Magnesium saw repair
RSS | Subscribe | Contact Us | Advertise | About Us
Results 1 to 9 of 9
  1. #1
    Join Date
    Mar 2016
    Location
    Far West Chicago Burbs
    Posts
    5

    Magnesium saw repair

    I dropped my circular saw and broke the blade guard, which is magnesium. I'm pretty good at tig with steel and aluminum, but never welded magnesium. What filler would I use, any tips on settings? Hopefully I can use argon. I've done some brazing, would that be a better option? Here's some photos:

    https://photos.app.goo.gl/Qu2Mga4nSXNBiYAD8
    Lincoln Square Wave 200
    Lincoln 225 AC/DC
    Harris Oxy/Ac

  2. #2
    Join Date
    Nov 2010
    Location
    SE Nebraska
    Posts
    679

    Re: Magnesium saw repair

    I bought some blue demon filler for the exact same repair but on a chainsaw. I can look tonight when I get back to my shop to see what exactly it is. I've used it several times on repairs. Works ok, a lot different than aluminum filler.

    It's definitely spendy!
    -Doogie

    Miller 350P
    Miller Trailblazer 325 EFI w/ Excel Power
    Lincoln LN25 suitcase welder
    XMT 304/22a feeder
    Miller Syncrowave 350LX
    Miller Econotig
    Hobart Handler 140
    (2) Uni-Hydro 42-14
    Hypertherm 65 plasma
    WEBB Gap bed lathe

  3. #3
    Join Date
    May 2015
    Posts
    808

    Re: Magnesium saw repair

    You can definitely weld it. You can use the following filler wire. You would do it on AC using similar settings that you would use for aluminum casting. Similar issue with the oxide layer. I would also use preheat to burn off any contaminants on the Guard. Needless to say get it as clean as possible as well as proper weld prep.

    I would also recommend You have access to Put out any fire that might occur. Either class D fire extinguisher or a bucket of sand.


    https://www.airgas.com/product/Weldi...y/p/HARAZ92T50

  4. #4
    Join Date
    Oct 2014
    Posts
    582

    Re: Magnesium saw repair

    Quote Originally Posted by Weld_ View Post
    You can definitely weld it. You can use the following filler wire. You would do it on AC using similar settings that you would use for aluminum casting. Similar issue with the oxide layer. I would also use preheat to burn off any contaminants on the Guard. Needless to say get it as clean as possible as well as proper weld prep.

    I would also recommend You have access to Put out any fire that might occur. Either class D fire extinguisher or a bucket of sand.


    https://www.airgas.com/product/Weldi...y/p/HARAZ92T50
    At $220 a pound with 3 pound minimum coming to $660 I think he could buy 6 new saws for that.

    Thinking 1/16" filler would be more suitable. Ebay is likely best bet for small order.

    https://www.ebay.com/itm/1-16-AZ61A-...cAAOSwzaJX4qIN

    This listing is for approx. 28 to 32 rods (approx. 4 oz) of Washington Alloy 1/16" AZ61A Magnesium Tig 36" Rod.

    Below is the Manufacturer's Description:

    Specifications:
    AWS A5.19

    Description:
    Washington Alloy AZ 61A is our most popular magnesium wire as it produces superior joints with the maximum tensile strengths offered a magnesium alloy.

    Tips for Welding with Magnesium:
    Cleanliness of both the base metal and filler metal is extremely important when welding with magnesium. Chemical or mechanical cleaning of the joint area and filler metal to remove any surface oxidation, should precede any welding. This can be accomplished using a solution of 24 oz. chromic acid, 5-1/3 oz. ferric nitrate and 1/16 oz. potassium fluoride in enough water to make one gallon. Bring the solution to 70-90°F, then immerse the part for 3 minutes, rinse in hot water, then air dry. Mechanical cleaning can be done using an aluminum or stainless steel wire brush, steel wool or an aluminumoxide abrasive cloth. Gloves should be worn.

    Tig Welding Procedure:
    Flux is not required for TIG welding processes. Although this is convenient, it means that cleanliness of the base metal and filler metal is even more critical. Argon is the recommended shielding gas, however, an argon-helium mixture can increase filler metal flow and penetration. Do not use pure helium as this will create undesirable results. TIG welding can be done with AC current, DC reverse polarity or DC straight polarity. AC current will give good penetration. DC reverse polarity (electrode positive) will give shallow penetration but wide weld deposits. DC straight polarity (electrode negative) will give deep penetration but narrow weld deposits.

    Oxyacetylene Welding:
    Oxyacetylene welding of magnesium is not commonly used. This process should only be considered for single-pass welding on thin gauges of magnesium. A fluoride or chloride flux should be used on the base metal and filler metal in order to clean and protect the weld pool. However, be sure to remove any flux residue by washing in hot water, pickle for 2 minutes in a chrome pickle solution, then boil in a 6% solution of sodium dichro-mate for 2 hours.

    Typical Composition:
    91% Magnesium
    6.5% Aluminum
    0.35% Manganese
    1.0% Zinc
    Trace amounts of Beryllium, Copper, Iron, Nickel, and Zinc

    Properties:
    -Tensile Strength: 44,000 PSI
    -Yield Strength: 30,000 PSI
    -Melting Point: 1,140 degrees F

    Shielding Gas:
    100% Argon or 75% Argon and 25% Helium. DO NOT USE 100% HELIUM.

  5. #5
    Join Date
    Mar 2016
    Location
    Far West Chicago Burbs
    Posts
    5

    Re: Magnesium saw repair

    Thanks for info. Local Airgas has AZ61 for $90/lb, still really expensive. I found the AZ61 on ebay, I'm going to order that. I probably need one piece, so I'll give the rest to the welding program at the local community college.
    This was on a saw so there's never been any oil around it, should be easy to get clean.
    Lincoln Square Wave 200
    Lincoln 225 AC/DC
    Harris Oxy/Ac

  6. #6
    Join Date
    Sep 2005
    Location
    Cave Creek AZ
    Posts
    2,852

    Re: Magnesium saw repair

    Quote Originally Posted by derekpfeiffer View Post
    I bought some blue demon filler for the exact same repair but on a chainsaw. I can look tonight when I get back to my shop to see what exactly it is. I've used it several times on repairs. Works ok, a lot different than aluminum filler.

    It's definitely spendy!
    You had a chainsaw with a blade guard???

  7. #7
    Join Date
    Nov 2005
    Location
    Nashville, TN
    Posts
    3,421

    Re: Magnesium saw repair

    Can the part be replaced?

  8. #8
    Join Date
    Jan 2019
    Location
    Tucson Arizona
    Posts
    121

    Re: Magnesium saw repair

    why not buy a new one for $15?

    https://www.ebay.com/itm/Original-Po...-/263594951919

    edit; if yours isn't a porter cable, can't tell for sure as your pic doesn't show the name fully, ya can search for the part which unless its real new will be discontinued BUT epartssource or one of those will list that part number ya can then search the part number and most likally someone is selling NOS online... that internet thing can be pretty handy,

    also check your local offerup and craigslist as those sidewinder saws sell used for $25 or so... get ya a whole parts doner if ya really like the saw
    Last edited by monsoon-mech; 11-07-2019 at 10:40 AM.

  9. #9
    Join Date
    May 2015
    Posts
    808

    Re: Magnesium saw repair

    Quote Originally Posted by MarkWeld View Post
    Thanks for info. Local Airgas has AZ61 for $90/lb, still really expensive. I found the AZ61 on ebay, I'm going to order that. I probably need one piece, so I'll give the rest to the welding program at the local community college.
    This was on a saw so there's never been any oil around it, should be easy to get clean.
    Without knowing the exact composition of the casting your best bet is going to be AZ92 IMHO.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
RSS | Home | Penton Media | Contact Us | Subscribe | For Advertisers | Terms of Use | Privacy Statement