecting one to another.
Wiping away the excess with a rag also doesn’t work here because it seems most of the Dura-Fix material will go with the rag. We had good results with a short-bristled brush.
On butt welds, Randy Weeks recommended that each piece be “tinned” before the two pieces are butted and welded. (“Tinning” is the word used for applying solder to copper. Here it means coating aluminum with Dura-Fix). We tried it both with and without tinning and achieved a reasonable degree of success either way.
Two different metals in a saltwater environment always create electrolysis. The rate of deterioration varies. We cannot yet report on this phenomena because tests have just begun and they will be reported at a later date. However, Randy Weeks said he’s repaired aluminum hulls with Dura-Fix and none have exhibited deterioration. The material turns dark, he said, but the weld remains strong.
Dura-Fix kits come in 1-, 2- and 3-lb. sizes with 22 rods per pound. Prices are $35, $60 and $80, shipping paid. It will take two or three rods of experimentation to learn how to use it. After that, working with it becomes a joy.
No longer will we hesitate to repair or make things with aluminum. A Bimini; a boarding ladder; repairing a canoe; a chipped prop; filling holes caused by corrosion—even mending the crack in the head of the old outboard we discarded because it was too expensive to fix.
We may not be so bold as to tackle the hinge of the mast we discussed earlier—there is still room for professionals—but, anything else, bring it on. We like this stuff and heartily recommend it. (Dura-Fix, Weeks Distributors, 36 Carolina Street, Taylors, South Carolina 29687-2063; 800/547-9353 or 800/380-3752 (24 hr. operator); Fax: 864/244-6349.)