Spyder Cracks

admin

What is causing me to get small cracks on a project I am doing using O/A? The cracks did not appear in all areas of what I have welded but they are showing up and are impossible to seal up. Where am I screwing up? I am using a new type of rod I found on the web that has a red flux coating and I am welding thin steel shelving.
Reply:What metal are you welding?  Interesting I have never used a fluxed o/a welding rod.  Are you sure it is not the flux cracking? Clean the metal after welding.Pictures would be helpful.  Why flux coated rod for welding?
Reply:Please post a link to the website where you found this rod. A/O steel welding rods with flux are something I've never seen. I'm curious what they are selling. Maybe I'll learn something new.
Reply:Here is the link to the web site. http://www.aluminumrepair.com/The metal is on a old gas tank and I am using a patch cut from some steel shelving I have. I bought the HTS528 figuring it wouldn't need as much heat as regular rod. I did fine on most of the patch  but then as I was almost done I got small cracks. I haven't done any welding in a long time and figure I am doing something wrong.
Reply:That stuff's brazing filler, not welding. Regular brazing alloys would work fine for what you're doing, probably be a lot cheaper tooI've never used this stuff- always wary of companies 'miracle' claims, especially when the alloys are 'secret' . were you melting the base metal? Was it cleaned well beforehand?
Reply:I would not weld on a gas tank ESPECIALLY with O/A !!When the small explosion happens i hope you still have some eyebrows.BTW I predict that someday someone will be hurt or killed by some internet product or misinformation and the seller WIL BE HELD LIABLE!!Last edited by Donald Branscom; 08-18-2008 at 03:51 PM.AWS certified welding inspectorAWS certified welder
Reply:Thanks for all of the advise guys! But what is causing the cracks?
Reply:Are the crack in the filler?  Are the cracks in the base metal?  Is the base metal cast?  Perhaps you are not heating your base metal enough.  It (base metal) really needs to soak up the heat, yet maintain you appropriate brazing temperature.  You might just have the local area hot.  It is not unusual to use a larger tip for brazing than welding to help heat larger area.could be cooling too fast.Who knows though... could use pictures of you project.
Reply:I went to the website and went to the specs on the rod for cast iron and steel. After reading their specs this must be some wonderful stuff but they aren't going to get any of my money.  I can't make a guess about the cracks without seeing your project.
Reply:Originally Posted by OldtimerI went to the website and went to the specs on the rod for cast iron and steel. After reading their specs this must be some wonderful stuff but they aren't going to get any of my money.  I can't make a guess about the cracks without seeing your project.
Reply:Well, For one thats a braze, not a weld. Looks like a nickel containing material. You are deffinately OVERHEATING the part. Do not melt the base metal, you are using adhesion of the brazing material, not melting it into the base material. Use a tip of about .028" orfice size, need only a pound or 2 pressure for both fuel and oxygen. Use a slightly carburizing flame with the nickel based brazing materials, or just fuzzy of neutral. Just heat the base material until its a dull red, and the hot base material melts the brazing material, it should flow smoothly without spitting or fizzling much. Where are you from? Maybe there is someone local to you here that can help?
Reply:Originally Posted by bschelleWhat is causing me to get small cracks on a project I am doing using O/A? The cracks did not appear in all areas of what I have welded but they are showing up and are impossible to seal up. Where am I screwing up? I am using a new type of rod I found on the web that has a red flux coating and I am welding thin steel shelving.
Reply:What is the tank from? A thickness of .090 isn't too common for most fuel tanks I've seen. If it belongs to some antique vehicle and you need to keep it 'original' and if it is mechanically sound enough to use, the inside can be coated with "sloshing compound" to keep it from leaking. I would agree that you probably overheated it while brazing; a small mild iron patch should have been able to stretch a bit if needed, but the crack appears to go across it too. It is always worth practicing on a comparable scrap first before starting on the real thing. Also, 1400* F isn't exactly a low temperature.  Much higher than most silver solders.There are some good 'soft' solders which melt at much lower temperatures that might have worked well if you only plan on repairs which won't be subjected to the original abuse the tank met.Just out of curiosity, what did this rod cost per pound and how does that price compare with low-fuming bronze?
Reply:Originally Posted by Donald BranscomI would not weld on a gas tank ESPECIALLY with O/A !!When the small explosion happens i hope you still have some eyebrows.BTW I predict that someday someone will be hurt or killed by some internet product or misinformation and the seller WIL BE HELD LIABLE!!
Reply:Originally Posted by Broccoli1Gas or 'lectric gonna make BOOM iffin' folks don't know what they are doing.Why should the manufacturer of Filler rod be held liable?This is from their Web-site"Notice: Drums, tanks and other containers should not be welded, brazed, repaired or cut up unless the operator has received adequate training in the risks involved and the precautions to be taken. The tank or drum that is to be welded or brazed should first be emptied by pumping or draining the liquid into a suitable container. The residues should be disposed of in line with EPA requirements and not tipped into drains, sewers or waterways."
Reply:torch pressures you are using  are for cutting, you need to drop way down and use a weld tip not a cutting tip imho
Reply:The tank is from my motorhome which is a 1987 Allegro. It is a 85 Gal. tank and the cost of a new one is close to $1000 with shipping. I think the rust was caused by the manufacturer coating the tank with insulating foam. I have infact been doing the brazing incorrectly and doing it as welding and puhing a puddle and overheating the metal. I will practice brazing the correct way using all of the suggestions from you guys and then fix the tank. Any further advice will be very much appreciated.
Reply:Originally Posted by bschelleI will practice brazing the correct way using all of the suggestions from you guys and then fix the tank. Any further advice will be very much appreciated.
Reply:Nice Screen nameEd Conleyhttp://www.screamingbroccoli.com/MM252MM211 (Sold)Passport Plus & Spool gunLincoln SP135 Plus- (Gone to a good home)Klutch 120v Plasma cutterSO 2020 benderBeer in the fridge
Reply:if you are down to pin-holes,go to por-15.com and buy their fuel tank repair kit--$75.00. it'll protect the weak areas and it works great.
Reply:Matt-amen to what you stated.1-As far as a blanket statement of pressure testing pressure of 5#--that's appropriate for ICC tanks, that have been designed and constructed to meet this criteria--in the NEW, PRIMO, un-fueled,  UN-USED CONDITION---but is pretty much a guarantee to deform or explode--non ICC tanks, passenger vehicle tanks, repaired tanks exhibiting damage or corrosion. (I've seen pressure testing setups where the manufacturer has cinched truck cargo tie down straps wrapping the tank body to keep it from permanent distortion. During pressure testing on a repaired tank, I'm paying attention to just what's happening with the tank sides.)-passenger vehicle tanks have vacuum/pressure relief at 2 #---to save the vehicle tank.-thin, lightly constructed aluminum marine or especially aircraft tanks, require simply some positive pressure; which may be seen as low as .25#--to avoid tank destruction. Such tanks are designed to function as free breathing tanks.-A well constructed ICC tank (rated for 5# and the 30 foot drop test)  will be heavy gauge, having full flanged, lapped heads, lapped seams, full flanged, form-fitted baffles, with full welding inside and out, plus plug welds, where required by the assembly sequence. They can easily cost 2-5 times the gypo tanks.....and that's 'why?'.-Tanks made from hot or cold rolled steel will experience interior and exterior corrosion. Aluminized  steel tanks (with the 'heavy coating thickness') can last for decades. Transfer Flow is one excellent supplier of this form of material and other tank materials...and no--they don't make 'cheap tanks'.2-Pressure testing on repaired tanks, requires sensitive pressure gauges and regulator, blow-off patches on some tank openings in the event of over-pressure, assembling what ever manner of fittings to do the pressure test.Pressure testing on wet, fuming tanks--requires inert gas to be used. Using compressed air, can produce spontaneous ignition and/or explosions. This form of explosion can be intense.bschelle--For what it's worth, 'yours truly'--has only repaired a good 1500 tanks in the last 20 years--from 1/2 gallon to 10,000 gallon, including restoration tanks, saving basket case tanks, designing and building CARB, USCG tanks, etc. However--as I commented previous--the pitting shown in your pictures-negates a leak proof repair--let alone the damage created by your attempts at brazing. IOW---I've seen this before and more than once. On a tank showing this amount of corrosion:-do visual inspection of what one can see on the tank's interior-on the external--due to this extensive, heavy pitting--take a stiff, cable wound, wire wheel on angle grinder to knock off some of the corrosion---this aggressive brushing will really help to expose additional pinholes, cracks, and break thru thin areas (areas too thin to weld or patch).  Coating the inside of a corroded, leaking  tank is....ahh....less than genius. Coating is to prevent further corrosion, not make the tank pressure tight--despite claims to the contrary.  Interior coating is done on clean interiors, (cleaned by blasting, acid washing/neutralize, etc.). I've used low pressure spraying, plus calculated rolling attitudes, then force drying with air; and doing multiple coats. There's more to coating, than most realize--as in other things.Replacement tanks?I would suggest contacting Transfer-Flow, they might have such or could refer you to a source.The after market tanks hyped by RV dealers are bare minimum tanks---at the best.Last edited by dave powelson; 08-19-2008 at 10:12 PM.Reason: grammarBlackbird
Reply:Dave,You must have caught that post early, because I realized my error and edited it within a few minutes of posting. For *automotive* tanks, you are absolutely correct. ~2 psi is about the highest pressure to go, I have been informed they tend to turn into a "pillow shape" once you go over about 4 or 5.Thanks for keeping me on my toes-Matt-Matt------------------------------------------
Reply:Originally Posted by HephaestusIf your life is worth more than $1000, get a new tank. Gas/fuel/oil tank welding is still risky business even when you have all the right equipment and know what you're doing.From the amount of oily residue and corrosion evident in the picture, that tank was never properly cleaned and purged prior to your attempted repair. Consider yourself a lucky individual that the results were not worse (boom!). Part of being a responsible craftsman is knowing your own limitations and when it's best to turn down a job unless you are properly prepared to do it correctly. If not for your own safety, for the safety of others.With any container that's held a petroleum product for 20 years you are going to have braze or weld contamination issues.It is very difficult to get the metal clean enough for a brazed repair to hold. Because you have overheated a brazed joint, now there's also braze filler contamination in the base metal and it cannot be repaired by welding without removing that contaminated base metal.To repair the tank "the right way":It must be thoroughly "boiled out".Inert gas purged. Any previously attempted repair area must be completely cut away (it is unweldable).Patch fabricated from same gauge sheet.Surface prepped to bare clean metal.Patch welded in to original strength with zero porosity by an experienced weldor.Pressure tested to reveal any other pinhole leaks, bad seams, or cracks.Tank interior cleaned and acid etchedTank interior sealant applied.Tank exterior prepped and painted with epoxy.If you choose to make the repair yourself, you will have well over $1000 invested in time, supplies, and the necessary equipment by the time you are done. You can't learn to successfully weld thin sheetmetal overnight. There are other options, but I'm not going to tell someone how to fix a tank "the wrong way". Good luck and be safe.
Reply:Originally Posted by bschelleThe tank is from my motorhome which is a 1987 Allegro. It is a 85 Gal. tank and the cost of a new one is close to $1000 with shipping. I think the rust was caused by the manufacturer coating the tank with insulating foam. I have infact been doing the brazing incorrectly and doing it as welding and puhing a puddle and overheating the metal. I will practice brazing the correct way using all of the suggestions from you guys and then fix the tank. Any further advice will be very much appreciated.
Reply:The $1000 for the new tank was from Allegro! As to finding someone local, how do you suggest I do it? I live in Antioch,IL.Try a Truck Repair shop.Ed Conleyhttp://www.screamingbroccoli.com/MM252MM211 (Sold)Passport Plus & Spool gunLincoln SP135 Plus- (Gone to a good home)Klutch 120v Plasma cutterSO 2020 benderBeer in the fridge