Need details about heat absorption paste

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Hello ,     We are machine shop people. we are machining of steel and stainless steel castings. After machining we have pinholes and crack in some castings. We will repair it by TIG welding process, but we facing the dimension deviation because of welding heat. Then i heard about heat sink paste , but i didnt get the full details and procedures of using. So anybody can help me out in this problem. I need the applying procedure and paste details.Thank you.RegardsR.Baraneedharan
Reply:A friend of mine dide a lot of gunsmithing in the past,he had a lot of parts tig welded some were heatreated and some were case hardened.They would just put the paste around the area to be protected and never had a problem.
Reply:there's a handful of different heat absorption products on the market.  Heat block, Cold paste, Thermo trap, etc.Like Thphtm said, there's no "real" directions, just clean the area, apply paste to where you want to limit heat, and press paste to avoid any bubbles.I worked at a body shop in high school, and they made their own with shredded newspaper and water.  The best paste used to be made of asbestos, not sure what the new stuff is like.Lincoln SA 200Esab Caddy 160Thermal Arc 201TSMiller Dialarc HFI don't like making plans for the day because then the word "premeditated" gets thrown around the courtroom....
Reply:"Heat Fence" is a fairly common brand,http://www.stoodyind.com/Catalogs/FI...05catpg467.pdf,  as for distortion, if the casting are large I recommend oven heat the casting to about 400 degrees.keep your weld small ie stringer beads, when done you can cover the casting with cat litter and it will cool slowly to help with distortion.
Reply:I use LA-CO Heat Gel heat barrier spray. It's a clear spray, there's a few youtube videos from the mfg about it. It works pretty well. I used it for copying a member's here idea for putting money in aluminum tube.. and it worked very well. It dries with nothing left.. They have it in stock at most GraingersI haven't used it much, but it does come in handy.. I put a new bov flange on an aluminum powdercoated ic pipe, and removed just a small amount of the coating and sprayed this stuff everywhere. I used pulse to limit heat input, and took a few breaks. I managed to NOT burn any powder coating, and only ground off about 3/8"-1/2" around the weld.I don't use it often but it hasn't let me down when I have needed it.Miller: 200dx, Bobcat 225, Passport, Powermax 45, Milwaukee: Dry Saw, MagDrill, grinders